Remove LLVM 8.0.1 files.

1 files changed, 0 insertions, 13859 deletions

diff --git a/gnu/llvm/tools/clang/lib/Sema/SemaOverload.cpp b/gnu/llvm/tools/clang/lib/Sema/SemaOverload.cpp
deleted file mode 100644
index 52be0598fbc..00000000000
--- a/gnu/llvm/tools/clang/lib/Sema/SemaOverload.cpp
+++ /dev/null
@@ -1,13859 +0,0 @@
-//===--- SemaOverload.cpp - C++ Overloading -------------------------------===//
-//
-//                     The LLVM Compiler Infrastructure
-//
-// This file is distributed under the University of Illinois Open Source
-// License. See LICENSE.TXT for details.
-//
-//===----------------------------------------------------------------------===//
-//
-// This file provides Sema routines for C++ overloading.
-//
-//===----------------------------------------------------------------------===//
-
-#include "clang/Sema/Overload.h"
-#include "clang/AST/ASTContext.h"
-#include "clang/AST/CXXInheritance.h"
-#include "clang/AST/DeclObjC.h"
-#include "clang/AST/Expr.h"
-#include "clang/AST/ExprCXX.h"
-#include "clang/AST/ExprObjC.h"
-#include "clang/AST/TypeOrdering.h"
-#include "clang/Basic/Diagnostic.h"
-#include "clang/Basic/DiagnosticOptions.h"
-#include "clang/Basic/PartialDiagnostic.h"
-#include "clang/Basic/TargetInfo.h"
-#include "clang/Sema/Initialization.h"
-#include "clang/Sema/Lookup.h"
-#include "clang/Sema/SemaInternal.h"
-#include "clang/Sema/Template.h"
-#include "clang/Sema/TemplateDeduction.h"
-#include "llvm/ADT/DenseSet.h"
-#include "llvm/ADT/Optional.h"
-#include "llvm/ADT/STLExtras.h"
-#include "llvm/ADT/SmallPtrSet.h"
-#include "llvm/ADT/SmallString.h"
-#include <algorithm>
-#include <cstdlib>
-
-using namespace clang;
-using namespace sema;
-
-static bool functionHasPassObjectSizeParams(const FunctionDecl *FD) {
-  return llvm::any_of(FD->parameters(), [](const ParmVarDecl *P) {
-    return P->hasAttr<PassObjectSizeAttr>();
-  });
-}
-
-/// A convenience routine for creating a decayed reference to a function.
-static ExprResult
-CreateFunctionRefExpr(Sema &S, FunctionDecl *Fn, NamedDecl *FoundDecl,
-                      const Expr *Base, bool HadMultipleCandidates,
-                      SourceLocation Loc = SourceLocation(),
-                      const DeclarationNameLoc &LocInfo = DeclarationNameLoc()){
-  if (S.DiagnoseUseOfDecl(FoundDecl, Loc))
-    return ExprError();
-  // If FoundDecl is different from Fn (such as if one is a template
-  // and the other a specialization), make sure DiagnoseUseOfDecl is
-  // called on both.
-  // FIXME: This would be more comprehensively addressed by modifying
-  // DiagnoseUseOfDecl to accept both the FoundDecl and the decl
-  // being used.
-  if (FoundDecl != Fn && S.DiagnoseUseOfDecl(Fn, Loc))
-    return ExprError();
-  if (auto *FPT = Fn->getType()->getAs<FunctionProtoType>())
-    S.ResolveExceptionSpec(Loc, FPT);
-  DeclRefExpr *DRE = new (S.Context)
-      DeclRefExpr(S.Context, Fn, false, Fn->getType(), VK_LValue, Loc, LocInfo);
-  if (HadMultipleCandidates)
-    DRE->setHadMultipleCandidates(true);
-
-  S.MarkDeclRefReferenced(DRE, Base);
-  return S.ImpCastExprToType(DRE, S.Context.getPointerType(DRE->getType()),
-                             CK_FunctionToPointerDecay);
-}
-
-static bool IsStandardConversion(Sema &S, Expr* From, QualType ToType,
-                                 bool InOverloadResolution,
-                                 StandardConversionSequence &SCS,
-                                 bool CStyle,
-                                 bool AllowObjCWritebackConversion);
-
-static bool IsTransparentUnionStandardConversion(Sema &S, Expr* From,
-                                                 QualType &ToType,
-                                                 bool InOverloadResolution,
-                                                 StandardConversionSequence &SCS,
-                                                 bool CStyle);
-static OverloadingResult
-IsUserDefinedConversion(Sema &S, Expr *From, QualType ToType,
-                        UserDefinedConversionSequence& User,
-                        OverloadCandidateSet& Conversions,
-                        bool AllowExplicit,
-                        bool AllowObjCConversionOnExplicit);
-
-
-static ImplicitConversionSequence::CompareKind
-CompareStandardConversionSequences(Sema &S, SourceLocation Loc,
-                                   const StandardConversionSequence& SCS1,
-                                   const StandardConversionSequence& SCS2);
-
-static ImplicitConversionSequence::CompareKind
-CompareQualificationConversions(Sema &S,
-                                const StandardConversionSequence& SCS1,
-                                const StandardConversionSequence& SCS2);
-
-static ImplicitConversionSequence::CompareKind
-CompareDerivedToBaseConversions(Sema &S, SourceLocation Loc,
-                                const StandardConversionSequence& SCS1,
-                                const StandardConversionSequence& SCS2);
-
-/// GetConversionRank - Retrieve the implicit conversion rank
-/// corresponding to the given implicit conversion kind.
-ImplicitConversionRank clang::GetConversionRank(ImplicitConversionKind Kind) {
-  static const ImplicitConversionRank
-    Rank[(int)ICK_Num_Conversion_Kinds] = {
-    ICR_Exact_Match,
-    ICR_Exact_Match,
-    ICR_Exact_Match,
-    ICR_Exact_Match,
-    ICR_Exact_Match,
-    ICR_Exact_Match,
-    ICR_Promotion,
-    ICR_Promotion,
-    ICR_Promotion,
-    ICR_Conversion,
-    ICR_Conversion,
-    ICR_Conversion,
-    ICR_Conversion,
-    ICR_Conversion,
-    ICR_Conversion,
-    ICR_Conversion,
-    ICR_Conversion,
-    ICR_Conversion,
-    ICR_Conversion,
-    ICR_OCL_Scalar_Widening,
-    ICR_Complex_Real_Conversion,
-    ICR_Conversion,
-    ICR_Conversion,
-    ICR_Writeback_Conversion,
-    ICR_Exact_Match, // NOTE(gbiv): This may not be completely right --
-                     // it was omitted by the patch that added
-                     // ICK_Zero_Event_Conversion
-    ICR_C_Conversion,
-    ICR_C_Conversion_Extension
-  };
-  return Rank[(int)Kind];
-}
-
-/// GetImplicitConversionName - Return the name of this kind of
-/// implicit conversion.
-static const char* GetImplicitConversionName(ImplicitConversionKind Kind) {
-  static const char* const Name[(int)ICK_Num_Conversion_Kinds] = {
-    "No conversion",
-    "Lvalue-to-rvalue",
-    "Array-to-pointer",
-    "Function-to-pointer",
-    "Function pointer conversion",
-    "Qualification",
-    "Integral promotion",
-    "Floating point promotion",
-    "Complex promotion",
-    "Integral conversion",
-    "Floating conversion",
-    "Complex conversion",
-    "Floating-integral conversion",
-    "Pointer conversion",
-    "Pointer-to-member conversion",
-    "Boolean conversion",
-    "Compatible-types conversion",
-    "Derived-to-base conversion",
-    "Vector conversion",
-    "Vector splat",
-    "Complex-real conversion",
-    "Block Pointer conversion",
-    "Transparent Union Conversion",
-    "Writeback conversion",
-    "OpenCL Zero Event Conversion",
-    "C specific type conversion",
-    "Incompatible pointer conversion"
-  };
-  return Name[Kind];
-}
-
-/// StandardConversionSequence - Set the standard conversion
-/// sequence to the identity conversion.
-void StandardConversionSequence::setAsIdentityConversion() {
-  First = ICK_Identity;
-  Second = ICK_Identity;
-  Third = ICK_Identity;
-  DeprecatedStringLiteralToCharPtr = false;
-  QualificationIncludesObjCLifetime = false;
-  ReferenceBinding = false;
-  DirectBinding = false;
-  IsLvalueReference = true;
-  BindsToFunctionLvalue = false;
-  BindsToRvalue = false;
-  BindsImplicitObjectArgumentWithoutRefQualifier = false;
-  ObjCLifetimeConversionBinding = false;
-  CopyConstructor = nullptr;
-}
-
-/// getRank - Retrieve the rank of this standard conversion sequence
-/// (C++ 13.3.3.1.1p3). The rank is the largest rank of each of the
-/// implicit conversions.
-ImplicitConversionRank StandardConversionSequence::getRank() const {
-  ImplicitConversionRank Rank = ICR_Exact_Match;
-  if  (GetConversionRank(First) > Rank)
-    Rank = GetConversionRank(First);
-  if  (GetConversionRank(Second) > Rank)
-    Rank = GetConversionRank(Second);
-  if  (GetConversionRank(Third) > Rank)
-    Rank = GetConversionRank(Third);
-  return Rank;
-}
-
-/// isPointerConversionToBool - Determines whether this conversion is
-/// a conversion of a pointer or pointer-to-member to bool. This is
-/// used as part of the ranking of standard conversion sequences
-/// (C++ 13.3.3.2p4).
-bool StandardConversionSequence::isPointerConversionToBool() const {
-  // Note that FromType has not necessarily been transformed by the
-  // array-to-pointer or function-to-pointer implicit conversions, so
-  // check for their presence as well as checking whether FromType is
-  // a pointer.
-  if (getToType(1)->isBooleanType() &&
-      (getFromType()->isPointerType() ||
-       getFromType()->isMemberPointerType() ||
-       getFromType()->isObjCObjectPointerType() ||
-       getFromType()->isBlockPointerType() ||
-       getFromType()->isNullPtrType() ||
-       First == ICK_Array_To_Pointer || First == ICK_Function_To_Pointer))
-    return true;
-
-  return false;
-}
-
-/// isPointerConversionToVoidPointer - Determines whether this
-/// conversion is a conversion of a pointer to a void pointer. This is
-/// used as part of the ranking of standard conversion sequences (C++
-/// 13.3.3.2p4).
-bool
-StandardConversionSequence::
-isPointerConversionToVoidPointer(ASTContext& Context) const {
-  QualType FromType = getFromType();
-  QualType ToType = getToType(1);
-
-  // Note that FromType has not necessarily been transformed by the
-  // array-to-pointer implicit conversion, so check for its presence
-  // and redo the conversion to get a pointer.
-  if (First == ICK_Array_To_Pointer)
-    FromType = Context.getArrayDecayedType(FromType);
-
-  if (Second == ICK_Pointer_Conversion && FromType->isAnyPointerType())
-    if (const PointerType* ToPtrType = ToType->getAs<PointerType>())
-      return ToPtrType->getPointeeType()->isVoidType();
-
-  return false;
-}
-
-/// Skip any implicit casts which could be either part of a narrowing conversion
-/// or after one in an implicit conversion.
-static const Expr *IgnoreNarrowingConversion(const Expr *Converted) {
-  while (const ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(Converted)) {
-    switch (ICE->getCastKind()) {
-    case CK_NoOp:
-    case CK_IntegralCast:
-    case CK_IntegralToBoolean:
-    case CK_IntegralToFloating:
-    case CK_BooleanToSignedIntegral:
-    case CK_FloatingToIntegral:
-    case CK_FloatingToBoolean:
-    case CK_FloatingCast:
-      Converted = ICE->getSubExpr();
-      continue;
-
-    default:
-      return Converted;
-    }
-  }
-
-  return Converted;
-}
-
-/// Check if this standard conversion sequence represents a narrowing
-/// conversion, according to C++11 [dcl.init.list]p7.
-///
-/// \param Ctx  The AST context.
-/// \param Converted  The result of applying this standard conversion sequence.
-/// \param ConstantValue  If this is an NK_Constant_Narrowing conversion, the
-///        value of the expression prior to the narrowing conversion.
-/// \param ConstantType  If this is an NK_Constant_Narrowing conversion, the
-///        type of the expression prior to the narrowing conversion.
-/// \param IgnoreFloatToIntegralConversion If true type-narrowing conversions
-///        from floating point types to integral types should be ignored.
-NarrowingKind StandardConversionSequence::getNarrowingKind(
-    ASTContext &Ctx, const Expr *Converted, APValue &ConstantValue,
-    QualType &ConstantType, bool IgnoreFloatToIntegralConversion) const {
-  assert(Ctx.getLangOpts().CPlusPlus && "narrowing check outside C++");
-
-  // C++11 [dcl.init.list]p7:
-  //   A narrowing conversion is an implicit conversion ...
-  QualType FromType = getToType(0);
-  QualType ToType = getToType(1);
-
-  // A conversion to an enumeration type is narrowing if the conversion to
-  // the underlying type is narrowing. This only arises for expressions of
-  // the form 'Enum{init}'.
-  if (auto *ET = ToType->getAs<EnumType>())
-    ToType = ET->getDecl()->getIntegerType();
-
-  switch (Second) {
-  // 'bool' is an integral type; dispatch to the right place to handle it.
-  case ICK_Boolean_Conversion:
-    if (FromType->isRealFloatingType())
-      goto FloatingIntegralConversion;
-    if (FromType->isIntegralOrUnscopedEnumerationType())
-      goto IntegralConversion;
-    // Boolean conversions can be from pointers and pointers to members
-    // [conv.bool], and those aren't considered narrowing conversions.
-    return NK_Not_Narrowing;
-
-  // -- from a floating-point type to an integer type, or
-  //
-  // -- from an integer type or unscoped enumeration type to a floating-point
-  //    type, except where the source is a constant expression and the actual
-  //    value after conversion will fit into the target type and will produce
-  //    the original value when converted back to the original type, or
-  case ICK_Floating_Integral:
-  FloatingIntegralConversion:
-    if (FromType->isRealFloatingType() && ToType->isIntegralType(Ctx)) {
-      return NK_Type_Narrowing;
-    } else if (FromType->isIntegralOrUnscopedEnumerationType() &&
-               ToType->isRealFloatingType()) {
-      if (IgnoreFloatToIntegralConversion)
-        return NK_Not_Narrowing;
-      llvm::APSInt IntConstantValue;
-      const Expr *Initializer = IgnoreNarrowingConversion(Converted);
-      assert(Initializer && "Unknown conversion expression");
-
-      // If it's value-dependent, we can't tell whether it's narrowing.
-      if (Initializer->isValueDependent())
-        return NK_Dependent_Narrowing;
-
-      if (Initializer->isIntegerConstantExpr(IntConstantValue, Ctx)) {
-        // Convert the integer to the floating type.
-        llvm::APFloat Result(Ctx.getFloatTypeSemantics(ToType));
-        Result.convertFromAPInt(IntConstantValue, IntConstantValue.isSigned(),
-                                llvm::APFloat::rmNearestTiesToEven);
-        // And back.
-        llvm::APSInt ConvertedValue = IntConstantValue;
-        bool ignored;
-        Result.convertToInteger(ConvertedValue,
-                                llvm::APFloat::rmTowardZero, &ignored);
-        // If the resulting value is different, this was a narrowing conversion.
-        if (IntConstantValue != ConvertedValue) {
-          ConstantValue = APValue(IntConstantValue);
-          ConstantType = Initializer->getType();
-          return NK_Constant_Narrowing;
-        }
-      } else {
-        // Variables are always narrowings.
-        return NK_Variable_Narrowing;
-      }
-    }
-    return NK_Not_Narrowing;
-
-  // -- from long double to double or float, or from double to float, except
-  //    where the source is a constant expression and the actual value after
-  //    conversion is within the range of values that can be represented (even
-  //    if it cannot be represented exactly), or
-  case ICK_Floating_Conversion:
-    if (FromType->isRealFloatingType() && ToType->isRealFloatingType() &&
-        Ctx.getFloatingTypeOrder(FromType, ToType) == 1) {
-      // FromType is larger than ToType.
-      const Expr *Initializer = IgnoreNarrowingConversion(Converted);
-
-      // If it's value-dependent, we can't tell whether it's narrowing.
-      if (Initializer->isValueDependent())
-        return NK_Dependent_Narrowing;
-
-      if (Initializer->isCXX11ConstantExpr(Ctx, &ConstantValue)) {
-        // Constant!
-        assert(ConstantValue.isFloat());
-        llvm::APFloat FloatVal = ConstantValue.getFloat();
-        // Convert the source value into the target type.
-        bool ignored;
-        llvm::APFloat::opStatus ConvertStatus = FloatVal.convert(
-          Ctx.getFloatTypeSemantics(ToType),
-          llvm::APFloat::rmNearestTiesToEven, &ignored);
-        // If there was no overflow, the source value is within the range of
-        // values that can be represented.
-        if (ConvertStatus & llvm::APFloat::opOverflow) {
-          ConstantType = Initializer->getType();
-          return NK_Constant_Narrowing;
-        }
-      } else {
-        return NK_Variable_Narrowing;
-      }
-    }
-    return NK_Not_Narrowing;
-
-  // -- from an integer type or unscoped enumeration type to an integer type
-  //    that cannot represent all the values of the original type, except where
-  //    the source is a constant expression and the actual value after
-  //    conversion will fit into the target type and will produce the original
-  //    value when converted back to the original type.
-  case ICK_Integral_Conversion:
-  IntegralConversion: {
-    assert(FromType->isIntegralOrUnscopedEnumerationType());
-    assert(ToType->isIntegralOrUnscopedEnumerationType());
-    const bool FromSigned = FromType->isSignedIntegerOrEnumerationType();
-    const unsigned FromWidth = Ctx.getIntWidth(FromType);
-    const bool ToSigned = ToType->isSignedIntegerOrEnumerationType();
-    const unsigned ToWidth = Ctx.getIntWidth(ToType);
-
-    if (FromWidth > ToWidth ||
-        (FromWidth == ToWidth && FromSigned != ToSigned) ||
-        (FromSigned && !ToSigned)) {
-      // Not all values of FromType can be represented in ToType.
-      llvm::APSInt InitializerValue;
-      const Expr *Initializer = IgnoreNarrowingConversion(Converted);
-
-      // If it's value-dependent, we can't tell whether it's narrowing.
-      if (Initializer->isValueDependent())
-        return NK_Dependent_Narrowing;
-
-      if (!Initializer->isIntegerConstantExpr(InitializerValue, Ctx)) {
-        // Such conversions on variables are always narrowing.
-        return NK_Variable_Narrowing;
-      }
-      bool Narrowing = false;
-      if (FromWidth < ToWidth) {
-        // Negative -> unsigned is narrowing. Otherwise, more bits is never
-        // narrowing.
-        if (InitializerValue.isSigned() && InitializerValue.isNegative())
-          Narrowing = true;
-      } else {
-        // Add a bit to the InitializerValue so we don't have to worry about
-        // signed vs. unsigned comparisons.
-        InitializerValue = InitializerValue.extend(
-          InitializerValue.getBitWidth() + 1);
-        // Convert the initializer to and from the target width and signed-ness.
-        llvm::APSInt ConvertedValue = InitializerValue;
-        ConvertedValue = ConvertedValue.trunc(ToWidth);
-        ConvertedValue.setIsSigned(ToSigned);
-        ConvertedValue = ConvertedValue.extend(InitializerValue.getBitWidth());
-        ConvertedValue.setIsSigned(InitializerValue.isSigned());
-        // If the result is different, this was a narrowing conversion.
-        if (ConvertedValue != InitializerValue)
-          Narrowing = true;
-      }
-      if (Narrowing) {
-        ConstantType = Initializer->getType();
-        ConstantValue = APValue(InitializerValue);
-        return NK_Constant_Narrowing;
-      }
-    }
-    return NK_Not_Narrowing;
-  }
-
-  default:
-    // Other kinds of conversions are not narrowings.
-    return NK_Not_Narrowing;
-  }
-}
-
-/// dump - Print this standard conversion sequence to standard
-/// error. Useful for debugging overloading issues.
-LLVM_DUMP_METHOD void StandardConversionSequence::dump() const {
-  raw_ostream &OS = llvm::errs();
-  bool PrintedSomething = false;
-  if (First != ICK_Identity) {
-    OS << GetImplicitConversionName(First);
-    PrintedSomething = true;
-  }
-
-  if (Second != ICK_Identity) {
-    if (PrintedSomething) {
-      OS << " -> ";
-    }
-    OS << GetImplicitConversionName(Second);
-
-    if (CopyConstructor) {
-      OS << " (by copy constructor)";
-    } else if (DirectBinding) {
-      OS << " (direct reference binding)";
-    } else if (ReferenceBinding) {
-      OS << " (reference binding)";
-    }
-    PrintedSomething = true;
-  }
-
-  if (Third != ICK_Identity) {
-    if (PrintedSomething) {
-      OS << " -> ";
-    }
-    OS << GetImplicitConversionName(Third);
-    PrintedSomething = true;
-  }
-
-  if (!PrintedSomething) {
-    OS << "No conversions required";
-  }
-}
-
-/// dump - Print this user-defined conversion sequence to standard
-/// error. Useful for debugging overloading issues.
-void UserDefinedConversionSequence::dump() const {
-  raw_ostream &OS = llvm::errs();
-  if (Before.First || Before.Second || Before.Third) {
-    Before.dump();
-    OS << " -> ";
-  }
-  if (ConversionFunction)
-    OS << '\'' << *ConversionFunction << '\'';
-  else
-    OS << "aggregate initialization";
-  if (After.First || After.Second || After.Third) {
-    OS << " -> ";
-    After.dump();
-  }
-}
-
-/// dump - Print this implicit conversion sequence to standard
-/// error. Useful for debugging overloading issues.
-void ImplicitConversionSequence::dump() const {
-  raw_ostream &OS = llvm::errs();
-  if (isStdInitializerListElement())
-    OS << "Worst std::initializer_list element conversion: ";
-  switch (ConversionKind) {
-  case StandardConversion:
-    OS << "Standard conversion: ";
-    Standard.dump();
-    break;
-  case UserDefinedConversion:
-    OS << "User-defined conversion: ";
-    UserDefined.dump();
-    break;
-  case EllipsisConversion:
-    OS << "Ellipsis conversion";
-    break;
-  case AmbiguousConversion:
-    OS << "Ambiguous conversion";
-    break;
-  case BadConversion:
-    OS << "Bad conversion";
-    break;
-  }
-
-  OS << "\n";
-}
-
-void AmbiguousConversionSequence::construct() {
-  new (&conversions()) ConversionSet();
-}
-
-void AmbiguousConversionSequence::destruct() {
-  conversions().~ConversionSet();
-}
-
-void
-AmbiguousConversionSequence::copyFrom(const AmbiguousConversionSequence &O) {
-  FromTypePtr = O.FromTypePtr;
-  ToTypePtr = O.ToTypePtr;
-  new (&conversions()) ConversionSet(O.conversions());
-}
-
-namespace {
-  // Structure used by DeductionFailureInfo to store
-  // template argument information.
-  struct DFIArguments {
-    TemplateArgument FirstArg;
-    TemplateArgument SecondArg;
-  };
-  // Structure used by DeductionFailureInfo to store
-  // template parameter and template argument information.
-  struct DFIParamWithArguments : DFIArguments {
-    TemplateParameter Param;
-  };
-  // Structure used by DeductionFailureInfo to store template argument
-  // information and the index of the problematic call argument.
-  struct DFIDeducedMismatchArgs : DFIArguments {
-    TemplateArgumentList *TemplateArgs;
-    unsigned CallArgIndex;
-  };
-}
-
-/// Convert from Sema's representation of template deduction information
-/// to the form used in overload-candidate information.
-DeductionFailureInfo
-clang::MakeDeductionFailureInfo(ASTContext &Context,
-                                Sema::TemplateDeductionResult TDK,
-                                TemplateDeductionInfo &Info) {
-  DeductionFailureInfo Result;
-  Result.Result = static_cast<unsigned>(TDK);
-  Result.HasDiagnostic = false;
-  switch (TDK) {
-  case Sema::TDK_Invalid:
-  case Sema::TDK_InstantiationDepth:
-  case Sema::TDK_TooManyArguments:
-  case Sema::TDK_TooFewArguments:
-  case Sema::TDK_MiscellaneousDeductionFailure:
-  case Sema::TDK_CUDATargetMismatch:
-    Result.Data = nullptr;
-    break;
-
-  case Sema::TDK_Incomplete:
-  case Sema::TDK_InvalidExplicitArguments:
-    Result.Data = Info.Param.getOpaqueValue();
-    break;
-
-  case Sema::TDK_DeducedMismatch:
-  case Sema::TDK_DeducedMismatchNested: {
-    // FIXME: Should allocate from normal heap so that we can free this later.
-    auto *Saved = new (Context) DFIDeducedMismatchArgs;
-    Saved->FirstArg = Info.FirstArg;
-    Saved->SecondArg = Info.SecondArg;
-    Saved->TemplateArgs = Info.take();
-    Saved->CallArgIndex = Info.CallArgIndex;
-    Result.Data = Saved;
-    break;
-  }
-
-  case Sema::TDK_NonDeducedMismatch: {
-    // FIXME: Should allocate from normal heap so that we can free this later.
-    DFIArguments *Saved = new (Context) DFIArguments;
-    Saved->FirstArg = Info.FirstArg;
-    Saved->SecondArg = Info.SecondArg;
-    Result.Data = Saved;
-    break;
-  }
-
-  case Sema::TDK_IncompletePack:
-    // FIXME: It's slightly wasteful to allocate two TemplateArguments for this.
-  case Sema::TDK_Inconsistent:
-  case Sema::TDK_Underqualified: {
-    // FIXME: Should allocate from normal heap so that we can free this later.
-    DFIParamWithArguments *Saved = new (Context) DFIParamWithArguments;
-    Saved->Param = Info.Param;
-    Saved->FirstArg = Info.FirstArg;
-    Saved->SecondArg = Info.SecondArg;
-    Result.Data = Saved;
-    break;
-  }
-
-  case Sema::TDK_SubstitutionFailure:
-    Result.Data = Info.take();
-    if (Info.hasSFINAEDiagnostic()) {
-      PartialDiagnosticAt *Diag = new (Result.Diagnostic) PartialDiagnosticAt(
-          SourceLocation(), PartialDiagnostic::NullDiagnostic());
-      Info.takeSFINAEDiagnostic(*Diag);
-      Result.HasDiagnostic = true;
-    }
-    break;
-
-  case Sema::TDK_Success:
-  case Sema::TDK_NonDependentConversionFailure:
-    llvm_unreachable("not a deduction failure");
-  }
-
-  return Result;
-}
-
-void DeductionFailureInfo::Destroy() {
-  switch (static_cast<Sema::TemplateDeductionResult>(Result)) {
-  case Sema::TDK_Success:
-  case Sema::TDK_Invalid:
-  case Sema::TDK_InstantiationDepth:
-  case Sema::TDK_Incomplete:
-  case Sema::TDK_TooManyArguments:
-  case Sema::TDK_TooFewArguments:
-  case Sema::TDK_InvalidExplicitArguments:
-  case Sema::TDK_CUDATargetMismatch:
-  case Sema::TDK_NonDependentConversionFailure:
-    break;
-
-  case Sema::TDK_IncompletePack:
-  case Sema::TDK_Inconsistent:
-  case Sema::TDK_Underqualified:
-  case Sema::TDK_DeducedMismatch:
-  case Sema::TDK_DeducedMismatchNested:
-  case Sema::TDK_NonDeducedMismatch:
-    // FIXME: Destroy the data?
-    Data = nullptr;
-    break;
-
-  case Sema::TDK_SubstitutionFailure:
-    // FIXME: Destroy the template argument list?
-    Data = nullptr;
-    if (PartialDiagnosticAt *Diag = getSFINAEDiagnostic()) {
-      Diag->~PartialDiagnosticAt();
-      HasDiagnostic = false;
-    }
-    break;
-
-  // Unhandled
-  case Sema::TDK_MiscellaneousDeductionFailure:
-    break;
-  }
-}
-
-PartialDiagnosticAt *DeductionFailureInfo::getSFINAEDiagnostic() {
-  if (HasDiagnostic)
-    return static_cast<PartialDiagnosticAt*>(static_cast<void*>(Diagnostic));
-  return nullptr;
-}
-
-TemplateParameter DeductionFailureInfo::getTemplateParameter() {
-  switch (static_cast<Sema::TemplateDeductionResult>(Result)) {
-  case Sema::TDK_Success:
-  case Sema::TDK_Invalid:
-  case Sema::TDK_InstantiationDepth:
-  case Sema::TDK_TooManyArguments:
-  case Sema::TDK_TooFewArguments:
-  case Sema::TDK_SubstitutionFailure:
-  case Sema::TDK_DeducedMismatch:
-  case Sema::TDK_DeducedMismatchNested:
-  case Sema::TDK_NonDeducedMismatch:
-  case Sema::TDK_CUDATargetMismatch:
-  case Sema::TDK_NonDependentConversionFailure:
-    return TemplateParameter();
-
-  case Sema::TDK_Incomplete:
-  case Sema::TDK_InvalidExplicitArguments:
-    return TemplateParameter::getFromOpaqueValue(Data);
-
-  case Sema::TDK_IncompletePack:
-  case Sema::TDK_Inconsistent:
-  case Sema::TDK_Underqualified:
-    return static_cast<DFIParamWithArguments*>(Data)->Param;
-
-  // Unhandled
-  case Sema::TDK_MiscellaneousDeductionFailure:
-    break;
-  }
-
-  return TemplateParameter();
-}
-
-TemplateArgumentList *DeductionFailureInfo::getTemplateArgumentList() {
-  switch (static_cast<Sema::TemplateDeductionResult>(Result)) {
-  case Sema::TDK_Success:
-  case Sema::TDK_Invalid:
-  case Sema::TDK_InstantiationDepth:
-  case Sema::TDK_TooManyArguments:
-  case Sema::TDK_TooFewArguments:
-  case Sema::TDK_Incomplete:
-  case Sema::TDK_IncompletePack:
-  case Sema::TDK_InvalidExplicitArguments:
-  case Sema::TDK_Inconsistent:
-  case Sema::TDK_Underqualified:
-  case Sema::TDK_NonDeducedMismatch:
-  case Sema::TDK_CUDATargetMismatch:
-  case Sema::TDK_NonDependentConversionFailure:
-    return nullptr;
-
-  case Sema::TDK_DeducedMismatch:
-  case Sema::TDK_DeducedMismatchNested:
-    return static_cast<DFIDeducedMismatchArgs*>(Data)->TemplateArgs;
-
-  case Sema::TDK_SubstitutionFailure:
-    return static_cast<TemplateArgumentList*>(Data);
-
-  // Unhandled
-  case Sema::TDK_MiscellaneousDeductionFailure:
-    break;
-  }
-
-  return nullptr;
-}
-
-const TemplateArgument *DeductionFailureInfo::getFirstArg() {
-  switch (static_cast<Sema::TemplateDeductionResult>(Result)) {
-  case Sema::TDK_Success:
-  case Sema::TDK_Invalid:
-  case Sema::TDK_InstantiationDepth:
-  case Sema::TDK_Incomplete:
-  case Sema::TDK_TooManyArguments:
-  case Sema::TDK_TooFewArguments:
-  case Sema::TDK_InvalidExplicitArguments:
-  case Sema::TDK_SubstitutionFailure:
-  case Sema::TDK_CUDATargetMismatch:
-  case Sema::TDK_NonDependentConversionFailure:
-    return nullptr;
-
-  case Sema::TDK_IncompletePack:
-  case Sema::TDK_Inconsistent:
-  case Sema::TDK_Underqualified:
-  case Sema::TDK_DeducedMismatch:
-  case Sema::TDK_DeducedMismatchNested:
-  case Sema::TDK_NonDeducedMismatch:
-    return &static_cast<DFIArguments*>(Data)->FirstArg;
-
-  // Unhandled
-  case Sema::TDK_MiscellaneousDeductionFailure:
-    break;
-  }
-
-  return nullptr;
-}
-
-const TemplateArgument *DeductionFailureInfo::getSecondArg() {
-  switch (static_cast<Sema::TemplateDeductionResult>(Result)) {
-  case Sema::TDK_Success:
-  case Sema::TDK_Invalid:
-  case Sema::TDK_InstantiationDepth:
-  case Sema::TDK_Incomplete:
-  case Sema::TDK_IncompletePack:
-  case Sema::TDK_TooManyArguments:
-  case Sema::TDK_TooFewArguments:
-  case Sema::TDK_InvalidExplicitArguments:
-  case Sema::TDK_SubstitutionFailure:
-  case Sema::TDK_CUDATargetMismatch:
-  case Sema::TDK_NonDependentConversionFailure:
-    return nullptr;
-
-  case Sema::TDK_Inconsistent:
-  case Sema::TDK_Underqualified:
-  case Sema::TDK_DeducedMismatch:
-  case Sema::TDK_DeducedMismatchNested:
-  case Sema::TDK_NonDeducedMismatch:
-    return &static_cast<DFIArguments*>(Data)->SecondArg;
-
-  // Unhandled
-  case Sema::TDK_MiscellaneousDeductionFailure:
-    break;
-  }
-
-  return nullptr;
-}
-
-llvm::Optional<unsigned> DeductionFailureInfo::getCallArgIndex() {
-  switch (static_cast<Sema::TemplateDeductionResult>(Result)) {
-  case Sema::TDK_DeducedMismatch:
-  case Sema::TDK_DeducedMismatchNested:
-    return static_cast<DFIDeducedMismatchArgs*>(Data)->CallArgIndex;
-
-  default:
-    return llvm::None;
-  }
-}
-
-void OverloadCandidateSet::destroyCandidates() {
-  for (iterator i = begin(), e = end(); i != e; ++i) {
-    for (auto &C : i->Conversions)
-      C.~ImplicitConversionSequence();
-    if (!i->Viable && i->FailureKind == ovl_fail_bad_deduction)
-      i->DeductionFailure.Destroy();
-  }
-}
-
-void OverloadCandidateSet::clear(CandidateSetKind CSK) {
-  destroyCandidates();
-  SlabAllocator.Reset();
-  NumInlineBytesUsed = 0;
-  Candidates.clear();
-  Functions.clear();
-  Kind = CSK;
-}
-
-namespace {
-  class UnbridgedCastsSet {
-    struct Entry {
-      Expr **Addr;
-      Expr *Saved;
-    };
-    SmallVector<Entry, 2> Entries;
-
-  public:
-    void save(Sema &S, Expr *&E) {
-      assert(E->hasPlaceholderType(BuiltinType::ARCUnbridgedCast));
-      Entry entry = { &E, E };
-      Entries.push_back(entry);
-      E = S.stripARCUnbridgedCast(E);
-    }
-
-    void restore() {
-      for (SmallVectorImpl<Entry>::iterator
-             i = Entries.begin(), e = Entries.end(); i != e; ++i)
-        *i->Addr = i->Saved;
-    }
-  };
-}
-
-/// checkPlaceholderForOverload - Do any interesting placeholder-like
-/// preprocessing on the given expression.
-///
-/// \param unbridgedCasts a collection to which to add unbridged casts;
-///   without this, they will be immediately diagnosed as errors
-///
-/// Return true on unrecoverable error.
-static bool
-checkPlaceholderForOverload(Sema &S, Expr *&E,
-                            UnbridgedCastsSet *unbridgedCasts = nullptr) {
-  if (const BuiltinType *placeholder =  E->getType()->getAsPlaceholderType()) {
-    // We can't handle overloaded expressions here because overload
-    // resolution might reasonably tweak them.
-    if (placeholder->getKind() == BuiltinType::Overload) return false;
-
-    // If the context potentially accepts unbridged ARC casts, strip
-    // the unbridged cast and add it to the collection for later restoration.
-    if (placeholder->getKind() == BuiltinType::ARCUnbridgedCast &&
-        unbridgedCasts) {
-      unbridgedCasts->save(S, E);
-      return false;
-    }
-
-    // Go ahead and check everything else.
-    ExprResult result = S.CheckPlaceholderExpr(E);
-    if (result.isInvalid())
-      return true;
-
-    E = result.get();
-    return false;
-  }
-
-  // Nothing to do.
-  return false;
-}
-
-/// checkArgPlaceholdersForOverload - Check a set of call operands for
-/// placeholders.
-static bool checkArgPlaceholdersForOverload(Sema &S,
-                                            MultiExprArg Args,
-                                            UnbridgedCastsSet &unbridged) {
-  for (unsigned i = 0, e = Args.size(); i != e; ++i)
-    if (checkPlaceholderForOverload(S, Args[i], &unbridged))
-      return true;
-
-  return false;
-}
-
-/// Determine whether the given New declaration is an overload of the
-/// declarations in Old. This routine returns Ovl_Match or Ovl_NonFunction if
-/// New and Old cannot be overloaded, e.g., if New has the same signature as
-/// some function in Old (C++ 1.3.10) or if the Old declarations aren't
-/// functions (or function templates) at all. When it does return Ovl_Match or
-/// Ovl_NonFunction, MatchedDecl will point to the decl that New cannot be
-/// overloaded with. This decl may be a UsingShadowDecl on top of the underlying
-/// declaration.
-///
-/// Example: Given the following input:
-///
-///   void f(int, float); // #1
-///   void f(int, int); // #2
-///   int f(int, int); // #3
-///
-/// When we process #1, there is no previous declaration of "f", so IsOverload
-/// will not be used.
-///
-/// When we process #2, Old contains only the FunctionDecl for #1. By comparing
-/// the parameter types, we see that #1 and #2 are overloaded (since they have
-/// different signatures), so this routine returns Ovl_Overload; MatchedDecl is
-/// unchanged.
-///
-/// When we process #3, Old is an overload set containing #1 and #2. We compare
-/// the signatures of #3 to #1 (they're overloaded, so we do nothing) and then
-/// #3 to #2. Since the signatures of #3 and #2 are identical (return types of
-/// functions are not part of the signature), IsOverload returns Ovl_Match and
-/// MatchedDecl will be set to point to the FunctionDecl for #2.
-///
-/// 'NewIsUsingShadowDecl' indicates that 'New' is being introduced into a class
-/// by a using declaration. The rules for whether to hide shadow declarations
-/// ignore some properties which otherwise figure into a function template's
-/// signature.
-Sema::OverloadKind
-Sema::CheckOverload(Scope *S, FunctionDecl *New, const LookupResult &Old,
-                    NamedDecl *&Match, bool NewIsUsingDecl) {
-  for (LookupResult::iterator I = Old.begin(), E = Old.end();
-         I != E; ++I) {
-    NamedDecl *OldD = *I;
-
-    bool OldIsUsingDecl = false;
-    if (isa<UsingShadowDecl>(OldD)) {
-      OldIsUsingDecl = true;
-
-      // We can always introduce two using declarations into the same
-      // context, even if they have identical signatures.
-      if (NewIsUsingDecl) continue;
-
-      OldD = cast<UsingShadowDecl>(OldD)->getTargetDecl();
-    }
-
-    // A using-declaration does not conflict with another declaration
-    // if one of them is hidden.
-    if ((OldIsUsingDecl || NewIsUsingDecl) && !isVisible(*I))
-      continue;
-
-    // If either declaration was introduced by a using declaration,
-    // we'll need to use slightly different rules for matching.
-    // Essentially, these rules are the normal rules, except that
-    // function templates hide function templates with different
-    // return types or template parameter lists.
-    bool UseMemberUsingDeclRules =
-      (OldIsUsingDecl || NewIsUsingDecl) && CurContext->isRecord() &&
-      !New->getFriendObjectKind();
-
-    if (FunctionDecl *OldF = OldD->getAsFunction()) {
-      if (!IsOverload(New, OldF, UseMemberUsingDeclRules)) {
-        if (UseMemberUsingDeclRules && OldIsUsingDecl) {
-          HideUsingShadowDecl(S, cast<UsingShadowDecl>(*I));
-          continue;
-        }
-
-        if (!isa<FunctionTemplateDecl>(OldD) &&
-            !shouldLinkPossiblyHiddenDecl(*I, New))
-          continue;
-
-        Match = *I;
-        return Ovl_Match;
-      }
-
-      // Builtins that have custom typechecking or have a reference should
-      // not be overloadable or redeclarable.
-      if (!getASTContext().canBuiltinBeRedeclared(OldF)) {
-        Match = *I;
-        return Ovl_NonFunction;
-      }
-    } else if (isa<UsingDecl>(OldD) || isa<UsingPackDecl>(OldD)) {
-      // We can overload with these, which can show up when doing
-      // redeclaration checks for UsingDecls.
-      assert(Old.getLookupKind() == LookupUsingDeclName);
-    } else if (isa<TagDecl>(OldD)) {
-      // We can always overload with tags by hiding them.
-    } else if (auto *UUD = dyn_cast<UnresolvedUsingValueDecl>(OldD)) {
-      // Optimistically assume that an unresolved using decl will
-      // overload; if it doesn't, we'll have to diagnose during
-      // template instantiation.
-      //
-      // Exception: if the scope is dependent and this is not a class
-      // member, the using declaration can only introduce an enumerator.
-      if (UUD->getQualifier()->isDependent() && !UUD->isCXXClassMember()) {
-        Match = *I;
-        return Ovl_NonFunction;
-      }
-    } else {
-      // (C++ 13p1):
-      //   Only function declarations can be overloaded; object and type
-      //   declarations cannot be overloaded.
-      Match = *I;
-      return Ovl_NonFunction;
-    }
-  }
-
-  // C++ [temp.friend]p1:
-  //   For a friend function declaration that is not a template declaration:
-  //    -- if the name of the friend is a qualified or unqualified template-id,
-  //       [...], otherwise
-  //    -- if the name of the friend is a qualified-id and a matching
-  //       non-template function is found in the specified class or namespace,
-  //       the friend declaration refers to that function, otherwise,
-  //    -- if the name of the friend is a qualified-id and a matching function
-  //       template is found in the specified class or namespace, the friend
-  //       declaration refers to the deduced specialization of that function
-  //       template, otherwise
-  //    -- the name shall be an unqualified-id [...]
-  // If we get here for a qualified friend declaration, we've just reached the
-  // third bullet. If the type of the friend is dependent, skip this lookup
-  // until instantiation.
-  if (New->getFriendObjectKind() && New->getQualifier() &&
-      !New->getDependentSpecializationInfo() &&
-      !New->getType()->isDependentType()) {
-    LookupResult TemplateSpecResult(LookupResult::Temporary, Old);
-    TemplateSpecResult.addAllDecls(Old);
-    if (CheckFunctionTemplateSpecialization(New, nullptr, TemplateSpecResult,
-                                            /*QualifiedFriend*/true)) {
-      New->setInvalidDecl();
-      return Ovl_Overload;
-    }
-
-    Match = TemplateSpecResult.getAsSingle<FunctionDecl>();
-    return Ovl_Match;
-  }
-
-  return Ovl_Overload;
-}
-
-bool Sema::IsOverload(FunctionDecl *New, FunctionDecl *Old,
-                      bool UseMemberUsingDeclRules, bool ConsiderCudaAttrs) {
-  // C++ [basic.start.main]p2: This function shall not be overloaded.
-  if (New->isMain())
-    return false;
-
-  // MSVCRT user defined entry points cannot be overloaded.
-  if (New->isMSVCRTEntryPoint())
-    return false;
-
-  FunctionTemplateDecl *OldTemplate = Old->getDescribedFunctionTemplate();
-  FunctionTemplateDecl *NewTemplate = New->getDescribedFunctionTemplate();
-
-  // C++ [temp.fct]p2:
-  //   A function template can be overloaded with other function templates
-  //   and with normal (non-template) functions.
-  if ((OldTemplate == nullptr) != (NewTemplate == nullptr))
-    return true;
-
-  // Is the function New an overload of the function Old?
-  QualType OldQType = Context.getCanonicalType(Old->getType());
-  QualType NewQType = Context.getCanonicalType(New->getType());
-
-  // Compare the signatures (C++ 1.3.10) of the two functions to
-  // determine whether they are overloads. If we find any mismatch
-  // in the signature, they are overloads.
-
-  // If either of these functions is a K&R-style function (no
-  // prototype), then we consider them to have matching signatures.
-  if (isa<FunctionNoProtoType>(OldQType.getTypePtr()) ||
-      isa<FunctionNoProtoType>(NewQType.getTypePtr()))
-    return false;
-
-  const FunctionProtoType *OldType = cast<FunctionProtoType>(OldQType);
-  const FunctionProtoType *NewType = cast<FunctionProtoType>(NewQType);
-
-  // The signature of a function includes the types of its
-  // parameters (C++ 1.3.10), which includes the presence or absence
-  // of the ellipsis; see C++ DR 357).
-  if (OldQType != NewQType &&
-      (OldType->getNumParams() != NewType->getNumParams() ||
-       OldType->isVariadic() != NewType->isVariadic() ||
-       !FunctionParamTypesAreEqual(OldType, NewType)))
-    return true;
-
-  // C++ [temp.over.link]p4:
-  //   The signature of a function template consists of its function
-  //   signature, its return type and its template parameter list. The names
-  //   of the template parameters are significant only for establishing the
-  //   relationship between the template parameters and the rest of the
-  //   signature.
-  //
-  // We check the return type and template parameter lists for function
-  // templates first; the remaining checks follow.
-  //
-  // However, we don't consider either of these when deciding whether
-  // a member introduced by a shadow declaration is hidden.
-  if (!UseMemberUsingDeclRules && NewTemplate &&
-      (!TemplateParameterListsAreEqual(NewTemplate->getTemplateParameters(),
-                                       OldTemplate->getTemplateParameters(),
-                                       false, TPL_TemplateMatch) ||
-       !Context.hasSameType(Old->getDeclaredReturnType(),
-                            New->getDeclaredReturnType())))
-    return true;
-
-  // If the function is a class member, its signature includes the
-  // cv-qualifiers (if any) and ref-qualifier (if any) on the function itself.
-  //
-  // As part of this, also check whether one of the member functions
-  // is static, in which case they are not overloads (C++
-  // 13.1p2). While not part of the definition of the signature,
-  // this check is important to determine whether these functions
-  // can be overloaded.
-  CXXMethodDecl *OldMethod = dyn_cast<CXXMethodDecl>(Old);
-  CXXMethodDecl *NewMethod = dyn_cast<CXXMethodDecl>(New);
-  if (OldMethod && NewMethod &&
-      !OldMethod->isStatic() && !NewMethod->isStatic()) {
-    if (OldMethod->getRefQualifier() != NewMethod->getRefQualifier()) {
-      if (!UseMemberUsingDeclRules &&
-          (OldMethod->getRefQualifier() == RQ_None ||
-           NewMethod->getRefQualifier() == RQ_None)) {
-        // C++0x [over.load]p2:
-        //   - Member function declarations with the same name and the same
-        //     parameter-type-list as well as member function template
-        //     declarations with the same name, the same parameter-type-list, and
-        //     the same template parameter lists cannot be overloaded if any of
-        //     them, but not all, have a ref-qualifier (8.3.5).
-        Diag(NewMethod->getLocation(), diag::err_ref_qualifier_overload)
-          << NewMethod->getRefQualifier() << OldMethod->getRefQualifier();
-        Diag(OldMethod->getLocation(), diag::note_previous_declaration);
-      }
-      return true;
-    }
-
-    // We may not have applied the implicit const for a constexpr member
-    // function yet (because we haven't yet resolved whether this is a static
-    // or non-static member function). Add it now, on the assumption that this
-    // is a redeclaration of OldMethod.
-    // FIXME: OpenCL: Need to consider address spaces
-    unsigned OldQuals = OldMethod->getTypeQualifiers().getCVRUQualifiers();
-    unsigned NewQuals = NewMethod->getTypeQualifiers().getCVRUQualifiers();
-    if (!getLangOpts().CPlusPlus14 && NewMethod->isConstexpr() &&
-        !isa<CXXConstructorDecl>(NewMethod))
-      NewQuals |= Qualifiers::Const;
-
-    // We do not allow overloading based off of '__restrict'.
-    OldQuals &= ~Qualifiers::Restrict;
-    NewQuals &= ~Qualifiers::Restrict;
-    if (OldQuals != NewQuals)
-      return true;
-  }
-
-  // Though pass_object_size is placed on parameters and takes an argument, we
-  // consider it to be a function-level modifier for the sake of function
-  // identity. Either the function has one or more parameters with
-  // pass_object_size or it doesn't.
-  if (functionHasPassObjectSizeParams(New) !=
-      functionHasPassObjectSizeParams(Old))
-    return true;
-
-  // enable_if attributes are an order-sensitive part of the signature.
-  for (specific_attr_iterator<EnableIfAttr>
-         NewI = New->specific_attr_begin<EnableIfAttr>(),
-         NewE = New->specific_attr_end<EnableIfAttr>(),
-         OldI = Old->specific_attr_begin<EnableIfAttr>(),
-         OldE = Old->specific_attr_end<EnableIfAttr>();
-       NewI != NewE || OldI != OldE; ++NewI, ++OldI) {
-    if (NewI == NewE || OldI == OldE)
-      return true;
-    llvm::FoldingSetNodeID NewID, OldID;
-    NewI->getCond()->Profile(NewID, Context, true);
-    OldI->getCond()->Profile(OldID, Context, true);
-    if (NewID != OldID)
-      return true;
-  }
-
-  if (getLangOpts().CUDA && ConsiderCudaAttrs) {
-    // Don't allow overloading of destructors.  (In theory we could, but it
-    // would be a giant change to clang.)
-    if (isa<CXXDestructorDecl>(New))
-      return false;
-
-    CUDAFunctionTarget NewTarget = IdentifyCUDATarget(New),
-                       OldTarget = IdentifyCUDATarget(Old);
-    if (NewTarget == CFT_InvalidTarget)
-      return false;
-
-    assert((OldTarget != CFT_InvalidTarget) && "Unexpected invalid target.");
-
-    // Allow overloading of functions with same signature and different CUDA
-    // target attributes.
-    return NewTarget != OldTarget;
-  }
-
-  // The signatures match; this is not an overload.
-  return false;
-}
-
-/// Checks availability of the function depending on the current
-/// function context. Inside an unavailable function, unavailability is ignored.
-///
-/// \returns true if \arg FD is unavailable and current context is inside
-/// an available function, false otherwise.
-bool Sema::isFunctionConsideredUnavailable(FunctionDecl *FD) {
-  if (!FD->isUnavailable())
-    return false;
-
-  // Walk up the context of the caller.
-  Decl *C = cast<Decl>(CurContext);
-  do {
-    if (C->isUnavailable())
-      return false;
-  } while ((C = cast_or_null<Decl>(C->getDeclContext())));
-  return true;
-}
-
-/// Tries a user-defined conversion from From to ToType.
-///
-/// Produces an implicit conversion sequence for when a standard conversion
-/// is not an option. See TryImplicitConversion for more information.
-static ImplicitConversionSequence
-TryUserDefinedConversion(Sema &S, Expr *From, QualType ToType,
-                         bool SuppressUserConversions,
-                         bool AllowExplicit,
-                         bool InOverloadResolution,
-                         bool CStyle,
-                         bool AllowObjCWritebackConversion,
-                         bool AllowObjCConversionOnExplicit) {
-  ImplicitConversionSequence ICS;
-
-  if (SuppressUserConversions) {
-    // We're not in the case above, so there is no conversion that
-    // we can perform.
-    ICS.setBad(BadConversionSequence::no_conversion, From, ToType);
-    return ICS;
-  }
-
-  // Attempt user-defined conversion.
-  OverloadCandidateSet Conversions(From->getExprLoc(),
-                                   OverloadCandidateSet::CSK_Normal);
-  switch (IsUserDefinedConversion(S, From, ToType, ICS.UserDefined,
-                                  Conversions, AllowExplicit,
-                                  AllowObjCConversionOnExplicit)) {
-  case OR_Success:
-  case OR_Deleted:
-    ICS.setUserDefined();
-    // C++ [over.ics.user]p4:
-    //   A conversion of an expression of class type to the same class
-    //   type is given Exact Match rank, and a conversion of an
-    //   expression of class type to a base class of that type is
-    //   given Conversion rank, in spite of the fact that a copy
-    //   constructor (i.e., a user-defined conversion function) is
-    //   called for those cases.
-    if (CXXConstructorDecl *Constructor
-          = dyn_cast<CXXConstructorDecl>(ICS.UserDefined.ConversionFunction)) {
-      QualType FromCanon
-        = S.Context.getCanonicalType(From->getType().getUnqualifiedType());
-      QualType ToCanon
-        = S.Context.getCanonicalType(ToType).getUnqualifiedType();
-      if (Constructor->isCopyConstructor() &&
-          (FromCanon == ToCanon ||
-           S.IsDerivedFrom(From->getBeginLoc(), FromCanon, ToCanon))) {
-        // Turn this into a "standard" conversion sequence, so that it
-        // gets ranked with standard conversion sequences.
-        DeclAccessPair Found = ICS.UserDefined.FoundConversionFunction;
-        ICS.setStandard();
-        ICS.Standard.setAsIdentityConversion();
-        ICS.Standard.setFromType(From->getType());
-        ICS.Standard.setAllToTypes(ToType);
-        ICS.Standard.CopyConstructor = Constructor;
-        ICS.Standard.FoundCopyConstructor = Found;
-        if (ToCanon != FromCanon)
-          ICS.Standard.Second = ICK_Derived_To_Base;
-      }
-    }
-    break;
-
-  case OR_Ambiguous:
-    ICS.setAmbiguous();
-    ICS.Ambiguous.setFromType(From->getType());
-    ICS.Ambiguous.setToType(ToType);
-    for (OverloadCandidateSet::iterator Cand = Conversions.begin();
-         Cand != Conversions.end(); ++Cand)
-      if (Cand->Viable)
-        ICS.Ambiguous.addConversion(Cand->FoundDecl, Cand->Function);
-    break;
-
-    // Fall through.
-  case OR_No_Viable_Function:
-    ICS.setBad(BadConversionSequence::no_conversion, From, ToType);
-    break;
-  }
-
-  return ICS;
-}
-
-/// TryImplicitConversion - Attempt to perform an implicit conversion
-/// from the given expression (Expr) to the given type (ToType). This
-/// function returns an implicit conversion sequence that can be used
-/// to perform the initialization. Given
-///
-///   void f(float f);
-///   void g(int i) { f(i); }
-///
-/// this routine would produce an implicit conversion sequence to
-/// describe the initialization of f from i, which will be a standard
-/// conversion sequence containing an lvalue-to-rvalue conversion (C++
-/// 4.1) followed by a floating-integral conversion (C++ 4.9).
-//
-/// Note that this routine only determines how the conversion can be
-/// performed; it does not actually perform the conversion. As such,
-/// it will not produce any diagnostics if no conversion is available,
-/// but will instead return an implicit conversion sequence of kind
-/// "BadConversion".
-///
-/// If @p SuppressUserConversions, then user-defined conversions are
-/// not permitted.
-/// If @p AllowExplicit, then explicit user-defined conversions are
-/// permitted.
-///
-/// \param AllowObjCWritebackConversion Whether we allow the Objective-C
-/// writeback conversion, which allows __autoreleasing id* parameters to
-/// be initialized with __strong id* or __weak id* arguments.
-static ImplicitConversionSequence
-TryImplicitConversion(Sema &S, Expr *From, QualType ToType,
-                      bool SuppressUserConversions,
-                      bool AllowExplicit,
-                      bool InOverloadResolution,
-                      bool CStyle,
-                      bool AllowObjCWritebackConversion,
-                      bool AllowObjCConversionOnExplicit) {
-  ImplicitConversionSequence ICS;
-  if (IsStandardConversion(S, From, ToType, InOverloadResolution,
-                           ICS.Standard, CStyle, AllowObjCWritebackConversion)){
-    ICS.setStandard();
-    return ICS;
-  }
-
-  if (!S.getLangOpts().CPlusPlus) {
-    ICS.setBad(BadConversionSequence::no_conversion, From, ToType);
-    return ICS;
-  }
-
-  // C++ [over.ics.user]p4:
-  //   A conversion of an expression of class type to the same class
-  //   type is given Exact Match rank, and a conversion of an
-  //   expression of class type to a base class of that type is
-  //   given Conversion rank, in spite of the fact that a copy/move
-  //   constructor (i.e., a user-defined conversion function) is
-  //   called for those cases.
-  QualType FromType = From->getType();
-  if (ToType->getAs<RecordType>() && FromType->getAs<RecordType>() &&
-      (S.Context.hasSameUnqualifiedType(FromType, ToType) ||
-       S.IsDerivedFrom(From->getBeginLoc(), FromType, ToType))) {
-    ICS.setStandard();
-    ICS.Standard.setAsIdentityConversion();
-    ICS.Standard.setFromType(FromType);
-    ICS.Standard.setAllToTypes(ToType);
-
-    // We don't actually check at this point whether there is a valid
-    // copy/move constructor, since overloading just assumes that it
-    // exists. When we actually perform initialization, we'll find the
-    // appropriate constructor to copy the returned object, if needed.
-    ICS.Standard.CopyConstructor = nullptr;
-
-    // Determine whether this is considered a derived-to-base conversion.
-    if (!S.Context.hasSameUnqualifiedType(FromType, ToType))
-      ICS.Standard.Second = ICK_Derived_To_Base;
-
-    return ICS;
-  }
-
-  return TryUserDefinedConversion(S, From, ToType, SuppressUserConversions,
-                                  AllowExplicit, InOverloadResolution, CStyle,
-                                  AllowObjCWritebackConversion,
-                                  AllowObjCConversionOnExplicit);
-}
-
-ImplicitConversionSequence
-Sema::TryImplicitConversion(Expr *From, QualType ToType,
-                            bool SuppressUserConversions,
-                            bool AllowExplicit,
-                            bool InOverloadResolution,
-                            bool CStyle,
-                            bool AllowObjCWritebackConversion) {
-  return ::TryImplicitConversion(*this, From, ToType,
-                                 SuppressUserConversions, AllowExplicit,
-                                 InOverloadResolution, CStyle,
-                                 AllowObjCWritebackConversion,
-                                 /*AllowObjCConversionOnExplicit=*/false);
-}
-
-/// PerformImplicitConversion - Perform an implicit conversion of the
-/// expression From to the type ToType. Returns the
-/// converted expression. Flavor is the kind of conversion we're
-/// performing, used in the error message. If @p AllowExplicit,
-/// explicit user-defined conversions are permitted.
-ExprResult
-Sema::PerformImplicitConversion(Expr *From, QualType ToType,
-                                AssignmentAction Action, bool AllowExplicit) {
-  ImplicitConversionSequence ICS;
-  return PerformImplicitConversion(From, ToType, Action, AllowExplicit, ICS);
-}
-
-ExprResult
-Sema::PerformImplicitConversion(Expr *From, QualType ToType,
-                                AssignmentAction Action, bool AllowExplicit,
-                                ImplicitConversionSequence& ICS) {
-  if (checkPlaceholderForOverload(*this, From))
-    return ExprError();
-
-  // Objective-C ARC: Determine whether we will allow the writeback conversion.
-  bool AllowObjCWritebackConversion
-    = getLangOpts().ObjCAutoRefCount &&
-      (Action == AA_Passing || Action == AA_Sending);
-  if (getLangOpts().ObjC)
-    CheckObjCBridgeRelatedConversions(From->getBeginLoc(), ToType,
-                                      From->getType(), From);
-  ICS = ::TryImplicitConversion(*this, From, ToType,
-                                /*SuppressUserConversions=*/false,
-                                AllowExplicit,
-                                /*InOverloadResolution=*/false,
-                                /*CStyle=*/false,
-                                AllowObjCWritebackConversion,
-                                /*AllowObjCConversionOnExplicit=*/false);
-  return PerformImplicitConversion(From, ToType, ICS, Action);
-}
-
-/// Determine whether the conversion from FromType to ToType is a valid
-/// conversion that strips "noexcept" or "noreturn" off the nested function
-/// type.
-bool Sema::IsFunctionConversion(QualType FromType, QualType ToType,
-                                QualType &ResultTy) {
-  if (Context.hasSameUnqualifiedType(FromType, ToType))
-    return false;
-
-  // Permit the conversion F(t __attribute__((noreturn))) -> F(t)
-  //                    or F(t noexcept) -> F(t)
-  // where F adds one of the following at most once:
-  //   - a pointer
-  //   - a member pointer
-  //   - a block pointer
-  // Changes here need matching changes in FindCompositePointerType.
-  CanQualType CanTo = Context.getCanonicalType(ToType);
-  CanQualType CanFrom = Context.getCanonicalType(FromType);
-  Type::TypeClass TyClass = CanTo->getTypeClass();
-  if (TyClass != CanFrom->getTypeClass()) return false;
-  if (TyClass != Type::FunctionProto && TyClass != Type::FunctionNoProto) {
-    if (TyClass == Type::Pointer) {
-      CanTo = CanTo.getAs<PointerType>()->getPointeeType();
-      CanFrom = CanFrom.getAs<PointerType>()->getPointeeType();
-    } else if (TyClass == Type::BlockPointer) {
-      CanTo = CanTo.getAs<BlockPointerType>()->getPointeeType();
-      CanFrom = CanFrom.getAs<BlockPointerType>()->getPointeeType();
-    } else if (TyClass == Type::MemberPointer) {
-      auto ToMPT = CanTo.getAs<MemberPointerType>();
-      auto FromMPT = CanFrom.getAs<MemberPointerType>();
-      // A function pointer conversion cannot change the class of the function.
-      if (ToMPT->getClass() != FromMPT->getClass())
-        return false;
-      CanTo = ToMPT->getPointeeType();
-      CanFrom = FromMPT->getPointeeType();
-    } else {
-      return false;
-    }
-
-    TyClass = CanTo->getTypeClass();
-    if (TyClass != CanFrom->getTypeClass()) return false;
-    if (TyClass != Type::FunctionProto && TyClass != Type::FunctionNoProto)
-      return false;
-  }
-
-  const auto *FromFn = cast<FunctionType>(CanFrom);
-  FunctionType::ExtInfo FromEInfo = FromFn->getExtInfo();
-
-  const auto *ToFn = cast<FunctionType>(CanTo);
-  FunctionType::ExtInfo ToEInfo = ToFn->getExtInfo();
-
-  bool Changed = false;
-
-  // Drop 'noreturn' if not present in target type.
-  if (FromEInfo.getNoReturn() && !ToEInfo.getNoReturn()) {
-    FromFn = Context.adjustFunctionType(FromFn, FromEInfo.withNoReturn(false));
-    Changed = true;
-  }
-
-  // Drop 'noexcept' if not present in target type.
-  if (const auto *FromFPT = dyn_cast<FunctionProtoType>(FromFn)) {
-    const auto *ToFPT = cast<FunctionProtoType>(ToFn);
-    if (FromFPT->isNothrow() && !ToFPT->isNothrow()) {
-      FromFn = cast<FunctionType>(
-          Context.getFunctionTypeWithExceptionSpec(QualType(FromFPT, 0),
-                                                   EST_None)
-                 .getTypePtr());
-      Changed = true;
-    }
-
-    // Convert FromFPT's ExtParameterInfo if necessary. The conversion is valid
-    // only if the ExtParameterInfo lists of the two function prototypes can be
-    // merged and the merged list is identical to ToFPT's ExtParameterInfo list.
-    SmallVector<FunctionProtoType::ExtParameterInfo, 4> NewParamInfos;
-    bool CanUseToFPT, CanUseFromFPT;
-    if (Context.mergeExtParameterInfo(ToFPT, FromFPT, CanUseToFPT,
-                                      CanUseFromFPT, NewParamInfos) &&
-        CanUseToFPT && !CanUseFromFPT) {
-      FunctionProtoType::ExtProtoInfo ExtInfo = FromFPT->getExtProtoInfo();
-      ExtInfo.ExtParameterInfos =
-          NewParamInfos.empty() ? nullptr : NewParamInfos.data();
-      QualType QT = Context.getFunctionType(FromFPT->getReturnType(),
-                                            FromFPT->getParamTypes(), ExtInfo);
-      FromFn = QT->getAs<FunctionType>();
-      Changed = true;
-    }
-  }
-
-  if (!Changed)
-    return false;
-
-  assert(QualType(FromFn, 0).isCanonical());
-  if (QualType(FromFn, 0) != CanTo) return false;
-
-  ResultTy = ToType;
-  return true;
-}
-
-/// Determine whether the conversion from FromType to ToType is a valid
-/// vector conversion.
-///
-/// \param ICK Will be set to the vector conversion kind, if this is a vector
-/// conversion.
-static bool IsVectorConversion(Sema &S, QualType FromType,
-                               QualType ToType, ImplicitConversionKind &ICK) {
-  // We need at least one of these types to be a vector type to have a vector
-  // conversion.
-  if (!ToType->isVectorType() && !FromType->isVectorType())
-    return false;
-
-  // Identical types require no conversions.
-  if (S.Context.hasSameUnqualifiedType(FromType, ToType))
-    return false;
-
-  // There are no conversions between extended vector types, only identity.
-  if (ToType->isExtVectorType()) {
-    // There are no conversions between extended vector types other than the
-    // identity conversion.
-    if (FromType->isExtVectorType())
-      return false;
-
-    // Vector splat from any arithmetic type to a vector.
-    if (FromType->isArithmeticType()) {
-      ICK = ICK_Vector_Splat;
-      return true;
-    }
-  }
-
-  // We can perform the conversion between vector types in the following cases:
-  // 1)vector types are equivalent AltiVec and GCC vector types
-  // 2)lax vector conversions are permitted and the vector types are of the
-  //   same size
-  if (ToType->isVectorType() && FromType->isVectorType()) {
-    if (S.Context.areCompatibleVectorTypes(FromType, ToType) ||
-        S.isLaxVectorConversion(FromType, ToType)) {
-      ICK = ICK_Vector_Conversion;
-      return true;
-    }
-  }
-
-  return false;
-}
-
-static bool tryAtomicConversion(Sema &S, Expr *From, QualType ToType,
-                                bool InOverloadResolution,
-                                StandardConversionSequence &SCS,
-                                bool CStyle);
-
-/// IsStandardConversion - Determines whether there is a standard
-/// conversion sequence (C++ [conv], C++ [over.ics.scs]) from the
-/// expression From to the type ToType. Standard conversion sequences
-/// only consider non-class types; for conversions that involve class
-/// types, use TryImplicitConversion. If a conversion exists, SCS will
-/// contain the standard conversion sequence required to perform this
-/// conversion and this routine will return true. Otherwise, this
-/// routine will return false and the value of SCS is unspecified.
-static bool IsStandardConversion(Sema &S, Expr* From, QualType ToType,
-                                 bool InOverloadResolution,
-                                 StandardConversionSequence &SCS,
-                                 bool CStyle,
-                                 bool AllowObjCWritebackConversion) {
-  QualType FromType = From->getType();
-
-  // Standard conversions (C++ [conv])
-  SCS.setAsIdentityConversion();
-  SCS.IncompatibleObjC = false;
-  SCS.setFromType(FromType);
-  SCS.CopyConstructor = nullptr;
-
-  // There are no standard conversions for class types in C++, so
-  // abort early. When overloading in C, however, we do permit them.
-  if (S.getLangOpts().CPlusPlus &&
-      (FromType->isRecordType() || ToType->isRecordType()))
-    return false;
-
-  // The first conversion can be an lvalue-to-rvalue conversion,
-  // array-to-pointer conversion, or function-to-pointer conversion
-  // (C++ 4p1).
-
-  if (FromType == S.Context.OverloadTy) {
-    DeclAccessPair AccessPair;
-    if (FunctionDecl *Fn
-          = S.ResolveAddressOfOverloadedFunction(From, ToType, false,
-                                                 AccessPair)) {
-      // We were able to resolve the address of the overloaded function,
-      // so we can convert to the type of that function.
-      FromType = Fn->getType();
-      SCS.setFromType(FromType);
-
-      // we can sometimes resolve &foo<int> regardless of ToType, so check
-      // if the type matches (identity) or we are converting to bool
-      if (!S.Context.hasSameUnqualifiedType(
-                      S.ExtractUnqualifiedFunctionType(ToType), FromType)) {
-        QualType resultTy;
-        // if the function type matches except for [[noreturn]], it's ok
-        if (!S.IsFunctionConversion(FromType,
-              S.ExtractUnqualifiedFunctionType(ToType), resultTy))
-          // otherwise, only a boolean conversion is standard
-          if (!ToType->isBooleanType())
-            return false;
-      }
-
-      // Check if the "from" expression is taking the address of an overloaded
-      // function and recompute the FromType accordingly. Take advantage of the
-      // fact that non-static member functions *must* have such an address-of
-      // expression.
-      CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(Fn);
-      if (Method && !Method->isStatic()) {
-        assert(isa<UnaryOperator>(From->IgnoreParens()) &&
-               "Non-unary operator on non-static member address");
-        assert(cast<UnaryOperator>(From->IgnoreParens())->getOpcode()
-               == UO_AddrOf &&
-               "Non-address-of operator on non-static member address");
-        const Type *ClassType
-          = S.Context.getTypeDeclType(Method->getParent()).getTypePtr();
-        FromType = S.Context.getMemberPointerType(FromType, ClassType);
-      } else if (isa<UnaryOperator>(From->IgnoreParens())) {
-        assert(cast<UnaryOperator>(From->IgnoreParens())->getOpcode() ==
-               UO_AddrOf &&
-               "Non-address-of operator for overloaded function expression");
-        FromType = S.Context.getPointerType(FromType);
-      }
-
-      // Check that we've computed the proper type after overload resolution.
-      // FIXME: FixOverloadedFunctionReference has side-effects; we shouldn't
-      // be calling it from within an NDEBUG block.
-      assert(S.Context.hasSameType(
-        FromType,
-        S.FixOverloadedFunctionReference(From, AccessPair, Fn)->getType()));
-    } else {
-      return false;
-    }
-  }
-  // Lvalue-to-rvalue conversion (C++11 4.1):
-  //   A glvalue (3.10) of a non-function, non-array type T can
-  //   be converted to a prvalue.
-  bool argIsLValue = From->isGLValue();
-  if (argIsLValue &&
-      !FromType->isFunctionType() && !FromType->isArrayType() &&
-      S.Context.getCanonicalType(FromType) != S.Context.OverloadTy) {
-    SCS.First = ICK_Lvalue_To_Rvalue;
-
-    // C11 6.3.2.1p2:
-    //   ... if the lvalue has atomic type, the value has the non-atomic version
-    //   of the type of the lvalue ...
-    if (const AtomicType *Atomic = FromType->getAs<AtomicType>())
-      FromType = Atomic->getValueType();
-
-    // If T is a non-class type, the type of the rvalue is the
-    // cv-unqualified version of T. Otherwise, the type of the rvalue
-    // is T (C++ 4.1p1). C++ can't get here with class types; in C, we
-    // just strip the qualifiers because they don't matter.
-    FromType = FromType.getUnqualifiedType();
-  } else if (FromType->isArrayType()) {
-    // Array-to-pointer conversion (C++ 4.2)
-    SCS.First = ICK_Array_To_Pointer;
-
-    // An lvalue or rvalue of type "array of N T" or "array of unknown
-    // bound of T" can be converted to an rvalue of type "pointer to
-    // T" (C++ 4.2p1).
-    FromType = S.Context.getArrayDecayedType(FromType);
-
-    if (S.IsStringLiteralToNonConstPointerConversion(From, ToType)) {
-      // This conversion is deprecated in C++03 (D.4)
-      SCS.DeprecatedStringLiteralToCharPtr = true;
-
-      // For the purpose of ranking in overload resolution
-      // (13.3.3.1.1), this conversion is considered an
-      // array-to-pointer conversion followed by a qualification
-      // conversion (4.4). (C++ 4.2p2)
-      SCS.Second = ICK_Identity;
-      SCS.Third = ICK_Qualification;
-      SCS.QualificationIncludesObjCLifetime = false;
-      SCS.setAllToTypes(FromType);
-      return true;
-    }
-  } else if (FromType->isFunctionType() && argIsLValue) {
-    // Function-to-pointer conversion (C++ 4.3).
-    SCS.First = ICK_Function_To_Pointer;
-
-    if (auto *DRE = dyn_cast<DeclRefExpr>(From->IgnoreParenCasts()))
-      if (auto *FD = dyn_cast<FunctionDecl>(DRE->getDecl()))
-        if (!S.checkAddressOfFunctionIsAvailable(FD))
-          return false;
-
-    // An lvalue of function type T can be converted to an rvalue of
-    // type "pointer to T." The result is a pointer to the
-    // function. (C++ 4.3p1).
-    FromType = S.Context.getPointerType(FromType);
-  } else {
-    // We don't require any conversions for the first step.
-    SCS.First = ICK_Identity;
-  }
-  SCS.setToType(0, FromType);
-
-  // The second conversion can be an integral promotion, floating
-  // point promotion, integral conversion, floating point conversion,
-  // floating-integral conversion, pointer conversion,
-  // pointer-to-member conversion, or boolean conversion (C++ 4p1).
-  // For overloading in C, this can also be a "compatible-type"
-  // conversion.
-  bool IncompatibleObjC = false;
-  ImplicitConversionKind SecondICK = ICK_Identity;
-  if (S.Context.hasSameUnqualifiedType(FromType, ToType)) {
-    // The unqualified versions of the types are the same: there's no
-    // conversion to do.
-    SCS.Second = ICK_Identity;
-  } else if (S.IsIntegralPromotion(From, FromType, ToType)) {
-    // Integral promotion (C++ 4.5).
-    SCS.Second = ICK_Integral_Promotion;
-    FromType = ToType.getUnqualifiedType();
-  } else if (S.IsFloatingPointPromotion(FromType, ToType)) {
-    // Floating point promotion (C++ 4.6).
-    SCS.Second = ICK_Floating_Promotion;
-    FromType = ToType.getUnqualifiedType();
-  } else if (S.IsComplexPromotion(FromType, ToType)) {
-    // Complex promotion (Clang extension)
-    SCS.Second = ICK_Complex_Promotion;
-    FromType = ToType.getUnqualifiedType();
-  } else if (ToType->isBooleanType() &&
-             (FromType->isArithmeticType() ||
-              FromType->isAnyPointerType() ||
-              FromType->isBlockPointerType() ||
-              FromType->isMemberPointerType() ||
-              FromType->isNullPtrType())) {
-    // Boolean conversions (C++ 4.12).
-    SCS.Second = ICK_Boolean_Conversion;
-    FromType = S.Context.BoolTy;
-  } else if (FromType->isIntegralOrUnscopedEnumerationType() &&
-             ToType->isIntegralType(S.Context)) {
-    // Integral conversions (C++ 4.7).
-    SCS.Second = ICK_Integral_Conversion;
-    FromType = ToType.getUnqualifiedType();
-  } else if (FromType->isAnyComplexType() && ToType->isAnyComplexType()) {
-    // Complex conversions (C99 6.3.1.6)
-    SCS.Second = ICK_Complex_Conversion;
-    FromType = ToType.getUnqualifiedType();
-  } else if ((FromType->isAnyComplexType() && ToType->isArithmeticType()) ||
-             (ToType->isAnyComplexType() && FromType->isArithmeticType())) {
-    // Complex-real conversions (C99 6.3.1.7)
-    SCS.Second = ICK_Complex_Real;
-    FromType = ToType.getUnqualifiedType();
-  } else if (FromType->isRealFloatingType() && ToType->isRealFloatingType()) {
-    // FIXME: disable conversions between long double and __float128 if
-    // their representation is different until there is back end support
-    // We of course allow this conversion if long double is really double.
-    if (&S.Context.getFloatTypeSemantics(FromType) !=
-        &S.Context.getFloatTypeSemantics(ToType)) {
-      bool Float128AndLongDouble = ((FromType == S.Context.Float128Ty &&
-                                    ToType == S.Context.LongDoubleTy) ||
-                                   (FromType == S.Context.LongDoubleTy &&
-                                    ToType == S.Context.Float128Ty));
-      if (Float128AndLongDouble &&
-          (&S.Context.getFloatTypeSemantics(S.Context.LongDoubleTy) ==
-           &llvm::APFloat::PPCDoubleDouble()))
-        return false;
-    }
-    // Floating point conversions (C++ 4.8).
-    SCS.Second = ICK_Floating_Conversion;
-    FromType = ToType.getUnqualifiedType();
-  } else if ((FromType->isRealFloatingType() &&
-              ToType->isIntegralType(S.Context)) ||
-             (FromType->isIntegralOrUnscopedEnumerationType() &&
-              ToType->isRealFloatingType())) {
-    // Floating-integral conversions (C++ 4.9).
-    SCS.Second = ICK_Floating_Integral;
-    FromType = ToType.getUnqualifiedType();
-  } else if (S.IsBlockPointerConversion(FromType, ToType, FromType)) {
-    SCS.Second = ICK_Block_Pointer_Conversion;
-  } else if (AllowObjCWritebackConversion &&
-             S.isObjCWritebackConversion(FromType, ToType, FromType)) {
-    SCS.Second = ICK_Writeback_Conversion;
-  } else if (S.IsPointerConversion(From, FromType, ToType, InOverloadResolution,
-                                   FromType, IncompatibleObjC)) {
-    // Pointer conversions (C++ 4.10).
-    SCS.Second = ICK_Pointer_Conversion;
-    SCS.IncompatibleObjC = IncompatibleObjC;
-    FromType = FromType.getUnqualifiedType();
-  } else if (S.IsMemberPointerConversion(From, FromType, ToType,
-                                         InOverloadResolution, FromType)) {
-    // Pointer to member conversions (4.11).
-    SCS.Second = ICK_Pointer_Member;
-  } else if (IsVectorConversion(S, FromType, ToType, SecondICK)) {
-    SCS.Second = SecondICK;
-    FromType = ToType.getUnqualifiedType();
-  } else if (!S.getLangOpts().CPlusPlus &&
-             S.Context.typesAreCompatible(ToType, FromType)) {
-    // Compatible conversions (Clang extension for C function overloading)
-    SCS.Second = ICK_Compatible_Conversion;
-    FromType = ToType.getUnqualifiedType();
-  } else if (IsTransparentUnionStandardConversion(S, From, ToType,
-                                             InOverloadResolution,
-                                             SCS, CStyle)) {
-    SCS.Second = ICK_TransparentUnionConversion;
-    FromType = ToType;
-  } else if (tryAtomicConversion(S, From, ToType, InOverloadResolution, SCS,
-                                 CStyle)) {
-    // tryAtomicConversion has updated the standard conversion sequence
-    // appropriately.
-    return true;
-  } else if (ToType->isEventT() &&
-             From->isIntegerConstantExpr(S.getASTContext()) &&
-             From->EvaluateKnownConstInt(S.getASTContext()) == 0) {
-    SCS.Second = ICK_Zero_Event_Conversion;
-    FromType = ToType;
-  } else if (ToType->isQueueT() &&
-             From->isIntegerConstantExpr(S.getASTContext()) &&
-             (From->EvaluateKnownConstInt(S.getASTContext()) == 0)) {
-    SCS.Second = ICK_Zero_Queue_Conversion;
-    FromType = ToType;
-  } else {
-    // No second conversion required.
-    SCS.Second = ICK_Identity;
-  }
-  SCS.setToType(1, FromType);
-
-  // The third conversion can be a function pointer conversion or a
-  // qualification conversion (C++ [conv.fctptr], [conv.qual]).
-  bool ObjCLifetimeConversion;
-  if (S.IsFunctionConversion(FromType, ToType, FromType)) {
-    // Function pointer conversions (removing 'noexcept') including removal of
-    // 'noreturn' (Clang extension).
-    SCS.Third = ICK_Function_Conversion;
-  } else if (S.IsQualificationConversion(FromType, ToType, CStyle,
-                                         ObjCLifetimeConversion)) {
-    SCS.Third = ICK_Qualification;
-    SCS.QualificationIncludesObjCLifetime = ObjCLifetimeConversion;
-    FromType = ToType;
-  } else {
-    // No conversion required
-    SCS.Third = ICK_Identity;
-  }
-
-  // C++ [over.best.ics]p6:
-  //   [...] Any difference in top-level cv-qualification is
-  //   subsumed by the initialization itself and does not constitute
-  //   a conversion. [...]
-  QualType CanonFrom = S.Context.getCanonicalType(FromType);
-  QualType CanonTo = S.Context.getCanonicalType(ToType);
-  if (CanonFrom.getLocalUnqualifiedType()
-                                     == CanonTo.getLocalUnqualifiedType() &&
-      CanonFrom.getLocalQualifiers() != CanonTo.getLocalQualifiers()) {
-    FromType = ToType;
-    CanonFrom = CanonTo;
-  }
-
-  SCS.setToType(2, FromType);
-
-  if (CanonFrom == CanonTo)
-    return true;
-
-  // If we have not converted the argument type to the parameter type,
-  // this is a bad conversion sequence, unless we're resolving an overload in C.
-  if (S.getLangOpts().CPlusPlus || !InOverloadResolution)
-    return false;
-
-  ExprResult ER = ExprResult{From};
-  Sema::AssignConvertType Conv =
-      S.CheckSingleAssignmentConstraints(ToType, ER,
-                                         /*Diagnose=*/false,
-                                         /*DiagnoseCFAudited=*/false,
-                                         /*ConvertRHS=*/false);
-  ImplicitConversionKind SecondConv;
-  switch (Conv) {
-  case Sema::Compatible:
-    SecondConv = ICK_C_Only_Conversion;
-    break;
-  // For our purposes, discarding qualifiers is just as bad as using an
-  // incompatible pointer. Note that an IncompatiblePointer conversion can drop
-  // qualifiers, as well.
-  case Sema::CompatiblePointerDiscardsQualifiers:
-  case Sema::IncompatiblePointer:
-  case Sema::IncompatiblePointerSign:
-    SecondConv = ICK_Incompatible_Pointer_Conversion;
-    break;
-  default:
-    return false;
-  }
-
-  // First can only be an lvalue conversion, so we pretend that this was the
-  // second conversion. First should already be valid from earlier in the
-  // function.
-  SCS.Second = SecondConv;
-  SCS.setToType(1, ToType);
-
-  // Third is Identity, because Second should rank us worse than any other
-  // conversion. This could also be ICK_Qualification, but it's simpler to just
-  // lump everything in with the second conversion, and we don't gain anything
-  // from making this ICK_Qualification.
-  SCS.Third = ICK_Identity;
-  SCS.setToType(2, ToType);
-  return true;
-}
-
-static bool
-IsTransparentUnionStandardConversion(Sema &S, Expr* From,
-                                     QualType &ToType,
-                                     bool InOverloadResolution,
-                                     StandardConversionSequence &SCS,
-                                     bool CStyle) {
-
-  const RecordType *UT = ToType->getAsUnionType();
-  if (!UT || !UT->getDecl()->hasAttr<TransparentUnionAttr>())
-    return false;
-  // The field to initialize within the transparent union.
-  RecordDecl *UD = UT->getDecl();
-  // It's compatible if the expression matches any of the fields.
-  for (const auto *it : UD->fields()) {
-    if (IsStandardConversion(S, From, it->getType(), InOverloadResolution, SCS,
-                             CStyle, /*ObjCWritebackConversion=*/false)) {
-      ToType = it->getType();
-      return true;
-    }
-  }
-  return false;
-}
-
-/// IsIntegralPromotion - Determines whether the conversion from the
-/// expression From (whose potentially-adjusted type is FromType) to
-/// ToType is an integral promotion (C++ 4.5). If so, returns true and
-/// sets PromotedType to the promoted type.
-bool Sema::IsIntegralPromotion(Expr *From, QualType FromType, QualType ToType) {
-  const BuiltinType *To = ToType->getAs<BuiltinType>();
-  // All integers are built-in.
-  if (!To) {
-    return false;
-  }
-
-  // An rvalue of type char, signed char, unsigned char, short int, or
-  // unsigned short int can be converted to an rvalue of type int if
-  // int can represent all the values of the source type; otherwise,
-  // the source rvalue can be converted to an rvalue of type unsigned
-  // int (C++ 4.5p1).
-  if (FromType->isPromotableIntegerType() && !FromType->isBooleanType() &&
-      !FromType->isEnumeralType()) {
-    if (// We can promote any signed, promotable integer type to an int
-        (FromType->isSignedIntegerType() ||
-         // We can promote any unsigned integer type whose size is
-         // less than int to an int.
-         Context.getTypeSize(FromType) < Context.getTypeSize(ToType))) {
-      return To->getKind() == BuiltinType::Int;
-    }
-
-    return To->getKind() == BuiltinType::UInt;
-  }
-
-  // C++11 [conv.prom]p3:
-  //   A prvalue of an unscoped enumeration type whose underlying type is not
-  //   fixed (7.2) can be converted to an rvalue a prvalue of the first of the
-  //   following types that can represent all the values of the enumeration
-  //   (i.e., the values in the range bmin to bmax as described in 7.2): int,
-  //   unsigned int, long int, unsigned long int, long long int, or unsigned
-  //   long long int. If none of the types in that list can represent all the
-  //   values of the enumeration, an rvalue a prvalue of an unscoped enumeration
-  //   type can be converted to an rvalue a prvalue of the extended integer type
-  //   with lowest integer conversion rank (4.13) greater than the rank of long
-  //   long in which all the values of the enumeration can be represented. If
-  //   there are two such extended types, the signed one is chosen.
-  // C++11 [conv.prom]p4:
-  //   A prvalue of an unscoped enumeration type whose underlying type is fixed
-  //   can be converted to a prvalue of its underlying type. Moreover, if
-  //   integral promotion can be applied to its underlying type, a prvalue of an
-  //   unscoped enumeration type whose underlying type is fixed can also be
-  //   converted to a prvalue of the promoted underlying type.
-  if (const EnumType *FromEnumType = FromType->getAs<EnumType>()) {
-    // C++0x 7.2p9: Note that this implicit enum to int conversion is not
-    // provided for a scoped enumeration.
-    if (FromEnumType->getDecl()->isScoped())
-      return false;
-
-    // We can perform an integral promotion to the underlying type of the enum,
-    // even if that's not the promoted type. Note that the check for promoting
-    // the underlying type is based on the type alone, and does not consider
-    // the bitfield-ness of the actual source expression.
-    if (FromEnumType->getDecl()->isFixed()) {
-      QualType Underlying = FromEnumType->getDecl()->getIntegerType();
-      return Context.hasSameUnqualifiedType(Underlying, ToType) ||
-             IsIntegralPromotion(nullptr, Underlying, ToType);
-    }
-
-    // We have already pre-calculated the promotion type, so this is trivial.
-    if (ToType->isIntegerType() &&
-        isCompleteType(From->getBeginLoc(), FromType))
-      return Context.hasSameUnqualifiedType(
-          ToType, FromEnumType->getDecl()->getPromotionType());
-
-    // C++ [conv.prom]p5:
-    //   If the bit-field has an enumerated type, it is treated as any other
-    //   value of that type for promotion purposes.
-    //
-    // ... so do not fall through into the bit-field checks below in C++.
-    if (getLangOpts().CPlusPlus)
-      return false;
-  }
-
-  // C++0x [conv.prom]p2:
-  //   A prvalue of type char16_t, char32_t, or wchar_t (3.9.1) can be converted
-  //   to an rvalue a prvalue of the first of the following types that can
-  //   represent all the values of its underlying type: int, unsigned int,
-  //   long int, unsigned long int, long long int, or unsigned long long int.
-  //   If none of the types in that list can represent all the values of its
-  //   underlying type, an rvalue a prvalue of type char16_t, char32_t,
-  //   or wchar_t can be converted to an rvalue a prvalue of its underlying
-  //   type.
-  if (FromType->isAnyCharacterType() && !FromType->isCharType() &&
-      ToType->isIntegerType()) {
-    // Determine whether the type we're converting from is signed or
-    // unsigned.
-    bool FromIsSigned = FromType->isSignedIntegerType();
-    uint64_t FromSize = Context.getTypeSize(FromType);
-
-    // The types we'll try to promote to, in the appropriate
-    // order. Try each of these types.
-    QualType PromoteTypes[6] = {
-      Context.IntTy, Context.UnsignedIntTy,
-      Context.LongTy, Context.UnsignedLongTy ,
-      Context.LongLongTy, Context.UnsignedLongLongTy
-    };
-    for (int Idx = 0; Idx < 6; ++Idx) {
-      uint64_t ToSize = Context.getTypeSize(PromoteTypes[Idx]);
-      if (FromSize < ToSize ||
-          (FromSize == ToSize &&
-           FromIsSigned == PromoteTypes[Idx]->isSignedIntegerType())) {
-        // We found the type that we can promote to. If this is the
-        // type we wanted, we have a promotion. Otherwise, no
-        // promotion.
-        return Context.hasSameUnqualifiedType(ToType, PromoteTypes[Idx]);
-      }
-    }
-  }
-
-  // An rvalue for an integral bit-field (9.6) can be converted to an
-  // rvalue of type int if int can represent all the values of the
-  // bit-field; otherwise, it can be converted to unsigned int if
-  // unsigned int can represent all the values of the bit-field. If
-  // the bit-field is larger yet, no integral promotion applies to
-  // it. If the bit-field has an enumerated type, it is treated as any
-  // other value of that type for promotion purposes (C++ 4.5p3).
-  // FIXME: We should delay checking of bit-fields until we actually perform the
-  // conversion.
-  //
-  // FIXME: In C, only bit-fields of types _Bool, int, or unsigned int may be
-  // promoted, per C11 6.3.1.1/2. We promote all bit-fields (including enum
-  // bit-fields and those whose underlying type is larger than int) for GCC
-  // compatibility.
-  if (From) {
-    if (FieldDecl *MemberDecl = From->getSourceBitField()) {
-      llvm::APSInt BitWidth;
-      if (FromType->isIntegralType(Context) &&
-          MemberDecl->getBitWidth()->isIntegerConstantExpr(BitWidth, Context)) {
-        llvm::APSInt ToSize(BitWidth.getBitWidth(), BitWidth.isUnsigned());
-        ToSize = Context.getTypeSize(ToType);
-
-        // Are we promoting to an int from a bitfield that fits in an int?
-        if (BitWidth < ToSize ||
-            (FromType->isSignedIntegerType() && BitWidth <= ToSize)) {
-          return To->getKind() == BuiltinType::Int;
-        }
-
-        // Are we promoting to an unsigned int from an unsigned bitfield
-        // that fits into an unsigned int?
-        if (FromType->isUnsignedIntegerType() && BitWidth <= ToSize) {
-          return To->getKind() == BuiltinType::UInt;
-        }
-
-        return false;
-      }
-    }
-  }
-
-  // An rvalue of type bool can be converted to an rvalue of type int,
-  // with false becoming zero and true becoming one (C++ 4.5p4).
-  if (FromType->isBooleanType() && To->getKind() == BuiltinType::Int) {
-    return true;
-  }
-
-  return false;
-}
-
-/// IsFloatingPointPromotion - Determines whether the conversion from
-/// FromType to ToType is a floating point promotion (C++ 4.6). If so,
-/// returns true and sets PromotedType to the promoted type.
-bool Sema::IsFloatingPointPromotion(QualType FromType, QualType ToType) {
-  if (const BuiltinType *FromBuiltin = FromType->getAs<BuiltinType>())
-    if (const BuiltinType *ToBuiltin = ToType->getAs<BuiltinType>()) {
-      /// An rvalue of type float can be converted to an rvalue of type
-      /// double. (C++ 4.6p1).
-      if (FromBuiltin->getKind() == BuiltinType::Float &&
-          ToBuiltin->getKind() == BuiltinType::Double)
-        return true;
-
-      // C99 6.3.1.5p1:
-      //   When a float is promoted to double or long double, or a
-      //   double is promoted to long double [...].
-      if (!getLangOpts().CPlusPlus &&
-          (FromBuiltin->getKind() == BuiltinType::Float ||
-           FromBuiltin->getKind() == BuiltinType::Double) &&
-          (ToBuiltin->getKind() == BuiltinType::LongDouble ||
-           ToBuiltin->getKind() == BuiltinType::Float128))
-        return true;
-
-      // Half can be promoted to float.
-      if (!getLangOpts().NativeHalfType &&
-           FromBuiltin->getKind() == BuiltinType::Half &&
-          ToBuiltin->getKind() == BuiltinType::Float)
-        return true;
-    }
-
-  return false;
-}
-
-/// Determine if a conversion is a complex promotion.
-///
-/// A complex promotion is defined as a complex -> complex conversion
-/// where the conversion between the underlying real types is a
-/// floating-point or integral promotion.
-bool Sema::IsComplexPromotion(QualType FromType, QualType ToType) {
-  const ComplexType *FromComplex = FromType->getAs<ComplexType>();
-  if (!FromComplex)
-    return false;
-
-  const ComplexType *ToComplex = ToType->getAs<ComplexType>();
-  if (!ToComplex)
-    return false;
-
-  return IsFloatingPointPromotion(FromComplex->getElementType(),
-                                  ToComplex->getElementType()) ||
-    IsIntegralPromotion(nullptr, FromComplex->getElementType(),
-                        ToComplex->getElementType());
-}
-
-/// BuildSimilarlyQualifiedPointerType - In a pointer conversion from
-/// the pointer type FromPtr to a pointer to type ToPointee, with the
-/// same type qualifiers as FromPtr has on its pointee type. ToType,
-/// if non-empty, will be a pointer to ToType that may or may not have
-/// the right set of qualifiers on its pointee.
-///
-static QualType
-BuildSimilarlyQualifiedPointerType(const Type *FromPtr,
-                                   QualType ToPointee, QualType ToType,
-                                   ASTContext &Context,
-                                   bool StripObjCLifetime = false) {
-  assert((FromPtr->getTypeClass() == Type::Pointer ||
-          FromPtr->getTypeClass() == Type::ObjCObjectPointer) &&
-         "Invalid similarly-qualified pointer type");
-
-  /// Conversions to 'id' subsume cv-qualifier conversions.
-  if (ToType->isObjCIdType() || ToType->isObjCQualifiedIdType())
-    return ToType.getUnqualifiedType();
-
-  QualType CanonFromPointee
-    = Context.getCanonicalType(FromPtr->getPointeeType());
-  QualType CanonToPointee = Context.getCanonicalType(ToPointee);
-  Qualifiers Quals = CanonFromPointee.getQualifiers();
-
-  if (StripObjCLifetime)
-    Quals.removeObjCLifetime();
-
-  // Exact qualifier match -> return the pointer type we're converting to.
-  if (CanonToPointee.getLocalQualifiers() == Quals) {
-    // ToType is exactly what we need. Return it.
-    if (!ToType.isNull())
-      return ToType.getUnqualifiedType();
-
-    // Build a pointer to ToPointee. It has the right qualifiers
-    // already.
-    if (isa<ObjCObjectPointerType>(ToType))
-      return Context.getObjCObjectPointerType(ToPointee);
-    return Context.getPointerType(ToPointee);
-  }
-
-  // Just build a canonical type that has the right qualifiers.
-  QualType QualifiedCanonToPointee
-    = Context.getQualifiedType(CanonToPointee.getLocalUnqualifiedType(), Quals);
-
-  if (isa<ObjCObjectPointerType>(ToType))
-    return Context.getObjCObjectPointerType(QualifiedCanonToPointee);
-  return Context.getPointerType(QualifiedCanonToPointee);
-}
-
-static bool isNullPointerConstantForConversion(Expr *Expr,
-                                               bool InOverloadResolution,
-                                               ASTContext &Context) {
-  // Handle value-dependent integral null pointer constants correctly.
-  // http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_active.html#903
-  if (Expr->isValueDependent() && !Expr->isTypeDependent() &&
-      Expr->getType()->isIntegerType() && !Expr->getType()->isEnumeralType())
-    return !InOverloadResolution;
-
-  return Expr->isNullPointerConstant(Context,
-                    InOverloadResolution? Expr::NPC_ValueDependentIsNotNull
-                                        : Expr::NPC_ValueDependentIsNull);
-}
-
-/// IsPointerConversion - Determines whether the conversion of the
-/// expression From, which has the (possibly adjusted) type FromType,
-/// can be converted to the type ToType via a pointer conversion (C++
-/// 4.10). If so, returns true and places the converted type (that
-/// might differ from ToType in its cv-qualifiers at some level) into
-/// ConvertedType.
-///
-/// This routine also supports conversions to and from block pointers
-/// and conversions with Objective-C's 'id', 'id<protocols...>', and
-/// pointers to interfaces. FIXME: Once we've determined the
-/// appropriate overloading rules for Objective-C, we may want to
-/// split the Objective-C checks into a different routine; however,
-/// GCC seems to consider all of these conversions to be pointer
-/// conversions, so for now they live here. IncompatibleObjC will be
-/// set if the conversion is an allowed Objective-C conversion that
-/// should result in a warning.
-bool Sema::IsPointerConversion(Expr *From, QualType FromType, QualType ToType,
-                               bool InOverloadResolution,
-                               QualType& ConvertedType,
-                               bool &IncompatibleObjC) {
-  IncompatibleObjC = false;
-  if (isObjCPointerConversion(FromType, ToType, ConvertedType,
-                              IncompatibleObjC))
-    return true;
-
-  // Conversion from a null pointer constant to any Objective-C pointer type.
-  if (ToType->isObjCObjectPointerType() &&
-      isNullPointerConstantForConversion(From, InOverloadResolution, Context)) {
-    ConvertedType = ToType;
-    return true;
-  }
-
-  // Blocks: Block pointers can be converted to void*.
-  if (FromType->isBlockPointerType() && ToType->isPointerType() &&
-      ToType->getAs<PointerType>()->getPointeeType()->isVoidType()) {
-    ConvertedType = ToType;
-    return true;
-  }
-  // Blocks: A null pointer constant can be converted to a block
-  // pointer type.
-  if (ToType->isBlockPointerType() &&
-      isNullPointerConstantForConversion(From, InOverloadResolution, Context)) {
-    ConvertedType = ToType;
-    return true;
-  }
-
-  // If the left-hand-side is nullptr_t, the right side can be a null
-  // pointer constant.
-  if (ToType->isNullPtrType() &&
-      isNullPointerConstantForConversion(From, InOverloadResolution, Context)) {
-    ConvertedType = ToType;
-    return true;
-  }
-
-  const PointerType* ToTypePtr = ToType->getAs<PointerType>();
-  if (!ToTypePtr)
-    return false;
-
-  // A null pointer constant can be converted to a pointer type (C++ 4.10p1).
-  if (isNullPointerConstantForConversion(From, InOverloadResolution, Context)) {
-    ConvertedType = ToType;
-    return true;
-  }
-
-  // Beyond this point, both types need to be pointers
-  // , including objective-c pointers.
-  QualType ToPointeeType = ToTypePtr->getPointeeType();
-  if (FromType->isObjCObjectPointerType() && ToPointeeType->isVoidType() &&
-      !getLangOpts().ObjCAutoRefCount) {
-    ConvertedType = BuildSimilarlyQualifiedPointerType(
-                                      FromType->getAs<ObjCObjectPointerType>(),
-                                                       ToPointeeType,
-                                                       ToType, Context);
-    return true;
-  }
-  const PointerType *FromTypePtr = FromType->getAs<PointerType>();
-  if (!FromTypePtr)
-    return false;
-
-  QualType FromPointeeType = FromTypePtr->getPointeeType();
-
-  // If the unqualified pointee types are the same, this can't be a
-  // pointer conversion, so don't do all of the work below.
-  if (Context.hasSameUnqualifiedType(FromPointeeType, ToPointeeType))
-    return false;
-
-  // An rvalue of type "pointer to cv T," where T is an object type,
-  // can be converted to an rvalue of type "pointer to cv void" (C++
-  // 4.10p2).
-  if (FromPointeeType->isIncompleteOrObjectType() &&
-      ToPointeeType->isVoidType()) {
-    ConvertedType = BuildSimilarlyQualifiedPointerType(FromTypePtr,
-                                                       ToPointeeType,
-                                                       ToType, Context,
-                                                   /*StripObjCLifetime=*/true);
-    return true;
-  }
-
-  // MSVC allows implicit function to void* type conversion.
-  if (getLangOpts().MSVCCompat && FromPointeeType->isFunctionType() &&
-      ToPointeeType->isVoidType()) {
-    ConvertedType = BuildSimilarlyQualifiedPointerType(FromTypePtr,
-                                                       ToPointeeType,
-                                                       ToType, Context);
-    return true;
-  }
-
-  // When we're overloading in C, we allow a special kind of pointer
-  // conversion for compatible-but-not-identical pointee types.
-  if (!getLangOpts().CPlusPlus &&
-      Context.typesAreCompatible(FromPointeeType, ToPointeeType)) {
-    ConvertedType = BuildSimilarlyQualifiedPointerType(FromTypePtr,
-                                                       ToPointeeType,
-                                                       ToType, Context);
-    return true;
-  }
-
-  // C++ [conv.ptr]p3:
-  //
-  //   An rvalue of type "pointer to cv D," where D is a class type,
-  //   can be converted to an rvalue of type "pointer to cv B," where
-  //   B is a base class (clause 10) of D. If B is an inaccessible
-  //   (clause 11) or ambiguous (10.2) base class of D, a program that
-  //   necessitates this conversion is ill-formed. The result of the
-  //   conversion is a pointer to the base class sub-object of the
-  //   derived class object. The null pointer value is converted to
-  //   the null pointer value of the destination type.
-  //
-  // Note that we do not check for ambiguity or inaccessibility
-  // here. That is handled by CheckPointerConversion.
-  if (getLangOpts().CPlusPlus && FromPointeeType->isRecordType() &&
-      ToPointeeType->isRecordType() &&
-      !Context.hasSameUnqualifiedType(FromPointeeType, ToPointeeType) &&
-      IsDerivedFrom(From->getBeginLoc(), FromPointeeType, ToPointeeType)) {
-    ConvertedType = BuildSimilarlyQualifiedPointerType(FromTypePtr,
-                                                       ToPointeeType,
-                                                       ToType, Context);
-    return true;
-  }
-
-  if (FromPointeeType->isVectorType() && ToPointeeType->isVectorType() &&
-      Context.areCompatibleVectorTypes(FromPointeeType, ToPointeeType)) {
-    ConvertedType = BuildSimilarlyQualifiedPointerType(FromTypePtr,
-                                                       ToPointeeType,
-                                                       ToType, Context);
-    return true;
-  }
-
-  return false;
-}
-
-/// Adopt the given qualifiers for the given type.
-static QualType AdoptQualifiers(ASTContext &Context, QualType T, Qualifiers Qs){
-  Qualifiers TQs = T.getQualifiers();
-
-  // Check whether qualifiers already match.
-  if (TQs == Qs)
-    return T;
-
-  if (Qs.compatiblyIncludes(TQs))
-    return Context.getQualifiedType(T, Qs);
-
-  return Context.getQualifiedType(T.getUnqualifiedType(), Qs);
-}
-
-/// isObjCPointerConversion - Determines whether this is an
-/// Objective-C pointer conversion. Subroutine of IsPointerConversion,
-/// with the same arguments and return values.
-bool Sema::isObjCPointerConversion(QualType FromType, QualType ToType,
-                                   QualType& ConvertedType,
-                                   bool &IncompatibleObjC) {
-  if (!getLangOpts().ObjC)
-    return false;
-
-  // The set of qualifiers on the type we're converting from.
-  Qualifiers FromQualifiers = FromType.getQualifiers();
-
-  // First, we handle all conversions on ObjC object pointer types.
-  const ObjCObjectPointerType* ToObjCPtr =
-    ToType->getAs<ObjCObjectPointerType>();
-  const ObjCObjectPointerType *FromObjCPtr =
-    FromType->getAs<ObjCObjectPointerType>();
-
-  if (ToObjCPtr && FromObjCPtr) {
-    // If the pointee types are the same (ignoring qualifications),
-    // then this is not a pointer conversion.
-    if (Context.hasSameUnqualifiedType(ToObjCPtr->getPointeeType(),
-                                       FromObjCPtr->getPointeeType()))
-      return false;
-
-    // Conversion between Objective-C pointers.
-    if (Context.canAssignObjCInterfaces(ToObjCPtr, FromObjCPtr)) {
-      const ObjCInterfaceType* LHS = ToObjCPtr->getInterfaceType();
-      const ObjCInterfaceType* RHS = FromObjCPtr->getInterfaceType();
-      if (getLangOpts().CPlusPlus && LHS && RHS &&
-          !ToObjCPtr->getPointeeType().isAtLeastAsQualifiedAs(
-                                                FromObjCPtr->getPointeeType()))
-        return false;
-      ConvertedType = BuildSimilarlyQualifiedPointerType(FromObjCPtr,
-                                                   ToObjCPtr->getPointeeType(),
-                                                         ToType, Context);
-      ConvertedType = AdoptQualifiers(Context, ConvertedType, FromQualifiers);
-      return true;
-    }
-
-    if (Context.canAssignObjCInterfaces(FromObjCPtr, ToObjCPtr)) {
-      // Okay: this is some kind of implicit downcast of Objective-C
-      // interfaces, which is permitted. However, we're going to
-      // complain about it.
-      IncompatibleObjC = true;
-      ConvertedType = BuildSimilarlyQualifiedPointerType(FromObjCPtr,
-                                                   ToObjCPtr->getPointeeType(),
-                                                         ToType, Context);
-      ConvertedType = AdoptQualifiers(Context, ConvertedType, FromQualifiers);
-      return true;
-    }
-  }
-  // Beyond this point, both types need to be C pointers or block pointers.
-  QualType ToPointeeType;
-  if (const PointerType *ToCPtr = ToType->getAs<PointerType>())
-    ToPointeeType = ToCPtr->getPointeeType();
-  else if (const BlockPointerType *ToBlockPtr =
-            ToType->getAs<BlockPointerType>()) {
-    // Objective C++: We're able to convert from a pointer to any object
-    // to a block pointer type.
-    if (FromObjCPtr && FromObjCPtr->isObjCBuiltinType()) {
-      ConvertedType = AdoptQualifiers(Context, ToType, FromQualifiers);
-      return true;
-    }
-    ToPointeeType = ToBlockPtr->getPointeeType();
-  }
-  else if (FromType->getAs<BlockPointerType>() &&
-           ToObjCPtr && ToObjCPtr->isObjCBuiltinType()) {
-    // Objective C++: We're able to convert from a block pointer type to a
-    // pointer to any object.
-    ConvertedType = AdoptQualifiers(Context, ToType, FromQualifiers);
-    return true;
-  }
-  else
-    return false;
-
-  QualType FromPointeeType;
-  if (const PointerType *FromCPtr = FromType->getAs<PointerType>())
-    FromPointeeType = FromCPtr->getPointeeType();
-  else if (const BlockPointerType *FromBlockPtr =
-           FromType->getAs<BlockPointerType>())
-    FromPointeeType = FromBlockPtr->getPointeeType();
-  else
-    return false;
-
-  // If we have pointers to pointers, recursively check whether this
-  // is an Objective-C conversion.
-  if (FromPointeeType->isPointerType() && ToPointeeType->isPointerType() &&
-      isObjCPointerConversion(FromPointeeType, ToPointeeType, ConvertedType,
-                              IncompatibleObjC)) {
-    // We always complain about this conversion.
-    IncompatibleObjC = true;
-    ConvertedType = Context.getPointerType(ConvertedType);
-    ConvertedType = AdoptQualifiers(Context, ConvertedType, FromQualifiers);
-    return true;
-  }
-  // Allow conversion of pointee being objective-c pointer to another one;
-  // as in I* to id.
-  if (FromPointeeType->getAs<ObjCObjectPointerType>() &&
-      ToPointeeType->getAs<ObjCObjectPointerType>() &&
-      isObjCPointerConversion(FromPointeeType, ToPointeeType, ConvertedType,
-                              IncompatibleObjC)) {
-
-    ConvertedType = Context.getPointerType(ConvertedType);
-    ConvertedType = AdoptQualifiers(Context, ConvertedType, FromQualifiers);
-    return true;
-  }
-
-  // If we have pointers to functions or blocks, check whether the only
-  // differences in the argument and result types are in Objective-C
-  // pointer conversions. If so, we permit the conversion (but
-  // complain about it).
-  const FunctionProtoType *FromFunctionType
-    = FromPointeeType->getAs<FunctionProtoType>();
-  const FunctionProtoType *ToFunctionType
-    = ToPointeeType->getAs<FunctionProtoType>();
-  if (FromFunctionType && ToFunctionType) {
-    // If the function types are exactly the same, this isn't an
-    // Objective-C pointer conversion.
-    if (Context.getCanonicalType(FromPointeeType)
-          == Context.getCanonicalType(ToPointeeType))
-      return false;
-
-    // Perform the quick checks that will tell us whether these
-    // function types are obviously different.
-    if (FromFunctionType->getNumParams() != ToFunctionType->getNumParams() ||
-        FromFunctionType->isVariadic() != ToFunctionType->isVariadic() ||
-        FromFunctionType->getTypeQuals() != ToFunctionType->getTypeQuals())
-      return false;
-
-    bool HasObjCConversion = false;
-    if (Context.getCanonicalType(FromFunctionType->getReturnType()) ==
-        Context.getCanonicalType(ToFunctionType->getReturnType())) {
-      // Okay, the types match exactly. Nothing to do.
-    } else if (isObjCPointerConversion(FromFunctionType->getReturnType(),
-                                       ToFunctionType->getReturnType(),
-                                       ConvertedType, IncompatibleObjC)) {
-      // Okay, we have an Objective-C pointer conversion.
-      HasObjCConversion = true;
-    } else {
-      // Function types are too different. Abort.
-      return false;
-    }
-
-    // Check argument types.
-    for (unsigned ArgIdx = 0, NumArgs = FromFunctionType->getNumParams();
-         ArgIdx != NumArgs; ++ArgIdx) {
-      QualType FromArgType = FromFunctionType->getParamType(ArgIdx);
-      QualType ToArgType = ToFunctionType->getParamType(ArgIdx);
-      if (Context.getCanonicalType(FromArgType)
-            == Context.getCanonicalType(ToArgType)) {
-        // Okay, the types match exactly. Nothing to do.
-      } else if (isObjCPointerConversion(FromArgType, ToArgType,
-                                         ConvertedType, IncompatibleObjC)) {
-        // Okay, we have an Objective-C pointer conversion.
-        HasObjCConversion = true;
-      } else {
-        // Argument types are too different. Abort.
-        return false;
-      }
-    }
-
-    if (HasObjCConversion) {
-      // We had an Objective-C conversion. Allow this pointer
-      // conversion, but complain about it.
-      ConvertedType = AdoptQualifiers(Context, ToType, FromQualifiers);
-      IncompatibleObjC = true;
-      return true;
-    }
-  }
-
-  return false;
-}
-
-/// Determine whether this is an Objective-C writeback conversion,
-/// used for parameter passing when performing automatic reference counting.
-///
-/// \param FromType The type we're converting form.
-///
-/// \param ToType The type we're converting to.
-///
-/// \param ConvertedType The type that will be produced after applying
-/// this conversion.
-bool Sema::isObjCWritebackConversion(QualType FromType, QualType ToType,
-                                     QualType &ConvertedType) {
-  if (!getLangOpts().ObjCAutoRefCount ||
-      Context.hasSameUnqualifiedType(FromType, ToType))
-    return false;
-
-  // Parameter must be a pointer to __autoreleasing (with no other qualifiers).
-  QualType ToPointee;
-  if (const PointerType *ToPointer = ToType->getAs<PointerType>())
-    ToPointee = ToPointer->getPointeeType();
-  else
-    return false;
-
-  Qualifiers ToQuals = ToPointee.getQualifiers();
-  if (!ToPointee->isObjCLifetimeType() ||
-      ToQuals.getObjCLifetime() != Qualifiers::OCL_Autoreleasing ||
-      !ToQuals.withoutObjCLifetime().empty())
-    return false;
-
-  // Argument must be a pointer to __strong to __weak.
-  QualType FromPointee;
-  if (const PointerType *FromPointer = FromType->getAs<PointerType>())
-    FromPointee = FromPointer->getPointeeType();
-  else
-    return false;
-
-  Qualifiers FromQuals = FromPointee.getQualifiers();
-  if (!FromPointee->isObjCLifetimeType() ||
-      (FromQuals.getObjCLifetime() != Qualifiers::OCL_Strong &&
-       FromQuals.getObjCLifetime() != Qualifiers::OCL_Weak))
-    return false;
-
-  // Make sure that we have compatible qualifiers.
-  FromQuals.setObjCLifetime(Qualifiers::OCL_Autoreleasing);
-  if (!ToQuals.compatiblyIncludes(FromQuals))
-    return false;
-
-  // Remove qualifiers from the pointee type we're converting from; they
-  // aren't used in the compatibility check belong, and we'll be adding back
-  // qualifiers (with __autoreleasing) if the compatibility check succeeds.
-  FromPointee = FromPointee.getUnqualifiedType();
-
-  // The unqualified form of the pointee types must be compatible.
-  ToPointee = ToPointee.getUnqualifiedType();
-  bool IncompatibleObjC;
-  if (Context.typesAreCompatible(FromPointee, ToPointee))
-    FromPointee = ToPointee;
-  else if (!isObjCPointerConversion(FromPointee, ToPointee, FromPointee,
-                                    IncompatibleObjC))
-    return false;
-
-  /// Construct the type we're converting to, which is a pointer to
-  /// __autoreleasing pointee.
-  FromPointee = Context.getQualifiedType(FromPointee, FromQuals);
-  ConvertedType = Context.getPointerType(FromPointee);
-  return true;
-}
-
-bool Sema::IsBlockPointerConversion(QualType FromType, QualType ToType,
-                                    QualType& ConvertedType) {
-  QualType ToPointeeType;
-  if (const BlockPointerType *ToBlockPtr =
-        ToType->getAs<BlockPointerType>())
-    ToPointeeType = ToBlockPtr->getPointeeType();
-  else
-    return false;
-
-  QualType FromPointeeType;
-  if (const BlockPointerType *FromBlockPtr =
-      FromType->getAs<BlockPointerType>())
-    FromPointeeType = FromBlockPtr->getPointeeType();
-  else
-    return false;
-  // We have pointer to blocks, check whether the only
-  // differences in the argument and result types are in Objective-C
-  // pointer conversions. If so, we permit the conversion.
-
-  const FunctionProtoType *FromFunctionType
-    = FromPointeeType->getAs<FunctionProtoType>();
-  const FunctionProtoType *ToFunctionType
-    = ToPointeeType->getAs<FunctionProtoType>();
-
-  if (!FromFunctionType || !ToFunctionType)
-    return false;
-
-  if (Context.hasSameType(FromPointeeType, ToPointeeType))
-    return true;
-
-  // Perform the quick checks that will tell us whether these
-  // function types are obviously different.
-  if (FromFunctionType->getNumParams() != ToFunctionType->getNumParams() ||
-      FromFunctionType->isVariadic() != ToFunctionType->isVariadic())
-    return false;
-
-  FunctionType::ExtInfo FromEInfo = FromFunctionType->getExtInfo();
-  FunctionType::ExtInfo ToEInfo = ToFunctionType->getExtInfo();
-  if (FromEInfo != ToEInfo)
-    return false;
-
-  bool IncompatibleObjC = false;
-  if (Context.hasSameType(FromFunctionType->getReturnType(),
-                          ToFunctionType->getReturnType())) {
-    // Okay, the types match exactly. Nothing to do.
-  } else {
-    QualType RHS = FromFunctionType->getReturnType();
-    QualType LHS = ToFunctionType->getReturnType();
-    if ((!getLangOpts().CPlusPlus || !RHS->isRecordType()) &&
-        !RHS.hasQualifiers() && LHS.hasQualifiers())
-       LHS = LHS.getUnqualifiedType();
-
-     if (Context.hasSameType(RHS,LHS)) {
-       // OK exact match.
-     } else if (isObjCPointerConversion(RHS, LHS,
-                                        ConvertedType, IncompatibleObjC)) {
-     if (IncompatibleObjC)
-       return false;
-     // Okay, we have an Objective-C pointer conversion.
-     }
-     else
-       return false;
-   }
-
-   // Check argument types.
-   for (unsigned ArgIdx = 0, NumArgs = FromFunctionType->getNumParams();
-        ArgIdx != NumArgs; ++ArgIdx) {
-     IncompatibleObjC = false;
-     QualType FromArgType = FromFunctionType->getParamType(ArgIdx);
-     QualType ToArgType = ToFunctionType->getParamType(ArgIdx);
-     if (Context.hasSameType(FromArgType, ToArgType)) {
-       // Okay, the types match exactly. Nothing to do.
-     } else if (isObjCPointerConversion(ToArgType, FromArgType,
-                                        ConvertedType, IncompatibleObjC)) {
-       if (IncompatibleObjC)
-         return false;
-       // Okay, we have an Objective-C pointer conversion.
-     } else
-       // Argument types are too different. Abort.
-       return false;
-   }
-
-   SmallVector<FunctionProtoType::ExtParameterInfo, 4> NewParamInfos;
-   bool CanUseToFPT, CanUseFromFPT;
-   if (!Context.mergeExtParameterInfo(ToFunctionType, FromFunctionType,
-                                      CanUseToFPT, CanUseFromFPT,
-                                      NewParamInfos))
-     return false;
-
-   ConvertedType = ToType;
-   return true;
-}
-
-enum {
-  ft_default,
-  ft_different_class,
-  ft_parameter_arity,
-  ft_parameter_mismatch,
-  ft_return_type,
-  ft_qualifer_mismatch,
-  ft_noexcept
-};
-
-/// Attempts to get the FunctionProtoType from a Type. Handles
-/// MemberFunctionPointers properly.
-static const FunctionProtoType *tryGetFunctionProtoType(QualType FromType) {
-  if (auto *FPT = FromType->getAs<FunctionProtoType>())
-    return FPT;
-
-  if (auto *MPT = FromType->getAs<MemberPointerType>())
-    return MPT->getPointeeType()->getAs<FunctionProtoType>();
-
-  return nullptr;
-}
-
-/// HandleFunctionTypeMismatch - Gives diagnostic information for differeing
-/// function types.  Catches different number of parameter, mismatch in
-/// parameter types, and different return types.
-void Sema::HandleFunctionTypeMismatch(PartialDiagnostic &PDiag,
-                                      QualType FromType, QualType ToType) {
-  // If either type is not valid, include no extra info.
-  if (FromType.isNull() || ToType.isNull()) {
-    PDiag << ft_default;
-    return;
-  }
-
-  // Get the function type from the pointers.
-  if (FromType->isMemberPointerType() && ToType->isMemberPointerType()) {
-    const MemberPointerType *FromMember = FromType->getAs<MemberPointerType>(),
-                            *ToMember = ToType->getAs<MemberPointerType>();
-    if (!Context.hasSameType(FromMember->getClass(), ToMember->getClass())) {
-      PDiag << ft_different_class << QualType(ToMember->getClass(), 0)
-            << QualType(FromMember->getClass(), 0);
-      return;
-    }
-    FromType = FromMember->getPointeeType();
-    ToType = ToMember->getPointeeType();
-  }
-
-  if (FromType->isPointerType())
-    FromType = FromType->getPointeeType();
-  if (ToType->isPointerType())
-    ToType = ToType->getPointeeType();
-
-  // Remove references.
-  FromType = FromType.getNonReferenceType();
-  ToType = ToType.getNonReferenceType();
-
-  // Don't print extra info for non-specialized template functions.
-  if (FromType->isInstantiationDependentType() &&
-      !FromType->getAs<TemplateSpecializationType>()) {
-    PDiag << ft_default;
-    return;
-  }
-
-  // No extra info for same types.
-  if (Context.hasSameType(FromType, ToType)) {
-    PDiag << ft_default;
-    return;
-  }
-
-  const FunctionProtoType *FromFunction = tryGetFunctionProtoType(FromType),
-                          *ToFunction = tryGetFunctionProtoType(ToType);
-
-  // Both types need to be function types.
-  if (!FromFunction || !ToFunction) {
-    PDiag << ft_default;
-    return;
-  }
-
-  if (FromFunction->getNumParams() != ToFunction->getNumParams()) {
-    PDiag << ft_parameter_arity << ToFunction->getNumParams()
-          << FromFunction->getNumParams();
-    return;
-  }
-
-  // Handle different parameter types.
-  unsigned ArgPos;
-  if (!FunctionParamTypesAreEqual(FromFunction, ToFunction, &ArgPos)) {
-    PDiag << ft_parameter_mismatch << ArgPos + 1
-          << ToFunction->getParamType(ArgPos)
-          << FromFunction->getParamType(ArgPos);
-    return;
-  }
-
-  // Handle different return type.
-  if (!Context.hasSameType(FromFunction->getReturnType(),
-                           ToFunction->getReturnType())) {
-    PDiag << ft_return_type << ToFunction->getReturnType()
-          << FromFunction->getReturnType();
-    return;
-  }
-
-  if (FromFunction->getTypeQuals() != ToFunction->getTypeQuals()) {
-    PDiag << ft_qualifer_mismatch << ToFunction->getTypeQuals()
-          << FromFunction->getTypeQuals();
-    return;
-  }
-
-  // Handle exception specification differences on canonical type (in C++17
-  // onwards).
-  if (cast<FunctionProtoType>(FromFunction->getCanonicalTypeUnqualified())
-          ->isNothrow() !=
-      cast<FunctionProtoType>(ToFunction->getCanonicalTypeUnqualified())
-          ->isNothrow()) {
-    PDiag << ft_noexcept;
-    return;
-  }
-
-  // Unable to find a difference, so add no extra info.
-  PDiag << ft_default;
-}
-
-/// FunctionParamTypesAreEqual - This routine checks two function proto types
-/// for equality of their argument types. Caller has already checked that
-/// they have same number of arguments.  If the parameters are different,
-/// ArgPos will have the parameter index of the first different parameter.
-bool Sema::FunctionParamTypesAreEqual(const FunctionProtoType *OldType,
-                                      const FunctionProtoType *NewType,
-                                      unsigned *ArgPos) {
-  for (FunctionProtoType::param_type_iterator O = OldType->param_type_begin(),
-                                              N = NewType->param_type_begin(),
-                                              E = OldType->param_type_end();
-       O && (O != E); ++O, ++N) {
-    if (!Context.hasSameType(O->getUnqualifiedType(),
-                             N->getUnqualifiedType())) {
-      if (ArgPos)
-        *ArgPos = O - OldType->param_type_begin();
-      return false;
-    }
-  }
-  return true;
-}
-
-/// CheckPointerConversion - Check the pointer conversion from the
-/// expression From to the type ToType. This routine checks for
-/// ambiguous or inaccessible derived-to-base pointer
-/// conversions for which IsPointerConversion has already returned
-/// true. It returns true and produces a diagnostic if there was an
-/// error, or returns false otherwise.
-bool Sema::CheckPointerConversion(Expr *From, QualType ToType,
-                                  CastKind &Kind,
-                                  CXXCastPath& BasePath,
-                                  bool IgnoreBaseAccess,
-                                  bool Diagnose) {
-  QualType FromType = From->getType();
-  bool IsCStyleOrFunctionalCast = IgnoreBaseAccess;
-
-  Kind = CK_BitCast;
-
-  if (Diagnose && !IsCStyleOrFunctionalCast && !FromType->isAnyPointerType() &&
-      From->isNullPointerConstant(Context, Expr::NPC_ValueDependentIsNotNull) ==
-          Expr::NPCK_ZeroExpression) {
-    if (Context.hasSameUnqualifiedType(From->getType(), Context.BoolTy))
-      DiagRuntimeBehavior(From->getExprLoc(), From,
-                          PDiag(diag::warn_impcast_bool_to_null_pointer)
-                            << ToType << From->getSourceRange());
-    else if (!isUnevaluatedContext())
-      Diag(From->getExprLoc(), diag::warn_non_literal_null_pointer)
-        << ToType << From->getSourceRange();
-  }
-  if (const PointerType *ToPtrType = ToType->getAs<PointerType>()) {
-    if (const PointerType *FromPtrType = FromType->getAs<PointerType>()) {
-      QualType FromPointeeType = FromPtrType->getPointeeType(),
-               ToPointeeType   = ToPtrType->getPointeeType();
-
-      if (FromPointeeType->isRecordType() && ToPointeeType->isRecordType() &&
-          !Context.hasSameUnqualifiedType(FromPointeeType, ToPointeeType)) {
-        // We must have a derived-to-base conversion. Check an
-        // ambiguous or inaccessible conversion.
-        unsigned InaccessibleID = 0;
-        unsigned AmbigiousID = 0;
-        if (Diagnose) {
-          InaccessibleID = diag::err_upcast_to_inaccessible_base;
-          AmbigiousID = diag::err_ambiguous_derived_to_base_conv;
-        }
-        if (CheckDerivedToBaseConversion(
-                FromPointeeType, ToPointeeType, InaccessibleID, AmbigiousID,
-                From->getExprLoc(), From->getSourceRange(), DeclarationName(),
-                &BasePath, IgnoreBaseAccess))
-          return true;
-
-        // The conversion was successful.
-        Kind = CK_DerivedToBase;
-      }
-
-      if (Diagnose && !IsCStyleOrFunctionalCast &&
-          FromPointeeType->isFunctionType() && ToPointeeType->isVoidType()) {
-        assert(getLangOpts().MSVCCompat &&
-               "this should only be possible with MSVCCompat!");
-        Diag(From->getExprLoc(), diag::ext_ms_impcast_fn_obj)
-            << From->getSourceRange();
-      }
-    }
-  } else if (const ObjCObjectPointerType *ToPtrType =
-               ToType->getAs<ObjCObjectPointerType>()) {
-    if (const ObjCObjectPointerType *FromPtrType =
-          FromType->getAs<ObjCObjectPointerType>()) {
-      // Objective-C++ conversions are always okay.
-      // FIXME: We should have a different class of conversions for the
-      // Objective-C++ implicit conversions.
-      if (FromPtrType->isObjCBuiltinType() || ToPtrType->isObjCBuiltinType())
-        return false;
-    } else if (FromType->isBlockPointerType()) {
-      Kind = CK_BlockPointerToObjCPointerCast;
-    } else {
-      Kind = CK_CPointerToObjCPointerCast;
-    }
-  } else if (ToType->isBlockPointerType()) {
-    if (!FromType->isBlockPointerType())
-      Kind = CK_AnyPointerToBlockPointerCast;
-  }
-
-  // We shouldn't fall into this case unless it's valid for other
-  // reasons.
-  if (From->isNullPointerConstant(Context, Expr::NPC_ValueDependentIsNull))
-    Kind = CK_NullToPointer;
-
-  return false;
-}
-
-/// IsMemberPointerConversion - Determines whether the conversion of the
-/// expression From, which has the (possibly adjusted) type FromType, can be
-/// converted to the type ToType via a member pointer conversion (C++ 4.11).
-/// If so, returns true and places the converted type (that might differ from
-/// ToType in its cv-qualifiers at some level) into ConvertedType.
-bool Sema::IsMemberPointerConversion(Expr *From, QualType FromType,
-                                     QualType ToType,
-                                     bool InOverloadResolution,
-                                     QualType &ConvertedType) {
-  const MemberPointerType *ToTypePtr = ToType->getAs<MemberPointerType>();
-  if (!ToTypePtr)
-    return false;
-
-  // A null pointer constant can be converted to a member pointer (C++ 4.11p1)
-  if (From->isNullPointerConstant(Context,
-                    InOverloadResolution? Expr::NPC_ValueDependentIsNotNull
-                                        : Expr::NPC_ValueDependentIsNull)) {
-    ConvertedType = ToType;
-    return true;
-  }
-
-  // Otherwise, both types have to be member pointers.
-  const MemberPointerType *FromTypePtr = FromType->getAs<MemberPointerType>();
-  if (!FromTypePtr)
-    return false;
-
-  // A pointer to member of B can be converted to a pointer to member of D,
-  // where D is derived from B (C++ 4.11p2).
-  QualType FromClass(FromTypePtr->getClass(), 0);
-  QualType ToClass(ToTypePtr->getClass(), 0);
-
-  if (!Context.hasSameUnqualifiedType(FromClass, ToClass) &&
-      IsDerivedFrom(From->getBeginLoc(), ToClass, FromClass)) {
-    ConvertedType = Context.getMemberPointerType(FromTypePtr->getPointeeType(),
-                                                 ToClass.getTypePtr());
-    return true;
-  }
-
-  return false;
-}
-
-/// CheckMemberPointerConversion - Check the member pointer conversion from the
-/// expression From to the type ToType. This routine checks for ambiguous or
-/// virtual or inaccessible base-to-derived member pointer conversions
-/// for which IsMemberPointerConversion has already returned true. It returns
-/// true and produces a diagnostic if there was an error, or returns false
-/// otherwise.
-bool Sema::CheckMemberPointerConversion(Expr *From, QualType ToType,
-                                        CastKind &Kind,
-                                        CXXCastPath &BasePath,
-                                        bool IgnoreBaseAccess) {
-  QualType FromType = From->getType();
-  const MemberPointerType *FromPtrType = FromType->getAs<MemberPointerType>();
-  if (!FromPtrType) {
-    // This must be a null pointer to member pointer conversion
-    assert(From->isNullPointerConstant(Context,
-                                       Expr::NPC_ValueDependentIsNull) &&
-           "Expr must be null pointer constant!");
-    Kind = CK_NullToMemberPointer;
-    return false;
-  }
-
-  const MemberPointerType *ToPtrType = ToType->getAs<MemberPointerType>();
-  assert(ToPtrType && "No member pointer cast has a target type "
-                      "that is not a member pointer.");
-
-  QualType FromClass = QualType(FromPtrType->getClass(), 0);
-  QualType ToClass   = QualType(ToPtrType->getClass(), 0);
-
-  // FIXME: What about dependent types?
-  assert(FromClass->isRecordType() && "Pointer into non-class.");
-  assert(ToClass->isRecordType() && "Pointer into non-class.");
-
-  CXXBasePaths Paths(/*FindAmbiguities=*/true, /*RecordPaths=*/true,
-                     /*DetectVirtual=*/true);
-  bool DerivationOkay =
-      IsDerivedFrom(From->getBeginLoc(), ToClass, FromClass, Paths);
-  assert(DerivationOkay &&
-         "Should not have been called if derivation isn't OK.");
-  (void)DerivationOkay;
-
-  if (Paths.isAmbiguous(Context.getCanonicalType(FromClass).
-                                  getUnqualifiedType())) {
-    std::string PathDisplayStr = getAmbiguousPathsDisplayString(Paths);
-    Diag(From->getExprLoc(), diag::err_ambiguous_memptr_conv)
-      << 0 << FromClass << ToClass << PathDisplayStr << From->getSourceRange();
-    return true;
-  }
-
-  if (const RecordType *VBase = Paths.getDetectedVirtual()) {
-    Diag(From->getExprLoc(), diag::err_memptr_conv_via_virtual)
-      << FromClass << ToClass << QualType(VBase, 0)
-      << From->getSourceRange();
-    return true;
-  }
-
-  if (!IgnoreBaseAccess)
-    CheckBaseClassAccess(From->getExprLoc(), FromClass, ToClass,
-                         Paths.front(),
-                         diag::err_downcast_from_inaccessible_base);
-
-  // Must be a base to derived member conversion.
-  BuildBasePathArray(Paths, BasePath);
-  Kind = CK_BaseToDerivedMemberPointer;
-  return false;
-}
-
-/// Determine whether the lifetime conversion between the two given
-/// qualifiers sets is nontrivial.
-static bool isNonTrivialObjCLifetimeConversion(Qualifiers FromQuals,
-                                               Qualifiers ToQuals) {
-  // Converting anything to const __unsafe_unretained is trivial.
-  if (ToQuals.hasConst() &&
-      ToQuals.getObjCLifetime() == Qualifiers::OCL_ExplicitNone)
-    return false;
-
-  return true;
-}
-
-/// IsQualificationConversion - Determines whether the conversion from
-/// an rvalue of type FromType to ToType is a qualification conversion
-/// (C++ 4.4).
-///
-/// \param ObjCLifetimeConversion Output parameter that will be set to indicate
-/// when the qualification conversion involves a change in the Objective-C
-/// object lifetime.
-bool
-Sema::IsQualificationConversion(QualType FromType, QualType ToType,
-                                bool CStyle, bool &ObjCLifetimeConversion) {
-  FromType = Context.getCanonicalType(FromType);
-  ToType = Context.getCanonicalType(ToType);
-  ObjCLifetimeConversion = false;
-
-  // If FromType and ToType are the same type, this is not a
-  // qualification conversion.
-  if (FromType.getUnqualifiedType() == ToType.getUnqualifiedType())
-    return false;
-
-  // (C++ 4.4p4):
-  //   A conversion can add cv-qualifiers at levels other than the first
-  //   in multi-level pointers, subject to the following rules: [...]
-  bool PreviousToQualsIncludeConst = true;
-  bool UnwrappedAnyPointer = false;
-  while (Context.UnwrapSimilarTypes(FromType, ToType)) {
-    // Within each iteration of the loop, we check the qualifiers to
-    // determine if this still looks like a qualification
-    // conversion. Then, if all is well, we unwrap one more level of
-    // pointers or pointers-to-members and do it all again
-    // until there are no more pointers or pointers-to-members left to
-    // unwrap.
-    UnwrappedAnyPointer = true;
-
-    Qualifiers FromQuals = FromType.getQualifiers();
-    Qualifiers ToQuals = ToType.getQualifiers();
-
-    // Ignore __unaligned qualifier if this type is void.
-    if (ToType.getUnqualifiedType()->isVoidType())
-      FromQuals.removeUnaligned();
-
-    // Objective-C ARC:
-    //   Check Objective-C lifetime conversions.
-    if (FromQuals.getObjCLifetime() != ToQuals.getObjCLifetime() &&
-        UnwrappedAnyPointer) {
-      if (ToQuals.compatiblyIncludesObjCLifetime(FromQuals)) {
-        if (isNonTrivialObjCLifetimeConversion(FromQuals, ToQuals))
-          ObjCLifetimeConversion = true;
-        FromQuals.removeObjCLifetime();
-        ToQuals.removeObjCLifetime();
-      } else {
-        // Qualification conversions cannot cast between different
-        // Objective-C lifetime qualifiers.
-        return false;
-      }
-    }
-
-    // Allow addition/removal of GC attributes but not changing GC attributes.
-    if (FromQuals.getObjCGCAttr() != ToQuals.getObjCGCAttr() &&
-        (!FromQuals.hasObjCGCAttr() || !ToQuals.hasObjCGCAttr())) {
-      FromQuals.removeObjCGCAttr();
-      ToQuals.removeObjCGCAttr();
-    }
-
-    //   -- for every j > 0, if const is in cv 1,j then const is in cv
-    //      2,j, and similarly for volatile.
-    if (!CStyle && !ToQuals.compatiblyIncludes(FromQuals))
-      return false;
-
-    //   -- if the cv 1,j and cv 2,j are different, then const is in
-    //      every cv for 0 < k < j.
-    if (!CStyle && FromQuals.getCVRQualifiers() != ToQuals.getCVRQualifiers()
-        && !PreviousToQualsIncludeConst)
-      return false;
-
-    // Keep track of whether all prior cv-qualifiers in the "to" type
-    // include const.
-    PreviousToQualsIncludeConst
-      = PreviousToQualsIncludeConst && ToQuals.hasConst();
-  }
-
-  // Allows address space promotion by language rules implemented in
-  // Type::Qualifiers::isAddressSpaceSupersetOf.
-  Qualifiers FromQuals = FromType.getQualifiers();
-  Qualifiers ToQuals = ToType.getQualifiers();
-  if (!ToQuals.isAddressSpaceSupersetOf(FromQuals) &&
-      !FromQuals.isAddressSpaceSupersetOf(ToQuals)) {
-    return false;
-  }
-
-  // We are left with FromType and ToType being the pointee types
-  // after unwrapping the original FromType and ToType the same number
-  // of types. If we unwrapped any pointers, and if FromType and
-  // ToType have the same unqualified type (since we checked
-  // qualifiers above), then this is a qualification conversion.
-  return UnwrappedAnyPointer && Context.hasSameUnqualifiedType(FromType,ToType);
-}
-
-/// - Determine whether this is a conversion from a scalar type to an
-/// atomic type.
-///
-/// If successful, updates \c SCS's second and third steps in the conversion
-/// sequence to finish the conversion.
-static bool tryAtomicConversion(Sema &S, Expr *From, QualType ToType,
-                                bool InOverloadResolution,
-                                StandardConversionSequence &SCS,
-                                bool CStyle) {
-  const AtomicType *ToAtomic = ToType->getAs<AtomicType>();
-  if (!ToAtomic)
-    return false;
-
-  StandardConversionSequence InnerSCS;
-  if (!IsStandardConversion(S, From, ToAtomic->getValueType(),
-                            InOverloadResolution, InnerSCS,
-                            CStyle, /*AllowObjCWritebackConversion=*/false))
-    return false;
-
-  SCS.Second = InnerSCS.Second;
-  SCS.setToType(1, InnerSCS.getToType(1));
-  SCS.Third = InnerSCS.Third;
-  SCS.QualificationIncludesObjCLifetime
-    = InnerSCS.QualificationIncludesObjCLifetime;
-  SCS.setToType(2, InnerSCS.getToType(2));
-  return true;
-}
-
-static bool isFirstArgumentCompatibleWithType(ASTContext &Context,
-                                              CXXConstructorDecl *Constructor,
-                                              QualType Type) {
-  const FunctionProtoType *CtorType =
-      Constructor->getType()->getAs<FunctionProtoType>();
-  if (CtorType->getNumParams() > 0) {
-    QualType FirstArg = CtorType->getParamType(0);
-    if (Context.hasSameUnqualifiedType(Type, FirstArg.getNonReferenceType()))
-      return true;
-  }
-  return false;
-}
-
-static OverloadingResult
-IsInitializerListConstructorConversion(Sema &S, Expr *From, QualType ToType,
-                                       CXXRecordDecl *To,
-                                       UserDefinedConversionSequence &User,
-                                       OverloadCandidateSet &CandidateSet,
-                                       bool AllowExplicit) {
-  CandidateSet.clear(OverloadCandidateSet::CSK_InitByUserDefinedConversion);
-  for (auto *D : S.LookupConstructors(To)) {
-    auto Info = getConstructorInfo(D);
-    if (!Info)
-      continue;
-
-    bool Usable = !Info.Constructor->isInvalidDecl() &&
-                  S.isInitListConstructor(Info.Constructor) &&
-                  (AllowExplicit || !Info.Constructor->isExplicit());
-    if (Usable) {
-      // If the first argument is (a reference to) the target type,
-      // suppress conversions.
-      bool SuppressUserConversions = isFirstArgumentCompatibleWithType(
-          S.Context, Info.Constructor, ToType);
-      if (Info.ConstructorTmpl)
-        S.AddTemplateOverloadCandidate(Info.ConstructorTmpl, Info.FoundDecl,
-                                       /*ExplicitArgs*/ nullptr, From,
-                                       CandidateSet, SuppressUserConversions);
-      else
-        S.AddOverloadCandidate(Info.Constructor, Info.FoundDecl, From,
-                               CandidateSet, SuppressUserConversions);
-    }
-  }
-
-  bool HadMultipleCandidates = (CandidateSet.size() > 1);
-
-  OverloadCandidateSet::iterator Best;
-  switch (auto Result =
-              CandidateSet.BestViableFunction(S, From->getBeginLoc(), Best)) {
-  case OR_Deleted:
-  case OR_Success: {
-    // Record the standard conversion we used and the conversion function.
-    CXXConstructorDecl *Constructor = cast<CXXConstructorDecl>(Best->Function);
-    QualType ThisType = Constructor->getThisType();
-    // Initializer lists don't have conversions as such.
-    User.Before.setAsIdentityConversion();
-    User.HadMultipleCandidates = HadMultipleCandidates;
-    User.ConversionFunction = Constructor;
-    User.FoundConversionFunction = Best->FoundDecl;
-    User.After.setAsIdentityConversion();
-    User.After.setFromType(ThisType->getAs<PointerType>()->getPointeeType());
-    User.After.setAllToTypes(ToType);
-    return Result;
-  }
-
-  case OR_No_Viable_Function:
-    return OR_No_Viable_Function;
-  case OR_Ambiguous:
-    return OR_Ambiguous;
-  }
-
-  llvm_unreachable("Invalid OverloadResult!");
-}
-
-/// Determines whether there is a user-defined conversion sequence
-/// (C++ [over.ics.user]) that converts expression From to the type
-/// ToType. If such a conversion exists, User will contain the
-/// user-defined conversion sequence that performs such a conversion
-/// and this routine will return true. Otherwise, this routine returns
-/// false and User is unspecified.
-///
-/// \param AllowExplicit  true if the conversion should consider C++0x
-/// "explicit" conversion functions as well as non-explicit conversion
-/// functions (C++0x [class.conv.fct]p2).
-///
-/// \param AllowObjCConversionOnExplicit true if the conversion should
-/// allow an extra Objective-C pointer conversion on uses of explicit
-/// constructors. Requires \c AllowExplicit to also be set.
-static OverloadingResult
-IsUserDefinedConversion(Sema &S, Expr *From, QualType ToType,
-                        UserDefinedConversionSequence &User,
-                        OverloadCandidateSet &CandidateSet,
-                        bool AllowExplicit,
-                        bool AllowObjCConversionOnExplicit) {
-  assert(AllowExplicit || !AllowObjCConversionOnExplicit);
-  CandidateSet.clear(OverloadCandidateSet::CSK_InitByUserDefinedConversion);
-
-  // Whether we will only visit constructors.
-  bool ConstructorsOnly = false;
-
-  // If the type we are conversion to is a class type, enumerate its
-  // constructors.
-  if (const RecordType *ToRecordType = ToType->getAs<RecordType>()) {
-    // C++ [over.match.ctor]p1:
-    //   When objects of class type are direct-initialized (8.5), or
-    //   copy-initialized from an expression of the same or a
-    //   derived class type (8.5), overload resolution selects the
-    //   constructor. [...] For copy-initialization, the candidate
-    //   functions are all the converting constructors (12.3.1) of
-    //   that class. The argument list is the expression-list within
-    //   the parentheses of the initializer.
-    if (S.Context.hasSameUnqualifiedType(ToType, From->getType()) ||
-        (From->getType()->getAs<RecordType>() &&
-         S.IsDerivedFrom(From->getBeginLoc(), From->getType(), ToType)))
-      ConstructorsOnly = true;
-
-    if (!S.isCompleteType(From->getExprLoc(), ToType)) {
-      // We're not going to find any constructors.
-    } else if (CXXRecordDecl *ToRecordDecl
-                 = dyn_cast<CXXRecordDecl>(ToRecordType->getDecl())) {
-
-      Expr **Args = &From;
-      unsigned NumArgs = 1;
-      bool ListInitializing = false;
-      if (InitListExpr *InitList = dyn_cast<InitListExpr>(From)) {
-        // But first, see if there is an init-list-constructor that will work.
-        OverloadingResult Result = IsInitializerListConstructorConversion(
-            S, From, ToType, ToRecordDecl, User, CandidateSet, AllowExplicit);
-        if (Result != OR_No_Viable_Function)
-          return Result;
-        // Never mind.
-        CandidateSet.clear(
-            OverloadCandidateSet::CSK_InitByUserDefinedConversion);
-
-        // If we're list-initializing, we pass the individual elements as
-        // arguments, not the entire list.
-        Args = InitList->getInits();
-        NumArgs = InitList->getNumInits();
-        ListInitializing = true;
-      }
-
-      for (auto *D : S.LookupConstructors(ToRecordDecl)) {
-        auto Info = getConstructorInfo(D);
-        if (!Info)
-          continue;
-
-        bool Usable = !Info.Constructor->isInvalidDecl();
-        if (ListInitializing)
-          Usable = Usable && (AllowExplicit || !Info.Constructor->isExplicit());
-        else
-          Usable = Usable &&
-                   Info.Constructor->isConvertingConstructor(AllowExplicit);
-        if (Usable) {
-          bool SuppressUserConversions = !ConstructorsOnly;
-          if (SuppressUserConversions && ListInitializing) {
-            SuppressUserConversions = false;
-            if (NumArgs == 1) {
-              // If the first argument is (a reference to) the target type,
-              // suppress conversions.
-              SuppressUserConversions = isFirstArgumentCompatibleWithType(
-                  S.Context, Info.Constructor, ToType);
-            }
-          }
-          if (Info.ConstructorTmpl)
-            S.AddTemplateOverloadCandidate(
-                Info.ConstructorTmpl, Info.FoundDecl,
-                /*ExplicitArgs*/ nullptr, llvm::makeArrayRef(Args, NumArgs),
-                CandidateSet, SuppressUserConversions);
-          else
-            // Allow one user-defined conversion when user specifies a
-            // From->ToType conversion via an static cast (c-style, etc).
-            S.AddOverloadCandidate(Info.Constructor, Info.FoundDecl,
-                                   llvm::makeArrayRef(Args, NumArgs),
-                                   CandidateSet, SuppressUserConversions);
-        }
-      }
-    }
-  }
-
-  // Enumerate conversion functions, if we're allowed to.
-  if (ConstructorsOnly || isa<InitListExpr>(From)) {
-  } else if (!S.isCompleteType(From->getBeginLoc(), From->getType())) {
-    // No conversion functions from incomplete types.
-  } else if (const RecordType *FromRecordType =
-                 From->getType()->getAs<RecordType>()) {
-    if (CXXRecordDecl *FromRecordDecl
-         = dyn_cast<CXXRecordDecl>(FromRecordType->getDecl())) {
-      // Add all of the conversion functions as candidates.
-      const auto &Conversions = FromRecordDecl->getVisibleConversionFunctions();
-      for (auto I = Conversions.begin(), E = Conversions.end(); I != E; ++I) {
-        DeclAccessPair FoundDecl = I.getPair();
-        NamedDecl *D = FoundDecl.getDecl();
-        CXXRecordDecl *ActingContext = cast<CXXRecordDecl>(D->getDeclContext());
-        if (isa<UsingShadowDecl>(D))
-          D = cast<UsingShadowDecl>(D)->getTargetDecl();
-
-        CXXConversionDecl *Conv;
-        FunctionTemplateDecl *ConvTemplate;
-        if ((ConvTemplate = dyn_cast<FunctionTemplateDecl>(D)))
-          Conv = cast<CXXConversionDecl>(ConvTemplate->getTemplatedDecl());
-        else
-          Conv = cast<CXXConversionDecl>(D);
-
-        if (AllowExplicit || !Conv->isExplicit()) {
-          if (ConvTemplate)
-            S.AddTemplateConversionCandidate(ConvTemplate, FoundDecl,
-                                             ActingContext, From, ToType,
-                                             CandidateSet,
-                                             AllowObjCConversionOnExplicit);
-          else
-            S.AddConversionCandidate(Conv, FoundDecl, ActingContext,
-                                     From, ToType, CandidateSet,
-                                     AllowObjCConversionOnExplicit);
-        }
-      }
-    }
-  }
-
-  bool HadMultipleCandidates = (CandidateSet.size() > 1);
-
-  OverloadCandidateSet::iterator Best;
-  switch (auto Result =
-              CandidateSet.BestViableFunction(S, From->getBeginLoc(), Best)) {
-  case OR_Success:
-  case OR_Deleted:
-    // Record the standard conversion we used and the conversion function.
-    if (CXXConstructorDecl *Constructor
-          = dyn_cast<CXXConstructorDecl>(Best->Function)) {
-      // C++ [over.ics.user]p1:
-      //   If the user-defined conversion is specified by a
-      //   constructor (12.3.1), the initial standard conversion
-      //   sequence converts the source type to the type required by
-      //   the argument of the constructor.
-      //
-      QualType ThisType = Constructor->getThisType();
-      if (isa<InitListExpr>(From)) {
-        // Initializer lists don't have conversions as such.
-        User.Before.setAsIdentityConversion();
-      } else {
-        if (Best->Conversions[0].isEllipsis())
-          User.EllipsisConversion = true;
-        else {
-          User.Before = Best->Conversions[0].Standard;
-          User.EllipsisConversion = false;
-        }
-      }
-      User.HadMultipleCandidates = HadMultipleCandidates;
-      User.ConversionFunction = Constructor;
-      User.FoundConversionFunction = Best->FoundDecl;
-      User.After.setAsIdentityConversion();
-      User.After.setFromType(ThisType->getAs<PointerType>()->getPointeeType());
-      User.After.setAllToTypes(ToType);
-      return Result;
-    }
-    if (CXXConversionDecl *Conversion
-                 = dyn_cast<CXXConversionDecl>(Best->Function)) {
-      // C++ [over.ics.user]p1:
-      //
-      //   [...] If the user-defined conversion is specified by a
-      //   conversion function (12.3.2), the initial standard
-      //   conversion sequence converts the source type to the
-      //   implicit object parameter of the conversion function.
-      User.Before = Best->Conversions[0].Standard;
-      User.HadMultipleCandidates = HadMultipleCandidates;
-      User.ConversionFunction = Conversion;
-      User.FoundConversionFunction = Best->FoundDecl;
-      User.EllipsisConversion = false;
-
-      // C++ [over.ics.user]p2:
-      //   The second standard conversion sequence converts the
-      //   result of the user-defined conversion to the target type
-      //   for the sequence. Since an implicit conversion sequence
-      //   is an initialization, the special rules for
-      //   initialization by user-defined conversion apply when
-      //   selecting the best user-defined conversion for a
-      //   user-defined conversion sequence (see 13.3.3 and
-      //   13.3.3.1).
-      User.After = Best->FinalConversion;
-      return Result;
-    }
-    llvm_unreachable("Not a constructor or conversion function?");
-
-  case OR_No_Viable_Function:
-    return OR_No_Viable_Function;
-
-  case OR_Ambiguous:
-    return OR_Ambiguous;
-  }
-
-  llvm_unreachable("Invalid OverloadResult!");
-}
-
-bool
-Sema::DiagnoseMultipleUserDefinedConversion(Expr *From, QualType ToType) {
-  ImplicitConversionSequence ICS;
-  OverloadCandidateSet CandidateSet(From->getExprLoc(),
-                                    OverloadCandidateSet::CSK_Normal);
-  OverloadingResult OvResult =
-    IsUserDefinedConversion(*this, From, ToType, ICS.UserDefined,
-                            CandidateSet, false, false);
-  if (OvResult == OR_Ambiguous)
-    Diag(From->getBeginLoc(), diag::err_typecheck_ambiguous_condition)
-        << From->getType() << ToType << From->getSourceRange();
-  else if (OvResult == OR_No_Viable_Function && !CandidateSet.empty()) {
-    if (!RequireCompleteType(From->getBeginLoc(), ToType,
-                             diag::err_typecheck_nonviable_condition_incomplete,
-                             From->getType(), From->getSourceRange()))
-      Diag(From->getBeginLoc(), diag::err_typecheck_nonviable_condition)
-          << false << From->getType() << From->getSourceRange() << ToType;
-  } else
-    return false;
-  CandidateSet.NoteCandidates(*this, OCD_AllCandidates, From);
-  return true;
-}
-
-/// Compare the user-defined conversion functions or constructors
-/// of two user-defined conversion sequences to determine whether any ordering
-/// is possible.
-static ImplicitConversionSequence::CompareKind
-compareConversionFunctions(Sema &S, FunctionDecl *Function1,
-                           FunctionDecl *Function2) {
-  if (!S.getLangOpts().ObjC || !S.getLangOpts().CPlusPlus11)
-    return ImplicitConversionSequence::Indistinguishable;
-
-  // Objective-C++:
-  //   If both conversion functions are implicitly-declared conversions from
-  //   a lambda closure type to a function pointer and a block pointer,
-  //   respectively, always prefer the conversion to a function pointer,
-  //   because the function pointer is more lightweight and is more likely
-  //   to keep code working.
-  CXXConversionDecl *Conv1 = dyn_cast_or_null<CXXConversionDecl>(Function1);
-  if (!Conv1)
-    return ImplicitConversionSequence::Indistinguishable;
-
-  CXXConversionDecl *Conv2 = dyn_cast<CXXConversionDecl>(Function2);
-  if (!Conv2)
-    return ImplicitConversionSequence::Indistinguishable;
-
-  if (Conv1->getParent()->isLambda() && Conv2->getParent()->isLambda()) {
-    bool Block1 = Conv1->getConversionType()->isBlockPointerType();
-    bool Block2 = Conv2->getConversionType()->isBlockPointerType();
-    if (Block1 != Block2)
-      return Block1 ? ImplicitConversionSequence::Worse
-                    : ImplicitConversionSequence::Better;
-  }
-
-  return ImplicitConversionSequence::Indistinguishable;
-}
-
-static bool hasDeprecatedStringLiteralToCharPtrConversion(
-    const ImplicitConversionSequence &ICS) {
-  return (ICS.isStandard() && ICS.Standard.DeprecatedStringLiteralToCharPtr) ||
-         (ICS.isUserDefined() &&
-          ICS.UserDefined.Before.DeprecatedStringLiteralToCharPtr);
-}
-
-/// CompareImplicitConversionSequences - Compare two implicit
-/// conversion sequences to determine whether one is better than the
-/// other or if they are indistinguishable (C++ 13.3.3.2).
-static ImplicitConversionSequence::CompareKind
-CompareImplicitConversionSequences(Sema &S, SourceLocation Loc,
-                                   const ImplicitConversionSequence& ICS1,
-                                   const ImplicitConversionSequence& ICS2)
-{
-  // (C++ 13.3.3.2p2): When comparing the basic forms of implicit
-  // conversion sequences (as defined in 13.3.3.1)
-  //   -- a standard conversion sequence (13.3.3.1.1) is a better
-  //      conversion sequence than a user-defined conversion sequence or
-  //      an ellipsis conversion sequence, and
-  //   -- a user-defined conversion sequence (13.3.3.1.2) is a better
-  //      conversion sequence than an ellipsis conversion sequence
-  //      (13.3.3.1.3).
-  //
-  // C++0x [over.best.ics]p10:
-  //   For the purpose of ranking implicit conversion sequences as
-  //   described in 13.3.3.2, the ambiguous conversion sequence is
-  //   treated as a user-defined sequence that is indistinguishable
-  //   from any other user-defined conversion sequence.
-
-  // String literal to 'char *' conversion has been deprecated in C++03. It has
-  // been removed from C++11. We still accept this conversion, if it happens at
-  // the best viable function. Otherwise, this conversion is considered worse
-  // than ellipsis conversion. Consider this as an extension; this is not in the
-  // standard. For example:
-  //
-  // int &f(...);    // #1
-  // void f(char*);  // #2
-  // void g() { int &r = f("foo"); }
-  //
-  // In C++03, we pick #2 as the best viable function.
-  // In C++11, we pick #1 as the best viable function, because ellipsis
-  // conversion is better than string-literal to char* conversion (since there
-  // is no such conversion in C++11). If there was no #1 at all or #1 couldn't
-  // convert arguments, #2 would be the best viable function in C++11.
-  // If the best viable function has this conversion, a warning will be issued
-  // in C++03, or an ExtWarn (+SFINAE failure) will be issued in C++11.
-
-  if (S.getLangOpts().CPlusPlus11 && !S.getLangOpts().WritableStrings &&
-      hasDeprecatedStringLiteralToCharPtrConversion(ICS1) !=
-      hasDeprecatedStringLiteralToCharPtrConversion(ICS2))
-    return hasDeprecatedStringLiteralToCharPtrConversion(ICS1)
-               ? ImplicitConversionSequence::Worse
-               : ImplicitConversionSequence::Better;
-
-  if (ICS1.getKindRank() < ICS2.getKindRank())
-    return ImplicitConversionSequence::Better;
-  if (ICS2.getKindRank() < ICS1.getKindRank())
-    return ImplicitConversionSequence::Worse;
-
-  // The following checks require both conversion sequences to be of
-  // the same kind.
-  if (ICS1.getKind() != ICS2.getKind())
-    return ImplicitConversionSequence::Indistinguishable;
-
-  ImplicitConversionSequence::CompareKind Result =
-      ImplicitConversionSequence::Indistinguishable;
-
-  // Two implicit conversion sequences of the same form are
-  // indistinguishable conversion sequences unless one of the
-  // following rules apply: (C++ 13.3.3.2p3):
-
-  // List-initialization sequence L1 is a better conversion sequence than
-  // list-initialization sequence L2 if:
-  // - L1 converts to std::initializer_list<X> for some X and L2 does not, or,
-  //   if not that,
-  // - L1 converts to type "array of N1 T", L2 converts to type "array of N2 T",
-  //   and N1 is smaller than N2.,
-  // even if one of the other rules in this paragraph would otherwise apply.
-  if (!ICS1.isBad()) {
-    if (ICS1.isStdInitializerListElement() &&
-        !ICS2.isStdInitializerListElement())
-      return ImplicitConversionSequence::Better;
-    if (!ICS1.isStdInitializerListElement() &&
-        ICS2.isStdInitializerListElement())
-      return ImplicitConversionSequence::Worse;
-  }
-
-  if (ICS1.isStandard())
-    // Standard conversion sequence S1 is a better conversion sequence than
-    // standard conversion sequence S2 if [...]
-    Result = CompareStandardConversionSequences(S, Loc,
-                                                ICS1.Standard, ICS2.Standard);
-  else if (ICS1.isUserDefined()) {
-    // User-defined conversion sequence U1 is a better conversion
-    // sequence than another user-defined conversion sequence U2 if
-    // they contain the same user-defined conversion function or
-    // constructor and if the second standard conversion sequence of
-    // U1 is better than the second standard conversion sequence of
-    // U2 (C++ 13.3.3.2p3).
-    if (ICS1.UserDefined.ConversionFunction ==
-          ICS2.UserDefined.ConversionFunction)
-      Result = CompareStandardConversionSequences(S, Loc,
-                                                  ICS1.UserDefined.After,
-                                                  ICS2.UserDefined.After);
-    else
-      Result = compareConversionFunctions(S,
-                                          ICS1.UserDefined.ConversionFunction,
-                                          ICS2.UserDefined.ConversionFunction);
-  }
-
-  return Result;
-}
-
-// Per 13.3.3.2p3, compare the given standard conversion sequences to
-// determine if one is a proper subset of the other.
-static ImplicitConversionSequence::CompareKind
-compareStandardConversionSubsets(ASTContext &Context,
-                                 const StandardConversionSequence& SCS1,
-                                 const StandardConversionSequence& SCS2) {
-  ImplicitConversionSequence::CompareKind Result
-    = ImplicitConversionSequence::Indistinguishable;
-
-  // the identity conversion sequence is considered to be a subsequence of
-  // any non-identity conversion sequence
-  if (SCS1.isIdentityConversion() && !SCS2.isIdentityConversion())
-    return ImplicitConversionSequence::Better;
-  else if (!SCS1.isIdentityConversion() && SCS2.isIdentityConversion())
-    return ImplicitConversionSequence::Worse;
-
-  if (SCS1.Second != SCS2.Second) {
-    if (SCS1.Second == ICK_Identity)
-      Result = ImplicitConversionSequence::Better;
-    else if (SCS2.Second == ICK_Identity)
-      Result = ImplicitConversionSequence::Worse;
-    else
-      return ImplicitConversionSequence::Indistinguishable;
-  } else if (!Context.hasSimilarType(SCS1.getToType(1), SCS2.getToType(1)))
-    return ImplicitConversionSequence::Indistinguishable;
-
-  if (SCS1.Third == SCS2.Third) {
-    return Context.hasSameType(SCS1.getToType(2), SCS2.getToType(2))? Result
-                             : ImplicitConversionSequence::Indistinguishable;
-  }
-
-  if (SCS1.Third == ICK_Identity)
-    return Result == ImplicitConversionSequence::Worse
-             ? ImplicitConversionSequence::Indistinguishable
-             : ImplicitConversionSequence::Better;
-
-  if (SCS2.Third == ICK_Identity)
-    return Result == ImplicitConversionSequence::Better
-             ? ImplicitConversionSequence::Indistinguishable
-             : ImplicitConversionSequence::Worse;
-
-  return ImplicitConversionSequence::Indistinguishable;
-}
-
-/// Determine whether one of the given reference bindings is better
-/// than the other based on what kind of bindings they are.
-static bool
-isBetterReferenceBindingKind(const StandardConversionSequence &SCS1,
-                             const StandardConversionSequence &SCS2) {
-  // C++0x [over.ics.rank]p3b4:
-  //   -- S1 and S2 are reference bindings (8.5.3) and neither refers to an
-  //      implicit object parameter of a non-static member function declared
-  //      without a ref-qualifier, and *either* S1 binds an rvalue reference
-  //      to an rvalue and S2 binds an lvalue reference *or S1 binds an
-  //      lvalue reference to a function lvalue and S2 binds an rvalue
-  //      reference*.
-  //
-  // FIXME: Rvalue references. We're going rogue with the above edits,
-  // because the semantics in the current C++0x working paper (N3225 at the
-  // time of this writing) break the standard definition of std::forward
-  // and std::reference_wrapper when dealing with references to functions.
-  // Proposed wording changes submitted to CWG for consideration.
-  if (SCS1.BindsImplicitObjectArgumentWithoutRefQualifier ||
-      SCS2.BindsImplicitObjectArgumentWithoutRefQualifier)
-    return false;
-
-  return (!SCS1.IsLvalueReference && SCS1.BindsToRvalue &&
-          SCS2.IsLvalueReference) ||
-         (SCS1.IsLvalueReference && SCS1.BindsToFunctionLvalue &&
-          !SCS2.IsLvalueReference && SCS2.BindsToFunctionLvalue);
-}
-
-/// CompareStandardConversionSequences - Compare two standard
-/// conversion sequences to determine whether one is better than the
-/// other or if they are indistinguishable (C++ 13.3.3.2p3).
-static ImplicitConversionSequence::CompareKind
-CompareStandardConversionSequences(Sema &S, SourceLocation Loc,
-                                   const StandardConversionSequence& SCS1,
-                                   const StandardConversionSequence& SCS2)
-{
-  // Standard conversion sequence S1 is a better conversion sequence
-  // than standard conversion sequence S2 if (C++ 13.3.3.2p3):
-
-  //  -- S1 is a proper subsequence of S2 (comparing the conversion
-  //     sequences in the canonical form defined by 13.3.3.1.1,
-  //     excluding any Lvalue Transformation; the identity conversion
-  //     sequence is considered to be a subsequence of any
-  //     non-identity conversion sequence) or, if not that,
-  if (ImplicitConversionSequence::CompareKind CK
-        = compareStandardConversionSubsets(S.Context, SCS1, SCS2))
-    return CK;
-
-  //  -- the rank of S1 is better than the rank of S2 (by the rules
-  //     defined below), or, if not that,
-  ImplicitConversionRank Rank1 = SCS1.getRank();
-  ImplicitConversionRank Rank2 = SCS2.getRank();
-  if (Rank1 < Rank2)
-    return ImplicitConversionSequence::Better;
-  else if (Rank2 < Rank1)
-    return ImplicitConversionSequence::Worse;
-
-  // (C++ 13.3.3.2p4): Two conversion sequences with the same rank
-  // are indistinguishable unless one of the following rules
-  // applies:
-
-  //   A conversion that is not a conversion of a pointer, or
-  //   pointer to member, to bool is better than another conversion
-  //   that is such a conversion.
-  if (SCS1.isPointerConversionToBool() != SCS2.isPointerConversionToBool())
-    return SCS2.isPointerConversionToBool()
-             ? ImplicitConversionSequence::Better
-             : ImplicitConversionSequence::Worse;
-
-  // C++ [over.ics.rank]p4b2:
-  //
-  //   If class B is derived directly or indirectly from class A,
-  //   conversion of B* to A* is better than conversion of B* to
-  //   void*, and conversion of A* to void* is better than conversion
-  //   of B* to void*.
-  bool SCS1ConvertsToVoid
-    = SCS1.isPointerConversionToVoidPointer(S.Context);
-  bool SCS2ConvertsToVoid
-    = SCS2.isPointerConversionToVoidPointer(S.Context);
-  if (SCS1ConvertsToVoid != SCS2ConvertsToVoid) {
-    // Exactly one of the conversion sequences is a conversion to
-    // a void pointer; it's the worse conversion.
-    return SCS2ConvertsToVoid ? ImplicitConversionSequence::Better
-                              : ImplicitConversionSequence::Worse;
-  } else if (!SCS1ConvertsToVoid && !SCS2ConvertsToVoid) {
-    // Neither conversion sequence converts to a void pointer; compare
-    // their derived-to-base conversions.
-    if (ImplicitConversionSequence::CompareKind DerivedCK
-          = CompareDerivedToBaseConversions(S, Loc, SCS1, SCS2))
-      return DerivedCK;
-  } else if (SCS1ConvertsToVoid && SCS2ConvertsToVoid &&
-             !S.Context.hasSameType(SCS1.getFromType(), SCS2.getFromType())) {
-    // Both conversion sequences are conversions to void
-    // pointers. Compare the source types to determine if there's an
-    // inheritance relationship in their sources.
-    QualType FromType1 = SCS1.getFromType();
-    QualType FromType2 = SCS2.getFromType();
-
-    // Adjust the types we're converting from via the array-to-pointer
-    // conversion, if we need to.
-    if (SCS1.First == ICK_Array_To_Pointer)
-      FromType1 = S.Context.getArrayDecayedType(FromType1);
-    if (SCS2.First == ICK_Array_To_Pointer)
-      FromType2 = S.Context.getArrayDecayedType(FromType2);
-
-    QualType FromPointee1 = FromType1->getPointeeType().getUnqualifiedType();
-    QualType FromPointee2 = FromType2->getPointeeType().getUnqualifiedType();
-
-    if (S.IsDerivedFrom(Loc, FromPointee2, FromPointee1))
-      return ImplicitConversionSequence::Better;
-    else if (S.IsDerivedFrom(Loc, FromPointee1, FromPointee2))
-      return ImplicitConversionSequence::Worse;
-
-    // Objective-C++: If one interface is more specific than the
-    // other, it is the better one.
-    const ObjCObjectPointerType* FromObjCPtr1
-      = FromType1->getAs<ObjCObjectPointerType>();
-    const ObjCObjectPointerType* FromObjCPtr2
-      = FromType2->getAs<ObjCObjectPointerType>();
-    if (FromObjCPtr1 && FromObjCPtr2) {
-      bool AssignLeft = S.Context.canAssignObjCInterfaces(FromObjCPtr1,
-                                                          FromObjCPtr2);
-      bool AssignRight = S.Context.canAssignObjCInterfaces(FromObjCPtr2,
-                                                           FromObjCPtr1);
-      if (AssignLeft != AssignRight) {
-        return AssignLeft? ImplicitConversionSequence::Better
-                         : ImplicitConversionSequence::Worse;
-      }
-    }
-  }
-
-  // Compare based on qualification conversions (C++ 13.3.3.2p3,
-  // bullet 3).
-  if (ImplicitConversionSequence::CompareKind QualCK
-        = CompareQualificationConversions(S, SCS1, SCS2))
-    return QualCK;
-
-  if (SCS1.ReferenceBinding && SCS2.ReferenceBinding) {
-    // Check for a better reference binding based on the kind of bindings.
-    if (isBetterReferenceBindingKind(SCS1, SCS2))
-      return ImplicitConversionSequence::Better;
-    else if (isBetterReferenceBindingKind(SCS2, SCS1))
-      return ImplicitConversionSequence::Worse;
-
-    // C++ [over.ics.rank]p3b4:
-    //   -- S1 and S2 are reference bindings (8.5.3), and the types to
-    //      which the references refer are the same type except for
-    //      top-level cv-qualifiers, and the type to which the reference
-    //      initialized by S2 refers is more cv-qualified than the type
-    //      to which the reference initialized by S1 refers.
-    QualType T1 = SCS1.getToType(2);
-    QualType T2 = SCS2.getToType(2);
-    T1 = S.Context.getCanonicalType(T1);
-    T2 = S.Context.getCanonicalType(T2);
-    Qualifiers T1Quals, T2Quals;
-    QualType UnqualT1 = S.Context.getUnqualifiedArrayType(T1, T1Quals);
-    QualType UnqualT2 = S.Context.getUnqualifiedArrayType(T2, T2Quals);
-    if (UnqualT1 == UnqualT2) {
-      // Objective-C++ ARC: If the references refer to objects with different
-      // lifetimes, prefer bindings that don't change lifetime.
-      if (SCS1.ObjCLifetimeConversionBinding !=
-                                          SCS2.ObjCLifetimeConversionBinding) {
-        return SCS1.ObjCLifetimeConversionBinding
-                                           ? ImplicitConversionSequence::Worse
-                                           : ImplicitConversionSequence::Better;
-      }
-
-      // If the type is an array type, promote the element qualifiers to the
-      // type for comparison.
-      if (isa<ArrayType>(T1) && T1Quals)
-        T1 = S.Context.getQualifiedType(UnqualT1, T1Quals);
-      if (isa<ArrayType>(T2) && T2Quals)
-        T2 = S.Context.getQualifiedType(UnqualT2, T2Quals);
-      if (T2.isMoreQualifiedThan(T1))
-        return ImplicitConversionSequence::Better;
-      else if (T1.isMoreQualifiedThan(T2))
-        return ImplicitConversionSequence::Worse;
-    }
-  }
-
-  // In Microsoft mode, prefer an integral conversion to a
-  // floating-to-integral conversion if the integral conversion
-  // is between types of the same size.
-  // For example:
-  // void f(float);
-  // void f(int);
-  // int main {
-  //    long a;
-  //    f(a);
-  // }
-  // Here, MSVC will call f(int) instead of generating a compile error
-  // as clang will do in standard mode.
-  if (S.getLangOpts().MSVCCompat && SCS1.Second == ICK_Integral_Conversion &&
-      SCS2.Second == ICK_Floating_Integral &&
-      S.Context.getTypeSize(SCS1.getFromType()) ==
-          S.Context.getTypeSize(SCS1.getToType(2)))
-    return ImplicitConversionSequence::Better;
-
-  // Prefer a compatible vector conversion over a lax vector conversion
-  // For example:
-  //
-  // typedef float __v4sf __attribute__((__vector_size__(16)));
-  // void f(vector float);
-  // void f(vector signed int);
-  // int main() {
-  //   __v4sf a;
-  //   f(a);
-  // }
-  // Here, we'd like to choose f(vector float) and not
-  // report an ambiguous call error
-  if (SCS1.Second == ICK_Vector_Conversion &&
-      SCS2.Second == ICK_Vector_Conversion) {
-    bool SCS1IsCompatibleVectorConversion = S.Context.areCompatibleVectorTypes(
-        SCS1.getFromType(), SCS1.getToType(2));
-    bool SCS2IsCompatibleVectorConversion = S.Context.areCompatibleVectorTypes(
-        SCS2.getFromType(), SCS2.getToType(2));
-
-    if (SCS1IsCompatibleVectorConversion != SCS2IsCompatibleVectorConversion)
-      return SCS1IsCompatibleVectorConversion
-                 ? ImplicitConversionSequence::Better
-                 : ImplicitConversionSequence::Worse;
-  }
-
-  return ImplicitConversionSequence::Indistinguishable;
-}
-
-/// CompareQualificationConversions - Compares two standard conversion
-/// sequences to determine whether they can be ranked based on their
-/// qualification conversions (C++ 13.3.3.2p3 bullet 3).
-static ImplicitConversionSequence::CompareKind
-CompareQualificationConversions(Sema &S,
-                                const StandardConversionSequence& SCS1,
-                                const StandardConversionSequence& SCS2) {
-  // C++ 13.3.3.2p3:
-  //  -- S1 and S2 differ only in their qualification conversion and
-  //     yield similar types T1 and T2 (C++ 4.4), respectively, and the
-  //     cv-qualification signature of type T1 is a proper subset of
-  //     the cv-qualification signature of type T2, and S1 is not the
-  //     deprecated string literal array-to-pointer conversion (4.2).
-  if (SCS1.First != SCS2.First || SCS1.Second != SCS2.Second ||
-      SCS1.Third != SCS2.Third || SCS1.Third != ICK_Qualification)
-    return ImplicitConversionSequence::Indistinguishable;
-
-  // FIXME: the example in the standard doesn't use a qualification
-  // conversion (!)
-  QualType T1 = SCS1.getToType(2);
-  QualType T2 = SCS2.getToType(2);
-  T1 = S.Context.getCanonicalType(T1);
-  T2 = S.Context.getCanonicalType(T2);
-  Qualifiers T1Quals, T2Quals;
-  QualType UnqualT1 = S.Context.getUnqualifiedArrayType(T1, T1Quals);
-  QualType UnqualT2 = S.Context.getUnqualifiedArrayType(T2, T2Quals);
-
-  // If the types are the same, we won't learn anything by unwrapped
-  // them.
-  if (UnqualT1 == UnqualT2)
-    return ImplicitConversionSequence::Indistinguishable;
-
-  // If the type is an array type, promote the element qualifiers to the type
-  // for comparison.
-  if (isa<ArrayType>(T1) && T1Quals)
-    T1 = S.Context.getQualifiedType(UnqualT1, T1Quals);
-  if (isa<ArrayType>(T2) && T2Quals)
-    T2 = S.Context.getQualifiedType(UnqualT2, T2Quals);
-
-  ImplicitConversionSequence::CompareKind Result
-    = ImplicitConversionSequence::Indistinguishable;
-
-  // Objective-C++ ARC:
-  //   Prefer qualification conversions not involving a change in lifetime
-  //   to qualification conversions that do not change lifetime.
-  if (SCS1.QualificationIncludesObjCLifetime !=
-                                      SCS2.QualificationIncludesObjCLifetime) {
-    Result = SCS1.QualificationIncludesObjCLifetime
-               ? ImplicitConversionSequence::Worse
-               : ImplicitConversionSequence::Better;
-  }
-
-  while (S.Context.UnwrapSimilarTypes(T1, T2)) {
-    // Within each iteration of the loop, we check the qualifiers to
-    // determine if this still looks like a qualification
-    // conversion. Then, if all is well, we unwrap one more level of
-    // pointers or pointers-to-members and do it all again
-    // until there are no more pointers or pointers-to-members left
-    // to unwrap. This essentially mimics what
-    // IsQualificationConversion does, but here we're checking for a
-    // strict subset of qualifiers.
-    if (T1.getCVRQualifiers() == T2.getCVRQualifiers())
-      // The qualifiers are the same, so this doesn't tell us anything
-      // about how the sequences rank.
-      ;
-    else if (T2.isMoreQualifiedThan(T1)) {
-      // T1 has fewer qualifiers, so it could be the better sequence.
-      if (Result == ImplicitConversionSequence::Worse)
-        // Neither has qualifiers that are a subset of the other's
-        // qualifiers.
-        return ImplicitConversionSequence::Indistinguishable;
-
-      Result = ImplicitConversionSequence::Better;
-    } else if (T1.isMoreQualifiedThan(T2)) {
-      // T2 has fewer qualifiers, so it could be the better sequence.
-      if (Result == ImplicitConversionSequence::Better)
-        // Neither has qualifiers that are a subset of the other's
-        // qualifiers.
-        return ImplicitConversionSequence::Indistinguishable;
-
-      Result = ImplicitConversionSequence::Worse;
-    } else {
-      // Qualifiers are disjoint.
-      return ImplicitConversionSequence::Indistinguishable;
-    }
-
-    // If the types after this point are equivalent, we're done.
-    if (S.Context.hasSameUnqualifiedType(T1, T2))
-      break;
-  }
-
-  // Check that the winning standard conversion sequence isn't using
-  // the deprecated string literal array to pointer conversion.
-  switch (Result) {
-  case ImplicitConversionSequence::Better:
-    if (SCS1.DeprecatedStringLiteralToCharPtr)
-      Result = ImplicitConversionSequence::Indistinguishable;
-    break;
-
-  case ImplicitConversionSequence::Indistinguishable:
-    break;
-
-  case ImplicitConversionSequence::Worse:
-    if (SCS2.DeprecatedStringLiteralToCharPtr)
-      Result = ImplicitConversionSequence::Indistinguishable;
-    break;
-  }
-
-  return Result;
-}
-
-/// CompareDerivedToBaseConversions - Compares two standard conversion
-/// sequences to determine whether they can be ranked based on their
-/// various kinds of derived-to-base conversions (C++
-/// [over.ics.rank]p4b3).  As part of these checks, we also look at
-/// conversions between Objective-C interface types.
-static ImplicitConversionSequence::CompareKind
-CompareDerivedToBaseConversions(Sema &S, SourceLocation Loc,
-                                const StandardConversionSequence& SCS1,
-                                const StandardConversionSequence& SCS2) {
-  QualType FromType1 = SCS1.getFromType();
-  QualType ToType1 = SCS1.getToType(1);
-  QualType FromType2 = SCS2.getFromType();
-  QualType ToType2 = SCS2.getToType(1);
-
-  // Adjust the types we're converting from via the array-to-pointer
-  // conversion, if we need to.
-  if (SCS1.First == ICK_Array_To_Pointer)
-    FromType1 = S.Context.getArrayDecayedType(FromType1);
-  if (SCS2.First == ICK_Array_To_Pointer)
-    FromType2 = S.Context.getArrayDecayedType(FromType2);
-
-  // Canonicalize all of the types.
-  FromType1 = S.Context.getCanonicalType(FromType1);
-  ToType1 = S.Context.getCanonicalType(ToType1);
-  FromType2 = S.Context.getCanonicalType(FromType2);
-  ToType2 = S.Context.getCanonicalType(ToType2);
-
-  // C++ [over.ics.rank]p4b3:
-  //
-  //   If class B is derived directly or indirectly from class A and
-  //   class C is derived directly or indirectly from B,
-  //
-  // Compare based on pointer conversions.
-  if (SCS1.Second == ICK_Pointer_Conversion &&
-      SCS2.Second == ICK_Pointer_Conversion &&
-      /*FIXME: Remove if Objective-C id conversions get their own rank*/
-      FromType1->isPointerType() && FromType2->isPointerType() &&
-      ToType1->isPointerType() && ToType2->isPointerType()) {
-    QualType FromPointee1
-      = FromType1->getAs<PointerType>()->getPointeeType().getUnqualifiedType();
-    QualType ToPointee1
-      = ToType1->getAs<PointerType>()->getPointeeType().getUnqualifiedType();
-    QualType FromPointee2
-      = FromType2->getAs<PointerType>()->getPointeeType().getUnqualifiedType();
-    QualType ToPointee2
-      = ToType2->getAs<PointerType>()->getPointeeType().getUnqualifiedType();
-
-    //   -- conversion of C* to B* is better than conversion of C* to A*,
-    if (FromPointee1 == FromPointee2 && ToPointee1 != ToPointee2) {
-      if (S.IsDerivedFrom(Loc, ToPointee1, ToPointee2))
-        return ImplicitConversionSequence::Better;
-      else if (S.IsDerivedFrom(Loc, ToPointee2, ToPointee1))
-        return ImplicitConversionSequence::Worse;
-    }
-
-    //   -- conversion of B* to A* is better than conversion of C* to A*,
-    if (FromPointee1 != FromPointee2 && ToPointee1 == ToPointee2) {
-      if (S.IsDerivedFrom(Loc, FromPointee2, FromPointee1))
-        return ImplicitConversionSequence::Better;
-      else if (S.IsDerivedFrom(Loc, FromPointee1, FromPointee2))
-        return ImplicitConversionSequence::Worse;
-    }
-  } else if (SCS1.Second == ICK_Pointer_Conversion &&
-             SCS2.Second == ICK_Pointer_Conversion) {
-    const ObjCObjectPointerType *FromPtr1
-      = FromType1->getAs<ObjCObjectPointerType>();
-    const ObjCObjectPointerType *FromPtr2
-      = FromType2->getAs<ObjCObjectPointerType>();
-    const ObjCObjectPointerType *ToPtr1
-      = ToType1->getAs<ObjCObjectPointerType>();
-    const ObjCObjectPointerType *ToPtr2
-      = ToType2->getAs<ObjCObjectPointerType>();
-
-    if (FromPtr1 && FromPtr2 && ToPtr1 && ToPtr2) {
-      // Apply the same conversion ranking rules for Objective-C pointer types
-      // that we do for C++ pointers to class types. However, we employ the
-      // Objective-C pseudo-subtyping relationship used for assignment of
-      // Objective-C pointer types.
-      bool FromAssignLeft
-        = S.Context.canAssignObjCInterfaces(FromPtr1, FromPtr2);
-      bool FromAssignRight
-        = S.Context.canAssignObjCInterfaces(FromPtr2, FromPtr1);
-      bool ToAssignLeft
-        = S.Context.canAssignObjCInterfaces(ToPtr1, ToPtr2);
-      bool ToAssignRight
-        = S.Context.canAssignObjCInterfaces(ToPtr2, ToPtr1);
-
-      // A conversion to an a non-id object pointer type or qualified 'id'
-      // type is better than a conversion to 'id'.
-      if (ToPtr1->isObjCIdType() &&
-          (ToPtr2->isObjCQualifiedIdType() || ToPtr2->getInterfaceDecl()))
-        return ImplicitConversionSequence::Worse;
-      if (ToPtr2->isObjCIdType() &&
-          (ToPtr1->isObjCQualifiedIdType() || ToPtr1->getInterfaceDecl()))
-        return ImplicitConversionSequence::Better;
-
-      // A conversion to a non-id object pointer type is better than a
-      // conversion to a qualified 'id' type
-      if (ToPtr1->isObjCQualifiedIdType() && ToPtr2->getInterfaceDecl())
-        return ImplicitConversionSequence::Worse;
-      if (ToPtr2->isObjCQualifiedIdType() && ToPtr1->getInterfaceDecl())
-        return ImplicitConversionSequence::Better;
-
-      // A conversion to an a non-Class object pointer type or qualified 'Class'
-      // type is better than a conversion to 'Class'.
-      if (ToPtr1->isObjCClassType() &&
-          (ToPtr2->isObjCQualifiedClassType() || ToPtr2->getInterfaceDecl()))
-        return ImplicitConversionSequence::Worse;
-      if (ToPtr2->isObjCClassType() &&
-          (ToPtr1->isObjCQualifiedClassType() || ToPtr1->getInterfaceDecl()))
-        return ImplicitConversionSequence::Better;
-
-      // A conversion to a non-Class object pointer type is better than a
-      // conversion to a qualified 'Class' type.
-      if (ToPtr1->isObjCQualifiedClassType() && ToPtr2->getInterfaceDecl())
-        return ImplicitConversionSequence::Worse;
-      if (ToPtr2->isObjCQualifiedClassType() && ToPtr1->getInterfaceDecl())
-        return ImplicitConversionSequence::Better;
-
-      //   -- "conversion of C* to B* is better than conversion of C* to A*,"
-      if (S.Context.hasSameType(FromType1, FromType2) &&
-          !FromPtr1->isObjCIdType() && !FromPtr1->isObjCClassType() &&
-          (ToAssignLeft != ToAssignRight)) {
-        if (FromPtr1->isSpecialized()) {
-          // "conversion of B<A> * to B * is better than conversion of B * to
-          // C *.
-          bool IsFirstSame =
-              FromPtr1->getInterfaceDecl() == ToPtr1->getInterfaceDecl();
-          bool IsSecondSame =
-              FromPtr1->getInterfaceDecl() == ToPtr2->getInterfaceDecl();
-          if (IsFirstSame) {
-            if (!IsSecondSame)
-              return ImplicitConversionSequence::Better;
-          } else if (IsSecondSame)
-            return ImplicitConversionSequence::Worse;
-        }
-        return ToAssignLeft? ImplicitConversionSequence::Worse
-                           : ImplicitConversionSequence::Better;
-      }
-
-      //   -- "conversion of B* to A* is better than conversion of C* to A*,"
-      if (S.Context.hasSameUnqualifiedType(ToType1, ToType2) &&
-          (FromAssignLeft != FromAssignRight))
-        return FromAssignLeft? ImplicitConversionSequence::Better
-        : ImplicitConversionSequence::Worse;
-    }
-  }
-
-  // Ranking of member-pointer types.
-  if (SCS1.Second == ICK_Pointer_Member && SCS2.Second == ICK_Pointer_Member &&
-      FromType1->isMemberPointerType() && FromType2->isMemberPointerType() &&
-      ToType1->isMemberPointerType() && ToType2->isMemberPointerType()) {
-    const MemberPointerType * FromMemPointer1 =
-                                        FromType1->getAs<MemberPointerType>();
-    const MemberPointerType * ToMemPointer1 =
-                                          ToType1->getAs<MemberPointerType>();
-    const MemberPointerType * FromMemPointer2 =
-                                          FromType2->getAs<MemberPointerType>();
-    const MemberPointerType * ToMemPointer2 =
-                                          ToType2->getAs<MemberPointerType>();
-    const Type *FromPointeeType1 = FromMemPointer1->getClass();
-    const Type *ToPointeeType1 = ToMemPointer1->getClass();
-    const Type *FromPointeeType2 = FromMemPointer2->getClass();
-    const Type *ToPointeeType2 = ToMemPointer2->getClass();
-    QualType FromPointee1 = QualType(FromPointeeType1, 0).getUnqualifiedType();
-    QualType ToPointee1 = QualType(ToPointeeType1, 0).getUnqualifiedType();
-    QualType FromPointee2 = QualType(FromPointeeType2, 0).getUnqualifiedType();
-    QualType ToPointee2 = QualType(ToPointeeType2, 0).getUnqualifiedType();
-    // conversion of A::* to B::* is better than conversion of A::* to C::*,
-    if (FromPointee1 == FromPointee2 && ToPointee1 != ToPointee2) {
-      if (S.IsDerivedFrom(Loc, ToPointee1, ToPointee2))
-        return ImplicitConversionSequence::Worse;
-      else if (S.IsDerivedFrom(Loc, ToPointee2, ToPointee1))
-        return ImplicitConversionSequence::Better;
-    }
-    // conversion of B::* to C::* is better than conversion of A::* to C::*
-    if (ToPointee1 == ToPointee2 && FromPointee1 != FromPointee2) {
-      if (S.IsDerivedFrom(Loc, FromPointee1, FromPointee2))
-        return ImplicitConversionSequence::Better;
-      else if (S.IsDerivedFrom(Loc, FromPointee2, FromPointee1))
-        return ImplicitConversionSequence::Worse;
-    }
-  }
-
-  if (SCS1.Second == ICK_Derived_To_Base) {
-    //   -- conversion of C to B is better than conversion of C to A,
-    //   -- binding of an expression of type C to a reference of type
-    //      B& is better than binding an expression of type C to a
-    //      reference of type A&,
-    if (S.Context.hasSameUnqualifiedType(FromType1, FromType2) &&
-        !S.Context.hasSameUnqualifiedType(ToType1, ToType2)) {
-      if (S.IsDerivedFrom(Loc, ToType1, ToType2))
-        return ImplicitConversionSequence::Better;
-      else if (S.IsDerivedFrom(Loc, ToType2, ToType1))
-        return ImplicitConversionSequence::Worse;
-    }
-
-    //   -- conversion of B to A is better than conversion of C to A.
-    //   -- binding of an expression of type B to a reference of type
-    //      A& is better than binding an expression of type C to a
-    //      reference of type A&,
-    if (!S.Context.hasSameUnqualifiedType(FromType1, FromType2) &&
-        S.Context.hasSameUnqualifiedType(ToType1, ToType2)) {
-      if (S.IsDerivedFrom(Loc, FromType2, FromType1))
-        return ImplicitConversionSequence::Better;
-      else if (S.IsDerivedFrom(Loc, FromType1, FromType2))
-        return ImplicitConversionSequence::Worse;
-    }
-  }
-
-  return ImplicitConversionSequence::Indistinguishable;
-}
-
-/// Determine whether the given type is valid, e.g., it is not an invalid
-/// C++ class.
-static bool isTypeValid(QualType T) {
-  if (CXXRecordDecl *Record = T->getAsCXXRecordDecl())
-    return !Record->isInvalidDecl();
-
-  return true;
-}
-
-/// CompareReferenceRelationship - Compare the two types T1 and T2 to
-/// determine whether they are reference-related,
-/// reference-compatible, reference-compatible with added
-/// qualification, or incompatible, for use in C++ initialization by
-/// reference (C++ [dcl.ref.init]p4). Neither type can be a reference
-/// type, and the first type (T1) is the pointee type of the reference
-/// type being initialized.
-Sema::ReferenceCompareResult
-Sema::CompareReferenceRelationship(SourceLocation Loc,
-                                   QualType OrigT1, QualType OrigT2,
-                                   bool &DerivedToBase,
-                                   bool &ObjCConversion,
-                                   bool &ObjCLifetimeConversion) {
-  assert(!OrigT1->isReferenceType() &&
-    "T1 must be the pointee type of the reference type");
-  assert(!OrigT2->isReferenceType() && "T2 cannot be a reference type");
-
-  QualType T1 = Context.getCanonicalType(OrigT1);
-  QualType T2 = Context.getCanonicalType(OrigT2);
-  Qualifiers T1Quals, T2Quals;
-  QualType UnqualT1 = Context.getUnqualifiedArrayType(T1, T1Quals);
-  QualType UnqualT2 = Context.getUnqualifiedArrayType(T2, T2Quals);
-
-  // C++ [dcl.init.ref]p4:
-  //   Given types "cv1 T1" and "cv2 T2," "cv1 T1" is
-  //   reference-related to "cv2 T2" if T1 is the same type as T2, or
-  //   T1 is a base class of T2.
-  DerivedToBase = false;
-  ObjCConversion = false;
-  ObjCLifetimeConversion = false;
-  QualType ConvertedT2;
-  if (UnqualT1 == UnqualT2) {
-    // Nothing to do.
-  } else if (isCompleteType(Loc, OrigT2) &&
-             isTypeValid(UnqualT1) && isTypeValid(UnqualT2) &&
-             IsDerivedFrom(Loc, UnqualT2, UnqualT1))
-    DerivedToBase = true;
-  else if (UnqualT1->isObjCObjectOrInterfaceType() &&
-           UnqualT2->isObjCObjectOrInterfaceType() &&
-           Context.canBindObjCObjectType(UnqualT1, UnqualT2))
-    ObjCConversion = true;
-  else if (UnqualT2->isFunctionType() &&
-           IsFunctionConversion(UnqualT2, UnqualT1, ConvertedT2))
-    // C++1z [dcl.init.ref]p4:
-    //   cv1 T1" is reference-compatible with "cv2 T2" if [...] T2 is "noexcept
-    //   function" and T1 is "function"
-    //
-    // We extend this to also apply to 'noreturn', so allow any function
-    // conversion between function types.
-    return Ref_Compatible;
-  else
-    return Ref_Incompatible;
-
-  // At this point, we know that T1 and T2 are reference-related (at
-  // least).
-
-  // If the type is an array type, promote the element qualifiers to the type
-  // for comparison.
-  if (isa<ArrayType>(T1) && T1Quals)
-    T1 = Context.getQualifiedType(UnqualT1, T1Quals);
-  if (isa<ArrayType>(T2) && T2Quals)
-    T2 = Context.getQualifiedType(UnqualT2, T2Quals);
-
-  // C++ [dcl.init.ref]p4:
-  //   "cv1 T1" is reference-compatible with "cv2 T2" if T1 is
-  //   reference-related to T2 and cv1 is the same cv-qualification
-  //   as, or greater cv-qualification than, cv2. For purposes of
-  //   overload resolution, cases for which cv1 is greater
-  //   cv-qualification than cv2 are identified as
-  //   reference-compatible with added qualification (see 13.3.3.2).
-  //
-  // Note that we also require equivalence of Objective-C GC and address-space
-  // qualifiers when performing these computations, so that e.g., an int in
-  // address space 1 is not reference-compatible with an int in address
-  // space 2.
-  if (T1Quals.getObjCLifetime() != T2Quals.getObjCLifetime() &&
-      T1Quals.compatiblyIncludesObjCLifetime(T2Quals)) {
-    if (isNonTrivialObjCLifetimeConversion(T2Quals, T1Quals))
-      ObjCLifetimeConversion = true;
-
-    T1Quals.removeObjCLifetime();
-    T2Quals.removeObjCLifetime();
-  }
-
-  // MS compiler ignores __unaligned qualifier for references; do the same.
-  T1Quals.removeUnaligned();
-  T2Quals.removeUnaligned();
-
-  if (T1Quals.compatiblyIncludes(T2Quals))
-    return Ref_Compatible;
-  else
-    return Ref_Related;
-}
-
-/// Look for a user-defined conversion to a value reference-compatible
-///        with DeclType. Return true if something definite is found.
-static bool
-FindConversionForRefInit(Sema &S, ImplicitConversionSequence &ICS,
-                         QualType DeclType, SourceLocation DeclLoc,
-                         Expr *Init, QualType T2, bool AllowRvalues,
-                         bool AllowExplicit) {
-  assert(T2->isRecordType() && "Can only find conversions of record types.");
-  CXXRecordDecl *T2RecordDecl
-    = dyn_cast<CXXRecordDecl>(T2->getAs<RecordType>()->getDecl());
-
-  OverloadCandidateSet CandidateSet(
-      DeclLoc, OverloadCandidateSet::CSK_InitByUserDefinedConversion);
-  const auto &Conversions = T2RecordDecl->getVisibleConversionFunctions();
-  for (auto I = Conversions.begin(), E = Conversions.end(); I != E; ++I) {
-    NamedDecl *D = *I;
-    CXXRecordDecl *ActingDC = cast<CXXRecordDecl>(D->getDeclContext());
-    if (isa<UsingShadowDecl>(D))
-      D = cast<UsingShadowDecl>(D)->getTargetDecl();
-
-    FunctionTemplateDecl *ConvTemplate
-      = dyn_cast<FunctionTemplateDecl>(D);
-    CXXConversionDecl *Conv;
-    if (ConvTemplate)
-      Conv = cast<CXXConversionDecl>(ConvTemplate->getTemplatedDecl());
-    else
-      Conv = cast<CXXConversionDecl>(D);
-
-    // If this is an explicit conversion, and we're not allowed to consider
-    // explicit conversions, skip it.
-    if (!AllowExplicit && Conv->isExplicit())
-      continue;
-
-    if (AllowRvalues) {
-      bool DerivedToBase = false;
-      bool ObjCConversion = false;
-      bool ObjCLifetimeConversion = false;
-
-      // If we are initializing an rvalue reference, don't permit conversion
-      // functions that return lvalues.
-      if (!ConvTemplate && DeclType->isRValueReferenceType()) {
-        const ReferenceType *RefType
-          = Conv->getConversionType()->getAs<LValueReferenceType>();
-        if (RefType && !RefType->getPointeeType()->isFunctionType())
-          continue;
-      }
-
-      if (!ConvTemplate &&
-          S.CompareReferenceRelationship(
-            DeclLoc,
-            Conv->getConversionType().getNonReferenceType()
-              .getUnqualifiedType(),
-            DeclType.getNonReferenceType().getUnqualifiedType(),
-            DerivedToBase, ObjCConversion, ObjCLifetimeConversion) ==
-          Sema::Ref_Incompatible)
-        continue;
-    } else {
-      // If the conversion function doesn't return a reference type,
-      // it can't be considered for this conversion. An rvalue reference
-      // is only acceptable if its referencee is a function type.
-
-      const ReferenceType *RefType =
-        Conv->getConversionType()->getAs<ReferenceType>();
-      if (!RefType ||
-          (!RefType->isLValueReferenceType() &&
-           !RefType->getPointeeType()->isFunctionType()))
-        continue;
-    }
-
-    if (ConvTemplate)
-      S.AddTemplateConversionCandidate(ConvTemplate, I.getPair(), ActingDC,
-                                       Init, DeclType, CandidateSet,
-                                       /*AllowObjCConversionOnExplicit=*/false);
-    else
-      S.AddConversionCandidate(Conv, I.getPair(), ActingDC, Init,
-                               DeclType, CandidateSet,
-                               /*AllowObjCConversionOnExplicit=*/false);
-  }
-
-  bool HadMultipleCandidates = (CandidateSet.size() > 1);
-
-  OverloadCandidateSet::iterator Best;
-  switch (CandidateSet.BestViableFunction(S, DeclLoc, Best)) {
-  case OR_Success:
-    // C++ [over.ics.ref]p1:
-    //
-    //   [...] If the parameter binds directly to the result of
-    //   applying a conversion function to the argument
-    //   expression, the implicit conversion sequence is a
-    //   user-defined conversion sequence (13.3.3.1.2), with the
-    //   second standard conversion sequence either an identity
-    //   conversion or, if the conversion function returns an
-    //   entity of a type that is a derived class of the parameter
-    //   type, a derived-to-base Conversion.
-    if (!Best->FinalConversion.DirectBinding)
-      return false;
-
-    ICS.setUserDefined();
-    ICS.UserDefined.Before = Best->Conversions[0].Standard;
-    ICS.UserDefined.After = Best->FinalConversion;
-    ICS.UserDefined.HadMultipleCandidates = HadMultipleCandidates;
-    ICS.UserDefined.ConversionFunction = Best->Function;
-    ICS.UserDefined.FoundConversionFunction = Best->FoundDecl;
-    ICS.UserDefined.EllipsisConversion = false;
-    assert(ICS.UserDefined.After.ReferenceBinding &&
-           ICS.UserDefined.After.DirectBinding &&
-           "Expected a direct reference binding!");
-    return true;
-
-  case OR_Ambiguous:
-    ICS.setAmbiguous();
-    for (OverloadCandidateSet::iterator Cand = CandidateSet.begin();
-         Cand != CandidateSet.end(); ++Cand)
-      if (Cand->Viable)
-        ICS.Ambiguous.addConversion(Cand->FoundDecl, Cand->Function);
-    return true;
-
-  case OR_No_Viable_Function:
-  case OR_Deleted:
-    // There was no suitable conversion, or we found a deleted
-    // conversion; continue with other checks.
-    return false;
-  }
-
-  llvm_unreachable("Invalid OverloadResult!");
-}
-
-/// Compute an implicit conversion sequence for reference
-/// initialization.
-static ImplicitConversionSequence
-TryReferenceInit(Sema &S, Expr *Init, QualType DeclType,
-                 SourceLocation DeclLoc,
-                 bool SuppressUserConversions,
-                 bool AllowExplicit) {
-  assert(DeclType->isReferenceType() && "Reference init needs a reference");
-
-  // Most paths end in a failed conversion.
-  ImplicitConversionSequence ICS;
-  ICS.setBad(BadConversionSequence::no_conversion, Init, DeclType);
-
-  QualType T1 = DeclType->getAs<ReferenceType>()->getPointeeType();
-  QualType T2 = Init->getType();
-
-  // If the initializer is the address of an overloaded function, try
-  // to resolve the overloaded function. If all goes well, T2 is the
-  // type of the resulting function.
-  if (S.Context.getCanonicalType(T2) == S.Context.OverloadTy) {
-    DeclAccessPair Found;
-    if (FunctionDecl *Fn = S.ResolveAddressOfOverloadedFunction(Init, DeclType,
-                                                                false, Found))
-      T2 = Fn->getType();
-  }
-
-  // Compute some basic properties of the types and the initializer.
-  bool isRValRef = DeclType->isRValueReferenceType();
-  bool DerivedToBase = false;
-  bool ObjCConversion = false;
-  bool ObjCLifetimeConversion = false;
-  Expr::Classification InitCategory = Init->Classify(S.Context);
-  Sema::ReferenceCompareResult RefRelationship
-    = S.CompareReferenceRelationship(DeclLoc, T1, T2, DerivedToBase,
-                                     ObjCConversion, ObjCLifetimeConversion);
-
-
-  // C++0x [dcl.init.ref]p5:
-  //   A reference to type "cv1 T1" is initialized by an expression
-  //   of type "cv2 T2" as follows:
-
-  //     -- If reference is an lvalue reference and the initializer expression
-  if (!isRValRef) {
-    //     -- is an lvalue (but is not a bit-field), and "cv1 T1" is
-    //        reference-compatible with "cv2 T2," or
-    //
-    // Per C++ [over.ics.ref]p4, we don't check the bit-field property here.
-    if (InitCategory.isLValue() && RefRelationship == Sema::Ref_Compatible) {
-      // C++ [over.ics.ref]p1:
-      //   When a parameter of reference type binds directly (8.5.3)
-      //   to an argument expression, the implicit conversion sequence
-      //   is the identity conversion, unless the argument expression
-      //   has a type that is a derived class of the parameter type,
-      //   in which case the implicit conversion sequence is a
-      //   derived-to-base Conversion (13.3.3.1).
-      ICS.setStandard();
-      ICS.Standard.First = ICK_Identity;
-      ICS.Standard.Second = DerivedToBase? ICK_Derived_To_Base
-                         : ObjCConversion? ICK_Compatible_Conversion
-                         : ICK_Identity;
-      ICS.Standard.Third = ICK_Identity;
-      ICS.Standard.FromTypePtr = T2.getAsOpaquePtr();
-      ICS.Standard.setToType(0, T2);
-      ICS.Standard.setToType(1, T1);
-      ICS.Standard.setToType(2, T1);
-      ICS.Standard.ReferenceBinding = true;
-      ICS.Standard.DirectBinding = true;
-      ICS.Standard.IsLvalueReference = !isRValRef;
-      ICS.Standard.BindsToFunctionLvalue = T2->isFunctionType();
-      ICS.Standard.BindsToRvalue = false;
-      ICS.Standard.BindsImplicitObjectArgumentWithoutRefQualifier = false;
-      ICS.Standard.ObjCLifetimeConversionBinding = ObjCLifetimeConversion;
-      ICS.Standard.CopyConstructor = nullptr;
-      ICS.Standard.DeprecatedStringLiteralToCharPtr = false;
-
-      // Nothing more to do: the inaccessibility/ambiguity check for
-      // derived-to-base conversions is suppressed when we're
-      // computing the implicit conversion sequence (C++
-      // [over.best.ics]p2).
-      return ICS;
-    }
-
-    //       -- has a class type (i.e., T2 is a class type), where T1 is
-    //          not reference-related to T2, and can be implicitly
-    //          converted to an lvalue of type "cv3 T3," where "cv1 T1"
-    //          is reference-compatible with "cv3 T3" 92) (this
-    //          conversion is selected by enumerating the applicable
-    //          conversion functions (13.3.1.6) and choosing the best
-    //          one through overload resolution (13.3)),
-    if (!SuppressUserConversions && T2->isRecordType() &&
-        S.isCompleteType(DeclLoc, T2) &&
-        RefRelationship == Sema::Ref_Incompatible) {
-      if (FindConversionForRefInit(S, ICS, DeclType, DeclLoc,
-                                   Init, T2, /*AllowRvalues=*/false,
-                                   AllowExplicit))
-        return ICS;
-    }
-  }
-
-  //     -- Otherwise, the reference shall be an lvalue reference to a
-  //        non-volatile const type (i.e., cv1 shall be const), or the reference
-  //        shall be an rvalue reference.
-  if (!isRValRef && (!T1.isConstQualified() || T1.isVolatileQualified()))
-    return ICS;
-
-  //       -- If the initializer expression
-  //
-  //            -- is an xvalue, class prvalue, array prvalue or function
-  //               lvalue and "cv1 T1" is reference-compatible with "cv2 T2", or
-  if (RefRelationship == Sema::Ref_Compatible &&
-      (InitCategory.isXValue() ||
-       (InitCategory.isPRValue() && (T2->isRecordType() || T2->isArrayType())) ||
-       (InitCategory.isLValue() && T2->isFunctionType()))) {
-    ICS.setStandard();
-    ICS.Standard.First = ICK_Identity;
-    ICS.Standard.Second = DerivedToBase? ICK_Derived_To_Base
-                      : ObjCConversion? ICK_Compatible_Conversion
-                      : ICK_Identity;
-    ICS.Standard.Third = ICK_Identity;
-    ICS.Standard.FromTypePtr = T2.getAsOpaquePtr();
-    ICS.Standard.setToType(0, T2);
-    ICS.Standard.setToType(1, T1);
-    ICS.Standard.setToType(2, T1);
-    ICS.Standard.ReferenceBinding = true;
-    // In C++0x, this is always a direct binding. In C++98/03, it's a direct
-    // binding unless we're binding to a class prvalue.
-    // Note: Although xvalues wouldn't normally show up in C++98/03 code, we
-    // allow the use of rvalue references in C++98/03 for the benefit of
-    // standard library implementors; therefore, we need the xvalue check here.
-    ICS.Standard.DirectBinding =
-      S.getLangOpts().CPlusPlus11 ||
-      !(InitCategory.isPRValue() || T2->isRecordType());
-    ICS.Standard.IsLvalueReference = !isRValRef;
-    ICS.Standard.BindsToFunctionLvalue = T2->isFunctionType();
-    ICS.Standard.BindsToRvalue = InitCategory.isRValue();
-    ICS.Standard.BindsImplicitObjectArgumentWithoutRefQualifier = false;
-    ICS.Standard.ObjCLifetimeConversionBinding = ObjCLifetimeConversion;
-    ICS.Standard.CopyConstructor = nullptr;
-    ICS.Standard.DeprecatedStringLiteralToCharPtr = false;
-    return ICS;
-  }
-
-  //            -- has a class type (i.e., T2 is a class type), where T1 is not
-  //               reference-related to T2, and can be implicitly converted to
-  //               an xvalue, class prvalue, or function lvalue of type
-  //               "cv3 T3", where "cv1 T1" is reference-compatible with
-  //               "cv3 T3",
-  //
-  //          then the reference is bound to the value of the initializer
-  //          expression in the first case and to the result of the conversion
-  //          in the second case (or, in either case, to an appropriate base
-  //          class subobject).
-  if (!SuppressUserConversions && RefRelationship == Sema::Ref_Incompatible &&
-      T2->isRecordType() && S.isCompleteType(DeclLoc, T2) &&
-      FindConversionForRefInit(S, ICS, DeclType, DeclLoc,
-                               Init, T2, /*AllowRvalues=*/true,
-                               AllowExplicit)) {
-    // In the second case, if the reference is an rvalue reference
-    // and the second standard conversion sequence of the
-    // user-defined conversion sequence includes an lvalue-to-rvalue
-    // conversion, the program is ill-formed.
-    if (ICS.isUserDefined() && isRValRef &&
-        ICS.UserDefined.After.First == ICK_Lvalue_To_Rvalue)
-      ICS.setBad(BadConversionSequence::no_conversion, Init, DeclType);
-
-    return ICS;
-  }
-
-  // A temporary of function type cannot be created; don't even try.
-  if (T1->isFunctionType())
-    return ICS;
-
-  //       -- Otherwise, a temporary of type "cv1 T1" is created and
-  //          initialized from the initializer expression using the
-  //          rules for a non-reference copy initialization (8.5). The
-  //          reference is then bound to the temporary. If T1 is
-  //          reference-related to T2, cv1 must be the same
-  //          cv-qualification as, or greater cv-qualification than,
-  //          cv2; otherwise, the program is ill-formed.
-  if (RefRelationship == Sema::Ref_Related) {
-    // If cv1 == cv2 or cv1 is a greater cv-qualified than cv2, then
-    // we would be reference-compatible or reference-compatible with
-    // added qualification. But that wasn't the case, so the reference
-    // initialization fails.
-    //
-    // Note that we only want to check address spaces and cvr-qualifiers here.
-    // ObjC GC, lifetime and unaligned qualifiers aren't important.
-    Qualifiers T1Quals = T1.getQualifiers();
-    Qualifiers T2Quals = T2.getQualifiers();
-    T1Quals.removeObjCGCAttr();
-    T1Quals.removeObjCLifetime();
-    T2Quals.removeObjCGCAttr();
-    T2Quals.removeObjCLifetime();
-    // MS compiler ignores __unaligned qualifier for references; do the same.
-    T1Quals.removeUnaligned();
-    T2Quals.removeUnaligned();
-    if (!T1Quals.compatiblyIncludes(T2Quals))
-      return ICS;
-  }
-
-  // If at least one of the types is a class type, the types are not
-  // related, and we aren't allowed any user conversions, the
-  // reference binding fails. This case is important for breaking
-  // recursion, since TryImplicitConversion below will attempt to
-  // create a temporary through the use of a copy constructor.
-  if (SuppressUserConversions && RefRelationship == Sema::Ref_Incompatible &&
-      (T1->isRecordType() || T2->isRecordType()))
-    return ICS;
-
-  // If T1 is reference-related to T2 and the reference is an rvalue
-  // reference, the initializer expression shall not be an lvalue.
-  if (RefRelationship >= Sema::Ref_Related &&
-      isRValRef && Init->Classify(S.Context).isLValue())
-    return ICS;
-
-  // C++ [over.ics.ref]p2:
-  //   When a parameter of reference type is not bound directly to
-  //   an argument expression, the conversion sequence is the one
-  //   required to convert the argument expression to the
-  //   underlying type of the reference according to
-  //   13.3.3.1. Conceptually, this conversion sequence corresponds
-  //   to copy-initializing a temporary of the underlying type with
-  //   the argument expression. Any difference in top-level
-  //   cv-qualification is subsumed by the initialization itself
-  //   and does not constitute a conversion.
-  ICS = TryImplicitConversion(S, Init, T1, SuppressUserConversions,
-                              /*AllowExplicit=*/false,
-                              /*InOverloadResolution=*/false,
-                              /*CStyle=*/false,
-                              /*AllowObjCWritebackConversion=*/false,
-                              /*AllowObjCConversionOnExplicit=*/false);
-
-  // Of course, that's still a reference binding.
-  if (ICS.isStandard()) {
-    ICS.Standard.ReferenceBinding = true;
-    ICS.Standard.IsLvalueReference = !isRValRef;
-    ICS.Standard.BindsToFunctionLvalue = false;
-    ICS.Standard.BindsToRvalue = true;
-    ICS.Standard.BindsImplicitObjectArgumentWithoutRefQualifier = false;
-    ICS.Standard.ObjCLifetimeConversionBinding = false;
-  } else if (ICS.isUserDefined()) {
-    const ReferenceType *LValRefType =
-        ICS.UserDefined.ConversionFunction->getReturnType()
-            ->getAs<LValueReferenceType>();
-
-    // C++ [over.ics.ref]p3:
-    //   Except for an implicit object parameter, for which see 13.3.1, a
-    //   standard conversion sequence cannot be formed if it requires [...]
-    //   binding an rvalue reference to an lvalue other than a function
-    //   lvalue.
-    // Note that the function case is not possible here.
-    if (DeclType->isRValueReferenceType() && LValRefType) {
-      // FIXME: This is the wrong BadConversionSequence. The problem is binding
-      // an rvalue reference to a (non-function) lvalue, not binding an lvalue
-      // reference to an rvalue!
-      ICS.setBad(BadConversionSequence::lvalue_ref_to_rvalue, Init, DeclType);
-      return ICS;
-    }
-
-    ICS.UserDefined.After.ReferenceBinding = true;
-    ICS.UserDefined.After.IsLvalueReference = !isRValRef;
-    ICS.UserDefined.After.BindsToFunctionLvalue = false;
-    ICS.UserDefined.After.BindsToRvalue = !LValRefType;
-    ICS.UserDefined.After.BindsImplicitObjectArgumentWithoutRefQualifier = false;
-    ICS.UserDefined.After.ObjCLifetimeConversionBinding = false;
-  }
-
-  return ICS;
-}
-
-static ImplicitConversionSequence
-TryCopyInitialization(Sema &S, Expr *From, QualType ToType,
-                      bool SuppressUserConversions,
-                      bool InOverloadResolution,
-                      bool AllowObjCWritebackConversion,
-                      bool AllowExplicit = false);
-
-/// TryListConversion - Try to copy-initialize a value of type ToType from the
-/// initializer list From.
-static ImplicitConversionSequence
-TryListConversion(Sema &S, InitListExpr *From, QualType ToType,
-                  bool SuppressUserConversions,
-                  bool InOverloadResolution,
-                  bool AllowObjCWritebackConversion) {
-  // C++11 [over.ics.list]p1:
-  //   When an argument is an initializer list, it is not an expression and
-  //   special rules apply for converting it to a parameter type.
-
-  ImplicitConversionSequence Result;
-  Result.setBad(BadConversionSequence::no_conversion, From, ToType);
-
-  // We need a complete type for what follows. Incomplete types can never be
-  // initialized from init lists.
-  if (!S.isCompleteType(From->getBeginLoc(), ToType))
-    return Result;
-
-  // Per DR1467:
-  //   If the parameter type is a class X and the initializer list has a single
-  //   element of type cv U, where U is X or a class derived from X, the
-  //   implicit conversion sequence is the one required to convert the element
-  //   to the parameter type.
-  //
-  //   Otherwise, if the parameter type is a character array [... ]
-  //   and the initializer list has a single element that is an
-  //   appropriately-typed string literal (8.5.2 [dcl.init.string]), the
-  //   implicit conversion sequence is the identity conversion.
-  if (From->getNumInits() == 1) {
-    if (ToType->isRecordType()) {
-      QualType InitType = From->getInit(0)->getType();
-      if (S.Context.hasSameUnqualifiedType(InitType, ToType) ||
-          S.IsDerivedFrom(From->getBeginLoc(), InitType, ToType))
-        return TryCopyInitialization(S, From->getInit(0), ToType,
-                                     SuppressUserConversions,
-                                     InOverloadResolution,
-                                     AllowObjCWritebackConversion);
-    }
-    // FIXME: Check the other conditions here: array of character type,
-    // initializer is a string literal.
-    if (ToType->isArrayType()) {
-      InitializedEntity Entity =
-        InitializedEntity::InitializeParameter(S.Context, ToType,
-                                               /*Consumed=*/false);
-      if (S.CanPerformCopyInitialization(Entity, From)) {
-        Result.setStandard();
-        Result.Standard.setAsIdentityConversion();
-        Result.Standard.setFromType(ToType);
-        Result.Standard.setAllToTypes(ToType);
-        return Result;
-      }
-    }
-  }
-
-  // C++14 [over.ics.list]p2: Otherwise, if the parameter type [...] (below).
-  // C++11 [over.ics.list]p2:
-  //   If the parameter type is std::initializer_list<X> or "array of X" and
-  //   all the elements can be implicitly converted to X, the implicit
-  //   conversion sequence is the worst conversion necessary to convert an
-  //   element of the list to X.
-  //
-  // C++14 [over.ics.list]p3:
-  //   Otherwise, if the parameter type is "array of N X", if the initializer
-  //   list has exactly N elements or if it has fewer than N elements and X is
-  //   default-constructible, and if all the elements of the initializer list
-  //   can be implicitly converted to X, the implicit conversion sequence is
-  //   the worst conversion necessary to convert an element of the list to X.
-  //
-  // FIXME: We're missing a lot of these checks.
-  bool toStdInitializerList = false;
-  QualType X;
-  if (ToType->isArrayType())
-    X = S.Context.getAsArrayType(ToType)->getElementType();
-  else
-    toStdInitializerList = S.isStdInitializerList(ToType, &X);
-  if (!X.isNull()) {
-    for (unsigned i = 0, e = From->getNumInits(); i < e; ++i) {
-      Expr *Init = From->getInit(i);
-      ImplicitConversionSequence ICS =
-          TryCopyInitialization(S, Init, X, SuppressUserConversions,
-                                InOverloadResolution,
-                                AllowObjCWritebackConversion);
-      // If a single element isn't convertible, fail.
-      if (ICS.isBad()) {
-        Result = ICS;
-        break;
-      }
-      // Otherwise, look for the worst conversion.
-      if (Result.isBad() || CompareImplicitConversionSequences(
-                                S, From->getBeginLoc(), ICS, Result) ==
-                                ImplicitConversionSequence::Worse)
-        Result = ICS;
-    }
-
-    // For an empty list, we won't have computed any conversion sequence.
-    // Introduce the identity conversion sequence.
-    if (From->getNumInits() == 0) {
-      Result.setStandard();
-      Result.Standard.setAsIdentityConversion();
-      Result.Standard.setFromType(ToType);
-      Result.Standard.setAllToTypes(ToType);
-    }
-
-    Result.setStdInitializerListElement(toStdInitializerList);
-    return Result;
-  }
-
-  // C++14 [over.ics.list]p4:
-  // C++11 [over.ics.list]p3:
-  //   Otherwise, if the parameter is a non-aggregate class X and overload
-  //   resolution chooses a single best constructor [...] the implicit
-  //   conversion sequence is a user-defined conversion sequence. If multiple
-  //   constructors are viable but none is better than the others, the
-  //   implicit conversion sequence is a user-defined conversion sequence.
-  if (ToType->isRecordType() && !ToType->isAggregateType()) {
-    // This function can deal with initializer lists.
-    return TryUserDefinedConversion(S, From, ToType, SuppressUserConversions,
-                                    /*AllowExplicit=*/false,
-                                    InOverloadResolution, /*CStyle=*/false,
-                                    AllowObjCWritebackConversion,
-                                    /*AllowObjCConversionOnExplicit=*/false);
-  }
-
-  // C++14 [over.ics.list]p5:
-  // C++11 [over.ics.list]p4:
-  //   Otherwise, if the parameter has an aggregate type which can be
-  //   initialized from the initializer list [...] the implicit conversion
-  //   sequence is a user-defined conversion sequence.
-  if (ToType->isAggregateType()) {
-    // Type is an aggregate, argument is an init list. At this point it comes
-    // down to checking whether the initialization works.
-    // FIXME: Find out whether this parameter is consumed or not.
-    // FIXME: Expose SemaInit's aggregate initialization code so that we don't
-    // need to call into the initialization code here; overload resolution
-    // should not be doing that.
-    InitializedEntity Entity =
-        InitializedEntity::InitializeParameter(S.Context, ToType,
-                                               /*Consumed=*/false);
-    if (S.CanPerformCopyInitialization(Entity, From)) {
-      Result.setUserDefined();
-      Result.UserDefined.Before.setAsIdentityConversion();
-      // Initializer lists don't have a type.
-      Result.UserDefined.Before.setFromType(QualType());
-      Result.UserDefined.Before.setAllToTypes(QualType());
-
-      Result.UserDefined.After.setAsIdentityConversion();
-      Result.UserDefined.After.setFromType(ToType);
-      Result.UserDefined.After.setAllToTypes(ToType);
-      Result.UserDefined.ConversionFunction = nullptr;
-    }
-    return Result;
-  }
-
-  // C++14 [over.ics.list]p6:
-  // C++11 [over.ics.list]p5:
-  //   Otherwise, if the parameter is a reference, see 13.3.3.1.4.
-  if (ToType->isReferenceType()) {
-    // The standard is notoriously unclear here, since 13.3.3.1.4 doesn't
-    // mention initializer lists in any way. So we go by what list-
-    // initialization would do and try to extrapolate from that.
-
-    QualType T1 = ToType->getAs<ReferenceType>()->getPointeeType();
-
-    // If the initializer list has a single element that is reference-related
-    // to the parameter type, we initialize the reference from that.
-    if (From->getNumInits() == 1) {
-      Expr *Init = From->getInit(0);
-
-      QualType T2 = Init->getType();
-
-      // If the initializer is the address of an overloaded function, try
-      // to resolve the overloaded function. If all goes well, T2 is the
-      // type of the resulting function.
-      if (S.Context.getCanonicalType(T2) == S.Context.OverloadTy) {
-        DeclAccessPair Found;
-        if (FunctionDecl *Fn = S.ResolveAddressOfOverloadedFunction(
-                                   Init, ToType, false, Found))
-          T2 = Fn->getType();
-      }
-
-      // Compute some basic properties of the types and the initializer.
-      bool dummy1 = false;
-      bool dummy2 = false;
-      bool dummy3 = false;
-      Sema::ReferenceCompareResult RefRelationship =
-          S.CompareReferenceRelationship(From->getBeginLoc(), T1, T2, dummy1,
-                                         dummy2, dummy3);
-
-      if (RefRelationship >= Sema::Ref_Related) {
-        return TryReferenceInit(S, Init, ToType, /*FIXME*/ From->getBeginLoc(),
-                                SuppressUserConversions,
-                                /*AllowExplicit=*/false);
-      }
-    }
-
-    // Otherwise, we bind the reference to a temporary created from the
-    // initializer list.
-    Result = TryListConversion(S, From, T1, SuppressUserConversions,
-                               InOverloadResolution,
-                               AllowObjCWritebackConversion);
-    if (Result.isFailure())
-      return Result;
-    assert(!Result.isEllipsis() &&
-           "Sub-initialization cannot result in ellipsis conversion.");
-
-    // Can we even bind to a temporary?
-    if (ToType->isRValueReferenceType() ||
-        (T1.isConstQualified() && !T1.isVolatileQualified())) {
-      StandardConversionSequence &SCS = Result.isStandard() ? Result.Standard :
-                                            Result.UserDefined.After;
-      SCS.ReferenceBinding = true;
-      SCS.IsLvalueReference = ToType->isLValueReferenceType();
-      SCS.BindsToRvalue = true;
-      SCS.BindsToFunctionLvalue = false;
-      SCS.BindsImplicitObjectArgumentWithoutRefQualifier = false;
-      SCS.ObjCLifetimeConversionBinding = false;
-    } else
-      Result.setBad(BadConversionSequence::lvalue_ref_to_rvalue,
-                    From, ToType);
-    return Result;
-  }
-
-  // C++14 [over.ics.list]p7:
-  // C++11 [over.ics.list]p6:
-  //   Otherwise, if the parameter type is not a class:
-  if (!ToType->isRecordType()) {
-    //    - if the initializer list has one element that is not itself an
-    //      initializer list, the implicit conversion sequence is the one
-    //      required to convert the element to the parameter type.
-    unsigned NumInits = From->getNumInits();
-    if (NumInits == 1 && !isa<InitListExpr>(From->getInit(0)))
-      Result = TryCopyInitialization(S, From->getInit(0), ToType,
-                                     SuppressUserConversions,
-                                     InOverloadResolution,
-                                     AllowObjCWritebackConversion);
-    //    - if the initializer list has no elements, the implicit conversion
-    //      sequence is the identity conversion.
-    else if (NumInits == 0) {
-      Result.setStandard();
-      Result.Standard.setAsIdentityConversion();
-      Result.Standard.setFromType(ToType);
-      Result.Standard.setAllToTypes(ToType);
-    }
-    return Result;
-  }
-
-  // C++14 [over.ics.list]p8:
-  // C++11 [over.ics.list]p7:
-  //   In all cases other than those enumerated above, no conversion is possible
-  return Result;
-}
-
-/// TryCopyInitialization - Try to copy-initialize a value of type
-/// ToType from the expression From. Return the implicit conversion
-/// sequence required to pass this argument, which may be a bad
-/// conversion sequence (meaning that the argument cannot be passed to
-/// a parameter of this type). If @p SuppressUserConversions, then we
-/// do not permit any user-defined conversion sequences.
-static ImplicitConversionSequence
-TryCopyInitialization(Sema &S, Expr *From, QualType ToType,
-                      bool SuppressUserConversions,
-                      bool InOverloadResolution,
-                      bool AllowObjCWritebackConversion,
-                      bool AllowExplicit) {
-  if (InitListExpr *FromInitList = dyn_cast<InitListExpr>(From))
-    return TryListConversion(S, FromInitList, ToType, SuppressUserConversions,
-                             InOverloadResolution,AllowObjCWritebackConversion);
-
-  if (ToType->isReferenceType())
-    return TryReferenceInit(S, From, ToType,
-                            /*FIXME:*/ From->getBeginLoc(),
-                            SuppressUserConversions, AllowExplicit);
-
-  return TryImplicitConversion(S, From, ToType,
-                               SuppressUserConversions,
-                               /*AllowExplicit=*/false,
-                               InOverloadResolution,
-                               /*CStyle=*/false,
-                               AllowObjCWritebackConversion,
-                               /*AllowObjCConversionOnExplicit=*/false);
-}
-
-static bool TryCopyInitialization(const CanQualType FromQTy,
-                                  const CanQualType ToQTy,
-                                  Sema &S,
-                                  SourceLocation Loc,
-                                  ExprValueKind FromVK) {
-  OpaqueValueExpr TmpExpr(Loc, FromQTy, FromVK);
-  ImplicitConversionSequence ICS =
-    TryCopyInitialization(S, &TmpExpr, ToQTy, true, true, false);
-
-  return !ICS.isBad();
-}
-
-/// TryObjectArgumentInitialization - Try to initialize the object
-/// parameter of the given member function (@c Method) from the
-/// expression @p From.
-static ImplicitConversionSequence
-TryObjectArgumentInitialization(Sema &S, SourceLocation Loc, QualType FromType,
-                                Expr::Classification FromClassification,
-                                CXXMethodDecl *Method,
-                                CXXRecordDecl *ActingContext) {
-  QualType ClassType = S.Context.getTypeDeclType(ActingContext);
-  // [class.dtor]p2: A destructor can be invoked for a const, volatile or
-  //                 const volatile object.
-  Qualifiers Quals;
-  if (isa<CXXDestructorDecl>(Method)) {
-    Quals.addConst();
-    Quals.addVolatile();
-  } else {
-    Quals = Method->getTypeQualifiers();
-  }
-
-  QualType ImplicitParamType = S.Context.getQualifiedType(ClassType, Quals);
-
-  // Set up the conversion sequence as a "bad" conversion, to allow us
-  // to exit early.
-  ImplicitConversionSequence ICS;
-
-  // We need to have an object of class type.
-  if (const PointerType *PT = FromType->getAs<PointerType>()) {
-    FromType = PT->getPointeeType();
-
-    // When we had a pointer, it's implicitly dereferenced, so we
-    // better have an lvalue.
-    assert(FromClassification.isLValue());
-  }
-
-  assert(FromType->isRecordType());
-
-  // C++0x [over.match.funcs]p4:
-  //   For non-static member functions, the type of the implicit object
-  //   parameter is
-  //
-  //     - "lvalue reference to cv X" for functions declared without a
-  //        ref-qualifier or with the & ref-qualifier
-  //     - "rvalue reference to cv X" for functions declared with the &&
-  //        ref-qualifier
-  //
-  // where X is the class of which the function is a member and cv is the
-  // cv-qualification on the member function declaration.
-  //
-  // However, when finding an implicit conversion sequence for the argument, we
-  // are not allowed to perform user-defined conversions
-  // (C++ [over.match.funcs]p5). We perform a simplified version of
-  // reference binding here, that allows class rvalues to bind to
-  // non-constant references.
-
-  // First check the qualifiers.
-  QualType FromTypeCanon = S.Context.getCanonicalType(FromType);
-  if (ImplicitParamType.getCVRQualifiers()
-                                    != FromTypeCanon.getLocalCVRQualifiers() &&
-      !ImplicitParamType.isAtLeastAsQualifiedAs(FromTypeCanon)) {
-    ICS.setBad(BadConversionSequence::bad_qualifiers,
-               FromType, ImplicitParamType);
-    return ICS;
-  }
-
-  // Check that we have either the same type or a derived type. It
-  // affects the conversion rank.
-  QualType ClassTypeCanon = S.Context.getCanonicalType(ClassType);
-  ImplicitConversionKind SecondKind;
-  if (ClassTypeCanon == FromTypeCanon.getLocalUnqualifiedType()) {
-    SecondKind = ICK_Identity;
-  } else if (S.IsDerivedFrom(Loc, FromType, ClassType))
-    SecondKind = ICK_Derived_To_Base;
-  else {
-    ICS.setBad(BadConversionSequence::unrelated_class,
-               FromType, ImplicitParamType);
-    return ICS;
-  }
-
-  // Check the ref-qualifier.
-  switch (Method->getRefQualifier()) {
-  case RQ_None:
-    // Do nothing; we don't care about lvalueness or rvalueness.
-    break;
-
-  case RQ_LValue:
-    if (!FromClassification.isLValue() && !Quals.hasOnlyConst()) {
-      // non-const lvalue reference cannot bind to an rvalue
-      ICS.setBad(BadConversionSequence::lvalue_ref_to_rvalue, FromType,
-                 ImplicitParamType);
-      return ICS;
-    }
-    break;
-
-  case RQ_RValue:
-    if (!FromClassification.isRValue()) {
-      // rvalue reference cannot bind to an lvalue
-      ICS.setBad(BadConversionSequence::rvalue_ref_to_lvalue, FromType,
-                 ImplicitParamType);
-      return ICS;
-    }
-    break;
-  }
-
-  // Success. Mark this as a reference binding.
-  ICS.setStandard();
-  ICS.Standard.setAsIdentityConversion();
-  ICS.Standard.Second = SecondKind;
-  ICS.Standard.setFromType(FromType);
-  ICS.Standard.setAllToTypes(ImplicitParamType);
-  ICS.Standard.ReferenceBinding = true;
-  ICS.Standard.DirectBinding = true;
-  ICS.Standard.IsLvalueReference = Method->getRefQualifier() != RQ_RValue;
-  ICS.Standard.BindsToFunctionLvalue = false;
-  ICS.Standard.BindsToRvalue = FromClassification.isRValue();
-  ICS.Standard.BindsImplicitObjectArgumentWithoutRefQualifier
-    = (Method->getRefQualifier() == RQ_None);
-  return ICS;
-}
-
-/// PerformObjectArgumentInitialization - Perform initialization of
-/// the implicit object parameter for the given Method with the given
-/// expression.
-ExprResult
-Sema::PerformObjectArgumentInitialization(Expr *From,
-                                          NestedNameSpecifier *Qualifier,
-                                          NamedDecl *FoundDecl,
-                                          CXXMethodDecl *Method) {
-  QualType FromRecordType, DestType;
-  QualType ImplicitParamRecordType  =
-    Method->getThisType()->getAs<PointerType>()->getPointeeType();
-
-  Expr::Classification FromClassification;
-  if (const PointerType *PT = From->getType()->getAs<PointerType>()) {
-    FromRecordType = PT->getPointeeType();
-    DestType = Method->getThisType();
-    FromClassification = Expr::Classification::makeSimpleLValue();
-  } else {
-    FromRecordType = From->getType();
-    DestType = ImplicitParamRecordType;
-    FromClassification = From->Classify(Context);
-
-    // When performing member access on an rvalue, materialize a temporary.
-    if (From->isRValue()) {
-      From = CreateMaterializeTemporaryExpr(FromRecordType, From,
-                                            Method->getRefQualifier() !=
-                                                RefQualifierKind::RQ_RValue);
-    }
-  }
-
-  // Note that we always use the true parent context when performing
-  // the actual argument initialization.
-  ImplicitConversionSequence ICS = TryObjectArgumentInitialization(
-      *this, From->getBeginLoc(), From->getType(), FromClassification, Method,
-      Method->getParent());
-  if (ICS.isBad()) {
-    switch (ICS.Bad.Kind) {
-    case BadConversionSequence::bad_qualifiers: {
-      Qualifiers FromQs = FromRecordType.getQualifiers();
-      Qualifiers ToQs = DestType.getQualifiers();
-      unsigned CVR = FromQs.getCVRQualifiers() & ~ToQs.getCVRQualifiers();
-      if (CVR) {
-        Diag(From->getBeginLoc(), diag::err_member_function_call_bad_cvr)
-            << Method->getDeclName() << FromRecordType << (CVR - 1)
-            << From->getSourceRange();
-        Diag(Method->getLocation(), diag::note_previous_decl)
-          << Method->getDeclName();
-        return ExprError();
-      }
-      break;
-    }
-
-    case BadConversionSequence::lvalue_ref_to_rvalue:
-    case BadConversionSequence::rvalue_ref_to_lvalue: {
-      bool IsRValueQualified =
-        Method->getRefQualifier() == RefQualifierKind::RQ_RValue;
-      Diag(From->getBeginLoc(), diag::err_member_function_call_bad_ref)
-          << Method->getDeclName() << FromClassification.isRValue()
-          << IsRValueQualified;
-      Diag(Method->getLocation(), diag::note_previous_decl)
-        << Method->getDeclName();
-      return ExprError();
-    }
-
-    case BadConversionSequence::no_conversion:
-    case BadConversionSequence::unrelated_class:
-      break;
-    }
-
-    return Diag(From->getBeginLoc(), diag::err_member_function_call_bad_type)
-           << ImplicitParamRecordType << FromRecordType
-           << From->getSourceRange();
-  }
-
-  if (ICS.Standard.Second == ICK_Derived_To_Base) {
-    ExprResult FromRes =
-      PerformObjectMemberConversion(From, Qualifier, FoundDecl, Method);
-    if (FromRes.isInvalid())
-      return ExprError();
-    From = FromRes.get();
-  }
-
-  if (!Context.hasSameType(From->getType(), DestType)) {
-    if (From->getType().getAddressSpace() != DestType.getAddressSpace())
-      From = ImpCastExprToType(From, DestType, CK_AddressSpaceConversion,
-                             From->getValueKind()).get();
-    else
-      From = ImpCastExprToType(From, DestType, CK_NoOp,
-                             From->getValueKind()).get();
-  }
-  return From;
-}
-
-/// TryContextuallyConvertToBool - Attempt to contextually convert the
-/// expression From to bool (C++0x [conv]p3).
-static ImplicitConversionSequence
-TryContextuallyConvertToBool(Sema &S, Expr *From) {
-  return TryImplicitConversion(S, From, S.Context.BoolTy,
-                               /*SuppressUserConversions=*/false,
-                               /*AllowExplicit=*/true,
-                               /*InOverloadResolution=*/false,
-                               /*CStyle=*/false,
-                               /*AllowObjCWritebackConversion=*/false,
-                               /*AllowObjCConversionOnExplicit=*/false);
-}
-
-/// PerformContextuallyConvertToBool - Perform a contextual conversion
-/// of the expression From to bool (C++0x [conv]p3).
-ExprResult Sema::PerformContextuallyConvertToBool(Expr *From) {
-  if (checkPlaceholderForOverload(*this, From))
-    return ExprError();
-
-  ImplicitConversionSequence ICS = TryContextuallyConvertToBool(*this, From);
-  if (!ICS.isBad())
-    return PerformImplicitConversion(From, Context.BoolTy, ICS, AA_Converting);
-
-  if (!DiagnoseMultipleUserDefinedConversion(From, Context.BoolTy))
-    return Diag(From->getBeginLoc(), diag::err_typecheck_bool_condition)
-           << From->getType() << From->getSourceRange();
-  return ExprError();
-}
-
-/// Check that the specified conversion is permitted in a converted constant
-/// expression, according to C++11 [expr.const]p3. Return true if the conversion
-/// is acceptable.
-static bool CheckConvertedConstantConversions(Sema &S,
-                                              StandardConversionSequence &SCS) {
-  // Since we know that the target type is an integral or unscoped enumeration
-  // type, most conversion kinds are impossible. All possible First and Third
-  // conversions are fine.
-  switch (SCS.Second) {
-  case ICK_Identity:
-  case ICK_Function_Conversion:
-  case ICK_Integral_Promotion:
-  case ICK_Integral_Conversion: // Narrowing conversions are checked elsewhere.
-  case ICK_Zero_Queue_Conversion:
-    return true;
-
-  case ICK_Boolean_Conversion:
-    // Conversion from an integral or unscoped enumeration type to bool is
-    // classified as ICK_Boolean_Conversion, but it's also arguably an integral
-    // conversion, so we allow it in a converted constant expression.
-    //
-    // FIXME: Per core issue 1407, we should not allow this, but that breaks
-    // a lot of popular code. We should at least add a warning for this
-    // (non-conforming) extension.
-    return SCS.getFromType()->isIntegralOrUnscopedEnumerationType() &&
-           SCS.getToType(2)->isBooleanType();
-
-  case ICK_Pointer_Conversion:
-  case ICK_Pointer_Member:
-    // C++1z: null pointer conversions and null member pointer conversions are
-    // only permitted if the source type is std::nullptr_t.
-    return SCS.getFromType()->isNullPtrType();
-
-  case ICK_Floating_Promotion:
-  case ICK_Complex_Promotion:
-  case ICK_Floating_Conversion:
-  case ICK_Complex_Conversion:
-  case ICK_Floating_Integral:
-  case ICK_Compatible_Conversion:
-  case ICK_Derived_To_Base:
-  case ICK_Vector_Conversion:
-  case ICK_Vector_Splat:
-  case ICK_Complex_Real:
-  case ICK_Block_Pointer_Conversion:
-  case ICK_TransparentUnionConversion:
-  case ICK_Writeback_Conversion:
-  case ICK_Zero_Event_Conversion:
-  case ICK_C_Only_Conversion:
-  case ICK_Incompatible_Pointer_Conversion:
-    return false;
-
-  case ICK_Lvalue_To_Rvalue:
-  case ICK_Array_To_Pointer:
-  case ICK_Function_To_Pointer:
-    llvm_unreachable("found a first conversion kind in Second");
-
-  case ICK_Qualification:
-    llvm_unreachable("found a third conversion kind in Second");
-
-  case ICK_Num_Conversion_Kinds:
-    break;
-  }
-
-  llvm_unreachable("unknown conversion kind");
-}
-
-/// CheckConvertedConstantExpression - Check that the expression From is a
-/// converted constant expression of type T, perform the conversion and produce
-/// the converted expression, per C++11 [expr.const]p3.
-static ExprResult CheckConvertedConstantExpression(Sema &S, Expr *From,
-                                                   QualType T, APValue &Value,
-                                                   Sema::CCEKind CCE,
-                                                   bool RequireInt) {
-  assert(S.getLangOpts().CPlusPlus11 &&
-         "converted constant expression outside C++11");
-
-  if (checkPlaceholderForOverload(S, From))
-    return ExprError();
-
-  // C++1z [expr.const]p3:
-  //  A converted constant expression of type T is an expression,
-  //  implicitly converted to type T, where the converted
-  //  expression is a constant expression and the implicit conversion
-  //  sequence contains only [... list of conversions ...].
-  // C++1z [stmt.if]p2:
-  //  If the if statement is of the form if constexpr, the value of the
-  //  condition shall be a contextually converted constant expression of type
-  //  bool.
-  ImplicitConversionSequence ICS =
-      CCE == Sema::CCEK_ConstexprIf
-          ? TryContextuallyConvertToBool(S, From)
-          : TryCopyInitialization(S, From, T,
-                                  /*SuppressUserConversions=*/false,
-                                  /*InOverloadResolution=*/false,
-                                  /*AllowObjcWritebackConversion=*/false,
-                                  /*AllowExplicit=*/false);
-  StandardConversionSequence *SCS = nullptr;
-  switch (ICS.getKind()) {
-  case ImplicitConversionSequence::StandardConversion:
-    SCS = &ICS.Standard;
-    break;
-  case ImplicitConversionSequence::UserDefinedConversion:
-    // We are converting to a non-class type, so the Before sequence
-    // must be trivial.
-    SCS = &ICS.UserDefined.After;
-    break;
-  case ImplicitConversionSequence::AmbiguousConversion:
-  case ImplicitConversionSequence::BadConversion:
-    if (!S.DiagnoseMultipleUserDefinedConversion(From, T))
-      return S.Diag(From->getBeginLoc(),
-                    diag::err_typecheck_converted_constant_expression)
-             << From->getType() << From->getSourceRange() << T;
-    return ExprError();
-
-  case ImplicitConversionSequence::EllipsisConversion:
-    llvm_unreachable("ellipsis conversion in converted constant expression");
-  }
-
-  // Check that we would only use permitted conversions.
-  if (!CheckConvertedConstantConversions(S, *SCS)) {
-    return S.Diag(From->getBeginLoc(),
-                  diag::err_typecheck_converted_constant_expression_disallowed)
-           << From->getType() << From->getSourceRange() << T;
-  }
-  // [...] and where the reference binding (if any) binds directly.
-  if (SCS->ReferenceBinding && !SCS->DirectBinding) {
-    return S.Diag(From->getBeginLoc(),
-                  diag::err_typecheck_converted_constant_expression_indirect)
-           << From->getType() << From->getSourceRange() << T;
-  }
-
-  ExprResult Result =
-      S.PerformImplicitConversion(From, T, ICS, Sema::AA_Converting);
-  if (Result.isInvalid())
-    return Result;
-
-  // Check for a narrowing implicit conversion.
-  APValue PreNarrowingValue;
-  QualType PreNarrowingType;
-  switch (SCS->getNarrowingKind(S.Context, Result.get(), PreNarrowingValue,
-                                PreNarrowingType)) {
-  case NK_Dependent_Narrowing:
-    // Implicit conversion to a narrower type, but the expression is
-    // value-dependent so we can't tell whether it's actually narrowing.
-  case NK_Variable_Narrowing:
-    // Implicit conversion to a narrower type, and the value is not a constant
-    // expression. We'll diagnose this in a moment.
-  case NK_Not_Narrowing:
-    break;
-
-  case NK_Constant_Narrowing:
-    S.Diag(From->getBeginLoc(), diag::ext_cce_narrowing)
-        << CCE << /*Constant*/ 1
-        << PreNarrowingValue.getAsString(S.Context, PreNarrowingType) << T;
-    break;
-
-  case NK_Type_Narrowing:
-    S.Diag(From->getBeginLoc(), diag::ext_cce_narrowing)
-        << CCE << /*Constant*/ 0 << From->getType() << T;
-    break;
-  }
-
-  if (Result.get()->isValueDependent()) {
-    Value = APValue();
-    return Result;
-  }
-
-  // Check the expression is a constant expression.
-  SmallVector<PartialDiagnosticAt, 8> Notes;
-  Expr::EvalResult Eval;
-  Eval.Diag = &Notes;
-  Expr::ConstExprUsage Usage = CCE == Sema::CCEK_TemplateArg
-                                   ? Expr::EvaluateForMangling
-                                   : Expr::EvaluateForCodeGen;
-
-  if (!Result.get()->EvaluateAsConstantExpr(Eval, Usage, S.Context) ||
-      (RequireInt && !Eval.Val.isInt())) {
-    // The expression can't be folded, so we can't keep it at this position in
-    // the AST.
-    Result = ExprError();
-  } else {
-    Value = Eval.Val;
-
-    if (Notes.empty()) {
-      // It's a constant expression.
-      return ConstantExpr::Create(S.Context, Result.get());
-    }
-  }
-
-  // It's not a constant expression. Produce an appropriate diagnostic.
-  if (Notes.size() == 1 &&
-      Notes[0].second.getDiagID() == diag::note_invalid_subexpr_in_const_expr)
-    S.Diag(Notes[0].first, diag::err_expr_not_cce) << CCE;
-  else {
-    S.Diag(From->getBeginLoc(), diag::err_expr_not_cce)
-        << CCE << From->getSourceRange();
-    for (unsigned I = 0; I < Notes.size(); ++I)
-      S.Diag(Notes[I].first, Notes[I].second);
-  }
-  return ExprError();
-}
-
-ExprResult Sema::CheckConvertedConstantExpression(Expr *From, QualType T,
-                                                  APValue &Value, CCEKind CCE) {
-  return ::CheckConvertedConstantExpression(*this, From, T, Value, CCE, false);
-}
-
-ExprResult Sema::CheckConvertedConstantExpression(Expr *From, QualType T,
-                                                  llvm::APSInt &Value,
-                                                  CCEKind CCE) {
-  assert(T->isIntegralOrEnumerationType() && "unexpected converted const type");
-
-  APValue V;
-  auto R = ::CheckConvertedConstantExpression(*this, From, T, V, CCE, true);
-  if (!R.isInvalid() && !R.get()->isValueDependent())
-    Value = V.getInt();
-  return R;
-}
-
-
-/// dropPointerConversions - If the given standard conversion sequence
-/// involves any pointer conversions, remove them.  This may change
-/// the result type of the conversion sequence.
-static void dropPointerConversion(StandardConversionSequence &SCS) {
-  if (SCS.Second == ICK_Pointer_Conversion) {
-    SCS.Second = ICK_Identity;
-    SCS.Third = ICK_Identity;
-    SCS.ToTypePtrs[2] = SCS.ToTypePtrs[1] = SCS.ToTypePtrs[0];
-  }
-}
-
-/// TryContextuallyConvertToObjCPointer - Attempt to contextually
-/// convert the expression From to an Objective-C pointer type.
-static ImplicitConversionSequence
-TryContextuallyConvertToObjCPointer(Sema &S, Expr *From) {
-  // Do an implicit conversion to 'id'.
-  QualType Ty = S.Context.getObjCIdType();
-  ImplicitConversionSequence ICS
-    = TryImplicitConversion(S, From, Ty,
-                            // FIXME: Are these flags correct?
-                            /*SuppressUserConversions=*/false,
-                            /*AllowExplicit=*/true,
-                            /*InOverloadResolution=*/false,
-                            /*CStyle=*/false,
-                            /*AllowObjCWritebackConversion=*/false,
-                            /*AllowObjCConversionOnExplicit=*/true);
-
-  // Strip off any final conversions to 'id'.
-  switch (ICS.getKind()) {
-  case ImplicitConversionSequence::BadConversion:
-  case ImplicitConversionSequence::AmbiguousConversion:
-  case ImplicitConversionSequence::EllipsisConversion:
-    break;
-
-  case ImplicitConversionSequence::UserDefinedConversion:
-    dropPointerConversion(ICS.UserDefined.After);
-    break;
-
-  case ImplicitConversionSequence::StandardConversion:
-    dropPointerConversion(ICS.Standard);
-    break;
-  }
-
-  return ICS;
-}
-
-/// PerformContextuallyConvertToObjCPointer - Perform a contextual
-/// conversion of the expression From to an Objective-C pointer type.
-/// Returns a valid but null ExprResult if no conversion sequence exists.
-ExprResult Sema::PerformContextuallyConvertToObjCPointer(Expr *From) {
-  if (checkPlaceholderForOverload(*this, From))
-    return ExprError();
-
-  QualType Ty = Context.getObjCIdType();
-  ImplicitConversionSequence ICS =
-    TryContextuallyConvertToObjCPointer(*this, From);
-  if (!ICS.isBad())
-    return PerformImplicitConversion(From, Ty, ICS, AA_Converting);
-  return ExprResult();
-}
-
-/// Determine whether the provided type is an integral type, or an enumeration
-/// type of a permitted flavor.
-bool Sema::ICEConvertDiagnoser::match(QualType T) {
-  return AllowScopedEnumerations ? T->isIntegralOrEnumerationType()
-                                 : T->isIntegralOrUnscopedEnumerationType();
-}
-
-static ExprResult
-diagnoseAmbiguousConversion(Sema &SemaRef, SourceLocation Loc, Expr *From,
-                            Sema::ContextualImplicitConverter &Converter,
-                            QualType T, UnresolvedSetImpl &ViableConversions) {
-
-  if (Converter.Suppress)
-    return ExprError();
-
-  Converter.diagnoseAmbiguous(SemaRef, Loc, T) << From->getSourceRange();
-  for (unsigned I = 0, N = ViableConversions.size(); I != N; ++I) {
-    CXXConversionDecl *Conv =
-        cast<CXXConversionDecl>(ViableConversions[I]->getUnderlyingDecl());
-    QualType ConvTy = Conv->getConversionType().getNonReferenceType();
-    Converter.noteAmbiguous(SemaRef, Conv, ConvTy);
-  }
-  return From;
-}
-
-static bool
-diagnoseNoViableConversion(Sema &SemaRef, SourceLocation Loc, Expr *&From,
-                           Sema::ContextualImplicitConverter &Converter,
-                           QualType T, bool HadMultipleCandidates,
-                           UnresolvedSetImpl &ExplicitConversions) {
-  if (ExplicitConversions.size() == 1 && !Converter.Suppress) {
-    DeclAccessPair Found = ExplicitConversions[0];
-    CXXConversionDecl *Conversion =
-        cast<CXXConversionDecl>(Found->getUnderlyingDecl());
-
-    // The user probably meant to invoke the given explicit
-    // conversion; use it.
-    QualType ConvTy = Conversion->getConversionType().getNonReferenceType();
-    std::string TypeStr;
-    ConvTy.getAsStringInternal(TypeStr, SemaRef.getPrintingPolicy());
-
-    Converter.diagnoseExplicitConv(SemaRef, Loc, T, ConvTy)
-        << FixItHint::CreateInsertion(From->getBeginLoc(),
-                                      "static_cast<" + TypeStr + ">(")
-        << FixItHint::CreateInsertion(
-               SemaRef.getLocForEndOfToken(From->getEndLoc()), ")");
-    Converter.noteExplicitConv(SemaRef, Conversion, ConvTy);
-
-    // If we aren't in a SFINAE context, build a call to the
-    // explicit conversion function.
-    if (SemaRef.isSFINAEContext())
-      return true;
-
-    SemaRef.CheckMemberOperatorAccess(From->getExprLoc(), From, nullptr, Found);
-    ExprResult Result = SemaRef.BuildCXXMemberCallExpr(From, Found, Conversion,
-                                                       HadMultipleCandidates);
-    if (Result.isInvalid())
-      return true;
-    // Record usage of conversion in an implicit cast.
-    From = ImplicitCastExpr::Create(SemaRef.Context, Result.get()->getType(),
-                                    CK_UserDefinedConversion, Result.get(),
-                                    nullptr, Result.get()->getValueKind());
-  }
-  return false;
-}
-
-static bool recordConversion(Sema &SemaRef, SourceLocation Loc, Expr *&From,
-                             Sema::ContextualImplicitConverter &Converter,
-                             QualType T, bool HadMultipleCandidates,
-                             DeclAccessPair &Found) {
-  CXXConversionDecl *Conversion =
-      cast<CXXConversionDecl>(Found->getUnderlyingDecl());
-  SemaRef.CheckMemberOperatorAccess(From->getExprLoc(), From, nullptr, Found);
-
-  QualType ToType = Conversion->getConversionType().getNonReferenceType();
-  if (!Converter.SuppressConversion) {
-    if (SemaRef.isSFINAEContext())
-      return true;
-
-    Converter.diagnoseConversion(SemaRef, Loc, T, ToType)
-        << From->getSourceRange();
-  }
-
-  ExprResult Result = SemaRef.BuildCXXMemberCallExpr(From, Found, Conversion,
-                                                     HadMultipleCandidates);
-  if (Result.isInvalid())
-    return true;
-  // Record usage of conversion in an implicit cast.
-  From = ImplicitCastExpr::Create(SemaRef.Context, Result.get()->getType(),
-                                  CK_UserDefinedConversion, Result.get(),
-                                  nullptr, Result.get()->getValueKind());
-  return false;
-}
-
-static ExprResult finishContextualImplicitConversion(
-    Sema &SemaRef, SourceLocation Loc, Expr *From,
-    Sema::ContextualImplicitConverter &Converter) {
-  if (!Converter.match(From->getType()) && !Converter.Suppress)
-    Converter.diagnoseNoMatch(SemaRef, Loc, From->getType())
-        << From->getSourceRange();
-
-  return SemaRef.DefaultLvalueConversion(From);
-}
-
-static void
-collectViableConversionCandidates(Sema &SemaRef, Expr *From, QualType ToType,
-                                  UnresolvedSetImpl &ViableConversions,
-                                  OverloadCandidateSet &CandidateSet) {
-  for (unsigned I = 0, N = ViableConversions.size(); I != N; ++I) {
-    DeclAccessPair FoundDecl = ViableConversions[I];
-    NamedDecl *D = FoundDecl.getDecl();
-    CXXRecordDecl *ActingContext = cast<CXXRecordDecl>(D->getDeclContext());
-    if (isa<UsingShadowDecl>(D))
-      D = cast<UsingShadowDecl>(D)->getTargetDecl();
-
-    CXXConversionDecl *Conv;
-    FunctionTemplateDecl *ConvTemplate;
-    if ((ConvTemplate = dyn_cast<FunctionTemplateDecl>(D)))
-      Conv = cast<CXXConversionDecl>(ConvTemplate->getTemplatedDecl());
-    else
-      Conv = cast<CXXConversionDecl>(D);
-
-    if (ConvTemplate)
-      SemaRef.AddTemplateConversionCandidate(
-        ConvTemplate, FoundDecl, ActingContext, From, ToType, CandidateSet,
-        /*AllowObjCConversionOnExplicit=*/false);
-    else
-      SemaRef.AddConversionCandidate(Conv, FoundDecl, ActingContext, From,
-                                     ToType, CandidateSet,
-                                     /*AllowObjCConversionOnExplicit=*/false);
-  }
-}
-
-/// Attempt to convert the given expression to a type which is accepted
-/// by the given converter.
-///
-/// This routine will attempt to convert an expression of class type to a
-/// type accepted by the specified converter. In C++11 and before, the class
-/// must have a single non-explicit conversion function converting to a matching
-/// type. In C++1y, there can be multiple such conversion functions, but only
-/// one target type.
-///
-/// \param Loc The source location of the construct that requires the
-/// conversion.
-///
-/// \param From The expression we're converting from.
-///
-/// \param Converter Used to control and diagnose the conversion process.
-///
-/// \returns The expression, converted to an integral or enumeration type if
-/// successful.
-ExprResult Sema::PerformContextualImplicitConversion(
-    SourceLocation Loc, Expr *From, ContextualImplicitConverter &Converter) {
-  // We can't perform any more checking for type-dependent expressions.
-  if (From->isTypeDependent())
-    return From;
-
-  // Process placeholders immediately.
-  if (From->hasPlaceholderType()) {
-    ExprResult result = CheckPlaceholderExpr(From);
-    if (result.isInvalid())
-      return result;
-    From = result.get();
-  }
-
-  // If the expression already has a matching type, we're golden.
-  QualType T = From->getType();
-  if (Converter.match(T))
-    return DefaultLvalueConversion(From);
-
-  // FIXME: Check for missing '()' if T is a function type?
-
-  // We can only perform contextual implicit conversions on objects of class
-  // type.
-  const RecordType *RecordTy = T->getAs<RecordType>();
-  if (!RecordTy || !getLangOpts().CPlusPlus) {
-    if (!Converter.Suppress)
-      Converter.diagnoseNoMatch(*this, Loc, T) << From->getSourceRange();
-    return From;
-  }
-
-  // We must have a complete class type.
-  struct TypeDiagnoserPartialDiag : TypeDiagnoser {
-    ContextualImplicitConverter &Converter;
-    Expr *From;
-
-    TypeDiagnoserPartialDiag(ContextualImplicitConverter &Converter, Expr *From)
-        : Converter(Converter), From(From) {}
-
-    void diagnose(Sema &S, SourceLocation Loc, QualType T) override {
-      Converter.diagnoseIncomplete(S, Loc, T) << From->getSourceRange();
-    }
-  } IncompleteDiagnoser(Converter, From);
-
-  if (Converter.Suppress ? !isCompleteType(Loc, T)
-                         : RequireCompleteType(Loc, T, IncompleteDiagnoser))
-    return From;
-
-  // Look for a conversion to an integral or enumeration type.
-  UnresolvedSet<4>
-      ViableConversions; // These are *potentially* viable in C++1y.
-  UnresolvedSet<4> ExplicitConversions;
-  const auto &Conversions =
-      cast<CXXRecordDecl>(RecordTy->getDecl())->getVisibleConversionFunctions();
-
-  bool HadMultipleCandidates =
-      (std::distance(Conversions.begin(), Conversions.end()) > 1);
-
-  // To check that there is only one target type, in C++1y:
-  QualType ToType;
-  bool HasUniqueTargetType = true;
-
-  // Collect explicit or viable (potentially in C++1y) conversions.
-  for (auto I = Conversions.begin(), E = Conversions.end(); I != E; ++I) {
-    NamedDecl *D = (*I)->getUnderlyingDecl();
-    CXXConversionDecl *Conversion;
-    FunctionTemplateDecl *ConvTemplate = dyn_cast<FunctionTemplateDecl>(D);
-    if (ConvTemplate) {
-      if (getLangOpts().CPlusPlus14)
-        Conversion = cast<CXXConversionDecl>(ConvTemplate->getTemplatedDecl());
-      else
-        continue; // C++11 does not consider conversion operator templates(?).
-    } else
-      Conversion = cast<CXXConversionDecl>(D);
-
-    assert((!ConvTemplate || getLangOpts().CPlusPlus14) &&
-           "Conversion operator templates are considered potentially "
-           "viable in C++1y");
-
-    QualType CurToType = Conversion->getConversionType().getNonReferenceType();
-    if (Converter.match(CurToType) || ConvTemplate) {
-
-      if (Conversion->isExplicit()) {
-        // FIXME: For C++1y, do we need this restriction?
-        // cf. diagnoseNoViableConversion()
-        if (!ConvTemplate)
-          ExplicitConversions.addDecl(I.getDecl(), I.getAccess());
-      } else {
-        if (!ConvTemplate && getLangOpts().CPlusPlus14) {
-          if (ToType.isNull())
-            ToType = CurToType.getUnqualifiedType();
-          else if (HasUniqueTargetType &&
-                   (CurToType.getUnqualifiedType() != ToType))
-            HasUniqueTargetType = false;
-        }
-        ViableConversions.addDecl(I.getDecl(), I.getAccess());
-      }
-    }
-  }
-
-  if (getLangOpts().CPlusPlus14) {
-    // C++1y [conv]p6:
-    // ... An expression e of class type E appearing in such a context
-    // is said to be contextually implicitly converted to a specified
-    // type T and is well-formed if and only if e can be implicitly
-    // converted to a type T that is determined as follows: E is searched
-    // for conversion functions whose return type is cv T or reference to
-    // cv T such that T is allowed by the context. There shall be
-    // exactly one such T.
-
-    // If no unique T is found:
-    if (ToType.isNull()) {
-      if (diagnoseNoViableConversion(*this, Loc, From, Converter, T,
-                                     HadMultipleCandidates,
-                                     ExplicitConversions))
-        return ExprError();
-      return finishContextualImplicitConversion(*this, Loc, From, Converter);
-    }
-
-    // If more than one unique Ts are found:
-    if (!HasUniqueTargetType)
-      return diagnoseAmbiguousConversion(*this, Loc, From, Converter, T,
-                                         ViableConversions);
-
-    // If one unique T is found:
-    // First, build a candidate set from the previously recorded
-    // potentially viable conversions.
-    OverloadCandidateSet CandidateSet(Loc, OverloadCandidateSet::CSK_Normal);
-    collectViableConversionCandidates(*this, From, ToType, ViableConversions,
-                                      CandidateSet);
-
-    // Then, perform overload resolution over the candidate set.
-    OverloadCandidateSet::iterator Best;
-    switch (CandidateSet.BestViableFunction(*this, Loc, Best)) {
-    case OR_Success: {
-      // Apply this conversion.
-      DeclAccessPair Found =
-          DeclAccessPair::make(Best->Function, Best->FoundDecl.getAccess());
-      if (recordConversion(*this, Loc, From, Converter, T,
-                           HadMultipleCandidates, Found))
-        return ExprError();
-      break;
-    }
-    case OR_Ambiguous:
-      return diagnoseAmbiguousConversion(*this, Loc, From, Converter, T,
-                                         ViableConversions);
-    case OR_No_Viable_Function:
-      if (diagnoseNoViableConversion(*this, Loc, From, Converter, T,
-                                     HadMultipleCandidates,
-                                     ExplicitConversions))
-        return ExprError();
-      LLVM_FALLTHROUGH;
-    case OR_Deleted:
-      // We'll complain below about a non-integral condition type.
-      break;
-    }
-  } else {
-    switch (ViableConversions.size()) {
-    case 0: {
-      if (diagnoseNoViableConversion(*this, Loc, From, Converter, T,
-                                     HadMultipleCandidates,
-                                     ExplicitConversions))
-        return ExprError();
-
-      // We'll complain below about a non-integral condition type.
-      break;
-    }
-    case 1: {
-      // Apply this conversion.
-      DeclAccessPair Found = ViableConversions[0];
-      if (recordConversion(*this, Loc, From, Converter, T,
-                           HadMultipleCandidates, Found))
-        return ExprError();
-      break;
-    }
-    default:
-      return diagnoseAmbiguousConversion(*this, Loc, From, Converter, T,
-                                         ViableConversions);
-    }
-  }
-
-  return finishContextualImplicitConversion(*this, Loc, From, Converter);
-}
-
-/// IsAcceptableNonMemberOperatorCandidate - Determine whether Fn is
-/// an acceptable non-member overloaded operator for a call whose
-/// arguments have types T1 (and, if non-empty, T2). This routine
-/// implements the check in C++ [over.match.oper]p3b2 concerning
-/// enumeration types.
-static bool IsAcceptableNonMemberOperatorCandidate(ASTContext &Context,
-                                                   FunctionDecl *Fn,
-                                                   ArrayRef<Expr *> Args) {
-  QualType T1 = Args[0]->getType();
-  QualType T2 = Args.size() > 1 ? Args[1]->getType() : QualType();
-
-  if (T1->isDependentType() || (!T2.isNull() && T2->isDependentType()))
-    return true;
-
-  if (T1->isRecordType() || (!T2.isNull() && T2->isRecordType()))
-    return true;
-
-  const FunctionProtoType *Proto = Fn->getType()->getAs<FunctionProtoType>();
-  if (Proto->getNumParams() < 1)
-    return false;
-
-  if (T1->isEnumeralType()) {
-    QualType ArgType = Proto->getParamType(0).getNonReferenceType();
-    if (Context.hasSameUnqualifiedType(T1, ArgType))
-      return true;
-  }
-
-  if (Proto->getNumParams() < 2)
-    return false;
-
-  if (!T2.isNull() && T2->isEnumeralType()) {
-    QualType ArgType = Proto->getParamType(1).getNonReferenceType();
-    if (Context.hasSameUnqualifiedType(T2, ArgType))
-      return true;
-  }
-
-  return false;
-}
-
-/// AddOverloadCandidate - Adds the given function to the set of
-/// candidate functions, using the given function call arguments.  If
-/// @p SuppressUserConversions, then don't allow user-defined
-/// conversions via constructors or conversion operators.
-///
-/// \param PartialOverloading true if we are performing "partial" overloading
-/// based on an incomplete set of function arguments. This feature is used by
-/// code completion.
-void Sema::AddOverloadCandidate(FunctionDecl *Function,
-                                DeclAccessPair FoundDecl, ArrayRef<Expr *> Args,
-                                OverloadCandidateSet &CandidateSet,
-                                bool SuppressUserConversions,
-                                bool PartialOverloading, bool AllowExplicit,
-                                ADLCallKind IsADLCandidate,
-                                ConversionSequenceList EarlyConversions) {
-  const FunctionProtoType *Proto
-    = dyn_cast<FunctionProtoType>(Function->getType()->getAs<FunctionType>());
-  assert(Proto && "Functions without a prototype cannot be overloaded");
-  assert(!Function->getDescribedFunctionTemplate() &&
-         "Use AddTemplateOverloadCandidate for function templates");
-
-  if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(Function)) {
-    if (!isa<CXXConstructorDecl>(Method)) {
-      // If we get here, it's because we're calling a member function
-      // that is named without a member access expression (e.g.,
-      // "this->f") that was either written explicitly or created
-      // implicitly. This can happen with a qualified call to a member
-      // function, e.g., X::f(). We use an empty type for the implied
-      // object argument (C++ [over.call.func]p3), and the acting context
-      // is irrelevant.
-      AddMethodCandidate(Method, FoundDecl, Method->getParent(), QualType(),
-                         Expr::Classification::makeSimpleLValue(), Args,
-                         CandidateSet, SuppressUserConversions,
-                         PartialOverloading, EarlyConversions);
-      return;
-    }
-    // We treat a constructor like a non-member function, since its object
-    // argument doesn't participate in overload resolution.
-  }
-
-  if (!CandidateSet.isNewCandidate(Function))
-    return;
-
-  // C++ [over.match.oper]p3:
-  //   if no operand has a class type, only those non-member functions in the
-  //   lookup set that have a first parameter of type T1 or "reference to
-  //   (possibly cv-qualified) T1", when T1 is an enumeration type, or (if there
-  //   is a right operand) a second parameter of type T2 or "reference to
-  //   (possibly cv-qualified) T2", when T2 is an enumeration type, are
-  //   candidate functions.
-  if (CandidateSet.getKind() == OverloadCandidateSet::CSK_Operator &&
-      !IsAcceptableNonMemberOperatorCandidate(Context, Function, Args))
-    return;
-
-  // C++11 [class.copy]p11: [DR1402]
-  //   A defaulted move constructor that is defined as deleted is ignored by
-  //   overload resolution.
-  CXXConstructorDecl *Constructor = dyn_cast<CXXConstructorDecl>(Function);
-  if (Constructor && Constructor->isDefaulted() && Constructor->isDeleted() &&
-      Constructor->isMoveConstructor())
-    return;
-
-  // Overload resolution is always an unevaluated context.
-  EnterExpressionEvaluationContext Unevaluated(
-      *this, Sema::ExpressionEvaluationContext::Unevaluated);
-
-  // Add this candidate
-  OverloadCandidate &Candidate =
-      CandidateSet.addCandidate(Args.size(), EarlyConversions);
-  Candidate.FoundDecl = FoundDecl;
-  Candidate.Function = Function;
-  Candidate.Viable = true;
-  Candidate.IsSurrogate = false;
-  Candidate.IsADLCandidate = IsADLCandidate;
-  Candidate.IgnoreObjectArgument = false;
-  Candidate.ExplicitCallArguments = Args.size();
-
-  if (Function->isMultiVersion() && Function->hasAttr<TargetAttr>() &&
-      !Function->getAttr<TargetAttr>()->isDefaultVersion()) {
-    Candidate.Viable = false;
-    Candidate.FailureKind = ovl_non_default_multiversion_function;
-    return;
-  }
-
-  if (Constructor) {
-    // C++ [class.copy]p3:
-    //   A member function template is never instantiated to perform the copy
-    //   of a class object to an object of its class type.
-    QualType ClassType = Context.getTypeDeclType(Constructor->getParent());
-    if (Args.size() == 1 && Constructor->isSpecializationCopyingObject() &&
-        (Context.hasSameUnqualifiedType(ClassType, Args[0]->getType()) ||
-         IsDerivedFrom(Args[0]->getBeginLoc(), Args[0]->getType(),
-                       ClassType))) {
-      Candidate.Viable = false;
-      Candidate.FailureKind = ovl_fail_illegal_constructor;
-      return;
-    }
-
-    // C++ [over.match.funcs]p8: (proposed DR resolution)
-    //   A constructor inherited from class type C that has a first parameter
-    //   of type "reference to P" (including such a constructor instantiated
-    //   from a template) is excluded from the set of candidate functions when
-    //   constructing an object of type cv D if the argument list has exactly
-    //   one argument and D is reference-related to P and P is reference-related
-    //   to C.
-    auto *Shadow = dyn_cast<ConstructorUsingShadowDecl>(FoundDecl.getDecl());
-    if (Shadow && Args.size() == 1 && Constructor->getNumParams() >= 1 &&
-        Constructor->getParamDecl(0)->getType()->isReferenceType()) {
-      QualType P = Constructor->getParamDecl(0)->getType()->getPointeeType();
-      QualType C = Context.getRecordType(Constructor->getParent());
-      QualType D = Context.getRecordType(Shadow->getParent());
-      SourceLocation Loc = Args.front()->getExprLoc();
-      if ((Context.hasSameUnqualifiedType(P, C) || IsDerivedFrom(Loc, P, C)) &&
-          (Context.hasSameUnqualifiedType(D, P) || IsDerivedFrom(Loc, D, P))) {
-        Candidate.Viable = false;
-        Candidate.FailureKind = ovl_fail_inhctor_slice;
-        return;
-      }
-    }
-  }
-
-  unsigned NumParams = Proto->getNumParams();
-
-  // (C++ 13.3.2p2): A candidate function having fewer than m
-  // parameters is viable only if it has an ellipsis in its parameter
-  // list (8.3.5).
-  if (TooManyArguments(NumParams, Args.size(), PartialOverloading) &&
-      !Proto->isVariadic()) {
-    Candidate.Viable = false;
-    Candidate.FailureKind = ovl_fail_too_many_arguments;
-    return;
-  }
-
-  // (C++ 13.3.2p2): A candidate function having more than m parameters
-  // is viable only if the (m+1)st parameter has a default argument
-  // (8.3.6). For the purposes of overload resolution, the
-  // parameter list is truncated on the right, so that there are
-  // exactly m parameters.
-  unsigned MinRequiredArgs = Function->getMinRequiredArguments();
-  if (Args.size() < MinRequiredArgs && !PartialOverloading) {
-    // Not enough arguments.
-    Candidate.Viable = false;
-    Candidate.FailureKind = ovl_fail_too_few_arguments;
-    return;
-  }
-
-  // (CUDA B.1): Check for invalid calls between targets.
-  if (getLangOpts().CUDA)
-    if (const FunctionDecl *Caller = dyn_cast<FunctionDecl>(CurContext))
-      // Skip the check for callers that are implicit members, because in this
-      // case we may not yet know what the member's target is; the target is
-      // inferred for the member automatically, based on the bases and fields of
-      // the class.
-      if (!Caller->isImplicit() && !IsAllowedCUDACall(Caller, Function)) {
-        Candidate.Viable = false;
-        Candidate.FailureKind = ovl_fail_bad_target;
-        return;
-      }
-
-  // Determine the implicit conversion sequences for each of the
-  // arguments.
-  for (unsigned ArgIdx = 0; ArgIdx < Args.size(); ++ArgIdx) {
-    if (Candidate.Conversions[ArgIdx].isInitialized()) {
-      // We already formed a conversion sequence for this parameter during
-      // template argument deduction.
-    } else if (ArgIdx < NumParams) {
-      // (C++ 13.3.2p3): for F to be a viable function, there shall
-      // exist for each argument an implicit conversion sequence
-      // (13.3.3.1) that converts that argument to the corresponding
-      // parameter of F.
-      QualType ParamType = Proto->getParamType(ArgIdx);
-      Candidate.Conversions[ArgIdx]
-        = TryCopyInitialization(*this, Args[ArgIdx], ParamType,
-                                SuppressUserConversions,
-                                /*InOverloadResolution=*/true,
-                                /*AllowObjCWritebackConversion=*/
-                                  getLangOpts().ObjCAutoRefCount,
-                                AllowExplicit);
-      if (Candidate.Conversions[ArgIdx].isBad()) {
-        Candidate.Viable = false;
-        Candidate.FailureKind = ovl_fail_bad_conversion;
-        return;
-      }
-    } else {
-      // (C++ 13.3.2p2): For the purposes of overload resolution, any
-      // argument for which there is no corresponding parameter is
-      // considered to ""match the ellipsis" (C+ 13.3.3.1.3).
-      Candidate.Conversions[ArgIdx].setEllipsis();
-    }
-  }
-
-  if (EnableIfAttr *FailedAttr = CheckEnableIf(Function, Args)) {
-    Candidate.Viable = false;
-    Candidate.FailureKind = ovl_fail_enable_if;
-    Candidate.DeductionFailure.Data = FailedAttr;
-    return;
-  }
-
-  if (LangOpts.OpenCL && isOpenCLDisabledDecl(Function)) {
-    Candidate.Viable = false;
-    Candidate.FailureKind = ovl_fail_ext_disabled;
-    return;
-  }
-}
-
-ObjCMethodDecl *
-Sema::SelectBestMethod(Selector Sel, MultiExprArg Args, bool IsInstance,
-                       SmallVectorImpl<ObjCMethodDecl *> &Methods) {
-  if (Methods.size() <= 1)
-    return nullptr;
-
-  for (unsigned b = 0, e = Methods.size(); b < e; b++) {
-    bool Match = true;
-    ObjCMethodDecl *Method = Methods[b];
-    unsigned NumNamedArgs = Sel.getNumArgs();
-    // Method might have more arguments than selector indicates. This is due
-    // to addition of c-style arguments in method.
-    if (Method->param_size() > NumNamedArgs)
-      NumNamedArgs = Method->param_size();
-    if (Args.size() < NumNamedArgs)
-      continue;
-
-    for (unsigned i = 0; i < NumNamedArgs; i++) {
-      // We can't do any type-checking on a type-dependent argument.
-      if (Args[i]->isTypeDependent()) {
-        Match = false;
-        break;
-      }
-
-      ParmVarDecl *param = Method->parameters()[i];
-      Expr *argExpr = Args[i];
-      assert(argExpr && "SelectBestMethod(): missing expression");
-
-      // Strip the unbridged-cast placeholder expression off unless it's
-      // a consumed argument.
-      if (argExpr->hasPlaceholderType(BuiltinType::ARCUnbridgedCast) &&
-          !param->hasAttr<CFConsumedAttr>())
-        argExpr = stripARCUnbridgedCast(argExpr);
-
-      // If the parameter is __unknown_anytype, move on to the next method.
-      if (param->getType() == Context.UnknownAnyTy) {
-        Match = false;
-        break;
-      }
-
-      ImplicitConversionSequence ConversionState
-        = TryCopyInitialization(*this, argExpr, param->getType(),
-                                /*SuppressUserConversions*/false,
-                                /*InOverloadResolution=*/true,
-                                /*AllowObjCWritebackConversion=*/
-                                getLangOpts().ObjCAutoRefCount,
-                                /*AllowExplicit*/false);
-      // This function looks for a reasonably-exact match, so we consider
-      // incompatible pointer conversions to be a failure here.
-      if (ConversionState.isBad() ||
-          (ConversionState.isStandard() &&
-           ConversionState.Standard.Second ==
-               ICK_Incompatible_Pointer_Conversion)) {
-        Match = false;
-        break;
-      }
-    }
-    // Promote additional arguments to variadic methods.
-    if (Match && Method->isVariadic()) {
-      for (unsigned i = NumNamedArgs, e = Args.size(); i < e; ++i) {
-        if (Args[i]->isTypeDependent()) {
-          Match = false;
-          break;
-        }
-        ExprResult Arg = DefaultVariadicArgumentPromotion(Args[i], VariadicMethod,
-                                                          nullptr);
-        if (Arg.isInvalid()) {
-          Match = false;
-          break;
-        }
-      }
-    } else {
-      // Check for extra arguments to non-variadic methods.
-      if (Args.size() != NumNamedArgs)
-        Match = false;
-      else if (Match && NumNamedArgs == 0 && Methods.size() > 1) {
-        // Special case when selectors have no argument. In this case, select
-        // one with the most general result type of 'id'.
-        for (unsigned b = 0, e = Methods.size(); b < e; b++) {
-          QualType ReturnT = Methods[b]->getReturnType();
-          if (ReturnT->isObjCIdType())
-            return Methods[b];
-        }
-      }
-    }
-
-    if (Match)
-      return Method;
-  }
-  return nullptr;
-}
-
-static bool
-convertArgsForAvailabilityChecks(Sema &S, FunctionDecl *Function, Expr *ThisArg,
-                                 ArrayRef<Expr *> Args, Sema::SFINAETrap &Trap,
-                                 bool MissingImplicitThis, Expr *&ConvertedThis,
-                                 SmallVectorImpl<Expr *> &ConvertedArgs) {
-  if (ThisArg) {
-    CXXMethodDecl *Method = cast<CXXMethodDecl>(Function);
-    assert(!isa<CXXConstructorDecl>(Method) &&
-           "Shouldn't have `this` for ctors!");
-    assert(!Method->isStatic() && "Shouldn't have `this` for static methods!");
-    ExprResult R = S.PerformObjectArgumentInitialization(
-        ThisArg, /*Qualifier=*/nullptr, Method, Method);
-    if (R.isInvalid())
-      return false;
-    ConvertedThis = R.get();
-  } else {
-    if (auto *MD = dyn_cast<CXXMethodDecl>(Function)) {
-      (void)MD;
-      assert((MissingImplicitThis || MD->isStatic() ||
-              isa<CXXConstructorDecl>(MD)) &&
-             "Expected `this` for non-ctor instance methods");
-    }
-    ConvertedThis = nullptr;
-  }
-
-  // Ignore any variadic arguments. Converting them is pointless, since the
-  // user can't refer to them in the function condition.
-  unsigned ArgSizeNoVarargs = std::min(Function->param_size(), Args.size());
-
-  // Convert the arguments.
-  for (unsigned I = 0; I != ArgSizeNoVarargs; ++I) {
-    ExprResult R;
-    R = S.PerformCopyInitialization(InitializedEntity::InitializeParameter(
-                                        S.Context, Function->getParamDecl(I)),
-                                    SourceLocation(), Args[I]);
-
-    if (R.isInvalid())
-      return false;
-
-    ConvertedArgs.push_back(R.get());
-  }
-
-  if (Trap.hasErrorOccurred())
-    return false;
-
-  // Push default arguments if needed.
-  if (!Function->isVariadic() && Args.size() < Function->getNumParams()) {
-    for (unsigned i = Args.size(), e = Function->getNumParams(); i != e; ++i) {
-      ParmVarDecl *P = Function->getParamDecl(i);
-      Expr *DefArg = P->hasUninstantiatedDefaultArg()
-                         ? P->getUninstantiatedDefaultArg()
-                         : P->getDefaultArg();
-      // This can only happen in code completion, i.e. when PartialOverloading
-      // is true.
-      if (!DefArg)
-        return false;
-      ExprResult R =
-          S.PerformCopyInitialization(InitializedEntity::InitializeParameter(
-                                          S.Context, Function->getParamDecl(i)),
-                                      SourceLocation(), DefArg);
-      if (R.isInvalid())
-        return false;
-      ConvertedArgs.push_back(R.get());
-    }
-
-    if (Trap.hasErrorOccurred())
-      return false;
-  }
-  return true;
-}
-
-EnableIfAttr *Sema::CheckEnableIf(FunctionDecl *Function, ArrayRef<Expr *> Args,
-                                  bool MissingImplicitThis) {
-  auto EnableIfAttrs = Function->specific_attrs<EnableIfAttr>();
-  if (EnableIfAttrs.begin() == EnableIfAttrs.end())
-    return nullptr;
-
-  SFINAETrap Trap(*this);
-  SmallVector<Expr *, 16> ConvertedArgs;
-  // FIXME: We should look into making enable_if late-parsed.
-  Expr *DiscardedThis;
-  if (!convertArgsForAvailabilityChecks(
-          *this, Function, /*ThisArg=*/nullptr, Args, Trap,
-          /*MissingImplicitThis=*/true, DiscardedThis, ConvertedArgs))
-    return *EnableIfAttrs.begin();
-
-  for (auto *EIA : EnableIfAttrs) {
-    APValue Result;
-    // FIXME: This doesn't consider value-dependent cases, because doing so is
-    // very difficult. Ideally, we should handle them more gracefully.
-    if (!EIA->getCond()->EvaluateWithSubstitution(
-            Result, Context, Function, llvm::makeArrayRef(ConvertedArgs)))
-      return EIA;
-
-    if (!Result.isInt() || !Result.getInt().getBoolValue())
-      return EIA;
-  }
-  return nullptr;
-}
-
-template <typename CheckFn>
-static bool diagnoseDiagnoseIfAttrsWith(Sema &S, const NamedDecl *ND,
-                                        bool ArgDependent, SourceLocation Loc,
-                                        CheckFn &&IsSuccessful) {
-  SmallVector<const DiagnoseIfAttr *, 8> Attrs;
-  for (const auto *DIA : ND->specific_attrs<DiagnoseIfAttr>()) {
-    if (ArgDependent == DIA->getArgDependent())
-      Attrs.push_back(DIA);
-  }
-
-  // Common case: No diagnose_if attributes, so we can quit early.
-  if (Attrs.empty())
-    return false;
-
-  auto WarningBegin = std::stable_partition(
-      Attrs.begin(), Attrs.end(),
-      [](const DiagnoseIfAttr *DIA) { return DIA->isError(); });
-
-  // Note that diagnose_if attributes are late-parsed, so they appear in the
-  // correct order (unlike enable_if attributes).
-  auto ErrAttr = llvm::find_if(llvm::make_range(Attrs.begin(), WarningBegin),
-                               IsSuccessful);
-  if (ErrAttr != WarningBegin) {
-    const DiagnoseIfAttr *DIA = *ErrAttr;
-    S.Diag(Loc, diag::err_diagnose_if_succeeded) << DIA->getMessage();
-    S.Diag(DIA->getLocation(), diag::note_from_diagnose_if)
-        << DIA->getParent() << DIA->getCond()->getSourceRange();
-    return true;
-  }
-
-  for (const auto *DIA : llvm::make_range(WarningBegin, Attrs.end()))
-    if (IsSuccessful(DIA)) {
-      S.Diag(Loc, diag::warn_diagnose_if_succeeded) << DIA->getMessage();
-      S.Diag(DIA->getLocation(), diag::note_from_diagnose_if)
-          << DIA->getParent() << DIA->getCond()->getSourceRange();
-    }
-
-  return false;
-}
-
-bool Sema::diagnoseArgDependentDiagnoseIfAttrs(const FunctionDecl *Function,
-                                               const Expr *ThisArg,
-                                               ArrayRef<const Expr *> Args,
-                                               SourceLocation Loc) {
-  return diagnoseDiagnoseIfAttrsWith(
-      *this, Function, /*ArgDependent=*/true, Loc,
-      [&](const DiagnoseIfAttr *DIA) {
-        APValue Result;
-        // It's sane to use the same Args for any redecl of this function, since
-        // EvaluateWithSubstitution only cares about the position of each
-        // argument in the arg list, not the ParmVarDecl* it maps to.
-        if (!DIA->getCond()->EvaluateWithSubstitution(
-                Result, Context, cast<FunctionDecl>(DIA->getParent()), Args, ThisArg))
-          return false;
-        return Result.isInt() && Result.getInt().getBoolValue();
-      });
-}
-
-bool Sema::diagnoseArgIndependentDiagnoseIfAttrs(const NamedDecl *ND,
-                                                 SourceLocation Loc) {
-  return diagnoseDiagnoseIfAttrsWith(
-      *this, ND, /*ArgDependent=*/false, Loc,
-      [&](const DiagnoseIfAttr *DIA) {
-        bool Result;
-        return DIA->getCond()->EvaluateAsBooleanCondition(Result, Context) &&
-               Result;
-      });
-}
-
-/// Add all of the function declarations in the given function set to
-/// the overload candidate set.
-void Sema::AddFunctionCandidates(const UnresolvedSetImpl &Fns,
-                                 ArrayRef<Expr *> Args,
-                                 OverloadCandidateSet &CandidateSet,
-                                 TemplateArgumentListInfo *ExplicitTemplateArgs,
-                                 bool SuppressUserConversions,
-                                 bool PartialOverloading,
-                                 bool FirstArgumentIsBase) {
-  for (UnresolvedSetIterator F = Fns.begin(), E = Fns.end(); F != E; ++F) {
-    NamedDecl *D = F.getDecl()->getUnderlyingDecl();
-    ArrayRef<Expr *> FunctionArgs = Args;
-
-    FunctionTemplateDecl *FunTmpl = dyn_cast<FunctionTemplateDecl>(D);
-    FunctionDecl *FD =
-        FunTmpl ? FunTmpl->getTemplatedDecl() : cast<FunctionDecl>(D);
-
-    if (isa<CXXMethodDecl>(FD) && !cast<CXXMethodDecl>(FD)->isStatic()) {
-      QualType ObjectType;
-      Expr::Classification ObjectClassification;
-      if (Args.size() > 0) {
-        if (Expr *E = Args[0]) {
-          // Use the explicit base to restrict the lookup:
-          ObjectType = E->getType();
-          // Pointers in the object arguments are implicitly dereferenced, so we
-          // always classify them as l-values.
-          if (!ObjectType.isNull() && ObjectType->isPointerType())
-            ObjectClassification = Expr::Classification::makeSimpleLValue();
-          else
-            ObjectClassification = E->Classify(Context);
-        } // .. else there is an implicit base.
-        FunctionArgs = Args.slice(1);
-      }
-      if (FunTmpl) {
-        AddMethodTemplateCandidate(
-            FunTmpl, F.getPair(),
-            cast<CXXRecordDecl>(FunTmpl->getDeclContext()),
-            ExplicitTemplateArgs, ObjectType, ObjectClassification,
-            FunctionArgs, CandidateSet, SuppressUserConversions,
-            PartialOverloading);
-      } else {
-        AddMethodCandidate(cast<CXXMethodDecl>(FD), F.getPair(),
-                           cast<CXXMethodDecl>(FD)->getParent(), ObjectType,
-                           ObjectClassification, FunctionArgs, CandidateSet,
-                           SuppressUserConversions, PartialOverloading);
-      }
-    } else {
-      // This branch handles both standalone functions and static methods.
-
-      // Slice the first argument (which is the base) when we access
-      // static method as non-static.
-      if (Args.size() > 0 &&
-          (!Args[0] || (FirstArgumentIsBase && isa<CXXMethodDecl>(FD) &&
-                        !isa<CXXConstructorDecl>(FD)))) {
-        assert(cast<CXXMethodDecl>(FD)->isStatic());
-        FunctionArgs = Args.slice(1);
-      }
-      if (FunTmpl) {
-        AddTemplateOverloadCandidate(
-            FunTmpl, F.getPair(), ExplicitTemplateArgs, FunctionArgs,
-            CandidateSet, SuppressUserConversions, PartialOverloading);
-      } else {
-        AddOverloadCandidate(FD, F.getPair(), FunctionArgs, CandidateSet,
-                             SuppressUserConversions, PartialOverloading);
-      }
-    }
-  }
-}
-
-/// AddMethodCandidate - Adds a named decl (which is some kind of
-/// method) as a method candidate to the given overload set.
-void Sema::AddMethodCandidate(DeclAccessPair FoundDecl,
-                              QualType ObjectType,
-                              Expr::Classification ObjectClassification,
-                              ArrayRef<Expr *> Args,
-                              OverloadCandidateSet& CandidateSet,
-                              bool SuppressUserConversions) {
-  NamedDecl *Decl = FoundDecl.getDecl();
-  CXXRecordDecl *ActingContext = cast<CXXRecordDecl>(Decl->getDeclContext());
-
-  if (isa<UsingShadowDecl>(Decl))
-    Decl = cast<UsingShadowDecl>(Decl)->getTargetDecl();
-
-  if (FunctionTemplateDecl *TD = dyn_cast<FunctionTemplateDecl>(Decl)) {
-    assert(isa<CXXMethodDecl>(TD->getTemplatedDecl()) &&
-           "Expected a member function template");
-    AddMethodTemplateCandidate(TD, FoundDecl, ActingContext,
-                               /*ExplicitArgs*/ nullptr, ObjectType,
-                               ObjectClassification, Args, CandidateSet,
-                               SuppressUserConversions);
-  } else {
-    AddMethodCandidate(cast<CXXMethodDecl>(Decl), FoundDecl, ActingContext,
-                       ObjectType, ObjectClassification, Args, CandidateSet,
-                       SuppressUserConversions);
-  }
-}
-
-/// AddMethodCandidate - Adds the given C++ member function to the set
-/// of candidate functions, using the given function call arguments
-/// and the object argument (@c Object). For example, in a call
-/// @c o.f(a1,a2), @c Object will contain @c o and @c Args will contain
-/// both @c a1 and @c a2. If @p SuppressUserConversions, then don't
-/// allow user-defined conversions via constructors or conversion
-/// operators.
-void
-Sema::AddMethodCandidate(CXXMethodDecl *Method, DeclAccessPair FoundDecl,
-                         CXXRecordDecl *ActingContext, QualType ObjectType,
-                         Expr::Classification ObjectClassification,
-                         ArrayRef<Expr *> Args,
-                         OverloadCandidateSet &CandidateSet,
-                         bool SuppressUserConversions,
-                         bool PartialOverloading,
-                         ConversionSequenceList EarlyConversions) {
-  const FunctionProtoType *Proto
-    = dyn_cast<FunctionProtoType>(Method->getType()->getAs<FunctionType>());
-  assert(Proto && "Methods without a prototype cannot be overloaded");
-  assert(!isa<CXXConstructorDecl>(Method) &&
-         "Use AddOverloadCandidate for constructors");
-
-  if (!CandidateSet.isNewCandidate(Method))
-    return;
-
-  // C++11 [class.copy]p23: [DR1402]
-  //   A defaulted move assignment operator that is defined as deleted is
-  //   ignored by overload resolution.
-  if (Method->isDefaulted() && Method->isDeleted() &&
-      Method->isMoveAssignmentOperator())
-    return;
-
-  // Overload resolution is always an unevaluated context.
-  EnterExpressionEvaluationContext Unevaluated(
-      *this, Sema::ExpressionEvaluationContext::Unevaluated);
-
-  // Add this candidate
-  OverloadCandidate &Candidate =
-      CandidateSet.addCandidate(Args.size() + 1, EarlyConversions);
-  Candidate.FoundDecl = FoundDecl;
-  Candidate.Function = Method;
-  Candidate.IsSurrogate = false;
-  Candidate.IgnoreObjectArgument = false;
-  Candidate.ExplicitCallArguments = Args.size();
-
-  unsigned NumParams = Proto->getNumParams();
-
-  // (C++ 13.3.2p2): A candidate function having fewer than m
-  // parameters is viable only if it has an ellipsis in its parameter
-  // list (8.3.5).
-  if (TooManyArguments(NumParams, Args.size(), PartialOverloading) &&
-      !Proto->isVariadic()) {
-    Candidate.Viable = false;
-    Candidate.FailureKind = ovl_fail_too_many_arguments;
-    return;
-  }
-
-  // (C++ 13.3.2p2): A candidate function having more than m parameters
-  // is viable only if the (m+1)st parameter has a default argument
-  // (8.3.6). For the purposes of overload resolution, the
-  // parameter list is truncated on the right, so that there are
-  // exactly m parameters.
-  unsigned MinRequiredArgs = Method->getMinRequiredArguments();
-  if (Args.size() < MinRequiredArgs && !PartialOverloading) {
-    // Not enough arguments.
-    Candidate.Viable = false;
-    Candidate.FailureKind = ovl_fail_too_few_arguments;
-    return;
-  }
-
-  Candidate.Viable = true;
-
-  if (Method->isStatic() || ObjectType.isNull())
-    // The implicit object argument is ignored.
-    Candidate.IgnoreObjectArgument = true;
-  else {
-    // Determine the implicit conversion sequence for the object
-    // parameter.
-    Candidate.Conversions[0] = TryObjectArgumentInitialization(
-        *this, CandidateSet.getLocation(), ObjectType, ObjectClassification,
-        Method, ActingContext);
-    if (Candidate.Conversions[0].isBad()) {
-      Candidate.Viable = false;
-      Candidate.FailureKind = ovl_fail_bad_conversion;
-      return;
-    }
-  }
-
-  // (CUDA B.1): Check for invalid calls between targets.
-  if (getLangOpts().CUDA)
-    if (const FunctionDecl *Caller = dyn_cast<FunctionDecl>(CurContext))
-      if (!IsAllowedCUDACall(Caller, Method)) {
-        Candidate.Viable = false;
-        Candidate.FailureKind = ovl_fail_bad_target;
-        return;
-      }
-
-  // Determine the implicit conversion sequences for each of the
-  // arguments.
-  for (unsigned ArgIdx = 0; ArgIdx < Args.size(); ++ArgIdx) {
-    if (Candidate.Conversions[ArgIdx + 1].isInitialized()) {
-      // We already formed a conversion sequence for this parameter during
-      // template argument deduction.
-    } else if (ArgIdx < NumParams) {
-      // (C++ 13.3.2p3): for F to be a viable function, there shall
-      // exist for each argument an implicit conversion sequence
-      // (13.3.3.1) that converts that argument to the corresponding
-      // parameter of F.
-      QualType ParamType = Proto->getParamType(ArgIdx);
-      Candidate.Conversions[ArgIdx + 1]
-        = TryCopyInitialization(*this, Args[ArgIdx], ParamType,
-                                SuppressUserConversions,
-                                /*InOverloadResolution=*/true,
-                                /*AllowObjCWritebackConversion=*/
-                                  getLangOpts().ObjCAutoRefCount);
-      if (Candidate.Conversions[ArgIdx + 1].isBad()) {
-        Candidate.Viable = false;
-        Candidate.FailureKind = ovl_fail_bad_conversion;
-        return;
-      }
-    } else {
-      // (C++ 13.3.2p2): For the purposes of overload resolution, any
-      // argument for which there is no corresponding parameter is
-      // considered to "match the ellipsis" (C+ 13.3.3.1.3).
-      Candidate.Conversions[ArgIdx + 1].setEllipsis();
-    }
-  }
-
-  if (EnableIfAttr *FailedAttr = CheckEnableIf(Method, Args, true)) {
-    Candidate.Viable = false;
-    Candidate.FailureKind = ovl_fail_enable_if;
-    Candidate.DeductionFailure.Data = FailedAttr;
-    return;
-  }
-
-  if (Method->isMultiVersion() && Method->hasAttr<TargetAttr>() &&
-      !Method->getAttr<TargetAttr>()->isDefaultVersion()) {
-    Candidate.Viable = false;
-    Candidate.FailureKind = ovl_non_default_multiversion_function;
-  }
-}
-
-/// Add a C++ member function template as a candidate to the candidate
-/// set, using template argument deduction to produce an appropriate member
-/// function template specialization.
-void
-Sema::AddMethodTemplateCandidate(FunctionTemplateDecl *MethodTmpl,
-                                 DeclAccessPair FoundDecl,
-                                 CXXRecordDecl *ActingContext,
-                                 TemplateArgumentListInfo *ExplicitTemplateArgs,
-                                 QualType ObjectType,
-                                 Expr::Classification ObjectClassification,
-                                 ArrayRef<Expr *> Args,
-                                 OverloadCandidateSet& CandidateSet,
-                                 bool SuppressUserConversions,
-                                 bool PartialOverloading) {
-  if (!CandidateSet.isNewCandidate(MethodTmpl))
-    return;
-
-  // C++ [over.match.funcs]p7:
-  //   In each case where a candidate is a function template, candidate
-  //   function template specializations are generated using template argument
-  //   deduction (14.8.3, 14.8.2). Those candidates are then handled as
-  //   candidate functions in the usual way.113) A given name can refer to one
-  //   or more function templates and also to a set of overloaded non-template
-  //   functions. In such a case, the candidate functions generated from each
-  //   function template are combined with the set of non-template candidate
-  //   functions.
-  TemplateDeductionInfo Info(CandidateSet.getLocation());
-  FunctionDecl *Specialization = nullptr;
-  ConversionSequenceList Conversions;
-  if (TemplateDeductionResult Result = DeduceTemplateArguments(
-          MethodTmpl, ExplicitTemplateArgs, Args, Specialization, Info,
-          PartialOverloading, [&](ArrayRef<QualType> ParamTypes) {
-            return CheckNonDependentConversions(
-                MethodTmpl, ParamTypes, Args, CandidateSet, Conversions,
-                SuppressUserConversions, ActingContext, ObjectType,
-                ObjectClassification);
-          })) {
-    OverloadCandidate &Candidate =
-        CandidateSet.addCandidate(Conversions.size(), Conversions);
-    Candidate.FoundDecl = FoundDecl;
-    Candidate.Function = MethodTmpl->getTemplatedDecl();
-    Candidate.Viable = false;
-    Candidate.IsSurrogate = false;
-    Candidate.IgnoreObjectArgument =
-        cast<CXXMethodDecl>(Candidate.Function)->isStatic() ||
-        ObjectType.isNull();
-    Candidate.ExplicitCallArguments = Args.size();
-    if (Result == TDK_NonDependentConversionFailure)
-      Candidate.FailureKind = ovl_fail_bad_conversion;
-    else {
-      Candidate.FailureKind = ovl_fail_bad_deduction;
-      Candidate.DeductionFailure = MakeDeductionFailureInfo(Context, Result,
-                                                            Info);
-    }
-    return;
-  }
-
-  // Add the function template specialization produced by template argument
-  // deduction as a candidate.
-  assert(Specialization && "Missing member function template specialization?");
-  assert(isa<CXXMethodDecl>(Specialization) &&
-         "Specialization is not a member function?");
-  AddMethodCandidate(cast<CXXMethodDecl>(Specialization), FoundDecl,
-                     ActingContext, ObjectType, ObjectClassification, Args,
-                     CandidateSet, SuppressUserConversions, PartialOverloading,
-                     Conversions);
-}
-
-/// Add a C++ function template specialization as a candidate
-/// in the candidate set, using template argument deduction to produce
-/// an appropriate function template specialization.
-void Sema::AddTemplateOverloadCandidate(
-    FunctionTemplateDecl *FunctionTemplate, DeclAccessPair FoundDecl,
-    TemplateArgumentListInfo *ExplicitTemplateArgs, ArrayRef<Expr *> Args,
-    OverloadCandidateSet &CandidateSet, bool SuppressUserConversions,
-    bool PartialOverloading, ADLCallKind IsADLCandidate) {
-  if (!CandidateSet.isNewCandidate(FunctionTemplate))
-    return;
-
-  // C++ [over.match.funcs]p7:
-  //   In each case where a candidate is a function template, candidate
-  //   function template specializations are generated using template argument
-  //   deduction (14.8.3, 14.8.2). Those candidates are then handled as
-  //   candidate functions in the usual way.113) A given name can refer to one
-  //   or more function templates and also to a set of overloaded non-template
-  //   functions. In such a case, the candidate functions generated from each
-  //   function template are combined with the set of non-template candidate
-  //   functions.
-  TemplateDeductionInfo Info(CandidateSet.getLocation());
-  FunctionDecl *Specialization = nullptr;
-  ConversionSequenceList Conversions;
-  if (TemplateDeductionResult Result = DeduceTemplateArguments(
-          FunctionTemplate, ExplicitTemplateArgs, Args, Specialization, Info,
-          PartialOverloading, [&](ArrayRef<QualType> ParamTypes) {
-            return CheckNonDependentConversions(FunctionTemplate, ParamTypes,
-                                                Args, CandidateSet, Conversions,
-                                                SuppressUserConversions);
-          })) {
-    OverloadCandidate &Candidate =
-        CandidateSet.addCandidate(Conversions.size(), Conversions);
-    Candidate.FoundDecl = FoundDecl;
-    Candidate.Function = FunctionTemplate->getTemplatedDecl();
-    Candidate.Viable = false;
-    Candidate.IsSurrogate = false;
-    Candidate.IsADLCandidate = IsADLCandidate;
-    // Ignore the object argument if there is one, since we don't have an object
-    // type.
-    Candidate.IgnoreObjectArgument =
-        isa<CXXMethodDecl>(Candidate.Function) &&
-        !isa<CXXConstructorDecl>(Candidate.Function);
-    Candidate.ExplicitCallArguments = Args.size();
-    if (Result == TDK_NonDependentConversionFailure)
-      Candidate.FailureKind = ovl_fail_bad_conversion;
-    else {
-      Candidate.FailureKind = ovl_fail_bad_deduction;
-      Candidate.DeductionFailure = MakeDeductionFailureInfo(Context, Result,
-                                                            Info);
-    }
-    return;
-  }
-
-  // Add the function template specialization produced by template argument
-  // deduction as a candidate.
-  assert(Specialization && "Missing function template specialization?");
-  AddOverloadCandidate(Specialization, FoundDecl, Args, CandidateSet,
-                       SuppressUserConversions, PartialOverloading,
-                       /*AllowExplicit*/ false, IsADLCandidate, Conversions);
-}
-
-/// Check that implicit conversion sequences can be formed for each argument
-/// whose corresponding parameter has a non-dependent type, per DR1391's
-/// [temp.deduct.call]p10.
-bool Sema::CheckNonDependentConversions(
-    FunctionTemplateDecl *FunctionTemplate, ArrayRef<QualType> ParamTypes,
-    ArrayRef<Expr *> Args, OverloadCandidateSet &CandidateSet,
-    ConversionSequenceList &Conversions, bool SuppressUserConversions,
-    CXXRecordDecl *ActingContext, QualType ObjectType,
-    Expr::Classification ObjectClassification) {
-  // FIXME: The cases in which we allow explicit conversions for constructor
-  // arguments never consider calling a constructor template. It's not clear
-  // that is correct.
-  const bool AllowExplicit = false;
-
-  auto *FD = FunctionTemplate->getTemplatedDecl();
-  auto *Method = dyn_cast<CXXMethodDecl>(FD);
-  bool HasThisConversion = Method && !isa<CXXConstructorDecl>(Method);
-  unsigned ThisConversions = HasThisConversion ? 1 : 0;
-
-  Conversions =
-      CandidateSet.allocateConversionSequences(ThisConversions + Args.size());
-
-  // Overload resolution is always an unevaluated context.
-  EnterExpressionEvaluationContext Unevaluated(
-      *this, Sema::ExpressionEvaluationContext::Unevaluated);
-
-  // For a method call, check the 'this' conversion here too. DR1391 doesn't
-  // require that, but this check should never result in a hard error, and
-  // overload resolution is permitted to sidestep instantiations.
-  if (HasThisConversion && !cast<CXXMethodDecl>(FD)->isStatic() &&
-      !ObjectType.isNull()) {
-    Conversions[0] = TryObjectArgumentInitialization(
-        *this, CandidateSet.getLocation(), ObjectType, ObjectClassification,
-        Method, ActingContext);
-    if (Conversions[0].isBad())
-      return true;
-  }
-
-  for (unsigned I = 0, N = std::min(ParamTypes.size(), Args.size()); I != N;
-       ++I) {
-    QualType ParamType = ParamTypes[I];
-    if (!ParamType->isDependentType()) {
-      Conversions[ThisConversions + I]
-        = TryCopyInitialization(*this, Args[I], ParamType,
-                                SuppressUserConversions,
-                                /*InOverloadResolution=*/true,
-                                /*AllowObjCWritebackConversion=*/
-                                  getLangOpts().ObjCAutoRefCount,
-                                AllowExplicit);
-      if (Conversions[ThisConversions + I].isBad())
-        return true;
-    }
-  }
-
-  return false;
-}
-
-/// Determine whether this is an allowable conversion from the result
-/// of an explicit conversion operator to the expected type, per C++
-/// [over.match.conv]p1 and [over.match.ref]p1.
-///
-/// \param ConvType The return type of the conversion function.
-///
-/// \param ToType The type we are converting to.
-///
-/// \param AllowObjCPointerConversion Allow a conversion from one
-/// Objective-C pointer to another.
-///
-/// \returns true if the conversion is allowable, false otherwise.
-static bool isAllowableExplicitConversion(Sema &S,
-                                          QualType ConvType, QualType ToType,
-                                          bool AllowObjCPointerConversion) {
-  QualType ToNonRefType = ToType.getNonReferenceType();
-
-  // Easy case: the types are the same.
-  if (S.Context.hasSameUnqualifiedType(ConvType, ToNonRefType))
-    return true;
-
-  // Allow qualification conversions.
-  bool ObjCLifetimeConversion;
-  if (S.IsQualificationConversion(ConvType, ToNonRefType, /*CStyle*/false,
-                                  ObjCLifetimeConversion))
-    return true;
-
-  // If we're not allowed to consider Objective-C pointer conversions,
-  // we're done.
-  if (!AllowObjCPointerConversion)
-    return false;
-
-  // Is this an Objective-C pointer conversion?
-  bool IncompatibleObjC = false;
-  QualType ConvertedType;
-  return S.isObjCPointerConversion(ConvType, ToNonRefType, ConvertedType,
-                                   IncompatibleObjC);
-}
-
-/// AddConversionCandidate - Add a C++ conversion function as a
-/// candidate in the candidate set (C++ [over.match.conv],
-/// C++ [over.match.copy]). From is the expression we're converting from,
-/// and ToType is the type that we're eventually trying to convert to
-/// (which may or may not be the same type as the type that the
-/// conversion function produces).
-void
-Sema::AddConversionCandidate(CXXConversionDecl *Conversion,
-                             DeclAccessPair FoundDecl,
-                             CXXRecordDecl *ActingContext,
-                             Expr *From, QualType ToType,
-                             OverloadCandidateSet& CandidateSet,
-                             bool AllowObjCConversionOnExplicit,
-                             bool AllowResultConversion) {
-  assert(!Conversion->getDescribedFunctionTemplate() &&
-         "Conversion function templates use AddTemplateConversionCandidate");
-  QualType ConvType = Conversion->getConversionType().getNonReferenceType();
-  if (!CandidateSet.isNewCandidate(Conversion))
-    return;
-
-  // If the conversion function has an undeduced return type, trigger its
-  // deduction now.
-  if (getLangOpts().CPlusPlus14 && ConvType->isUndeducedType()) {
-    if (DeduceReturnType(Conversion, From->getExprLoc()))
-      return;
-    ConvType = Conversion->getConversionType().getNonReferenceType();
-  }
-
-  // If we don't allow any conversion of the result type, ignore conversion
-  // functions that don't convert to exactly (possibly cv-qualified) T.
-  if (!AllowResultConversion &&
-      !Context.hasSameUnqualifiedType(Conversion->getConversionType(), ToType))
-    return;
-
-  // Per C++ [over.match.conv]p1, [over.match.ref]p1, an explicit conversion
-  // operator is only a candidate if its return type is the target type or
-  // can be converted to the target type with a qualification conversion.
-  if (Conversion->isExplicit() &&
-      !isAllowableExplicitConversion(*this, ConvType, ToType,
-                                     AllowObjCConversionOnExplicit))
-    return;
-
-  // Overload resolution is always an unevaluated context.
-  EnterExpressionEvaluationContext Unevaluated(
-      *this, Sema::ExpressionEvaluationContext::Unevaluated);
-
-  // Add this candidate
-  OverloadCandidate &Candidate = CandidateSet.addCandidate(1);
-  Candidate.FoundDecl = FoundDecl;
-  Candidate.Function = Conversion;
-  Candidate.IsSurrogate = false;
-  Candidate.IgnoreObjectArgument = false;
-  Candidate.FinalConversion.setAsIdentityConversion();
-  Candidate.FinalConversion.setFromType(ConvType);
-  Candidate.FinalConversion.setAllToTypes(ToType);
-  Candidate.Viable = true;
-  Candidate.ExplicitCallArguments = 1;
-
-  // C++ [over.match.funcs]p4:
-  //   For conversion functions, the function is considered to be a member of
-  //   the class of the implicit implied object argument for the purpose of
-  //   defining the type of the implicit object parameter.
-  //
-  // Determine the implicit conversion sequence for the implicit
-  // object parameter.
-  QualType ImplicitParamType = From->getType();
-  if (const PointerType *FromPtrType = ImplicitParamType->getAs<PointerType>())
-    ImplicitParamType = FromPtrType->getPointeeType();
-  CXXRecordDecl *ConversionContext
-    = cast<CXXRecordDecl>(ImplicitParamType->getAs<RecordType>()->getDecl());
-
-  Candidate.Conversions[0] = TryObjectArgumentInitialization(
-      *this, CandidateSet.getLocation(), From->getType(),
-      From->Classify(Context), Conversion, ConversionContext);
-
-  if (Candidate.Conversions[0].isBad()) {
-    Candidate.Viable = false;
-    Candidate.FailureKind = ovl_fail_bad_conversion;
-    return;
-  }
-
-  // We won't go through a user-defined type conversion function to convert a
-  // derived to base as such conversions are given Conversion Rank. They only
-  // go through a copy constructor. 13.3.3.1.2-p4 [over.ics.user]
-  QualType FromCanon
-    = Context.getCanonicalType(From->getType().getUnqualifiedType());
-  QualType ToCanon = Context.getCanonicalType(ToType).getUnqualifiedType();
-  if (FromCanon == ToCanon ||
-      IsDerivedFrom(CandidateSet.getLocation(), FromCanon, ToCanon)) {
-    Candidate.Viable = false;
-    Candidate.FailureKind = ovl_fail_trivial_conversion;
-    return;
-  }
-
-  // To determine what the conversion from the result of calling the
-  // conversion function to the type we're eventually trying to
-  // convert to (ToType), we need to synthesize a call to the
-  // conversion function and attempt copy initialization from it. This
-  // makes sure that we get the right semantics with respect to
-  // lvalues/rvalues and the type. Fortunately, we can allocate this
-  // call on the stack and we don't need its arguments to be
-  // well-formed.
-  DeclRefExpr ConversionRef(Context, Conversion, false, Conversion->getType(),
-                            VK_LValue, From->getBeginLoc());
-  ImplicitCastExpr ConversionFn(ImplicitCastExpr::OnStack,
-                                Context.getPointerType(Conversion->getType()),
-                                CK_FunctionToPointerDecay,
-                                &ConversionRef, VK_RValue);
-
-  QualType ConversionType = Conversion->getConversionType();
-  if (!isCompleteType(From->getBeginLoc(), ConversionType)) {
-    Candidate.Viable = false;
-    Candidate.FailureKind = ovl_fail_bad_final_conversion;
-    return;
-  }
-
-  ExprValueKind VK = Expr::getValueKindForType(ConversionType);
-
-  // Note that it is safe to allocate CallExpr on the stack here because
-  // there are 0 arguments (i.e., nothing is allocated using ASTContext's
-  // allocator).
-  QualType CallResultType = ConversionType.getNonLValueExprType(Context);
-
-  llvm::AlignedCharArray<alignof(CallExpr), sizeof(CallExpr) + sizeof(Stmt *)>
-      Buffer;
-  CallExpr *TheTemporaryCall = CallExpr::CreateTemporary(
-      Buffer.buffer, &ConversionFn, CallResultType, VK, From->getBeginLoc());
-
-  ImplicitConversionSequence ICS =
-      TryCopyInitialization(*this, TheTemporaryCall, ToType,
-                            /*SuppressUserConversions=*/true,
-                            /*InOverloadResolution=*/false,
-                            /*AllowObjCWritebackConversion=*/false);
-
-  switch (ICS.getKind()) {
-  case ImplicitConversionSequence::StandardConversion:
-    Candidate.FinalConversion = ICS.Standard;
-
-    // C++ [over.ics.user]p3:
-    //   If the user-defined conversion is specified by a specialization of a
-    //   conversion function template, the second standard conversion sequence
-    //   shall have exact match rank.
-    if (Conversion->getPrimaryTemplate() &&
-        GetConversionRank(ICS.Standard.Second) != ICR_Exact_Match) {
-      Candidate.Viable = false;
-      Candidate.FailureKind = ovl_fail_final_conversion_not_exact;
-      return;
-    }
-
-    // C++0x [dcl.init.ref]p5:
-    //    In the second case, if the reference is an rvalue reference and
-    //    the second standard conversion sequence of the user-defined
-    //    conversion sequence includes an lvalue-to-rvalue conversion, the
-    //    program is ill-formed.
-    if (ToType->isRValueReferenceType() &&
-        ICS.Standard.First == ICK_Lvalue_To_Rvalue) {
-      Candidate.Viable = false;
-      Candidate.FailureKind = ovl_fail_bad_final_conversion;
-      return;
-    }
-    break;
-
-  case ImplicitConversionSequence::BadConversion:
-    Candidate.Viable = false;
-    Candidate.FailureKind = ovl_fail_bad_final_conversion;
-    return;
-
-  default:
-    llvm_unreachable(
-           "Can only end up with a standard conversion sequence or failure");
-  }
-
-  if (EnableIfAttr *FailedAttr = CheckEnableIf(Conversion, None)) {
-    Candidate.Viable = false;
-    Candidate.FailureKind = ovl_fail_enable_if;
-    Candidate.DeductionFailure.Data = FailedAttr;
-    return;
-  }
-
-  if (Conversion->isMultiVersion() && Conversion->hasAttr<TargetAttr>() &&
-      !Conversion->getAttr<TargetAttr>()->isDefaultVersion()) {
-    Candidate.Viable = false;
-    Candidate.FailureKind = ovl_non_default_multiversion_function;
-  }
-}
-
-/// Adds a conversion function template specialization
-/// candidate to the overload set, using template argument deduction
-/// to deduce the template arguments of the conversion function
-/// template from the type that we are converting to (C++
-/// [temp.deduct.conv]).
-void
-Sema::AddTemplateConversionCandidate(FunctionTemplateDecl *FunctionTemplate,
-                                     DeclAccessPair FoundDecl,
-                                     CXXRecordDecl *ActingDC,
-                                     Expr *From, QualType ToType,
-                                     OverloadCandidateSet &CandidateSet,
-                                     bool AllowObjCConversionOnExplicit,
-                                     bool AllowResultConversion) {
-  assert(isa<CXXConversionDecl>(FunctionTemplate->getTemplatedDecl()) &&
-         "Only conversion function templates permitted here");
-
-  if (!CandidateSet.isNewCandidate(FunctionTemplate))
-    return;
-
-  TemplateDeductionInfo Info(CandidateSet.getLocation());
-  CXXConversionDecl *Specialization = nullptr;
-  if (TemplateDeductionResult Result
-        = DeduceTemplateArguments(FunctionTemplate, ToType,
-                                  Specialization, Info)) {
-    OverloadCandidate &Candidate = CandidateSet.addCandidate();
-    Candidate.FoundDecl = FoundDecl;
-    Candidate.Function = FunctionTemplate->getTemplatedDecl();
-    Candidate.Viable = false;
-    Candidate.FailureKind = ovl_fail_bad_deduction;
-    Candidate.IsSurrogate = false;
-    Candidate.IgnoreObjectArgument = false;
-    Candidate.ExplicitCallArguments = 1;
-    Candidate.DeductionFailure = MakeDeductionFailureInfo(Context, Result,
-                                                          Info);
-    return;
-  }
-
-  // Add the conversion function template specialization produced by
-  // template argument deduction as a candidate.
-  assert(Specialization && "Missing function template specialization?");
-  AddConversionCandidate(Specialization, FoundDecl, ActingDC, From, ToType,
-                         CandidateSet, AllowObjCConversionOnExplicit,
-                         AllowResultConversion);
-}
-
-/// AddSurrogateCandidate - Adds a "surrogate" candidate function that
-/// converts the given @c Object to a function pointer via the
-/// conversion function @c Conversion, and then attempts to call it
-/// with the given arguments (C++ [over.call.object]p2-4). Proto is
-/// the type of function that we'll eventually be calling.
-void Sema::AddSurrogateCandidate(CXXConversionDecl *Conversion,
-                                 DeclAccessPair FoundDecl,
-                                 CXXRecordDecl *ActingContext,
-                                 const FunctionProtoType *Proto,
-                                 Expr *Object,
-                                 ArrayRef<Expr *> Args,
-                                 OverloadCandidateSet& CandidateSet) {
-  if (!CandidateSet.isNewCandidate(Conversion))
-    return;
-
-  // Overload resolution is always an unevaluated context.
-  EnterExpressionEvaluationContext Unevaluated(
-      *this, Sema::ExpressionEvaluationContext::Unevaluated);
-
-  OverloadCandidate &Candidate = CandidateSet.addCandidate(Args.size() + 1);
-  Candidate.FoundDecl = FoundDecl;
-  Candidate.Function = nullptr;
-  Candidate.Surrogate = Conversion;
-  Candidate.Viable = true;
-  Candidate.IsSurrogate = true;
-  Candidate.IgnoreObjectArgument = false;
-  Candidate.ExplicitCallArguments = Args.size();
-
-  // Determine the implicit conversion sequence for the implicit
-  // object parameter.
-  ImplicitConversionSequence ObjectInit = TryObjectArgumentInitialization(
-      *this, CandidateSet.getLocation(), Object->getType(),
-      Object->Classify(Context), Conversion, ActingContext);
-  if (ObjectInit.isBad()) {
-    Candidate.Viable = false;
-    Candidate.FailureKind = ovl_fail_bad_conversion;
-    Candidate.Conversions[0] = ObjectInit;
-    return;
-  }
-
-  // The first conversion is actually a user-defined conversion whose
-  // first conversion is ObjectInit's standard conversion (which is
-  // effectively a reference binding). Record it as such.
-  Candidate.Conversions[0].setUserDefined();
-  Candidate.Conversions[0].UserDefined.Before = ObjectInit.Standard;
-  Candidate.Conversions[0].UserDefined.EllipsisConversion = false;
-  Candidate.Conversions[0].UserDefined.HadMultipleCandidates = false;
-  Candidate.Conversions[0].UserDefined.ConversionFunction = Conversion;
-  Candidate.Conversions[0].UserDefined.FoundConversionFunction = FoundDecl;
-  Candidate.Conversions[0].UserDefined.After
-    = Candidate.Conversions[0].UserDefined.Before;
-  Candidate.Conversions[0].UserDefined.After.setAsIdentityConversion();
-
-  // Find the
-  unsigned NumParams = Proto->getNumParams();
-
-  // (C++ 13.3.2p2): A candidate function having fewer than m
-  // parameters is viable only if it has an ellipsis in its parameter
-  // list (8.3.5).
-  if (Args.size() > NumParams && !Proto->isVariadic()) {
-    Candidate.Viable = false;
-    Candidate.FailureKind = ovl_fail_too_many_arguments;
-    return;
-  }
-
-  // Function types don't have any default arguments, so just check if
-  // we have enough arguments.
-  if (Args.size() < NumParams) {
-    // Not enough arguments.
-    Candidate.Viable = false;
-    Candidate.FailureKind = ovl_fail_too_few_arguments;
-    return;
-  }
-
-  // Determine the implicit conversion sequences for each of the
-  // arguments.
-  for (unsigned ArgIdx = 0, N = Args.size(); ArgIdx != N; ++ArgIdx) {
-    if (ArgIdx < NumParams) {
-      // (C++ 13.3.2p3): for F to be a viable function, there shall
-      // exist for each argument an implicit conversion sequence
-      // (13.3.3.1) that converts that argument to the corresponding
-      // parameter of F.
-      QualType ParamType = Proto->getParamType(ArgIdx);
-      Candidate.Conversions[ArgIdx + 1]
-        = TryCopyInitialization(*this, Args[ArgIdx], ParamType,
-                                /*SuppressUserConversions=*/false,
-                                /*InOverloadResolution=*/false,
-                                /*AllowObjCWritebackConversion=*/
-                                  getLangOpts().ObjCAutoRefCount);
-      if (Candidate.Conversions[ArgIdx + 1].isBad()) {
-        Candidate.Viable = false;
-        Candidate.FailureKind = ovl_fail_bad_conversion;
-        return;
-      }
-    } else {
-      // (C++ 13.3.2p2): For the purposes of overload resolution, any
-      // argument for which there is no corresponding parameter is
-      // considered to ""match the ellipsis" (C+ 13.3.3.1.3).
-      Candidate.Conversions[ArgIdx + 1].setEllipsis();
-    }
-  }
-
-  if (EnableIfAttr *FailedAttr = CheckEnableIf(Conversion, None)) {
-    Candidate.Viable = false;
-    Candidate.FailureKind = ovl_fail_enable_if;
-    Candidate.DeductionFailure.Data = FailedAttr;
-    return;
-  }
-}
-
-/// Add overload candidates for overloaded operators that are
-/// member functions.
-///
-/// Add the overloaded operator candidates that are member functions
-/// for the operator Op that was used in an operator expression such
-/// as "x Op y". , Args/NumArgs provides the operator arguments, and
-/// CandidateSet will store the added overload candidates. (C++
-/// [over.match.oper]).
-void Sema::AddMemberOperatorCandidates(OverloadedOperatorKind Op,
-                                       SourceLocation OpLoc,
-                                       ArrayRef<Expr *> Args,
-                                       OverloadCandidateSet& CandidateSet,
-                                       SourceRange OpRange) {
-  DeclarationName OpName = Context.DeclarationNames.getCXXOperatorName(Op);
-
-  // C++ [over.match.oper]p3:
-  //   For a unary operator @ with an operand of a type whose
-  //   cv-unqualified version is T1, and for a binary operator @ with
-  //   a left operand of a type whose cv-unqualified version is T1 and
-  //   a right operand of a type whose cv-unqualified version is T2,
-  //   three sets of candidate functions, designated member
-  //   candidates, non-member candidates and built-in candidates, are
-  //   constructed as follows:
-  QualType T1 = Args[0]->getType();
-
-  //     -- If T1 is a complete class type or a class currently being
-  //        defined, the set of member candidates is the result of the
-  //        qualified lookup of T1::operator@ (13.3.1.1.1); otherwise,
-  //        the set of member candidates is empty.
-  if (const RecordType *T1Rec = T1->getAs<RecordType>()) {
-    // Complete the type if it can be completed.
-    if (!isCompleteType(OpLoc, T1) && !T1Rec->isBeingDefined())
-      return;
-    // If the type is neither complete nor being defined, bail out now.
-    if (!T1Rec->getDecl()->getDefinition())
-      return;
-
-    LookupResult Operators(*this, OpName, OpLoc, LookupOrdinaryName);
-    LookupQualifiedName(Operators, T1Rec->getDecl());
-    Operators.suppressDiagnostics();
-
-    for (LookupResult::iterator Oper = Operators.begin(),
-                             OperEnd = Operators.end();
-         Oper != OperEnd;
-         ++Oper)
-      AddMethodCandidate(Oper.getPair(), Args[0]->getType(),
-                         Args[0]->Classify(Context), Args.slice(1),
-                         CandidateSet, /*SuppressUserConversions=*/false);
-  }
-}
-
-/// AddBuiltinCandidate - Add a candidate for a built-in
-/// operator. ResultTy and ParamTys are the result and parameter types
-/// of the built-in candidate, respectively. Args and NumArgs are the
-/// arguments being passed to the candidate. IsAssignmentOperator
-/// should be true when this built-in candidate is an assignment
-/// operator. NumContextualBoolArguments is the number of arguments
-/// (at the beginning of the argument list) that will be contextually
-/// converted to bool.
-void Sema::AddBuiltinCandidate(QualType *ParamTys, ArrayRef<Expr *> Args,
-                               OverloadCandidateSet& CandidateSet,
-                               bool IsAssignmentOperator,
-                               unsigned NumContextualBoolArguments) {
-  // Overload resolution is always an unevaluated context.
-  EnterExpressionEvaluationContext Unevaluated(
-      *this, Sema::ExpressionEvaluationContext::Unevaluated);
-
-  // Add this candidate
-  OverloadCandidate &Candidate = CandidateSet.addCandidate(Args.size());
-  Candidate.FoundDecl = DeclAccessPair::make(nullptr, AS_none);
-  Candidate.Function = nullptr;
-  Candidate.IsSurrogate = false;
-  Candidate.IgnoreObjectArgument = false;
-  std::copy(ParamTys, ParamTys + Args.size(), Candidate.BuiltinParamTypes);
-
-  // Determine the implicit conversion sequences for each of the
-  // arguments.
-  Candidate.Viable = true;
-  Candidate.ExplicitCallArguments = Args.size();
-  for (unsigned ArgIdx = 0, N = Args.size(); ArgIdx != N; ++ArgIdx) {
-    // C++ [over.match.oper]p4:
-    //   For the built-in assignment operators, conversions of the
-    //   left operand are restricted as follows:
-    //     -- no temporaries are introduced to hold the left operand, and
-    //     -- no user-defined conversions are applied to the left
-    //        operand to achieve a type match with the left-most
-    //        parameter of a built-in candidate.
-    //
-    // We block these conversions by turning off user-defined
-    // conversions, since that is the only way that initialization of
-    // a reference to a non-class type can occur from something that
-    // is not of the same type.
-    if (ArgIdx < NumContextualBoolArguments) {
-      assert(ParamTys[ArgIdx] == Context.BoolTy &&
-             "Contextual conversion to bool requires bool type");
-      Candidate.Conversions[ArgIdx]
-        = TryContextuallyConvertToBool(*this, Args[ArgIdx]);
-    } else {
-      Candidate.Conversions[ArgIdx]
-        = TryCopyInitialization(*this, Args[ArgIdx], ParamTys[ArgIdx],
-                                ArgIdx == 0 && IsAssignmentOperator,
-                                /*InOverloadResolution=*/false,
-                                /*AllowObjCWritebackConversion=*/
-                                  getLangOpts().ObjCAutoRefCount);
-    }
-    if (Candidate.Conversions[ArgIdx].isBad()) {
-      Candidate.Viable = false;
-      Candidate.FailureKind = ovl_fail_bad_conversion;
-      break;
-    }
-  }
-}
-
-namespace {
-
-/// BuiltinCandidateTypeSet - A set of types that will be used for the
-/// candidate operator functions for built-in operators (C++
-/// [over.built]). The types are separated into pointer types and
-/// enumeration types.
-class BuiltinCandidateTypeSet  {
-  /// TypeSet - A set of types.
-  typedef llvm::SetVector<QualType, SmallVector<QualType, 8>,
-                          llvm::SmallPtrSet<QualType, 8>> TypeSet;
-
-  /// PointerTypes - The set of pointer types that will be used in the
-  /// built-in candidates.
-  TypeSet PointerTypes;
-
-  /// MemberPointerTypes - The set of member pointer types that will be
-  /// used in the built-in candidates.
-  TypeSet MemberPointerTypes;
-
-  /// EnumerationTypes - The set of enumeration types that will be
-  /// used in the built-in candidates.
-  TypeSet EnumerationTypes;
-
-  /// The set of vector types that will be used in the built-in
-  /// candidates.
-  TypeSet VectorTypes;
-
-  /// A flag indicating non-record types are viable candidates
-  bool HasNonRecordTypes;
-
-  /// A flag indicating whether either arithmetic or enumeration types
-  /// were present in the candidate set.
-  bool HasArithmeticOrEnumeralTypes;
-
-  /// A flag indicating whether the nullptr type was present in the
-  /// candidate set.
-  bool HasNullPtrType;
-
-  /// Sema - The semantic analysis instance where we are building the
-  /// candidate type set.
-  Sema &SemaRef;
-
-  /// Context - The AST context in which we will build the type sets.
-  ASTContext &Context;
-
-  bool AddPointerWithMoreQualifiedTypeVariants(QualType Ty,
-                                               const Qualifiers &VisibleQuals);
-  bool AddMemberPointerWithMoreQualifiedTypeVariants(QualType Ty);
-
-public:
-  /// iterator - Iterates through the types that are part of the set.
-  typedef TypeSet::iterator iterator;
-
-  BuiltinCandidateTypeSet(Sema &SemaRef)
-    : HasNonRecordTypes(false),
-      HasArithmeticOrEnumeralTypes(false),
-      HasNullPtrType(false),
-      SemaRef(SemaRef),
-      Context(SemaRef.Context) { }
-
-  void AddTypesConvertedFrom(QualType Ty,
-                             SourceLocation Loc,
-                             bool AllowUserConversions,
-                             bool AllowExplicitConversions,
-                             const Qualifiers &VisibleTypeConversionsQuals);
-
-  /// pointer_begin - First pointer type found;
-  iterator pointer_begin() { return PointerTypes.begin(); }
-
-  /// pointer_end - Past the last pointer type found;
-  iterator pointer_end() { return PointerTypes.end(); }
-
-  /// member_pointer_begin - First member pointer type found;
-  iterator member_pointer_begin() { return MemberPointerTypes.begin(); }
-
-  /// member_pointer_end - Past the last member pointer type found;
-  iterator member_pointer_end() { return MemberPointerTypes.end(); }
-
-  /// enumeration_begin - First enumeration type found;
-  iterator enumeration_begin() { return EnumerationTypes.begin(); }
-
-  /// enumeration_end - Past the last enumeration type found;
-  iterator enumeration_end() { return EnumerationTypes.end(); }
-
-  iterator vector_begin() { return VectorTypes.begin(); }
-  iterator vector_end() { return VectorTypes.end(); }
-
-  bool hasNonRecordTypes() { return HasNonRecordTypes; }
-  bool hasArithmeticOrEnumeralTypes() { return HasArithmeticOrEnumeralTypes; }
-  bool hasNullPtrType() const { return HasNullPtrType; }
-};
-
-} // end anonymous namespace
-
-/// AddPointerWithMoreQualifiedTypeVariants - Add the pointer type @p Ty to
-/// the set of pointer types along with any more-qualified variants of
-/// that type. For example, if @p Ty is "int const *", this routine
-/// will add "int const *", "int const volatile *", "int const
-/// restrict *", and "int const volatile restrict *" to the set of
-/// pointer types. Returns true if the add of @p Ty itself succeeded,
-/// false otherwise.
-///
-/// FIXME: what to do about extended qualifiers?
-bool
-BuiltinCandidateTypeSet::AddPointerWithMoreQualifiedTypeVariants(QualType Ty,
-                                             const Qualifiers &VisibleQuals) {
-
-  // Insert this type.
-  if (!PointerTypes.insert(Ty))
-    return false;
-
-  QualType PointeeTy;
-  const PointerType *PointerTy = Ty->getAs<PointerType>();
-  bool buildObjCPtr = false;
-  if (!PointerTy) {
-    const ObjCObjectPointerType *PTy = Ty->castAs<ObjCObjectPointerType>();
-    PointeeTy = PTy->getPointeeType();
-    buildObjCPtr = true;
-  } else {
-    PointeeTy = PointerTy->getPointeeType();
-  }
-
-  // Don't add qualified variants of arrays. For one, they're not allowed
-  // (the qualifier would sink to the element type), and for another, the
-  // only overload situation where it matters is subscript or pointer +- int,
-  // and those shouldn't have qualifier variants anyway.
-  if (PointeeTy->isArrayType())
-    return true;
-
-  unsigned BaseCVR = PointeeTy.getCVRQualifiers();
-  bool hasVolatile = VisibleQuals.hasVolatile();
-  bool hasRestrict = VisibleQuals.hasRestrict();
-
-  // Iterate through all strict supersets of BaseCVR.
-  for (unsigned CVR = BaseCVR+1; CVR <= Qualifiers::CVRMask; ++CVR) {
-    if ((CVR | BaseCVR) != CVR) continue;
-    // Skip over volatile if no volatile found anywhere in the types.
-    if ((CVR & Qualifiers::Volatile) && !hasVolatile) continue;
-
-    // Skip over restrict if no restrict found anywhere in the types, or if
-    // the type cannot be restrict-qualified.
-    if ((CVR & Qualifiers::Restrict) &&
-        (!hasRestrict ||
-         (!(PointeeTy->isAnyPointerType() || PointeeTy->isReferenceType()))))
-      continue;
-
-    // Build qualified pointee type.
-    QualType QPointeeTy = Context.getCVRQualifiedType(PointeeTy, CVR);
-
-    // Build qualified pointer type.
-    QualType QPointerTy;
-    if (!buildObjCPtr)
-      QPointerTy = Context.getPointerType(QPointeeTy);
-    else
-      QPointerTy = Context.getObjCObjectPointerType(QPointeeTy);
-
-    // Insert qualified pointer type.
-    PointerTypes.insert(QPointerTy);
-  }
-
-  return true;
-}
-
-/// AddMemberPointerWithMoreQualifiedTypeVariants - Add the pointer type @p Ty
-/// to the set of pointer types along with any more-qualified variants of
-/// that type. For example, if @p Ty is "int const *", this routine
-/// will add "int const *", "int const volatile *", "int const
-/// restrict *", and "int const volatile restrict *" to the set of
-/// pointer types. Returns true if the add of @p Ty itself succeeded,
-/// false otherwise.
-///
-/// FIXME: what to do about extended qualifiers?
-bool
-BuiltinCandidateTypeSet::AddMemberPointerWithMoreQualifiedTypeVariants(
-    QualType Ty) {
-  // Insert this type.
-  if (!MemberPointerTypes.insert(Ty))
-    return false;
-
-  const MemberPointerType *PointerTy = Ty->getAs<MemberPointerType>();
-  assert(PointerTy && "type was not a member pointer type!");
-
-  QualType PointeeTy = PointerTy->getPointeeType();
-  // Don't add qualified variants of arrays. For one, they're not allowed
-  // (the qualifier would sink to the element type), and for another, the
-  // only overload situation where it matters is subscript or pointer +- int,
-  // and those shouldn't have qualifier variants anyway.
-  if (PointeeTy->isArrayType())
-    return true;
-  const Type *ClassTy = PointerTy->getClass();
-
-  // Iterate through all strict supersets of the pointee type's CVR
-  // qualifiers.
-  unsigned BaseCVR = PointeeTy.getCVRQualifiers();
-  for (unsigned CVR = BaseCVR+1; CVR <= Qualifiers::CVRMask; ++CVR) {
-    if ((CVR | BaseCVR) != CVR) continue;
-
-    QualType QPointeeTy = Context.getCVRQualifiedType(PointeeTy, CVR);
-    MemberPointerTypes.insert(
-      Context.getMemberPointerType(QPointeeTy, ClassTy));
-  }
-
-  return true;
-}
-
-/// AddTypesConvertedFrom - Add each of the types to which the type @p
-/// Ty can be implicit converted to the given set of @p Types. We're
-/// primarily interested in pointer types and enumeration types. We also
-/// take member pointer types, for the conditional operator.
-/// AllowUserConversions is true if we should look at the conversion
-/// functions of a class type, and AllowExplicitConversions if we
-/// should also include the explicit conversion functions of a class
-/// type.
-void
-BuiltinCandidateTypeSet::AddTypesConvertedFrom(QualType Ty,
-                                               SourceLocation Loc,
-                                               bool AllowUserConversions,
-                                               bool AllowExplicitConversions,
-                                               const Qualifiers &VisibleQuals) {
-  // Only deal with canonical types.
-  Ty = Context.getCanonicalType(Ty);
-
-  // Look through reference types; they aren't part of the type of an
-  // expression for the purposes of conversions.
-  if (const ReferenceType *RefTy = Ty->getAs<ReferenceType>())
-    Ty = RefTy->getPointeeType();
-
-  // If we're dealing with an array type, decay to the pointer.
-  if (Ty->isArrayType())
-    Ty = SemaRef.Context.getArrayDecayedType(Ty);
-
-  // Otherwise, we don't care about qualifiers on the type.
-  Ty = Ty.getLocalUnqualifiedType();
-
-  // Flag if we ever add a non-record type.
-  const RecordType *TyRec = Ty->getAs<RecordType>();
-  HasNonRecordTypes = HasNonRecordTypes || !TyRec;
-
-  // Flag if we encounter an arithmetic type.
-  HasArithmeticOrEnumeralTypes =
-    HasArithmeticOrEnumeralTypes || Ty->isArithmeticType();
-
-  if (Ty->isObjCIdType() || Ty->isObjCClassType())
-    PointerTypes.insert(Ty);
-  else if (Ty->getAs<PointerType>() || Ty->getAs<ObjCObjectPointerType>()) {
-    // Insert our type, and its more-qualified variants, into the set
-    // of types.
-    if (!AddPointerWithMoreQualifiedTypeVariants(Ty, VisibleQuals))
-      return;
-  } else if (Ty->isMemberPointerType()) {
-    // Member pointers are far easier, since the pointee can't be converted.
-    if (!AddMemberPointerWithMoreQualifiedTypeVariants(Ty))
-      return;
-  } else if (Ty->isEnumeralType()) {
-    HasArithmeticOrEnumeralTypes = true;
-    EnumerationTypes.insert(Ty);
-  } else if (Ty->isVectorType()) {
-    // We treat vector types as arithmetic types in many contexts as an
-    // extension.
-    HasArithmeticOrEnumeralTypes = true;
-    VectorTypes.insert(Ty);
-  } else if (Ty->isNullPtrType()) {
-    HasNullPtrType = true;
-  } else if (AllowUserConversions && TyRec) {
-    // No conversion functions in incomplete types.
-    if (!SemaRef.isCompleteType(Loc, Ty))
-      return;
-
-    CXXRecordDecl *ClassDecl = cast<CXXRecordDecl>(TyRec->getDecl());
-    for (NamedDecl *D : ClassDecl->getVisibleConversionFunctions()) {
-      if (isa<UsingShadowDecl>(D))
-        D = cast<UsingShadowDecl>(D)->getTargetDecl();
-
-      // Skip conversion function templates; they don't tell us anything
-      // about which builtin types we can convert to.
-      if (isa<FunctionTemplateDecl>(D))
-        continue;
-
-      CXXConversionDecl *Conv = cast<CXXConversionDecl>(D);
-      if (AllowExplicitConversions || !Conv->isExplicit()) {
-        AddTypesConvertedFrom(Conv->getConversionType(), Loc, false, false,
-                              VisibleQuals);
-      }
-    }
-  }
-}
-
-/// Helper function for AddBuiltinOperatorCandidates() that adds
-/// the volatile- and non-volatile-qualified assignment operators for the
-/// given type to the candidate set.
-static void AddBuiltinAssignmentOperatorCandidates(Sema &S,
-                                                   QualType T,
-                                                   ArrayRef<Expr *> Args,
-                                    OverloadCandidateSet &CandidateSet) {
-  QualType ParamTypes[2];
-
-  // T& operator=(T&, T)
-  ParamTypes[0] = S.Context.getLValueReferenceType(T);
-  ParamTypes[1] = T;
-  S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet,
-                        /*IsAssignmentOperator=*/true);
-
-  if (!S.Context.getCanonicalType(T).isVolatileQualified()) {
-    // volatile T& operator=(volatile T&, T)
-    ParamTypes[0]
-      = S.Context.getLValueReferenceType(S.Context.getVolatileType(T));
-    ParamTypes[1] = T;
-    S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet,
-                          /*IsAssignmentOperator=*/true);
-  }
-}
-
-/// CollectVRQualifiers - This routine returns Volatile/Restrict qualifiers,
-/// if any, found in visible type conversion functions found in ArgExpr's type.
-static  Qualifiers CollectVRQualifiers(ASTContext &Context, Expr* ArgExpr) {
-    Qualifiers VRQuals;
-    const RecordType *TyRec;
-    if (const MemberPointerType *RHSMPType =
-        ArgExpr->getType()->getAs<MemberPointerType>())
-      TyRec = RHSMPType->getClass()->getAs<RecordType>();
-    else
-      TyRec = ArgExpr->getType()->getAs<RecordType>();
-    if (!TyRec) {
-      // Just to be safe, assume the worst case.
-      VRQuals.addVolatile();
-      VRQuals.addRestrict();
-      return VRQuals;
-    }
-
-    CXXRecordDecl *ClassDecl = cast<CXXRecordDecl>(TyRec->getDecl());
-    if (!ClassDecl->hasDefinition())
-      return VRQuals;
-
-    for (NamedDecl *D : ClassDecl->getVisibleConversionFunctions()) {
-      if (isa<UsingShadowDecl>(D))
-        D = cast<UsingShadowDecl>(D)->getTargetDecl();
-      if (CXXConversionDecl *Conv = dyn_cast<CXXConversionDecl>(D)) {
-        QualType CanTy = Context.getCanonicalType(Conv->getConversionType());
-        if (const ReferenceType *ResTypeRef = CanTy->getAs<ReferenceType>())
-          CanTy = ResTypeRef->getPointeeType();
-        // Need to go down the pointer/mempointer chain and add qualifiers
-        // as see them.
-        bool done = false;
-        while (!done) {
-          if (CanTy.isRestrictQualified())
-            VRQuals.addRestrict();
-          if (const PointerType *ResTypePtr = CanTy->getAs<PointerType>())
-            CanTy = ResTypePtr->getPointeeType();
-          else if (const MemberPointerType *ResTypeMPtr =
-                CanTy->getAs<MemberPointerType>())
-            CanTy = ResTypeMPtr->getPointeeType();
-          else
-            done = true;
-          if (CanTy.isVolatileQualified())
-            VRQuals.addVolatile();
-          if (VRQuals.hasRestrict() && VRQuals.hasVolatile())
-            return VRQuals;
-        }
-      }
-    }
-    return VRQuals;
-}
-
-namespace {
-
-/// Helper class to manage the addition of builtin operator overload
-/// candidates. It provides shared state and utility methods used throughout
-/// the process, as well as a helper method to add each group of builtin
-/// operator overloads from the standard to a candidate set.
-class BuiltinOperatorOverloadBuilder {
-  // Common instance state available to all overload candidate addition methods.
-  Sema &S;
-  ArrayRef<Expr *> Args;
-  Qualifiers VisibleTypeConversionsQuals;
-  bool HasArithmeticOrEnumeralCandidateType;
-  SmallVectorImpl<BuiltinCandidateTypeSet> &CandidateTypes;
-  OverloadCandidateSet &CandidateSet;
-
-  static constexpr int ArithmeticTypesCap = 24;
-  SmallVector<CanQualType, ArithmeticTypesCap> ArithmeticTypes;
-
-  // Define some indices used to iterate over the arithemetic types in
-  // ArithmeticTypes.  The "promoted arithmetic types" are the arithmetic
-  // types are that preserved by promotion (C++ [over.built]p2).
-  unsigned FirstIntegralType,
-           LastIntegralType;
-  unsigned FirstPromotedIntegralType,
-           LastPromotedIntegralType;
-  unsigned FirstPromotedArithmeticType,
-           LastPromotedArithmeticType;
-  unsigned NumArithmeticTypes;
-
-  void InitArithmeticTypes() {
-    // Start of promoted types.
-    FirstPromotedArithmeticType = 0;
-    ArithmeticTypes.push_back(S.Context.FloatTy);
-    ArithmeticTypes.push_back(S.Context.DoubleTy);
-    ArithmeticTypes.push_back(S.Context.LongDoubleTy);
-    if (S.Context.getTargetInfo().hasFloat128Type())
-      ArithmeticTypes.push_back(S.Context.Float128Ty);
-
-    // Start of integral types.
-    FirstIntegralType = ArithmeticTypes.size();
-    FirstPromotedIntegralType = ArithmeticTypes.size();
-    ArithmeticTypes.push_back(S.Context.IntTy);
-    ArithmeticTypes.push_back(S.Context.LongTy);
-    ArithmeticTypes.push_back(S.Context.LongLongTy);
-    if (S.Context.getTargetInfo().hasInt128Type())
-      ArithmeticTypes.push_back(S.Context.Int128Ty);
-    ArithmeticTypes.push_back(S.Context.UnsignedIntTy);
-    ArithmeticTypes.push_back(S.Context.UnsignedLongTy);
-    ArithmeticTypes.push_back(S.Context.UnsignedLongLongTy);
-    if (S.Context.getTargetInfo().hasInt128Type())
-      ArithmeticTypes.push_back(S.Context.UnsignedInt128Ty);
-    LastPromotedIntegralType = ArithmeticTypes.size();
-    LastPromotedArithmeticType = ArithmeticTypes.size();
-    // End of promoted types.
-
-    ArithmeticTypes.push_back(S.Context.BoolTy);
-    ArithmeticTypes.push_back(S.Context.CharTy);
-    ArithmeticTypes.push_back(S.Context.WCharTy);
-    if (S.Context.getLangOpts().Char8)
-      ArithmeticTypes.push_back(S.Context.Char8Ty);
-    ArithmeticTypes.push_back(S.Context.Char16Ty);
-    ArithmeticTypes.push_back(S.Context.Char32Ty);
-    ArithmeticTypes.push_back(S.Context.SignedCharTy);
-    ArithmeticTypes.push_back(S.Context.ShortTy);
-    ArithmeticTypes.push_back(S.Context.UnsignedCharTy);
-    ArithmeticTypes.push_back(S.Context.UnsignedShortTy);
-    LastIntegralType = ArithmeticTypes.size();
-    NumArithmeticTypes = ArithmeticTypes.size();
-    // End of integral types.
-    // FIXME: What about complex? What about half?
-
-    assert(ArithmeticTypes.size() <= ArithmeticTypesCap &&
-           "Enough inline storage for all arithmetic types.");
-  }
-
-  /// Helper method to factor out the common pattern of adding overloads
-  /// for '++' and '--' builtin operators.
-  void addPlusPlusMinusMinusStyleOverloads(QualType CandidateTy,
-                                           bool HasVolatile,
-                                           bool HasRestrict) {
-    QualType ParamTypes[2] = {
-      S.Context.getLValueReferenceType(CandidateTy),
-      S.Context.IntTy
-    };
-
-    // Non-volatile version.
-    S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet);
-
-    // Use a heuristic to reduce number of builtin candidates in the set:
-    // add volatile version only if there are conversions to a volatile type.
-    if (HasVolatile) {
-      ParamTypes[0] =
-        S.Context.getLValueReferenceType(
-          S.Context.getVolatileType(CandidateTy));
-      S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet);
-    }
-
-    // Add restrict version only if there are conversions to a restrict type
-    // and our candidate type is a non-restrict-qualified pointer.
-    if (HasRestrict && CandidateTy->isAnyPointerType() &&
-        !CandidateTy.isRestrictQualified()) {
-      ParamTypes[0]
-        = S.Context.getLValueReferenceType(
-            S.Context.getCVRQualifiedType(CandidateTy, Qualifiers::Restrict));
-      S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet);
-
-      if (HasVolatile) {
-        ParamTypes[0]
-          = S.Context.getLValueReferenceType(
-              S.Context.getCVRQualifiedType(CandidateTy,
-                                            (Qualifiers::Volatile |
-                                             Qualifiers::Restrict)));
-        S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet);
-      }
-    }
-
-  }
-
-public:
-  BuiltinOperatorOverloadBuilder(
-    Sema &S, ArrayRef<Expr *> Args,
-    Qualifiers VisibleTypeConversionsQuals,
-    bool HasArithmeticOrEnumeralCandidateType,
-    SmallVectorImpl<BuiltinCandidateTypeSet> &CandidateTypes,
-    OverloadCandidateSet &CandidateSet)
-    : S(S), Args(Args),
-      VisibleTypeConversionsQuals(VisibleTypeConversionsQuals),
-      HasArithmeticOrEnumeralCandidateType(
-        HasArithmeticOrEnumeralCandidateType),
-      CandidateTypes(CandidateTypes),
-      CandidateSet(CandidateSet) {
-
-    InitArithmeticTypes();
-  }
-
-  // Increment is deprecated for bool since C++17.
-  //
-  // C++ [over.built]p3:
-  //
-  //   For every pair (T, VQ), where T is an arithmetic type other
-  //   than bool, and VQ is either volatile or empty, there exist
-  //   candidate operator functions of the form
-  //
-  //       VQ T&      operator++(VQ T&);
-  //       T          operator++(VQ T&, int);
-  //
-  // C++ [over.built]p4:
-  //
-  //   For every pair (T, VQ), where T is an arithmetic type other
-  //   than bool, and VQ is either volatile or empty, there exist
-  //   candidate operator functions of the form
-  //
-  //       VQ T&      operator--(VQ T&);
-  //       T          operator--(VQ T&, int);
-  void addPlusPlusMinusMinusArithmeticOverloads(OverloadedOperatorKind Op) {
-    if (!HasArithmeticOrEnumeralCandidateType)
-      return;
-
-    for (unsigned Arith = 0; Arith < NumArithmeticTypes; ++Arith) {
-      const auto TypeOfT = ArithmeticTypes[Arith];
-      if (TypeOfT == S.Context.BoolTy) {
-        if (Op == OO_MinusMinus)
-          continue;
-        if (Op == OO_PlusPlus && S.getLangOpts().CPlusPlus17)
-          continue;
-      }
-      addPlusPlusMinusMinusStyleOverloads(
-        TypeOfT,
-        VisibleTypeConversionsQuals.hasVolatile(),
-        VisibleTypeConversionsQuals.hasRestrict());
-    }
-  }
-
-  // C++ [over.built]p5:
-  //
-  //   For every pair (T, VQ), where T is a cv-qualified or
-  //   cv-unqualified object type, and VQ is either volatile or
-  //   empty, there exist candidate operator functions of the form
-  //
-  //       T*VQ&      operator++(T*VQ&);
-  //       T*VQ&      operator--(T*VQ&);
-  //       T*         operator++(T*VQ&, int);
-  //       T*         operator--(T*VQ&, int);
-  void addPlusPlusMinusMinusPointerOverloads() {
-    for (BuiltinCandidateTypeSet::iterator
-              Ptr = CandidateTypes[0].pointer_begin(),
-           PtrEnd = CandidateTypes[0].pointer_end();
-         Ptr != PtrEnd; ++Ptr) {
-      // Skip pointer types that aren't pointers to object types.
-      if (!(*Ptr)->getPointeeType()->isObjectType())
-        continue;
-
-      addPlusPlusMinusMinusStyleOverloads(*Ptr,
-        (!(*Ptr).isVolatileQualified() &&
-         VisibleTypeConversionsQuals.hasVolatile()),
-        (!(*Ptr).isRestrictQualified() &&
-         VisibleTypeConversionsQuals.hasRestrict()));
-    }
-  }
-
-  // C++ [over.built]p6:
-  //   For every cv-qualified or cv-unqualified object type T, there
-  //   exist candidate operator functions of the form
-  //
-  //       T&         operator*(T*);
-  //
-  // C++ [over.built]p7:
-  //   For every function type T that does not have cv-qualifiers or a
-  //   ref-qualifier, there exist candidate operator functions of the form
-  //       T&         operator*(T*);
-  void addUnaryStarPointerOverloads() {
-    for (BuiltinCandidateTypeSet::iterator
-              Ptr = CandidateTypes[0].pointer_begin(),
-           PtrEnd = CandidateTypes[0].pointer_end();
-         Ptr != PtrEnd; ++Ptr) {
-      QualType ParamTy = *Ptr;
-      QualType PointeeTy = ParamTy->getPointeeType();
-      if (!PointeeTy->isObjectType() && !PointeeTy->isFunctionType())
-        continue;
-
-      if (const FunctionProtoType *Proto =PointeeTy->getAs<FunctionProtoType>())
-        if (Proto->getTypeQuals() || Proto->getRefQualifier())
-          continue;
-
-      S.AddBuiltinCandidate(&ParamTy, Args, CandidateSet);
-    }
-  }
-
-  // C++ [over.built]p9:
-  //  For every promoted arithmetic type T, there exist candidate
-  //  operator functions of the form
-  //
-  //       T         operator+(T);
-  //       T         operator-(T);
-  void addUnaryPlusOrMinusArithmeticOverloads() {
-    if (!HasArithmeticOrEnumeralCandidateType)
-      return;
-
-    for (unsigned Arith = FirstPromotedArithmeticType;
-         Arith < LastPromotedArithmeticType; ++Arith) {
-      QualType ArithTy = ArithmeticTypes[Arith];
-      S.AddBuiltinCandidate(&ArithTy, Args, CandidateSet);
-    }
-
-    // Extension: We also add these operators for vector types.
-    for (BuiltinCandidateTypeSet::iterator
-              Vec = CandidateTypes[0].vector_begin(),
-           VecEnd = CandidateTypes[0].vector_end();
-         Vec != VecEnd; ++Vec) {
-      QualType VecTy = *Vec;
-      S.AddBuiltinCandidate(&VecTy, Args, CandidateSet);
-    }
-  }
-
-  // C++ [over.built]p8:
-  //   For every type T, there exist candidate operator functions of
-  //   the form
-  //
-  //       T*         operator+(T*);
-  void addUnaryPlusPointerOverloads() {
-    for (BuiltinCandidateTypeSet::iterator
-              Ptr = CandidateTypes[0].pointer_begin(),
-           PtrEnd = CandidateTypes[0].pointer_end();
-         Ptr != PtrEnd; ++Ptr) {
-      QualType ParamTy = *Ptr;
-      S.AddBuiltinCandidate(&ParamTy, Args, CandidateSet);
-    }
-  }
-
-  // C++ [over.built]p10:
-  //   For every promoted integral type T, there exist candidate
-  //   operator functions of the form
-  //
-  //        T         operator~(T);
-  void addUnaryTildePromotedIntegralOverloads() {
-    if (!HasArithmeticOrEnumeralCandidateType)
-      return;
-
-    for (unsigned Int = FirstPromotedIntegralType;
-         Int < LastPromotedIntegralType; ++Int) {
-      QualType IntTy = ArithmeticTypes[Int];
-      S.AddBuiltinCandidate(&IntTy, Args, CandidateSet);
-    }
-
-    // Extension: We also add this operator for vector types.
-    for (BuiltinCandidateTypeSet::iterator
-              Vec = CandidateTypes[0].vector_begin(),
-           VecEnd = CandidateTypes[0].vector_end();
-         Vec != VecEnd; ++Vec) {
-      QualType VecTy = *Vec;
-      S.AddBuiltinCandidate(&VecTy, Args, CandidateSet);
-    }
-  }
-
-  // C++ [over.match.oper]p16:
-  //   For every pointer to member type T or type std::nullptr_t, there
-  //   exist candidate operator functions of the form
-  //
-  //        bool operator==(T,T);
-  //        bool operator!=(T,T);
-  void addEqualEqualOrNotEqualMemberPointerOrNullptrOverloads() {
-    /// Set of (canonical) types that we've already handled.
-    llvm::SmallPtrSet<QualType, 8> AddedTypes;
-
-    for (unsigned ArgIdx = 0, N = Args.size(); ArgIdx != N; ++ArgIdx) {
-      for (BuiltinCandidateTypeSet::iterator
-                MemPtr = CandidateTypes[ArgIdx].member_pointer_begin(),
-             MemPtrEnd = CandidateTypes[ArgIdx].member_pointer_end();
-           MemPtr != MemPtrEnd;
-           ++MemPtr) {
-        // Don't add the same builtin candidate twice.
-        if (!AddedTypes.insert(S.Context.getCanonicalType(*MemPtr)).second)
-          continue;
-
-        QualType ParamTypes[2] = { *MemPtr, *MemPtr };
-        S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet);
-      }
-
-      if (CandidateTypes[ArgIdx].hasNullPtrType()) {
-        CanQualType NullPtrTy = S.Context.getCanonicalType(S.Context.NullPtrTy);
-        if (AddedTypes.insert(NullPtrTy).second) {
-          QualType ParamTypes[2] = { NullPtrTy, NullPtrTy };
-          S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet);
-        }
-      }
-    }
-  }
-
-  // C++ [over.built]p15:
-  //
-  //   For every T, where T is an enumeration type or a pointer type,
-  //   there exist candidate operator functions of the form
-  //
-  //        bool       operator<(T, T);
-  //        bool       operator>(T, T);
-  //        bool       operator<=(T, T);
-  //        bool       operator>=(T, T);
-  //        bool       operator==(T, T);
-  //        bool       operator!=(T, T);
-  //           R       operator<=>(T, T)
-  void addGenericBinaryPointerOrEnumeralOverloads() {
-    // C++ [over.match.oper]p3:
-    //   [...]the built-in candidates include all of the candidate operator
-    //   functions defined in 13.6 that, compared to the given operator, [...]
-    //   do not have the same parameter-type-list as any non-template non-member
-    //   candidate.
-    //
-    // Note that in practice, this only affects enumeration types because there
-    // aren't any built-in candidates of record type, and a user-defined operator
-    // must have an operand of record or enumeration type. Also, the only other
-    // overloaded operator with enumeration arguments, operator=,
-    // cannot be overloaded for enumeration types, so this is the only place
-    // where we must suppress candidates like this.
-    llvm::DenseSet<std::pair<CanQualType, CanQualType> >
-      UserDefinedBinaryOperators;
-
-    for (unsigned ArgIdx = 0, N = Args.size(); ArgIdx != N; ++ArgIdx) {
-      if (CandidateTypes[ArgIdx].enumeration_begin() !=
-          CandidateTypes[ArgIdx].enumeration_end()) {
-        for (OverloadCandidateSet::iterator C = CandidateSet.begin(),
-                                         CEnd = CandidateSet.end();
-             C != CEnd; ++C) {
-          if (!C->Viable || !C->Function || C->Function->getNumParams() != 2)
-            continue;
-
-          if (C->Function->isFunctionTemplateSpecialization())
-            continue;
-
-          QualType FirstParamType =
-            C->Function->getParamDecl(0)->getType().getUnqualifiedType();
-          QualType SecondParamType =
-            C->Function->getParamDecl(1)->getType().getUnqualifiedType();
-
-          // Skip if either parameter isn't of enumeral type.
-          if (!FirstParamType->isEnumeralType() ||
-              !SecondParamType->isEnumeralType())
-            continue;
-
-          // Add this operator to the set of known user-defined operators.
-          UserDefinedBinaryOperators.insert(
-            std::make_pair(S.Context.getCanonicalType(FirstParamType),
-                           S.Context.getCanonicalType(SecondParamType)));
-        }
-      }
-    }
-
-    /// Set of (canonical) types that we've already handled.
-    llvm::SmallPtrSet<QualType, 8> AddedTypes;
-
-    for (unsigned ArgIdx = 0, N = Args.size(); ArgIdx != N; ++ArgIdx) {
-      for (BuiltinCandidateTypeSet::iterator
-                Ptr = CandidateTypes[ArgIdx].pointer_begin(),
-             PtrEnd = CandidateTypes[ArgIdx].pointer_end();
-           Ptr != PtrEnd; ++Ptr) {
-        // Don't add the same builtin candidate twice.
-        if (!AddedTypes.insert(S.Context.getCanonicalType(*Ptr)).second)
-          continue;
-
-        QualType ParamTypes[2] = { *Ptr, *Ptr };
-        S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet);
-      }
-      for (BuiltinCandidateTypeSet::iterator
-                Enum = CandidateTypes[ArgIdx].enumeration_begin(),
-             EnumEnd = CandidateTypes[ArgIdx].enumeration_end();
-           Enum != EnumEnd; ++Enum) {
-        CanQualType CanonType = S.Context.getCanonicalType(*Enum);
-
-        // Don't add the same builtin candidate twice, or if a user defined
-        // candidate exists.
-        if (!AddedTypes.insert(CanonType).second ||
-            UserDefinedBinaryOperators.count(std::make_pair(CanonType,
-                                                            CanonType)))
-          continue;
-        QualType ParamTypes[2] = { *Enum, *Enum };
-        S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet);
-      }
-    }
-  }
-
-  // C++ [over.built]p13:
-  //
-  //   For every cv-qualified or cv-unqualified object type T
-  //   there exist candidate operator functions of the form
-  //
-  //      T*         operator+(T*, ptrdiff_t);
-  //      T&         operator[](T*, ptrdiff_t);    [BELOW]
-  //      T*         operator-(T*, ptrdiff_t);
-  //      T*         operator+(ptrdiff_t, T*);
-  //      T&         operator[](ptrdiff_t, T*);    [BELOW]
-  //
-  // C++ [over.built]p14:
-  //
-  //   For every T, where T is a pointer to object type, there
-  //   exist candidate operator functions of the form
-  //
-  //      ptrdiff_t  operator-(T, T);
-  void addBinaryPlusOrMinusPointerOverloads(OverloadedOperatorKind Op) {
-    /// Set of (canonical) types that we've already handled.
-    llvm::SmallPtrSet<QualType, 8> AddedTypes;
-
-    for (int Arg = 0; Arg < 2; ++Arg) {
-      QualType AsymmetricParamTypes[2] = {
-        S.Context.getPointerDiffType(),
-        S.Context.getPointerDiffType(),
-      };
-      for (BuiltinCandidateTypeSet::iterator
-                Ptr = CandidateTypes[Arg].pointer_begin(),
-             PtrEnd = CandidateTypes[Arg].pointer_end();
-           Ptr != PtrEnd; ++Ptr) {
-        QualType PointeeTy = (*Ptr)->getPointeeType();
-        if (!PointeeTy->isObjectType())
-          continue;
-
-        AsymmetricParamTypes[Arg] = *Ptr;
-        if (Arg == 0 || Op == OO_Plus) {
-          // operator+(T*, ptrdiff_t) or operator-(T*, ptrdiff_t)
-          // T* operator+(ptrdiff_t, T*);
-          S.AddBuiltinCandidate(AsymmetricParamTypes, Args, CandidateSet);
-        }
-        if (Op == OO_Minus) {
-          // ptrdiff_t operator-(T, T);
-          if (!AddedTypes.insert(S.Context.getCanonicalType(*Ptr)).second)
-            continue;
-
-          QualType ParamTypes[2] = { *Ptr, *Ptr };
-          S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet);
-        }
-      }
-    }
-  }
-
-  // C++ [over.built]p12:
-  //
-  //   For every pair of promoted arithmetic types L and R, there
-  //   exist candidate operator functions of the form
-  //
-  //        LR         operator*(L, R);
-  //        LR         operator/(L, R);
-  //        LR         operator+(L, R);
-  //        LR         operator-(L, R);
-  //        bool       operator<(L, R);
-  //        bool       operator>(L, R);
-  //        bool       operator<=(L, R);
-  //        bool       operator>=(L, R);
-  //        bool       operator==(L, R);
-  //        bool       operator!=(L, R);
-  //
-  //   where LR is the result of the usual arithmetic conversions
-  //   between types L and R.
-  //
-  // C++ [over.built]p24:
-  //
-  //   For every pair of promoted arithmetic types L and R, there exist
-  //   candidate operator functions of the form
-  //
-  //        LR       operator?(bool, L, R);
-  //
-  //   where LR is the result of the usual arithmetic conversions
-  //   between types L and R.
-  // Our candidates ignore the first parameter.
-  void addGenericBinaryArithmeticOverloads() {
-    if (!HasArithmeticOrEnumeralCandidateType)
-      return;
-
-    for (unsigned Left = FirstPromotedArithmeticType;
-         Left < LastPromotedArithmeticType; ++Left) {
-      for (unsigned Right = FirstPromotedArithmeticType;
-           Right < LastPromotedArithmeticType; ++Right) {
-        QualType LandR[2] = { ArithmeticTypes[Left],
-                              ArithmeticTypes[Right] };
-        S.AddBuiltinCandidate(LandR, Args, CandidateSet);
-      }
-    }
-
-    // Extension: Add the binary operators ==, !=, <, <=, >=, >, *, /, and the
-    // conditional operator for vector types.
-    for (BuiltinCandidateTypeSet::iterator
-              Vec1 = CandidateTypes[0].vector_begin(),
-           Vec1End = CandidateTypes[0].vector_end();
-         Vec1 != Vec1End; ++Vec1) {
-      for (BuiltinCandidateTypeSet::iterator
-                Vec2 = CandidateTypes[1].vector_begin(),
-             Vec2End = CandidateTypes[1].vector_end();
-           Vec2 != Vec2End; ++Vec2) {
-        QualType LandR[2] = { *Vec1, *Vec2 };
-        S.AddBuiltinCandidate(LandR, Args, CandidateSet);
-      }
-    }
-  }
-
-  // C++2a [over.built]p14:
-  //
-  //   For every integral type T there exists a candidate operator function
-  //   of the form
-  //
-  //        std::strong_ordering operator<=>(T, T)
-  //
-  // C++2a [over.built]p15:
-  //
-  //   For every pair of floating-point types L and R, there exists a candidate
-  //   operator function of the form
-  //
-  //       std::partial_ordering operator<=>(L, R);
-  //
-  // FIXME: The current specification for integral types doesn't play nice with
-  // the direction of p0946r0, which allows mixed integral and unscoped-enum
-  // comparisons. Under the current spec this can lead to ambiguity during
-  // overload resolution. For example:
-  //
-  //   enum A : int {a};
-  //   auto x = (a <=> (long)42);
-  //
-  //   error: call is ambiguous for arguments 'A' and 'long'.
-  //   note: candidate operator<=>(int, int)
-  //   note: candidate operator<=>(long, long)
-  //
-  // To avoid this error, this function deviates from the specification and adds
-  // the mixed overloads `operator<=>(L, R)` where L and R are promoted
-  // arithmetic types (the same as the generic relational overloads).
-  //
-  // For now this function acts as a placeholder.
-  void addThreeWayArithmeticOverloads() {
-    addGenericBinaryArithmeticOverloads();
-  }
-
-  // C++ [over.built]p17:
-  //
-  //   For every pair of promoted integral types L and R, there
-  //   exist candidate operator functions of the form
-  //
-  //      LR         operator%(L, R);
-  //      LR         operator&(L, R);
-  //      LR         operator^(L, R);
-  //      LR         operator|(L, R);
-  //      L          operator<<(L, R);
-  //      L          operator>>(L, R);
-  //
-  //   where LR is the result of the usual arithmetic conversions
-  //   between types L and R.
-  void addBinaryBitwiseArithmeticOverloads(OverloadedOperatorKind Op) {
-    if (!HasArithmeticOrEnumeralCandidateType)
-      return;
-
-    for (unsigned Left = FirstPromotedIntegralType;
-         Left < LastPromotedIntegralType; ++Left) {
-      for (unsigned Right = FirstPromotedIntegralType;
-           Right < LastPromotedIntegralType; ++Right) {
-        QualType LandR[2] = { ArithmeticTypes[Left],
-                              ArithmeticTypes[Right] };
-        S.AddBuiltinCandidate(LandR, Args, CandidateSet);
-      }
-    }
-  }
-
-  // C++ [over.built]p20:
-  //
-  //   For every pair (T, VQ), where T is an enumeration or
-  //   pointer to member type and VQ is either volatile or
-  //   empty, there exist candidate operator functions of the form
-  //
-  //        VQ T&      operator=(VQ T&, T);
-  void addAssignmentMemberPointerOrEnumeralOverloads() {
-    /// Set of (canonical) types that we've already handled.
-    llvm::SmallPtrSet<QualType, 8> AddedTypes;
-
-    for (unsigned ArgIdx = 0; ArgIdx < 2; ++ArgIdx) {
-      for (BuiltinCandidateTypeSet::iterator
-                Enum = CandidateTypes[ArgIdx].enumeration_begin(),
-             EnumEnd = CandidateTypes[ArgIdx].enumeration_end();
-           Enum != EnumEnd; ++Enum) {
-        if (!AddedTypes.insert(S.Context.getCanonicalType(*Enum)).second)
-          continue;
-
-        AddBuiltinAssignmentOperatorCandidates(S, *Enum, Args, CandidateSet);
-      }
-
-      for (BuiltinCandidateTypeSet::iterator
-                MemPtr = CandidateTypes[ArgIdx].member_pointer_begin(),
-             MemPtrEnd = CandidateTypes[ArgIdx].member_pointer_end();
-           MemPtr != MemPtrEnd; ++MemPtr) {
-        if (!AddedTypes.insert(S.Context.getCanonicalType(*MemPtr)).second)
-          continue;
-
-        AddBuiltinAssignmentOperatorCandidates(S, *MemPtr, Args, CandidateSet);
-      }
-    }
-  }
-
-  // C++ [over.built]p19:
-  //
-  //   For every pair (T, VQ), where T is any type and VQ is either
-  //   volatile or empty, there exist candidate operator functions
-  //   of the form
-  //
-  //        T*VQ&      operator=(T*VQ&, T*);
-  //
-  // C++ [over.built]p21:
-  //
-  //   For every pair (T, VQ), where T is a cv-qualified or
-  //   cv-unqualified object type and VQ is either volatile or
-  //   empty, there exist candidate operator functions of the form
-  //
-  //        T*VQ&      operator+=(T*VQ&, ptrdiff_t);
-  //        T*VQ&      operator-=(T*VQ&, ptrdiff_t);
-  void addAssignmentPointerOverloads(bool isEqualOp) {
-    /// Set of (canonical) types that we've already handled.
-    llvm::SmallPtrSet<QualType, 8> AddedTypes;
-
-    for (BuiltinCandidateTypeSet::iterator
-              Ptr = CandidateTypes[0].pointer_begin(),
-           PtrEnd = CandidateTypes[0].pointer_end();
-         Ptr != PtrEnd; ++Ptr) {
-      // If this is operator=, keep track of the builtin candidates we added.
-      if (isEqualOp)
-        AddedTypes.insert(S.Context.getCanonicalType(*Ptr));
-      else if (!(*Ptr)->getPointeeType()->isObjectType())
-        continue;
-
-      // non-volatile version
-      QualType ParamTypes[2] = {
-        S.Context.getLValueReferenceType(*Ptr),
-        isEqualOp ? *Ptr : S.Context.getPointerDiffType(),
-      };
-      S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet,
-                            /*IsAssigmentOperator=*/ isEqualOp);
-
-      bool NeedVolatile = !(*Ptr).isVolatileQualified() &&
-                          VisibleTypeConversionsQuals.hasVolatile();
-      if (NeedVolatile) {
-        // volatile version
-        ParamTypes[0] =
-          S.Context.getLValueReferenceType(S.Context.getVolatileType(*Ptr));
-        S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet,
-                              /*IsAssigmentOperator=*/isEqualOp);
-      }
-
-      if (!(*Ptr).isRestrictQualified() &&
-          VisibleTypeConversionsQuals.hasRestrict()) {
-        // restrict version
-        ParamTypes[0]
-          = S.Context.getLValueReferenceType(S.Context.getRestrictType(*Ptr));
-        S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet,
-                              /*IsAssigmentOperator=*/isEqualOp);
-
-        if (NeedVolatile) {
-          // volatile restrict version
-          ParamTypes[0]
-            = S.Context.getLValueReferenceType(
-                S.Context.getCVRQualifiedType(*Ptr,
-                                              (Qualifiers::Volatile |
-                                               Qualifiers::Restrict)));
-          S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet,
-                                /*IsAssigmentOperator=*/isEqualOp);
-        }
-      }
-    }
-
-    if (isEqualOp) {
-      for (BuiltinCandidateTypeSet::iterator
-                Ptr = CandidateTypes[1].pointer_begin(),
-             PtrEnd = CandidateTypes[1].pointer_end();
-           Ptr != PtrEnd; ++Ptr) {
-        // Make sure we don't add the same candidate twice.
-        if (!AddedTypes.insert(S.Context.getCanonicalType(*Ptr)).second)
-          continue;
-
-        QualType ParamTypes[2] = {
-          S.Context.getLValueReferenceType(*Ptr),
-          *Ptr,
-        };
-
-        // non-volatile version
-        S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet,
-                              /*IsAssigmentOperator=*/true);
-
-        bool NeedVolatile = !(*Ptr).isVolatileQualified() &&
-                           VisibleTypeConversionsQuals.hasVolatile();
-        if (NeedVolatile) {
-          // volatile version
-          ParamTypes[0] =
-            S.Context.getLValueReferenceType(S.Context.getVolatileType(*Ptr));
-          S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet,
-                                /*IsAssigmentOperator=*/true);
-        }
-
-        if (!(*Ptr).isRestrictQualified() &&
-            VisibleTypeConversionsQuals.hasRestrict()) {
-          // restrict version
-          ParamTypes[0]
-            = S.Context.getLValueReferenceType(S.Context.getRestrictType(*Ptr));
-          S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet,
-                                /*IsAssigmentOperator=*/true);
-
-          if (NeedVolatile) {
-            // volatile restrict version
-            ParamTypes[0]
-              = S.Context.getLValueReferenceType(
-                  S.Context.getCVRQualifiedType(*Ptr,
-                                                (Qualifiers::Volatile |
-                                                 Qualifiers::Restrict)));
-            S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet,
-                                  /*IsAssigmentOperator=*/true);
-          }
-        }
-      }
-    }
-  }
-
-  // C++ [over.built]p18:
-  //
-  //   For every triple (L, VQ, R), where L is an arithmetic type,
-  //   VQ is either volatile or empty, and R is a promoted
-  //   arithmetic type, there exist candidate operator functions of
-  //   the form
-  //
-  //        VQ L&      operator=(VQ L&, R);
-  //        VQ L&      operator*=(VQ L&, R);
-  //        VQ L&      operator/=(VQ L&, R);
-  //        VQ L&      operator+=(VQ L&, R);
-  //        VQ L&      operator-=(VQ L&, R);
-  void addAssignmentArithmeticOverloads(bool isEqualOp) {
-    if (!HasArithmeticOrEnumeralCandidateType)
-      return;
-
-    for (unsigned Left = 0; Left < NumArithmeticTypes; ++Left) {
-      for (unsigned Right = FirstPromotedArithmeticType;
-           Right < LastPromotedArithmeticType; ++Right) {
-        QualType ParamTypes[2];
-        ParamTypes[1] = ArithmeticTypes[Right];
-
-        // Add this built-in operator as a candidate (VQ is empty).
-        ParamTypes[0] =
-          S.Context.getLValueReferenceType(ArithmeticTypes[Left]);
-        S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet,
-                              /*IsAssigmentOperator=*/isEqualOp);
-
-        // Add this built-in operator as a candidate (VQ is 'volatile').
-        if (VisibleTypeConversionsQuals.hasVolatile()) {
-          ParamTypes[0] =
-            S.Context.getVolatileType(ArithmeticTypes[Left]);
-          ParamTypes[0] = S.Context.getLValueReferenceType(ParamTypes[0]);
-          S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet,
-                                /*IsAssigmentOperator=*/isEqualOp);
-        }
-      }
-    }
-
-    // Extension: Add the binary operators =, +=, -=, *=, /= for vector types.
-    for (BuiltinCandidateTypeSet::iterator
-              Vec1 = CandidateTypes[0].vector_begin(),
-           Vec1End = CandidateTypes[0].vector_end();
-         Vec1 != Vec1End; ++Vec1) {
-      for (BuiltinCandidateTypeSet::iterator
-                Vec2 = CandidateTypes[1].vector_begin(),
-             Vec2End = CandidateTypes[1].vector_end();
-           Vec2 != Vec2End; ++Vec2) {
-        QualType ParamTypes[2];
-        ParamTypes[1] = *Vec2;
-        // Add this built-in operator as a candidate (VQ is empty).
-        ParamTypes[0] = S.Context.getLValueReferenceType(*Vec1);
-        S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet,
-                              /*IsAssigmentOperator=*/isEqualOp);
-
-        // Add this built-in operator as a candidate (VQ is 'volatile').
-        if (VisibleTypeConversionsQuals.hasVolatile()) {
-          ParamTypes[0] = S.Context.getVolatileType(*Vec1);
-          ParamTypes[0] = S.Context.getLValueReferenceType(ParamTypes[0]);
-          S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet,
-                                /*IsAssigmentOperator=*/isEqualOp);
-        }
-      }
-    }
-  }
-
-  // C++ [over.built]p22:
-  //
-  //   For every triple (L, VQ, R), where L is an integral type, VQ
-  //   is either volatile or empty, and R is a promoted integral
-  //   type, there exist candidate operator functions of the form
-  //
-  //        VQ L&       operator%=(VQ L&, R);
-  //        VQ L&       operator<<=(VQ L&, R);
-  //        VQ L&       operator>>=(VQ L&, R);
-  //        VQ L&       operator&=(VQ L&, R);
-  //        VQ L&       operator^=(VQ L&, R);
-  //        VQ L&       operator|=(VQ L&, R);
-  void addAssignmentIntegralOverloads() {
-    if (!HasArithmeticOrEnumeralCandidateType)
-      return;
-
-    for (unsigned Left = FirstIntegralType; Left < LastIntegralType; ++Left) {
-      for (unsigned Right = FirstPromotedIntegralType;
-           Right < LastPromotedIntegralType; ++Right) {
-        QualType ParamTypes[2];
-        ParamTypes[1] = ArithmeticTypes[Right];
-
-        // Add this built-in operator as a candidate (VQ is empty).
-        ParamTypes[0] =
-          S.Context.getLValueReferenceType(ArithmeticTypes[Left]);
-        S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet);
-        if (VisibleTypeConversionsQuals.hasVolatile()) {
-          // Add this built-in operator as a candidate (VQ is 'volatile').
-          ParamTypes[0] = ArithmeticTypes[Left];
-          ParamTypes[0] = S.Context.getVolatileType(ParamTypes[0]);
-          ParamTypes[0] = S.Context.getLValueReferenceType(ParamTypes[0]);
-          S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet);
-        }
-      }
-    }
-  }
-
-  // C++ [over.operator]p23:
-  //
-  //   There also exist candidate operator functions of the form
-  //
-  //        bool        operator!(bool);
-  //        bool        operator&&(bool, bool);
-  //        bool        operator||(bool, bool);
-  void addExclaimOverload() {
-    QualType ParamTy = S.Context.BoolTy;
-    S.AddBuiltinCandidate(&ParamTy, Args, CandidateSet,
-                          /*IsAssignmentOperator=*/false,
-                          /*NumContextualBoolArguments=*/1);
-  }
-  void addAmpAmpOrPipePipeOverload() {
-    QualType ParamTypes[2] = { S.Context.BoolTy, S.Context.BoolTy };
-    S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet,
-                          /*IsAssignmentOperator=*/false,
-                          /*NumContextualBoolArguments=*/2);
-  }
-
-  // C++ [over.built]p13:
-  //
-  //   For every cv-qualified or cv-unqualified object type T there
-  //   exist candidate operator functions of the form
-  //
-  //        T*         operator+(T*, ptrdiff_t);     [ABOVE]
-  //        T&         operator[](T*, ptrdiff_t);
-  //        T*         operator-(T*, ptrdiff_t);     [ABOVE]
-  //        T*         operator+(ptrdiff_t, T*);     [ABOVE]
-  //        T&         operator[](ptrdiff_t, T*);
-  void addSubscriptOverloads() {
-    for (BuiltinCandidateTypeSet::iterator
-              Ptr = CandidateTypes[0].pointer_begin(),
-           PtrEnd = CandidateTypes[0].pointer_end();
-         Ptr != PtrEnd; ++Ptr) {
-      QualType ParamTypes[2] = { *Ptr, S.Context.getPointerDiffType() };
-      QualType PointeeType = (*Ptr)->getPointeeType();
-      if (!PointeeType->isObjectType())
-        continue;
-
-      // T& operator[](T*, ptrdiff_t)
-      S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet);
-    }
-
-    for (BuiltinCandidateTypeSet::iterator
-              Ptr = CandidateTypes[1].pointer_begin(),
-           PtrEnd = CandidateTypes[1].pointer_end();
-         Ptr != PtrEnd; ++Ptr) {
-      QualType ParamTypes[2] = { S.Context.getPointerDiffType(), *Ptr };
-      QualType PointeeType = (*Ptr)->getPointeeType();
-      if (!PointeeType->isObjectType())
-        continue;
-
-      // T& operator[](ptrdiff_t, T*)
-      S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet);
-    }
-  }
-
-  // C++ [over.built]p11:
-  //    For every quintuple (C1, C2, T, CV1, CV2), where C2 is a class type,
-  //    C1 is the same type as C2 or is a derived class of C2, T is an object
-  //    type or a function type, and CV1 and CV2 are cv-qualifier-seqs,
-  //    there exist candidate operator functions of the form
-  //
-  //      CV12 T& operator->*(CV1 C1*, CV2 T C2::*);
-  //
-  //    where CV12 is the union of CV1 and CV2.
-  void addArrowStarOverloads() {
-    for (BuiltinCandidateTypeSet::iterator
-             Ptr = CandidateTypes[0].pointer_begin(),
-           PtrEnd = CandidateTypes[0].pointer_end();
-         Ptr != PtrEnd; ++Ptr) {
-      QualType C1Ty = (*Ptr);
-      QualType C1;
-      QualifierCollector Q1;
-      C1 = QualType(Q1.strip(C1Ty->getPointeeType()), 0);
-      if (!isa<RecordType>(C1))
-        continue;
-      // heuristic to reduce number of builtin candidates in the set.
-      // Add volatile/restrict version only if there are conversions to a
-      // volatile/restrict type.
-      if (!VisibleTypeConversionsQuals.hasVolatile() && Q1.hasVolatile())
-        continue;
-      if (!VisibleTypeConversionsQuals.hasRestrict() && Q1.hasRestrict())
-        continue;
-      for (BuiltinCandidateTypeSet::iterator
-                MemPtr = CandidateTypes[1].member_pointer_begin(),
-             MemPtrEnd = CandidateTypes[1].member_pointer_end();
-           MemPtr != MemPtrEnd; ++MemPtr) {
-        const MemberPointerType *mptr = cast<MemberPointerType>(*MemPtr);
-        QualType C2 = QualType(mptr->getClass(), 0);
-        C2 = C2.getUnqualifiedType();
-        if (C1 != C2 && !S.IsDerivedFrom(CandidateSet.getLocation(), C1, C2))
-          break;
-        QualType ParamTypes[2] = { *Ptr, *MemPtr };
-        // build CV12 T&
-        QualType T = mptr->getPointeeType();
-        if (!VisibleTypeConversionsQuals.hasVolatile() &&
-            T.isVolatileQualified())
-          continue;
-        if (!VisibleTypeConversionsQuals.hasRestrict() &&
-            T.isRestrictQualified())
-          continue;
-        T = Q1.apply(S.Context, T);
-        S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet);
-      }
-    }
-  }
-
-  // Note that we don't consider the first argument, since it has been
-  // contextually converted to bool long ago. The candidates below are
-  // therefore added as binary.
-  //
-  // C++ [over.built]p25:
-  //   For every type T, where T is a pointer, pointer-to-member, or scoped
-  //   enumeration type, there exist candidate operator functions of the form
-  //
-  //        T        operator?(bool, T, T);
-  //
-  void addConditionalOperatorOverloads() {
-    /// Set of (canonical) types that we've already handled.
-    llvm::SmallPtrSet<QualType, 8> AddedTypes;
-
-    for (unsigned ArgIdx = 0; ArgIdx < 2; ++ArgIdx) {
-      for (BuiltinCandidateTypeSet::iterator
-                Ptr = CandidateTypes[ArgIdx].pointer_begin(),
-             PtrEnd = CandidateTypes[ArgIdx].pointer_end();
-           Ptr != PtrEnd; ++Ptr) {
-        if (!AddedTypes.insert(S.Context.getCanonicalType(*Ptr)).second)
-          continue;
-
-        QualType ParamTypes[2] = { *Ptr, *Ptr };
-        S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet);
-      }
-
-      for (BuiltinCandidateTypeSet::iterator
-                MemPtr = CandidateTypes[ArgIdx].member_pointer_begin(),
-             MemPtrEnd = CandidateTypes[ArgIdx].member_pointer_end();
-           MemPtr != MemPtrEnd; ++MemPtr) {
-        if (!AddedTypes.insert(S.Context.getCanonicalType(*MemPtr)).second)
-          continue;
-
-        QualType ParamTypes[2] = { *MemPtr, *MemPtr };
-        S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet);
-      }
-
-      if (S.getLangOpts().CPlusPlus11) {
-        for (BuiltinCandidateTypeSet::iterator
-                  Enum = CandidateTypes[ArgIdx].enumeration_begin(),
-               EnumEnd = CandidateTypes[ArgIdx].enumeration_end();
-             Enum != EnumEnd; ++Enum) {
-          if (!(*Enum)->getAs<EnumType>()->getDecl()->isScoped())
-            continue;
-
-          if (!AddedTypes.insert(S.Context.getCanonicalType(*Enum)).second)
-            continue;
-
-          QualType ParamTypes[2] = { *Enum, *Enum };
-          S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet);
-        }
-      }
-    }
-  }
-};
-
-} // end anonymous namespace
-
-/// AddBuiltinOperatorCandidates - Add the appropriate built-in
-/// operator overloads to the candidate set (C++ [over.built]), based
-/// on the operator @p Op and the arguments given. For example, if the
-/// operator is a binary '+', this routine might add "int
-/// operator+(int, int)" to cover integer addition.
-void Sema::AddBuiltinOperatorCandidates(OverloadedOperatorKind Op,
-                                        SourceLocation OpLoc,
-                                        ArrayRef<Expr *> Args,
-                                        OverloadCandidateSet &CandidateSet) {
-  // Find all of the types that the arguments can convert to, but only
-  // if the operator we're looking at has built-in operator candidates
-  // that make use of these types. Also record whether we encounter non-record
-  // candidate types or either arithmetic or enumeral candidate types.
-  Qualifiers VisibleTypeConversionsQuals;
-  VisibleTypeConversionsQuals.addConst();
-  for (unsigned ArgIdx = 0, N = Args.size(); ArgIdx != N; ++ArgIdx)
-    VisibleTypeConversionsQuals += CollectVRQualifiers(Context, Args[ArgIdx]);
-
-  bool HasNonRecordCandidateType = false;
-  bool HasArithmeticOrEnumeralCandidateType = false;
-  SmallVector<BuiltinCandidateTypeSet, 2> CandidateTypes;
-  for (unsigned ArgIdx = 0, N = Args.size(); ArgIdx != N; ++ArgIdx) {
-    CandidateTypes.emplace_back(*this);
-    CandidateTypes[ArgIdx].AddTypesConvertedFrom(Args[ArgIdx]->getType(),
-                                                 OpLoc,
-                                                 true,
-                                                 (Op == OO_Exclaim ||
-                                                  Op == OO_AmpAmp ||
-                                                  Op == OO_PipePipe),
-                                                 VisibleTypeConversionsQuals);
-    HasNonRecordCandidateType = HasNonRecordCandidateType ||
-        CandidateTypes[ArgIdx].hasNonRecordTypes();
-    HasArithmeticOrEnumeralCandidateType =
-        HasArithmeticOrEnumeralCandidateType ||
-        CandidateTypes[ArgIdx].hasArithmeticOrEnumeralTypes();
-  }
-
-  // Exit early when no non-record types have been added to the candidate set
-  // for any of the arguments to the operator.
-  //
-  // We can't exit early for !, ||, or &&, since there we have always have
-  // 'bool' overloads.
-  if (!HasNonRecordCandidateType &&
-      !(Op == OO_Exclaim || Op == OO_AmpAmp || Op == OO_PipePipe))
-    return;
-
-  // Setup an object to manage the common state for building overloads.
-  BuiltinOperatorOverloadBuilder OpBuilder(*this, Args,
-                                           VisibleTypeConversionsQuals,
-                                           HasArithmeticOrEnumeralCandidateType,
-                                           CandidateTypes, CandidateSet);
-
-  // Dispatch over the operation to add in only those overloads which apply.
-  switch (Op) {
-  case OO_None:
-  case NUM_OVERLOADED_OPERATORS:
-    llvm_unreachable("Expected an overloaded operator");
-
-  case OO_New:
-  case OO_Delete:
-  case OO_Array_New:
-  case OO_Array_Delete:
-  case OO_Call:
-    llvm_unreachable(
-                    "Special operators don't use AddBuiltinOperatorCandidates");
-
-  case OO_Comma:
-  case OO_Arrow:
-  case OO_Coawait:
-    // C++ [over.match.oper]p3:
-    //   -- For the operator ',', the unary operator '&', the
-    //      operator '->', or the operator 'co_await', the
-    //      built-in candidates set is empty.
-    break;
-
-  case OO_Plus: // '+' is either unary or binary
-    if (Args.size() == 1)
-      OpBuilder.addUnaryPlusPointerOverloads();
-    LLVM_FALLTHROUGH;
-
-  case OO_Minus: // '-' is either unary or binary
-    if (Args.size() == 1) {
-      OpBuilder.addUnaryPlusOrMinusArithmeticOverloads();
-    } else {
-      OpBuilder.addBinaryPlusOrMinusPointerOverloads(Op);
-      OpBuilder.addGenericBinaryArithmeticOverloads();
-    }
-    break;
-
-  case OO_Star: // '*' is either unary or binary
-    if (Args.size() == 1)
-      OpBuilder.addUnaryStarPointerOverloads();
-    else
-      OpBuilder.addGenericBinaryArithmeticOverloads();
-    break;
-
-  case OO_Slash:
-    OpBuilder.addGenericBinaryArithmeticOverloads();
-    break;
-
-  case OO_PlusPlus:
-  case OO_MinusMinus:
-    OpBuilder.addPlusPlusMinusMinusArithmeticOverloads(Op);
-    OpBuilder.addPlusPlusMinusMinusPointerOverloads();
-    break;
-
-  case OO_EqualEqual:
-  case OO_ExclaimEqual:
-    OpBuilder.addEqualEqualOrNotEqualMemberPointerOrNullptrOverloads();
-    LLVM_FALLTHROUGH;
-
-  case OO_Less:
-  case OO_Greater:
-  case OO_LessEqual:
-  case OO_GreaterEqual:
-    OpBuilder.addGenericBinaryPointerOrEnumeralOverloads();
-    OpBuilder.addGenericBinaryArithmeticOverloads();
-    break;
-
-  case OO_Spaceship:
-    OpBuilder.addGenericBinaryPointerOrEnumeralOverloads();
-    OpBuilder.addThreeWayArithmeticOverloads();
-    break;
-
-  case OO_Percent:
-  case OO_Caret:
-  case OO_Pipe:
-  case OO_LessLess:
-  case OO_GreaterGreater:
-    OpBuilder.addBinaryBitwiseArithmeticOverloads(Op);
-    break;
-
-  case OO_Amp: // '&' is either unary or binary
-    if (Args.size() == 1)
-      // C++ [over.match.oper]p3:
-      //   -- For the operator ',', the unary operator '&', or the
-      //      operator '->', the built-in candidates set is empty.
-      break;
-
-    OpBuilder.addBinaryBitwiseArithmeticOverloads(Op);
-    break;
-
-  case OO_Tilde:
-    OpBuilder.addUnaryTildePromotedIntegralOverloads();
-    break;
-
-  case OO_Equal:
-    OpBuilder.addAssignmentMemberPointerOrEnumeralOverloads();
-    LLVM_FALLTHROUGH;
-
-  case OO_PlusEqual:
-  case OO_MinusEqual:
-    OpBuilder.addAssignmentPointerOverloads(Op == OO_Equal);
-    LLVM_FALLTHROUGH;
-
-  case OO_StarEqual:
-  case OO_SlashEqual:
-    OpBuilder.addAssignmentArithmeticOverloads(Op == OO_Equal);
-    break;
-
-  case OO_PercentEqual:
-  case OO_LessLessEqual:
-  case OO_GreaterGreaterEqual:
-  case OO_AmpEqual:
-  case OO_CaretEqual:
-  case OO_PipeEqual:
-    OpBuilder.addAssignmentIntegralOverloads();
-    break;
-
-  case OO_Exclaim:
-    OpBuilder.addExclaimOverload();
-    break;
-
-  case OO_AmpAmp:
-  case OO_PipePipe:
-    OpBuilder.addAmpAmpOrPipePipeOverload();
-    break;
-
-  case OO_Subscript:
-    OpBuilder.addSubscriptOverloads();
-    break;
-
-  case OO_ArrowStar:
-    OpBuilder.addArrowStarOverloads();
-    break;
-
-  case OO_Conditional:
-    OpBuilder.addConditionalOperatorOverloads();
-    OpBuilder.addGenericBinaryArithmeticOverloads();
-    break;
-  }
-}
-
-/// Add function candidates found via argument-dependent lookup
-/// to the set of overloading candidates.
-///
-/// This routine performs argument-dependent name lookup based on the
-/// given function name (which may also be an operator name) and adds
-/// all of the overload candidates found by ADL to the overload
-/// candidate set (C++ [basic.lookup.argdep]).
-void
-Sema::AddArgumentDependentLookupCandidates(DeclarationName Name,
-                                           SourceLocation Loc,
-                                           ArrayRef<Expr *> Args,
-                                 TemplateArgumentListInfo *ExplicitTemplateArgs,
-                                           OverloadCandidateSet& CandidateSet,
-                                           bool PartialOverloading) {
-  ADLResult Fns;
-
-  // FIXME: This approach for uniquing ADL results (and removing
-  // redundant candidates from the set) relies on pointer-equality,
-  // which means we need to key off the canonical decl.  However,
-  // always going back to the canonical decl might not get us the
-  // right set of default arguments.  What default arguments are
-  // we supposed to consider on ADL candidates, anyway?
-
-  // FIXME: Pass in the explicit template arguments?
-  ArgumentDependentLookup(Name, Loc, Args, Fns);
-
-  // Erase all of the candidates we already knew about.
-  for (OverloadCandidateSet::iterator Cand = CandidateSet.begin(),
-                                   CandEnd = CandidateSet.end();
-       Cand != CandEnd; ++Cand)
-    if (Cand->Function) {
-      Fns.erase(Cand->Function);
-      if (FunctionTemplateDecl *FunTmpl = Cand->Function->getPrimaryTemplate())
-        Fns.erase(FunTmpl);
-    }
-
-  // For each of the ADL candidates we found, add it to the overload
-  // set.
-  for (ADLResult::iterator I = Fns.begin(), E = Fns.end(); I != E; ++I) {
-    DeclAccessPair FoundDecl = DeclAccessPair::make(*I, AS_none);
-
-    if (FunctionDecl *FD = dyn_cast<FunctionDecl>(*I)) {
-      if (ExplicitTemplateArgs)
-        continue;
-
-      AddOverloadCandidate(FD, FoundDecl, Args, CandidateSet,
-                           /*SupressUserConversions=*/false, PartialOverloading,
-                           /*AllowExplicit=*/false, ADLCallKind::UsesADL);
-    } else {
-      AddTemplateOverloadCandidate(cast<FunctionTemplateDecl>(*I), FoundDecl,
-                                   ExplicitTemplateArgs, Args, CandidateSet,
-                                   /*SupressUserConversions=*/false,
-                                   PartialOverloading, ADLCallKind::UsesADL);
-    }
-  }
-}
-
-namespace {
-enum class Comparison { Equal, Better, Worse };
-}
-
-/// Compares the enable_if attributes of two FunctionDecls, for the purposes of
-/// overload resolution.
-///
-/// Cand1's set of enable_if attributes are said to be "better" than Cand2's iff
-/// Cand1's first N enable_if attributes have precisely the same conditions as
-/// Cand2's first N enable_if attributes (where N = the number of enable_if
-/// attributes on Cand2), and Cand1 has more than N enable_if attributes.
-///
-/// Note that you can have a pair of candidates such that Cand1's enable_if
-/// attributes are worse than Cand2's, and Cand2's enable_if attributes are
-/// worse than Cand1's.
-static Comparison compareEnableIfAttrs(const Sema &S, const FunctionDecl *Cand1,
-                                       const FunctionDecl *Cand2) {
-  // Common case: One (or both) decls don't have enable_if attrs.
-  bool Cand1Attr = Cand1->hasAttr<EnableIfAttr>();
-  bool Cand2Attr = Cand2->hasAttr<EnableIfAttr>();
-  if (!Cand1Attr || !Cand2Attr) {
-    if (Cand1Attr == Cand2Attr)
-      return Comparison::Equal;
-    return Cand1Attr ? Comparison::Better : Comparison::Worse;
-  }
-
-  auto Cand1Attrs = Cand1->specific_attrs<EnableIfAttr>();
-  auto Cand2Attrs = Cand2->specific_attrs<EnableIfAttr>();
-
-  llvm::FoldingSetNodeID Cand1ID, Cand2ID;
-  for (auto Pair : zip_longest(Cand1Attrs, Cand2Attrs)) {
-    Optional<EnableIfAttr *> Cand1A = std::get<0>(Pair);
-    Optional<EnableIfAttr *> Cand2A = std::get<1>(Pair);
-
-    // It's impossible for Cand1 to be better than (or equal to) Cand2 if Cand1
-    // has fewer enable_if attributes than Cand2, and vice versa.
-    if (!Cand1A)
-      return Comparison::Worse;
-    if (!Cand2A)
-      return Comparison::Better;
-
-    Cand1ID.clear();
-    Cand2ID.clear();
-
-    (*Cand1A)->getCond()->Profile(Cand1ID, S.getASTContext(), true);
-    (*Cand2A)->getCond()->Profile(Cand2ID, S.getASTContext(), true);
-    if (Cand1ID != Cand2ID)
-      return Comparison::Worse;
-  }
-
-  return Comparison::Equal;
-}
-
-static bool isBetterMultiversionCandidate(const OverloadCandidate &Cand1,
-                                          const OverloadCandidate &Cand2) {
-  if (!Cand1.Function || !Cand1.Function->isMultiVersion() || !Cand2.Function ||
-      !Cand2.Function->isMultiVersion())
-    return false;
-
-  // If Cand1 is invalid, it cannot be a better match, if Cand2 is invalid, this
-  // is obviously better.
-  if (Cand1.Function->isInvalidDecl()) return false;
-  if (Cand2.Function->isInvalidDecl()) return true;
-
-  // If this is a cpu_dispatch/cpu_specific multiversion situation, prefer
-  // cpu_dispatch, else arbitrarily based on the identifiers.
-  bool Cand1CPUDisp = Cand1.Function->hasAttr<CPUDispatchAttr>();
-  bool Cand2CPUDisp = Cand2.Function->hasAttr<CPUDispatchAttr>();
-  const auto *Cand1CPUSpec = Cand1.Function->getAttr<CPUSpecificAttr>();
-  const auto *Cand2CPUSpec = Cand2.Function->getAttr<CPUSpecificAttr>();
-
-  if (!Cand1CPUDisp && !Cand2CPUDisp && !Cand1CPUSpec && !Cand2CPUSpec)
-    return false;
-
-  if (Cand1CPUDisp && !Cand2CPUDisp)
-    return true;
-  if (Cand2CPUDisp && !Cand1CPUDisp)
-    return false;
-
-  if (Cand1CPUSpec && Cand2CPUSpec) {
-    if (Cand1CPUSpec->cpus_size() != Cand2CPUSpec->cpus_size())
-      return Cand1CPUSpec->cpus_size() < Cand2CPUSpec->cpus_size();
-
-    std::pair<CPUSpecificAttr::cpus_iterator, CPUSpecificAttr::cpus_iterator>
-        FirstDiff = std::mismatch(
-            Cand1CPUSpec->cpus_begin(), Cand1CPUSpec->cpus_end(),
-            Cand2CPUSpec->cpus_begin(),
-            [](const IdentifierInfo *LHS, const IdentifierInfo *RHS) {
-              return LHS->getName() == RHS->getName();
-            });
-
-    assert(FirstDiff.first != Cand1CPUSpec->cpus_end() &&
-           "Two different cpu-specific versions should not have the same "
-           "identifier list, otherwise they'd be the same decl!");
-    return (*FirstDiff.first)->getName() < (*FirstDiff.second)->getName();
-  }
-  llvm_unreachable("No way to get here unless both had cpu_dispatch");
-}
-
-/// isBetterOverloadCandidate - Determines whether the first overload
-/// candidate is a better candidate than the second (C++ 13.3.3p1).
-bool clang::isBetterOverloadCandidate(
-    Sema &S, const OverloadCandidate &Cand1, const OverloadCandidate &Cand2,
-    SourceLocation Loc, OverloadCandidateSet::CandidateSetKind Kind) {
-  // Define viable functions to be better candidates than non-viable
-  // functions.
-  if (!Cand2.Viable)
-    return Cand1.Viable;
-  else if (!Cand1.Viable)
-    return false;
-
-  // C++ [over.match.best]p1:
-  //
-  //   -- if F is a static member function, ICS1(F) is defined such
-  //      that ICS1(F) is neither better nor worse than ICS1(G) for
-  //      any function G, and, symmetrically, ICS1(G) is neither
-  //      better nor worse than ICS1(F).
-  unsigned StartArg = 0;
-  if (Cand1.IgnoreObjectArgument || Cand2.IgnoreObjectArgument)
-    StartArg = 1;
-
-  auto IsIllFormedConversion = [&](const ImplicitConversionSequence &ICS) {
-    // We don't allow incompatible pointer conversions in C++.
-    if (!S.getLangOpts().CPlusPlus)
-      return ICS.isStandard() &&
-             ICS.Standard.Second == ICK_Incompatible_Pointer_Conversion;
-
-    // The only ill-formed conversion we allow in C++ is the string literal to
-    // char* conversion, which is only considered ill-formed after C++11.
-    return S.getLangOpts().CPlusPlus11 && !S.getLangOpts().WritableStrings &&
-           hasDeprecatedStringLiteralToCharPtrConversion(ICS);
-  };
-
-  // Define functions that don't require ill-formed conversions for a given
-  // argument to be better candidates than functions that do.
-  unsigned NumArgs = Cand1.Conversions.size();
-  assert(Cand2.Conversions.size() == NumArgs && "Overload candidate mismatch");
-  bool HasBetterConversion = false;
-  for (unsigned ArgIdx = StartArg; ArgIdx < NumArgs; ++ArgIdx) {
-    bool Cand1Bad = IsIllFormedConversion(Cand1.Conversions[ArgIdx]);
-    bool Cand2Bad = IsIllFormedConversion(Cand2.Conversions[ArgIdx]);
-    if (Cand1Bad != Cand2Bad) {
-      if (Cand1Bad)
-        return false;
-      HasBetterConversion = true;
-    }
-  }
-
-  if (HasBetterConversion)
-    return true;
-
-  // C++ [over.match.best]p1:
-  //   A viable function F1 is defined to be a better function than another
-  //   viable function F2 if for all arguments i, ICSi(F1) is not a worse
-  //   conversion sequence than ICSi(F2), and then...
-  for (unsigned ArgIdx = StartArg; ArgIdx < NumArgs; ++ArgIdx) {
-    switch (CompareImplicitConversionSequences(S, Loc,
-                                               Cand1.Conversions[ArgIdx],
-                                               Cand2.Conversions[ArgIdx])) {
-    case ImplicitConversionSequence::Better:
-      // Cand1 has a better conversion sequence.
-      HasBetterConversion = true;
-      break;
-
-    case ImplicitConversionSequence::Worse:
-      // Cand1 can't be better than Cand2.
-      return false;
-
-    case ImplicitConversionSequence::Indistinguishable:
-      // Do nothing.
-      break;
-    }
-  }
-
-  //    -- for some argument j, ICSj(F1) is a better conversion sequence than
-  //       ICSj(F2), or, if not that,
-  if (HasBetterConversion)
-    return true;
-
-  //   -- the context is an initialization by user-defined conversion
-  //      (see 8.5, 13.3.1.5) and the standard conversion sequence
-  //      from the return type of F1 to the destination type (i.e.,
-  //      the type of the entity being initialized) is a better
-  //      conversion sequence than the standard conversion sequence
-  //      from the return type of F2 to the destination type.
-  if (Kind == OverloadCandidateSet::CSK_InitByUserDefinedConversion &&
-      Cand1.Function && Cand2.Function &&
-      isa<CXXConversionDecl>(Cand1.Function) &&
-      isa<CXXConversionDecl>(Cand2.Function)) {
-    // First check whether we prefer one of the conversion functions over the
-    // other. This only distinguishes the results in non-standard, extension
-    // cases such as the conversion from a lambda closure type to a function
-    // pointer or block.
-    ImplicitConversionSequence::CompareKind Result =
-        compareConversionFunctions(S, Cand1.Function, Cand2.Function);
-    if (Result == ImplicitConversionSequence::Indistinguishable)
-      Result = CompareStandardConversionSequences(S, Loc,
-                                                  Cand1.FinalConversion,
-                                                  Cand2.FinalConversion);
-
-    if (Result != ImplicitConversionSequence::Indistinguishable)
-      return Result == ImplicitConversionSequence::Better;
-
-    // FIXME: Compare kind of reference binding if conversion functions
-    // convert to a reference type used in direct reference binding, per
-    // C++14 [over.match.best]p1 section 2 bullet 3.
-  }
-
-  // FIXME: Work around a defect in the C++17 guaranteed copy elision wording,
-  // as combined with the resolution to CWG issue 243.
-  //
-  // When the context is initialization by constructor ([over.match.ctor] or
-  // either phase of [over.match.list]), a constructor is preferred over
-  // a conversion function.
-  if (Kind == OverloadCandidateSet::CSK_InitByConstructor && NumArgs == 1 &&
-      Cand1.Function && Cand2.Function &&
-      isa<CXXConstructorDecl>(Cand1.Function) !=
-          isa<CXXConstructorDecl>(Cand2.Function))
-    return isa<CXXConstructorDecl>(Cand1.Function);
-
-  //    -- F1 is a non-template function and F2 is a function template
-  //       specialization, or, if not that,
-  bool Cand1IsSpecialization = Cand1.Function &&
-                               Cand1.Function->getPrimaryTemplate();
-  bool Cand2IsSpecialization = Cand2.Function &&
-                               Cand2.Function->getPrimaryTemplate();
-  if (Cand1IsSpecialization != Cand2IsSpecialization)
-    return Cand2IsSpecialization;
-
-  //   -- F1 and F2 are function template specializations, and the function
-  //      template for F1 is more specialized than the template for F2
-  //      according to the partial ordering rules described in 14.5.5.2, or,
-  //      if not that,
-  if (Cand1IsSpecialization && Cand2IsSpecialization) {
-    if (FunctionTemplateDecl *BetterTemplate
-          = S.getMoreSpecializedTemplate(Cand1.Function->getPrimaryTemplate(),
-                                         Cand2.Function->getPrimaryTemplate(),
-                                         Loc,
-                       isa<CXXConversionDecl>(Cand1.Function)? TPOC_Conversion
-                                                             : TPOC_Call,
-                                         Cand1.ExplicitCallArguments,
-                                         Cand2.ExplicitCallArguments))
-      return BetterTemplate == Cand1.Function->getPrimaryTemplate();
-  }
-
-  // FIXME: Work around a defect in the C++17 inheriting constructor wording.
-  // A derived-class constructor beats an (inherited) base class constructor.
-  bool Cand1IsInherited =
-      dyn_cast_or_null<ConstructorUsingShadowDecl>(Cand1.FoundDecl.getDecl());
-  bool Cand2IsInherited =
-      dyn_cast_or_null<ConstructorUsingShadowDecl>(Cand2.FoundDecl.getDecl());
-  if (Cand1IsInherited != Cand2IsInherited)
-    return Cand2IsInherited;
-  else if (Cand1IsInherited) {
-    assert(Cand2IsInherited);
-    auto *Cand1Class = cast<CXXRecordDecl>(Cand1.Function->getDeclContext());
-    auto *Cand2Class = cast<CXXRecordDecl>(Cand2.Function->getDeclContext());
-    if (Cand1Class->isDerivedFrom(Cand2Class))
-      return true;
-    if (Cand2Class->isDerivedFrom(Cand1Class))
-      return false;
-    // Inherited from sibling base classes: still ambiguous.
-  }
-
-  // Check C++17 tie-breakers for deduction guides.
-  {
-    auto *Guide1 = dyn_cast_or_null<CXXDeductionGuideDecl>(Cand1.Function);
-    auto *Guide2 = dyn_cast_or_null<CXXDeductionGuideDecl>(Cand2.Function);
-    if (Guide1 && Guide2) {
-      //  -- F1 is generated from a deduction-guide and F2 is not
-      if (Guide1->isImplicit() != Guide2->isImplicit())
-        return Guide2->isImplicit();
-
-      //  -- F1 is the copy deduction candidate(16.3.1.8) and F2 is not
-      if (Guide1->isCopyDeductionCandidate())
-        return true;
-    }
-  }
-
-  // Check for enable_if value-based overload resolution.
-  if (Cand1.Function && Cand2.Function) {
-    Comparison Cmp = compareEnableIfAttrs(S, Cand1.Function, Cand2.Function);
-    if (Cmp != Comparison::Equal)
-      return Cmp == Comparison::Better;
-  }
-
-  if (S.getLangOpts().CUDA && Cand1.Function && Cand2.Function) {
-    FunctionDecl *Caller = dyn_cast<FunctionDecl>(S.CurContext);
-    return S.IdentifyCUDAPreference(Caller, Cand1.Function) >
-           S.IdentifyCUDAPreference(Caller, Cand2.Function);
-  }
-
-  bool HasPS1 = Cand1.Function != nullptr &&
-                functionHasPassObjectSizeParams(Cand1.Function);
-  bool HasPS2 = Cand2.Function != nullptr &&
-                functionHasPassObjectSizeParams(Cand2.Function);
-  if (HasPS1 != HasPS2 && HasPS1)
-    return true;
-
-  return isBetterMultiversionCandidate(Cand1, Cand2);
-}
-
-/// Determine whether two declarations are "equivalent" for the purposes of
-/// name lookup and overload resolution. This applies when the same internal/no
-/// linkage entity is defined by two modules (probably by textually including
-/// the same header). In such a case, we don't consider the declarations to
-/// declare the same entity, but we also don't want lookups with both
-/// declarations visible to be ambiguous in some cases (this happens when using
-/// a modularized libstdc++).
-bool Sema::isEquivalentInternalLinkageDeclaration(const NamedDecl *A,
-                                                  const NamedDecl *B) {
-  auto *VA = dyn_cast_or_null<ValueDecl>(A);
-  auto *VB = dyn_cast_or_null<ValueDecl>(B);
-  if (!VA || !VB)
-    return false;
-
-  // The declarations must be declaring the same name as an internal linkage
-  // entity in different modules.
-  if (!VA->getDeclContext()->getRedeclContext()->Equals(
-          VB->getDeclContext()->getRedeclContext()) ||
-      getOwningModule(const_cast<ValueDecl *>(VA)) ==
-          getOwningModule(const_cast<ValueDecl *>(VB)) ||
-      VA->isExternallyVisible() || VB->isExternallyVisible())
-    return false;
-
-  // Check that the declarations appear to be equivalent.
-  //
-  // FIXME: Checking the type isn't really enough to resolve the ambiguity.
-  // For constants and functions, we should check the initializer or body is
-  // the same. For non-constant variables, we shouldn't allow it at all.
-  if (Context.hasSameType(VA->getType(), VB->getType()))
-    return true;
-
-  // Enum constants within unnamed enumerations will have different types, but
-  // may still be similar enough to be interchangeable for our purposes.
-  if (auto *EA = dyn_cast<EnumConstantDecl>(VA)) {
-    if (auto *EB = dyn_cast<EnumConstantDecl>(VB)) {
-      // Only handle anonymous enums. If the enumerations were named and
-      // equivalent, they would have been merged to the same type.
-      auto *EnumA = cast<EnumDecl>(EA->getDeclContext());
-      auto *EnumB = cast<EnumDecl>(EB->getDeclContext());
-      if (EnumA->hasNameForLinkage() || EnumB->hasNameForLinkage() ||
-          !Context.hasSameType(EnumA->getIntegerType(),
-                               EnumB->getIntegerType()))
-        return false;
-      // Allow this only if the value is the same for both enumerators.
-      return llvm::APSInt::isSameValue(EA->getInitVal(), EB->getInitVal());
-    }
-  }
-
-  // Nothing else is sufficiently similar.
-  return false;
-}
-
-void Sema::diagnoseEquivalentInternalLinkageDeclarations(
-    SourceLocation Loc, const NamedDecl *D, ArrayRef<const NamedDecl *> Equiv) {
-  Diag(Loc, diag::ext_equivalent_internal_linkage_decl_in_modules) << D;
-
-  Module *M = getOwningModule(const_cast<NamedDecl*>(D));
-  Diag(D->getLocation(), diag::note_equivalent_internal_linkage_decl)
-      << !M << (M ? M->getFullModuleName() : "");
-
-  for (auto *E : Equiv) {
-    Module *M = getOwningModule(const_cast<NamedDecl*>(E));
-    Diag(E->getLocation(), diag::note_equivalent_internal_linkage_decl)
-        << !M << (M ? M->getFullModuleName() : "");
-  }
-}
-
-/// Computes the best viable function (C++ 13.3.3)
-/// within an overload candidate set.
-///
-/// \param Loc The location of the function name (or operator symbol) for
-/// which overload resolution occurs.
-///
-/// \param Best If overload resolution was successful or found a deleted
-/// function, \p Best points to the candidate function found.
-///
-/// \returns The result of overload resolution.
-OverloadingResult
-OverloadCandidateSet::BestViableFunction(Sema &S, SourceLocation Loc,
-                                         iterator &Best) {
-  llvm::SmallVector<OverloadCandidate *, 16> Candidates;
-  std::transform(begin(), end(), std::back_inserter(Candidates),
-                 [](OverloadCandidate &Cand) { return &Cand; });
-
-  // [CUDA] HD->H or HD->D calls are technically not allowed by CUDA but
-  // are accepted by both clang and NVCC. However, during a particular
-  // compilation mode only one call variant is viable. We need to
-  // exclude non-viable overload candidates from consideration based
-  // only on their host/device attributes. Specifically, if one
-  // candidate call is WrongSide and the other is SameSide, we ignore
-  // the WrongSide candidate.
-  if (S.getLangOpts().CUDA) {
-    const FunctionDecl *Caller = dyn_cast<FunctionDecl>(S.CurContext);
-    bool ContainsSameSideCandidate =
-        llvm::any_of(Candidates, [&](OverloadCandidate *Cand) {
-          return Cand->Function &&
-                 S.IdentifyCUDAPreference(Caller, Cand->Function) ==
-                     Sema::CFP_SameSide;
-        });
-    if (ContainsSameSideCandidate) {
-      auto IsWrongSideCandidate = [&](OverloadCandidate *Cand) {
-        return Cand->Function &&
-               S.IdentifyCUDAPreference(Caller, Cand->Function) ==
-                   Sema::CFP_WrongSide;
-      };
-      llvm::erase_if(Candidates, IsWrongSideCandidate);
-    }
-  }
-
-  // Find the best viable function.
-  Best = end();
-  for (auto *Cand : Candidates)
-    if (Cand->Viable)
-      if (Best == end() ||
-          isBetterOverloadCandidate(S, *Cand, *Best, Loc, Kind))
-        Best = Cand;
-
-  // If we didn't find any viable functions, abort.
-  if (Best == end())
-    return OR_No_Viable_Function;
-
-  llvm::SmallVector<const NamedDecl *, 4> EquivalentCands;
-
-  // Make sure that this function is better than every other viable
-  // function. If not, we have an ambiguity.
-  for (auto *Cand : Candidates) {
-    if (Cand->Viable && Cand != Best &&
-        !isBetterOverloadCandidate(S, *Best, *Cand, Loc, Kind)) {
-      if (S.isEquivalentInternalLinkageDeclaration(Best->Function,
-                                                   Cand->Function)) {
-        EquivalentCands.push_back(Cand->Function);
-        continue;
-      }
-
-      Best = end();
-      return OR_Ambiguous;
-    }
-  }
-
-  // Best is the best viable function.
-  if (Best->Function &&
-      (Best->Function->isDeleted() ||
-       S.isFunctionConsideredUnavailable(Best->Function)))
-    return OR_Deleted;
-
-  if (!EquivalentCands.empty())
-    S.diagnoseEquivalentInternalLinkageDeclarations(Loc, Best->Function,
-                                                    EquivalentCands);
-
-  return OR_Success;
-}
-
-namespace {
-
-enum OverloadCandidateKind {
-  oc_function,
-  oc_method,
-  oc_constructor,
-  oc_implicit_default_constructor,
-  oc_implicit_copy_constructor,
-  oc_implicit_move_constructor,
-  oc_implicit_copy_assignment,
-  oc_implicit_move_assignment,
-  oc_inherited_constructor
-};
-
-enum OverloadCandidateSelect {
-  ocs_non_template,
-  ocs_template,
-  ocs_described_template,
-};
-
-static std::pair<OverloadCandidateKind, OverloadCandidateSelect>
-ClassifyOverloadCandidate(Sema &S, NamedDecl *Found, FunctionDecl *Fn,
-                          std::string &Description) {
-
-  bool isTemplate = Fn->isTemplateDecl() || Found->isTemplateDecl();
-  if (FunctionTemplateDecl *FunTmpl = Fn->getPrimaryTemplate()) {
-    isTemplate = true;
-    Description = S.getTemplateArgumentBindingsText(
-        FunTmpl->getTemplateParameters(), *Fn->getTemplateSpecializationArgs());
-  }
-
-  OverloadCandidateSelect Select = [&]() {
-    if (!Description.empty())
-      return ocs_described_template;
-    return isTemplate ? ocs_template : ocs_non_template;
-  }();
-
-  OverloadCandidateKind Kind = [&]() {
-    if (CXXConstructorDecl *Ctor = dyn_cast<CXXConstructorDecl>(Fn)) {
-      if (!Ctor->isImplicit()) {
-        if (isa<ConstructorUsingShadowDecl>(Found))
-          return oc_inherited_constructor;
-        else
-          return oc_constructor;
-      }
-
-      if (Ctor->isDefaultConstructor())
-        return oc_implicit_default_constructor;
-
-      if (Ctor->isMoveConstructor())
-        return oc_implicit_move_constructor;
-
-      assert(Ctor->isCopyConstructor() &&
-             "unexpected sort of implicit constructor");
-      return oc_implicit_copy_constructor;
-    }
-
-    if (CXXMethodDecl *Meth = dyn_cast<CXXMethodDecl>(Fn)) {
-      // This actually gets spelled 'candidate function' for now, but
-      // it doesn't hurt to split it out.
-      if (!Meth->isImplicit())
-        return oc_method;
-
-      if (Meth->isMoveAssignmentOperator())
-        return oc_implicit_move_assignment;
-
-      if (Meth->isCopyAssignmentOperator())
-        return oc_implicit_copy_assignment;
-
-      assert(isa<CXXConversionDecl>(Meth) && "expected conversion");
-      return oc_method;
-    }
-
-    return oc_function;
-  }();
-
-  return std::make_pair(Kind, Select);
-}
-
-void MaybeEmitInheritedConstructorNote(Sema &S, Decl *FoundDecl) {
-  // FIXME: It'd be nice to only emit a note once per using-decl per overload
-  // set.
-  if (auto *Shadow = dyn_cast<ConstructorUsingShadowDecl>(FoundDecl))
-    S.Diag(FoundDecl->getLocation(),
-           diag::note_ovl_candidate_inherited_constructor)
-      << Shadow->getNominatedBaseClass();
-}
-
-} // end anonymous namespace
-
-static bool isFunctionAlwaysEnabled(const ASTContext &Ctx,
-                                    const FunctionDecl *FD) {
-  for (auto *EnableIf : FD->specific_attrs<EnableIfAttr>()) {
-    bool AlwaysTrue;
-    if (!EnableIf->getCond()->EvaluateAsBooleanCondition(AlwaysTrue, Ctx))
-      return false;
-    if (!AlwaysTrue)
-      return false;
-  }
-  return true;
-}
-
-/// Returns true if we can take the address of the function.
-///
-/// \param Complain - If true, we'll emit a diagnostic
-/// \param InOverloadResolution - For the purposes of emitting a diagnostic, are
-///   we in overload resolution?
-/// \param Loc - The location of the statement we're complaining about. Ignored
-///   if we're not complaining, or if we're in overload resolution.
-static bool checkAddressOfFunctionIsAvailable(Sema &S, const FunctionDecl *FD,
-                                              bool Complain,
-                                              bool InOverloadResolution,
-                                              SourceLocation Loc) {
-  if (!isFunctionAlwaysEnabled(S.Context, FD)) {
-    if (Complain) {
-      if (InOverloadResolution)
-        S.Diag(FD->getBeginLoc(),
-               diag::note_addrof_ovl_candidate_disabled_by_enable_if_attr);
-      else
-        S.Diag(Loc, diag::err_addrof_function_disabled_by_enable_if_attr) << FD;
-    }
-    return false;
-  }
-
-  auto I = llvm::find_if(FD->parameters(), [](const ParmVarDecl *P) {
-    return P->hasAttr<PassObjectSizeAttr>();
-  });
-  if (I == FD->param_end())
-    return true;
-
-  if (Complain) {
-    // Add one to ParamNo because it's user-facing
-    unsigned ParamNo = std::distance(FD->param_begin(), I) + 1;
-    if (InOverloadResolution)
-      S.Diag(FD->getLocation(),
-             diag::note_ovl_candidate_has_pass_object_size_params)
-          << ParamNo;
-    else
-      S.Diag(Loc, diag::err_address_of_function_with_pass_object_size_params)
-          << FD << ParamNo;
-  }
-  return false;
-}
-
-static bool checkAddressOfCandidateIsAvailable(Sema &S,
-                                               const FunctionDecl *FD) {
-  return checkAddressOfFunctionIsAvailable(S, FD, /*Complain=*/true,
-                                           /*InOverloadResolution=*/true,
-                                           /*Loc=*/SourceLocation());
-}
-
-bool Sema::checkAddressOfFunctionIsAvailable(const FunctionDecl *Function,
-                                             bool Complain,
-                                             SourceLocation Loc) {
-  return ::checkAddressOfFunctionIsAvailable(*this, Function, Complain,
-                                             /*InOverloadResolution=*/false,
-                                             Loc);
-}
-
-// Notes the location of an overload candidate.
-void Sema::NoteOverloadCandidate(NamedDecl *Found, FunctionDecl *Fn,
-                                 QualType DestType, bool TakingAddress) {
-  if (TakingAddress && !checkAddressOfCandidateIsAvailable(*this, Fn))
-    return;
-  if (Fn->isMultiVersion() && Fn->hasAttr<TargetAttr>() &&
-      !Fn->getAttr<TargetAttr>()->isDefaultVersion())
-    return;
-
-  std::string FnDesc;
-  std::pair<OverloadCandidateKind, OverloadCandidateSelect> KSPair =
-      ClassifyOverloadCandidate(*this, Found, Fn, FnDesc);
-  PartialDiagnostic PD = PDiag(diag::note_ovl_candidate)
-                         << (unsigned)KSPair.first << (unsigned)KSPair.second
-                         << Fn << FnDesc;
-
-  HandleFunctionTypeMismatch(PD, Fn->getType(), DestType);
-  Diag(Fn->getLocation(), PD);
-  MaybeEmitInheritedConstructorNote(*this, Found);
-}
-
-// Notes the location of all overload candidates designated through
-// OverloadedExpr
-void Sema::NoteAllOverloadCandidates(Expr *OverloadedExpr, QualType DestType,
-                                     bool TakingAddress) {
-  assert(OverloadedExpr->getType() == Context.OverloadTy);
-
-  OverloadExpr::FindResult Ovl = OverloadExpr::find(OverloadedExpr);
-  OverloadExpr *OvlExpr = Ovl.Expression;
-
-  for (UnresolvedSetIterator I = OvlExpr->decls_begin(),
-                            IEnd = OvlExpr->decls_end();
-       I != IEnd; ++I) {
-    if (FunctionTemplateDecl *FunTmpl =
-                dyn_cast<FunctionTemplateDecl>((*I)->getUnderlyingDecl()) ) {
-      NoteOverloadCandidate(*I, FunTmpl->getTemplatedDecl(), DestType,
-                            TakingAddress);
-    } else if (FunctionDecl *Fun
-                      = dyn_cast<FunctionDecl>((*I)->getUnderlyingDecl()) ) {
-      NoteOverloadCandidate(*I, Fun, DestType, TakingAddress);
-    }
-  }
-}
-
-/// Diagnoses an ambiguous conversion.  The partial diagnostic is the
-/// "lead" diagnostic; it will be given two arguments, the source and
-/// target types of the conversion.
-void ImplicitConversionSequence::DiagnoseAmbiguousConversion(
-                                 Sema &S,
-                                 SourceLocation CaretLoc,
-                                 const PartialDiagnostic &PDiag) const {
-  S.Diag(CaretLoc, PDiag)
-    << Ambiguous.getFromType() << Ambiguous.getToType();
-  // FIXME: The note limiting machinery is borrowed from
-  // OverloadCandidateSet::NoteCandidates; there's an opportunity for
-  // refactoring here.
-  const OverloadsShown ShowOverloads = S.Diags.getShowOverloads();
-  unsigned CandsShown = 0;
-  AmbiguousConversionSequence::const_iterator I, E;
-  for (I = Ambiguous.begin(), E = Ambiguous.end(); I != E; ++I) {
-    if (CandsShown >= 4 && ShowOverloads == Ovl_Best)
-      break;
-    ++CandsShown;
-    S.NoteOverloadCandidate(I->first, I->second);
-  }
-  if (I != E)
-    S.Diag(SourceLocation(), diag::note_ovl_too_many_candidates) << int(E - I);
-}
-
-static void DiagnoseBadConversion(Sema &S, OverloadCandidate *Cand,
-                                  unsigned I, bool TakingCandidateAddress) {
-  const ImplicitConversionSequence &Conv = Cand->Conversions[I];
-  assert(Conv.isBad());
-  assert(Cand->Function && "for now, candidate must be a function");
-  FunctionDecl *Fn = Cand->Function;
-
-  // There's a conversion slot for the object argument if this is a
-  // non-constructor method.  Note that 'I' corresponds the
-  // conversion-slot index.
-  bool isObjectArgument = false;
-  if (isa<CXXMethodDecl>(Fn) && !isa<CXXConstructorDecl>(Fn)) {
-    if (I == 0)
-      isObjectArgument = true;
-    else
-      I--;
-  }
-
-  std::string FnDesc;
-  std::pair<OverloadCandidateKind, OverloadCandidateSelect> FnKindPair =
-      ClassifyOverloadCandidate(S, Cand->FoundDecl, Fn, FnDesc);
-
-  Expr *FromExpr = Conv.Bad.FromExpr;
-  QualType FromTy = Conv.Bad.getFromType();
-  QualType ToTy = Conv.Bad.getToType();
-
-  if (FromTy == S.Context.OverloadTy) {
-    assert(FromExpr && "overload set argument came from implicit argument?");
-    Expr *E = FromExpr->IgnoreParens();
-    if (isa<UnaryOperator>(E))
-      E = cast<UnaryOperator>(E)->getSubExpr()->IgnoreParens();
-    DeclarationName Name = cast<OverloadExpr>(E)->getName();
-
-    S.Diag(Fn->getLocation(), diag::note_ovl_candidate_bad_overload)
-        << (unsigned)FnKindPair.first << (unsigned)FnKindPair.second << FnDesc
-        << (FromExpr ? FromExpr->getSourceRange() : SourceRange()) << ToTy
-        << Name << I + 1;
-    MaybeEmitInheritedConstructorNote(S, Cand->FoundDecl);
-    return;
-  }
-
-  // Do some hand-waving analysis to see if the non-viability is due
-  // to a qualifier mismatch.
-  CanQualType CFromTy = S.Context.getCanonicalType(FromTy);
-  CanQualType CToTy = S.Context.getCanonicalType(ToTy);
-  if (CanQual<ReferenceType> RT = CToTy->getAs<ReferenceType>())
-    CToTy = RT->getPointeeType();
-  else {
-    // TODO: detect and diagnose the full richness of const mismatches.
-    if (CanQual<PointerType> FromPT = CFromTy->getAs<PointerType>())
-      if (CanQual<PointerType> ToPT = CToTy->getAs<PointerType>()) {
-        CFromTy = FromPT->getPointeeType();
-        CToTy = ToPT->getPointeeType();
-      }
-  }
-
-  if (CToTy.getUnqualifiedType() == CFromTy.getUnqualifiedType() &&
-      !CToTy.isAtLeastAsQualifiedAs(CFromTy)) {
-    Qualifiers FromQs = CFromTy.getQualifiers();
-    Qualifiers ToQs = CToTy.getQualifiers();
-
-    if (FromQs.getAddressSpace() != ToQs.getAddressSpace()) {
-      S.Diag(Fn->getLocation(), diag::note_ovl_candidate_bad_addrspace)
-          << (unsigned)FnKindPair.first << (unsigned)FnKindPair.second << FnDesc
-          << (FromExpr ? FromExpr->getSourceRange() : SourceRange()) << FromTy
-          << ToTy << (unsigned)isObjectArgument << I + 1;
-      MaybeEmitInheritedConstructorNote(S, Cand->FoundDecl);
-      return;
-    }
-
-    if (FromQs.getObjCLifetime() != ToQs.getObjCLifetime()) {
-      S.Diag(Fn->getLocation(), diag::note_ovl_candidate_bad_ownership)
-          << (unsigned)FnKindPair.first << (unsigned)FnKindPair.second << FnDesc
-          << (FromExpr ? FromExpr->getSourceRange() : SourceRange()) << FromTy
-          << FromQs.getObjCLifetime() << ToQs.getObjCLifetime()
-          << (unsigned)isObjectArgument << I + 1;
-      MaybeEmitInheritedConstructorNote(S, Cand->FoundDecl);
-      return;
-    }
-
-    if (FromQs.getObjCGCAttr() != ToQs.getObjCGCAttr()) {
-      S.Diag(Fn->getLocation(), diag::note_ovl_candidate_bad_gc)
-          << (unsigned)FnKindPair.first << (unsigned)FnKindPair.second << FnDesc
-          << (FromExpr ? FromExpr->getSourceRange() : SourceRange()) << FromTy
-          << FromQs.getObjCGCAttr() << ToQs.getObjCGCAttr()
-          << (unsigned)isObjectArgument << I + 1;
-      MaybeEmitInheritedConstructorNote(S, Cand->FoundDecl);
-      return;
-    }
-
-    if (FromQs.hasUnaligned() != ToQs.hasUnaligned()) {
-      S.Diag(Fn->getLocation(), diag::note_ovl_candidate_bad_unaligned)
-          << (unsigned)FnKindPair.first << (unsigned)FnKindPair.second << FnDesc
-          << (FromExpr ? FromExpr->getSourceRange() : SourceRange()) << FromTy
-          << FromQs.hasUnaligned() << I + 1;
-      MaybeEmitInheritedConstructorNote(S, Cand->FoundDecl);
-      return;
-    }
-
-    unsigned CVR = FromQs.getCVRQualifiers() & ~ToQs.getCVRQualifiers();
-    assert(CVR && "unexpected qualifiers mismatch");
-
-    if (isObjectArgument) {
-      S.Diag(Fn->getLocation(), diag::note_ovl_candidate_bad_cvr_this)
-          << (unsigned)FnKindPair.first << (unsigned)FnKindPair.second << FnDesc
-          << (FromExpr ? FromExpr->getSourceRange() : SourceRange()) << FromTy
-          << (CVR - 1);
-    } else {
-      S.Diag(Fn->getLocation(), diag::note_ovl_candidate_bad_cvr)
-          << (unsigned)FnKindPair.first << (unsigned)FnKindPair.second << FnDesc
-          << (FromExpr ? FromExpr->getSourceRange() : SourceRange()) << FromTy
-          << (CVR - 1) << I + 1;
-    }
-    MaybeEmitInheritedConstructorNote(S, Cand->FoundDecl);
-    return;
-  }
-
-  // Special diagnostic for failure to convert an initializer list, since
-  // telling the user that it has type void is not useful.
-  if (FromExpr && isa<InitListExpr>(FromExpr)) {
-    S.Diag(Fn->getLocation(), diag::note_ovl_candidate_bad_list_argument)
-        << (unsigned)FnKindPair.first << (unsigned)FnKindPair.second << FnDesc
-        << (FromExpr ? FromExpr->getSourceRange() : SourceRange()) << FromTy
-        << ToTy << (unsigned)isObjectArgument << I + 1;
-    MaybeEmitInheritedConstructorNote(S, Cand->FoundDecl);
-    return;
-  }
-
-  // Diagnose references or pointers to incomplete types differently,
-  // since it's far from impossible that the incompleteness triggered
-  // the failure.
-  QualType TempFromTy = FromTy.getNonReferenceType();
-  if (const PointerType *PTy = TempFromTy->getAs<PointerType>())
-    TempFromTy = PTy->getPointeeType();
-  if (TempFromTy->isIncompleteType()) {
-    // Emit the generic diagnostic and, optionally, add the hints to it.
-    S.Diag(Fn->getLocation(), diag::note_ovl_candidate_bad_conv_incomplete)
-        << (unsigned)FnKindPair.first << (unsigned)FnKindPair.second << FnDesc
-        << (FromExpr ? FromExpr->getSourceRange() : SourceRange()) << FromTy
-        << ToTy << (unsigned)isObjectArgument << I + 1
-        << (unsigned)(Cand->Fix.Kind);
-
-    MaybeEmitInheritedConstructorNote(S, Cand->FoundDecl);
-    return;
-  }
-
-  // Diagnose base -> derived pointer conversions.
-  unsigned BaseToDerivedConversion = 0;
-  if (const PointerType *FromPtrTy = FromTy->getAs<PointerType>()) {
-    if (const PointerType *ToPtrTy = ToTy->getAs<PointerType>()) {
-      if (ToPtrTy->getPointeeType().isAtLeastAsQualifiedAs(
-                                               FromPtrTy->getPointeeType()) &&
-          !FromPtrTy->getPointeeType()->isIncompleteType() &&
-          !ToPtrTy->getPointeeType()->isIncompleteType() &&
-          S.IsDerivedFrom(SourceLocation(), ToPtrTy->getPointeeType(),
-                          FromPtrTy->getPointeeType()))
-        BaseToDerivedConversion = 1;
-    }
-  } else if (const ObjCObjectPointerType *FromPtrTy
-                                    = FromTy->getAs<ObjCObjectPointerType>()) {
-    if (const ObjCObjectPointerType *ToPtrTy
-                                        = ToTy->getAs<ObjCObjectPointerType>())
-      if (const ObjCInterfaceDecl *FromIface = FromPtrTy->getInterfaceDecl())
-        if (const ObjCInterfaceDecl *ToIface = ToPtrTy->getInterfaceDecl())
-          if (ToPtrTy->getPointeeType().isAtLeastAsQualifiedAs(
-                                                FromPtrTy->getPointeeType()) &&
-              FromIface->isSuperClassOf(ToIface))
-            BaseToDerivedConversion = 2;
-  } else if (const ReferenceType *ToRefTy = ToTy->getAs<ReferenceType>()) {
-    if (ToRefTy->getPointeeType().isAtLeastAsQualifiedAs(FromTy) &&
-        !FromTy->isIncompleteType() &&
-        !ToRefTy->getPointeeType()->isIncompleteType() &&
-        S.IsDerivedFrom(SourceLocation(), ToRefTy->getPointeeType(), FromTy)) {
-      BaseToDerivedConversion = 3;
-    } else if (ToTy->isLValueReferenceType() && !FromExpr->isLValue() &&
-               ToTy.getNonReferenceType().getCanonicalType() ==
-               FromTy.getNonReferenceType().getCanonicalType()) {
-      S.Diag(Fn->getLocation(), diag::note_ovl_candidate_bad_lvalue)
-          << (unsigned)FnKindPair.first << (unsigned)FnKindPair.second << FnDesc
-          << (unsigned)isObjectArgument << I + 1
-          << (FromExpr ? FromExpr->getSourceRange() : SourceRange());
-      MaybeEmitInheritedConstructorNote(S, Cand->FoundDecl);
-      return;
-    }
-  }
-
-  if (BaseToDerivedConversion) {
-    S.Diag(Fn->getLocation(), diag::note_ovl_candidate_bad_base_to_derived_conv)
-        << (unsigned)FnKindPair.first << (unsigned)FnKindPair.second << FnDesc
-        << (FromExpr ? FromExpr->getSourceRange() : SourceRange())
-        << (BaseToDerivedConversion - 1) << FromTy << ToTy << I + 1;
-    MaybeEmitInheritedConstructorNote(S, Cand->FoundDecl);
-    return;
-  }
-
-  if (isa<ObjCObjectPointerType>(CFromTy) &&
-      isa<PointerType>(CToTy)) {
-      Qualifiers FromQs = CFromTy.getQualifiers();
-      Qualifiers ToQs = CToTy.getQualifiers();
-      if (FromQs.getObjCLifetime() != ToQs.getObjCLifetime()) {
-        S.Diag(Fn->getLocation(), diag::note_ovl_candidate_bad_arc_conv)
-            << (unsigned)FnKindPair.first << (unsigned)FnKindPair.second
-            << FnDesc << (FromExpr ? FromExpr->getSourceRange() : SourceRange())
-            << FromTy << ToTy << (unsigned)isObjectArgument << I + 1;
-        MaybeEmitInheritedConstructorNote(S, Cand->FoundDecl);
-        return;
-      }
-  }
-
-  if (TakingCandidateAddress &&
-      !checkAddressOfCandidateIsAvailable(S, Cand->Function))
-    return;
-
-  // Emit the generic diagnostic and, optionally, add the hints to it.
-  PartialDiagnostic FDiag = S.PDiag(diag::note_ovl_candidate_bad_conv);
-  FDiag << (unsigned)FnKindPair.first << (unsigned)FnKindPair.second << FnDesc
-        << (FromExpr ? FromExpr->getSourceRange() : SourceRange()) << FromTy
-        << ToTy << (unsigned)isObjectArgument << I + 1
-        << (unsigned)(Cand->Fix.Kind);
-
-  // If we can fix the conversion, suggest the FixIts.
-  for (std::vector<FixItHint>::iterator HI = Cand->Fix.Hints.begin(),
-       HE = Cand->Fix.Hints.end(); HI != HE; ++HI)
-    FDiag << *HI;
-  S.Diag(Fn->getLocation(), FDiag);
-
-  MaybeEmitInheritedConstructorNote(S, Cand->FoundDecl);
-}
-
-/// Additional arity mismatch diagnosis specific to a function overload
-/// candidates. This is not covered by the more general DiagnoseArityMismatch()
-/// over a candidate in any candidate set.
-static bool CheckArityMismatch(Sema &S, OverloadCandidate *Cand,
-                               unsigned NumArgs) {
-  FunctionDecl *Fn = Cand->Function;
-  unsigned MinParams = Fn->getMinRequiredArguments();
-
-  // With invalid overloaded operators, it's possible that we think we
-  // have an arity mismatch when in fact it looks like we have the
-  // right number of arguments, because only overloaded operators have
-  // the weird behavior of overloading member and non-member functions.
-  // Just don't report anything.
-  if (Fn->isInvalidDecl() &&
-      Fn->getDeclName().getNameKind() == DeclarationName::CXXOperatorName)
-    return true;
-
-  if (NumArgs < MinParams) {
-    assert((Cand->FailureKind == ovl_fail_too_few_arguments) ||
-           (Cand->FailureKind == ovl_fail_bad_deduction &&
-            Cand->DeductionFailure.Result == Sema::TDK_TooFewArguments));
-  } else {
-    assert((Cand->FailureKind == ovl_fail_too_many_arguments) ||
-           (Cand->FailureKind == ovl_fail_bad_deduction &&
-            Cand->DeductionFailure.Result == Sema::TDK_TooManyArguments));
-  }
-
-  return false;
-}
-
-/// General arity mismatch diagnosis over a candidate in a candidate set.
-static void DiagnoseArityMismatch(Sema &S, NamedDecl *Found, Decl *D,
-                                  unsigned NumFormalArgs) {
-  assert(isa<FunctionDecl>(D) &&
-      "The templated declaration should at least be a function"
-      " when diagnosing bad template argument deduction due to too many"
-      " or too few arguments");
-
-  FunctionDecl *Fn = cast<FunctionDecl>(D);
-
-  // TODO: treat calls to a missing default constructor as a special case
-  const FunctionProtoType *FnTy = Fn->getType()->getAs<FunctionProtoType>();
-  unsigned MinParams = Fn->getMinRequiredArguments();
-
-  // at least / at most / exactly
-  unsigned mode, modeCount;
-  if (NumFormalArgs < MinParams) {
-    if (MinParams != FnTy->getNumParams() || FnTy->isVariadic() ||
-        FnTy->isTemplateVariadic())
-      mode = 0; // "at least"
-    else
-      mode = 2; // "exactly"
-    modeCount = MinParams;
-  } else {
-    if (MinParams != FnTy->getNumParams())
-      mode = 1; // "at most"
-    else
-      mode = 2; // "exactly"
-    modeCount = FnTy->getNumParams();
-  }
-
-  std::string Description;
-  std::pair<OverloadCandidateKind, OverloadCandidateSelect> FnKindPair =
-      ClassifyOverloadCandidate(S, Found, Fn, Description);
-
-  if (modeCount == 1 && Fn->getParamDecl(0)->getDeclName())
-    S.Diag(Fn->getLocation(), diag::note_ovl_candidate_arity_one)
-        << (unsigned)FnKindPair.first << (unsigned)FnKindPair.second
-        << Description << mode << Fn->getParamDecl(0) << NumFormalArgs;
-  else
-    S.Diag(Fn->getLocation(), diag::note_ovl_candidate_arity)
-        << (unsigned)FnKindPair.first << (unsigned)FnKindPair.second
-        << Description << mode << modeCount << NumFormalArgs;
-
-  MaybeEmitInheritedConstructorNote(S, Found);
-}
-
-/// Arity mismatch diagnosis specific to a function overload candidate.
-static void DiagnoseArityMismatch(Sema &S, OverloadCandidate *Cand,
-                                  unsigned NumFormalArgs) {
-  if (!CheckArityMismatch(S, Cand, NumFormalArgs))
-    DiagnoseArityMismatch(S, Cand->FoundDecl, Cand->Function, NumFormalArgs);
-}
-
-static TemplateDecl *getDescribedTemplate(Decl *Templated) {
-  if (TemplateDecl *TD = Templated->getDescribedTemplate())
-    return TD;
-  llvm_unreachable("Unsupported: Getting the described template declaration"
-                   " for bad deduction diagnosis");
-}
-
-/// Diagnose a failed template-argument deduction.
-static void DiagnoseBadDeduction(Sema &S, NamedDecl *Found, Decl *Templated,
-                                 DeductionFailureInfo &DeductionFailure,
-                                 unsigned NumArgs,
-                                 bool TakingCandidateAddress) {
-  TemplateParameter Param = DeductionFailure.getTemplateParameter();
-  NamedDecl *ParamD;
-  (ParamD = Param.dyn_cast<TemplateTypeParmDecl*>()) ||
-  (ParamD = Param.dyn_cast<NonTypeTemplateParmDecl*>()) ||
-  (ParamD = Param.dyn_cast<TemplateTemplateParmDecl*>());
-  switch (DeductionFailure.Result) {
-  case Sema::TDK_Success:
-    llvm_unreachable("TDK_success while diagnosing bad deduction");
-
-  case Sema::TDK_Incomplete: {
-    assert(ParamD && "no parameter found for incomplete deduction result");
-    S.Diag(Templated->getLocation(),
-           diag::note_ovl_candidate_incomplete_deduction)
-        << ParamD->getDeclName();
-    MaybeEmitInheritedConstructorNote(S, Found);
-    return;
-  }
-
-  case Sema::TDK_IncompletePack: {
-    assert(ParamD && "no parameter found for incomplete deduction result");
-    S.Diag(Templated->getLocation(),
-           diag::note_ovl_candidate_incomplete_deduction_pack)
-        << ParamD->getDeclName()
-        << (DeductionFailure.getFirstArg()->pack_size() + 1)
-        << *DeductionFailure.getFirstArg();
-    MaybeEmitInheritedConstructorNote(S, Found);
-    return;
-  }
-
-  case Sema::TDK_Underqualified: {
-    assert(ParamD && "no parameter found for bad qualifiers deduction result");
-    TemplateTypeParmDecl *TParam = cast<TemplateTypeParmDecl>(ParamD);
-
-    QualType Param = DeductionFailure.getFirstArg()->getAsType();
-
-    // Param will have been canonicalized, but it should just be a
-    // qualified version of ParamD, so move the qualifiers to that.
-    QualifierCollector Qs;
-    Qs.strip(Param);
-    QualType NonCanonParam = Qs.apply(S.Context, TParam->getTypeForDecl());
-    assert(S.Context.hasSameType(Param, NonCanonParam));
-
-    // Arg has also been canonicalized, but there's nothing we can do
-    // about that.  It also doesn't matter as much, because it won't
-    // have any template parameters in it (because deduction isn't
-    // done on dependent types).
-    QualType Arg = DeductionFailure.getSecondArg()->getAsType();
-
-    S.Diag(Templated->getLocation(), diag::note_ovl_candidate_underqualified)
-        << ParamD->getDeclName() << Arg << NonCanonParam;
-    MaybeEmitInheritedConstructorNote(S, Found);
-    return;
-  }
-
-  case Sema::TDK_Inconsistent: {
-    assert(ParamD && "no parameter found for inconsistent deduction result");
-    int which = 0;
-    if (isa<TemplateTypeParmDecl>(ParamD))
-      which = 0;
-    else if (isa<NonTypeTemplateParmDecl>(ParamD)) {
-      // Deduction might have failed because we deduced arguments of two
-      // different types for a non-type template parameter.
-      // FIXME: Use a different TDK value for this.
-      QualType T1 =
-          DeductionFailure.getFirstArg()->getNonTypeTemplateArgumentType();
-      QualType T2 =
-          DeductionFailure.getSecondArg()->getNonTypeTemplateArgumentType();
-      if (!T1.isNull() && !T2.isNull() && !S.Context.hasSameType(T1, T2)) {
-        S.Diag(Templated->getLocation(),
-               diag::note_ovl_candidate_inconsistent_deduction_types)
-          << ParamD->getDeclName() << *DeductionFailure.getFirstArg() << T1
-          << *DeductionFailure.getSecondArg() << T2;
-        MaybeEmitInheritedConstructorNote(S, Found);
-        return;
-      }
-
-      which = 1;
-    } else {
-      which = 2;
-    }
-
-    S.Diag(Templated->getLocation(),
-           diag::note_ovl_candidate_inconsistent_deduction)
-        << which << ParamD->getDeclName() << *DeductionFailure.getFirstArg()
-        << *DeductionFailure.getSecondArg();
-    MaybeEmitInheritedConstructorNote(S, Found);
-    return;
-  }
-
-  case Sema::TDK_InvalidExplicitArguments:
-    assert(ParamD && "no parameter found for invalid explicit arguments");
-    if (ParamD->getDeclName())
-      S.Diag(Templated->getLocation(),
-             diag::note_ovl_candidate_explicit_arg_mismatch_named)
-          << ParamD->getDeclName();
-    else {
-      int index = 0;
-      if (TemplateTypeParmDecl *TTP = dyn_cast<TemplateTypeParmDecl>(ParamD))
-        index = TTP->getIndex();
-      else if (NonTypeTemplateParmDecl *NTTP
-                                  = dyn_cast<NonTypeTemplateParmDecl>(ParamD))
-        index = NTTP->getIndex();
-      else
-        index = cast<TemplateTemplateParmDecl>(ParamD)->getIndex();
-      S.Diag(Templated->getLocation(),
-             diag::note_ovl_candidate_explicit_arg_mismatch_unnamed)
-          << (index + 1);
-    }
-    MaybeEmitInheritedConstructorNote(S, Found);
-    return;
-
-  case Sema::TDK_TooManyArguments:
-  case Sema::TDK_TooFewArguments:
-    DiagnoseArityMismatch(S, Found, Templated, NumArgs);
-    return;
-
-  case Sema::TDK_InstantiationDepth:
-    S.Diag(Templated->getLocation(),
-           diag::note_ovl_candidate_instantiation_depth);
-    MaybeEmitInheritedConstructorNote(S, Found);
-    return;
-
-  case Sema::TDK_SubstitutionFailure: {
-    // Format the template argument list into the argument string.
-    SmallString<128> TemplateArgString;
-    if (TemplateArgumentList *Args =
-            DeductionFailure.getTemplateArgumentList()) {
-      TemplateArgString = " ";
-      TemplateArgString += S.getTemplateArgumentBindingsText(
-          getDescribedTemplate(Templated)->getTemplateParameters(), *Args);
-    }
-
-    // If this candidate was disabled by enable_if, say so.
-    PartialDiagnosticAt *PDiag = DeductionFailure.getSFINAEDiagnostic();
-    if (PDiag && PDiag->second.getDiagID() ==
-          diag::err_typename_nested_not_found_enable_if) {
-      // FIXME: Use the source range of the condition, and the fully-qualified
-      //        name of the enable_if template. These are both present in PDiag.
-      S.Diag(PDiag->first, diag::note_ovl_candidate_disabled_by_enable_if)
-        << "'enable_if'" << TemplateArgString;
-      return;
-    }
-
-    // We found a specific requirement that disabled the enable_if.
-    if (PDiag && PDiag->second.getDiagID() ==
-        diag::err_typename_nested_not_found_requirement) {
-      S.Diag(Templated->getLocation(),
-             diag::note_ovl_candidate_disabled_by_requirement)
-        << PDiag->second.getStringArg(0) << TemplateArgString;
-      return;
-    }
-
-    // Format the SFINAE diagnostic into the argument string.
-    // FIXME: Add a general mechanism to include a PartialDiagnostic *'s
-    //        formatted message in another diagnostic.
-    SmallString<128> SFINAEArgString;
-    SourceRange R;
-    if (PDiag) {
-      SFINAEArgString = ": ";
-      R = SourceRange(PDiag->first, PDiag->first);
-      PDiag->second.EmitToString(S.getDiagnostics(), SFINAEArgString);
-    }
-
-    S.Diag(Templated->getLocation(),
-           diag::note_ovl_candidate_substitution_failure)
-        << TemplateArgString << SFINAEArgString << R;
-    MaybeEmitInheritedConstructorNote(S, Found);
-    return;
-  }
-
-  case Sema::TDK_DeducedMismatch:
-  case Sema::TDK_DeducedMismatchNested: {
-    // Format the template argument list into the argument string.
-    SmallString<128> TemplateArgString;
-    if (TemplateArgumentList *Args =
-            DeductionFailure.getTemplateArgumentList()) {
-      TemplateArgString = " ";
-      TemplateArgString += S.getTemplateArgumentBindingsText(
-          getDescribedTemplate(Templated)->getTemplateParameters(), *Args);
-    }
-
-    S.Diag(Templated->getLocation(), diag::note_ovl_candidate_deduced_mismatch)
-        << (*DeductionFailure.getCallArgIndex() + 1)
-        << *DeductionFailure.getFirstArg() << *DeductionFailure.getSecondArg()
-        << TemplateArgString
-        << (DeductionFailure.Result == Sema::TDK_DeducedMismatchNested);
-    break;
-  }
-
-  case Sema::TDK_NonDeducedMismatch: {
-    // FIXME: Provide a source location to indicate what we couldn't match.
-    TemplateArgument FirstTA = *DeductionFailure.getFirstArg();
-    TemplateArgument SecondTA = *DeductionFailure.getSecondArg();
-    if (FirstTA.getKind() == TemplateArgument::Template &&
-        SecondTA.getKind() == TemplateArgument::Template) {
-      TemplateName FirstTN = FirstTA.getAsTemplate();
-      TemplateName SecondTN = SecondTA.getAsTemplate();
-      if (FirstTN.getKind() == TemplateName::Template &&
-          SecondTN.getKind() == TemplateName::Template) {
-        if (FirstTN.getAsTemplateDecl()->getName() ==
-            SecondTN.getAsTemplateDecl()->getName()) {
-          // FIXME: This fixes a bad diagnostic where both templates are named
-          // the same.  This particular case is a bit difficult since:
-          // 1) It is passed as a string to the diagnostic printer.
-          // 2) The diagnostic printer only attempts to find a better
-          //    name for types, not decls.
-          // Ideally, this should folded into the diagnostic printer.
-          S.Diag(Templated->getLocation(),
-                 diag::note_ovl_candidate_non_deduced_mismatch_qualified)
-              << FirstTN.getAsTemplateDecl() << SecondTN.getAsTemplateDecl();
-          return;
-        }
-      }
-    }
-
-    if (TakingCandidateAddress && isa<FunctionDecl>(Templated) &&
-        !checkAddressOfCandidateIsAvailable(S, cast<FunctionDecl>(Templated)))
-      return;
-
-    // FIXME: For generic lambda parameters, check if the function is a lambda
-    // call operator, and if so, emit a prettier and more informative
-    // diagnostic that mentions 'auto' and lambda in addition to
-    // (or instead of?) the canonical template type parameters.
-    S.Diag(Templated->getLocation(),
-           diag::note_ovl_candidate_non_deduced_mismatch)
-        << FirstTA << SecondTA;
-    return;
-  }
-  // TODO: diagnose these individually, then kill off
-  // note_ovl_candidate_bad_deduction, which is uselessly vague.
-  case Sema::TDK_MiscellaneousDeductionFailure:
-    S.Diag(Templated->getLocation(), diag::note_ovl_candidate_bad_deduction);
-    MaybeEmitInheritedConstructorNote(S, Found);
-    return;
-  case Sema::TDK_CUDATargetMismatch:
-    S.Diag(Templated->getLocation(),
-           diag::note_cuda_ovl_candidate_target_mismatch);
-    return;
-  }
-}
-
-/// Diagnose a failed template-argument deduction, for function calls.
-static void DiagnoseBadDeduction(Sema &S, OverloadCandidate *Cand,
-                                 unsigned NumArgs,
-                                 bool TakingCandidateAddress) {
-  unsigned TDK = Cand->DeductionFailure.Result;
-  if (TDK == Sema::TDK_TooFewArguments || TDK == Sema::TDK_TooManyArguments) {
-    if (CheckArityMismatch(S, Cand, NumArgs))
-      return;
-  }
-  DiagnoseBadDeduction(S, Cand->FoundDecl, Cand->Function, // pattern
-                       Cand->DeductionFailure, NumArgs, TakingCandidateAddress);
-}
-
-/// CUDA: diagnose an invalid call across targets.
-static void DiagnoseBadTarget(Sema &S, OverloadCandidate *Cand) {
-  FunctionDecl *Caller = cast<FunctionDecl>(S.CurContext);
-  FunctionDecl *Callee = Cand->Function;
-
-  Sema::CUDAFunctionTarget CallerTarget = S.IdentifyCUDATarget(Caller),
-                           CalleeTarget = S.IdentifyCUDATarget(Callee);
-
-  std::string FnDesc;
-  std::pair<OverloadCandidateKind, OverloadCandidateSelect> FnKindPair =
-      ClassifyOverloadCandidate(S, Cand->FoundDecl, Callee, FnDesc);
-
-  S.Diag(Callee->getLocation(), diag::note_ovl_candidate_bad_target)
-      << (unsigned)FnKindPair.first << (unsigned)ocs_non_template
-      << FnDesc /* Ignored */
-      << CalleeTarget << CallerTarget;
-
-  // This could be an implicit constructor for which we could not infer the
-  // target due to a collsion. Diagnose that case.
-  CXXMethodDecl *Meth = dyn_cast<CXXMethodDecl>(Callee);
-  if (Meth != nullptr && Meth->isImplicit()) {
-    CXXRecordDecl *ParentClass = Meth->getParent();
-    Sema::CXXSpecialMember CSM;
-
-    switch (FnKindPair.first) {
-    default:
-      return;
-    case oc_implicit_default_constructor:
-      CSM = Sema::CXXDefaultConstructor;
-      break;
-    case oc_implicit_copy_constructor:
-      CSM = Sema::CXXCopyConstructor;
-      break;
-    case oc_implicit_move_constructor:
-      CSM = Sema::CXXMoveConstructor;
-      break;
-    case oc_implicit_copy_assignment:
-      CSM = Sema::CXXCopyAssignment;
-      break;
-    case oc_implicit_move_assignment:
-      CSM = Sema::CXXMoveAssignment;
-      break;
-    };
-
-    bool ConstRHS = false;
-    if (Meth->getNumParams()) {
-      if (const ReferenceType *RT =
-              Meth->getParamDecl(0)->getType()->getAs<ReferenceType>()) {
-        ConstRHS = RT->getPointeeType().isConstQualified();
-      }
-    }
-
-    S.inferCUDATargetForImplicitSpecialMember(ParentClass, CSM, Meth,
-                                              /* ConstRHS */ ConstRHS,
-                                              /* Diagnose */ true);
-  }
-}
-
-static void DiagnoseFailedEnableIfAttr(Sema &S, OverloadCandidate *Cand) {
-  FunctionDecl *Callee = Cand->Function;
-  EnableIfAttr *Attr = static_cast<EnableIfAttr*>(Cand->DeductionFailure.Data);
-
-  S.Diag(Callee->getLocation(),
-         diag::note_ovl_candidate_disabled_by_function_cond_attr)
-      << Attr->getCond()->getSourceRange() << Attr->getMessage();
-}
-
-static void DiagnoseOpenCLExtensionDisabled(Sema &S, OverloadCandidate *Cand) {
-  FunctionDecl *Callee = Cand->Function;
-
-  S.Diag(Callee->getLocation(),
-         diag::note_ovl_candidate_disabled_by_extension)
-    << S.getOpenCLExtensionsFromDeclExtMap(Callee);
-}
-
-/// Generates a 'note' diagnostic for an overload candidate.  We've
-/// already generated a primary error at the call site.
-///
-/// It really does need to be a single diagnostic with its caret
-/// pointed at the candidate declaration.  Yes, this creates some
-/// major challenges of technical writing.  Yes, this makes pointing
-/// out problems with specific arguments quite awkward.  It's still
-/// better than generating twenty screens of text for every failed
-/// overload.
-///
-/// It would be great to be able to express per-candidate problems
-/// more richly for those diagnostic clients that cared, but we'd
-/// still have to be just as careful with the default diagnostics.
-static void NoteFunctionCandidate(Sema &S, OverloadCandidate *Cand,
-                                  unsigned NumArgs,
-                                  bool TakingCandidateAddress) {
-  FunctionDecl *Fn = Cand->Function;
-
-  // Note deleted candidates, but only if they're viable.
-  if (Cand->Viable) {
-    if (Fn->isDeleted() || S.isFunctionConsideredUnavailable(Fn)) {
-      std::string FnDesc;
-      std::pair<OverloadCandidateKind, OverloadCandidateSelect> FnKindPair =
-          ClassifyOverloadCandidate(S, Cand->FoundDecl, Fn, FnDesc);
-
-      S.Diag(Fn->getLocation(), diag::note_ovl_candidate_deleted)
-          << (unsigned)FnKindPair.first << (unsigned)FnKindPair.second << FnDesc
-          << (Fn->isDeleted() ? (Fn->isDeletedAsWritten() ? 1 : 2) : 0);
-      MaybeEmitInheritedConstructorNote(S, Cand->FoundDecl);
-      return;
-    }
-
-    // We don't really have anything else to say about viable candidates.
-    S.NoteOverloadCandidate(Cand->FoundDecl, Fn);
-    return;
-  }
-
-  switch (Cand->FailureKind) {
-  case ovl_fail_too_many_arguments:
-  case ovl_fail_too_few_arguments:
-    return DiagnoseArityMismatch(S, Cand, NumArgs);
-
-  case ovl_fail_bad_deduction:
-    return DiagnoseBadDeduction(S, Cand, NumArgs,
-                                TakingCandidateAddress);
-
-  case ovl_fail_illegal_constructor: {
-    S.Diag(Fn->getLocation(), diag::note_ovl_candidate_illegal_constructor)
-      << (Fn->getPrimaryTemplate() ? 1 : 0);
-    MaybeEmitInheritedConstructorNote(S, Cand->FoundDecl);
-    return;
-  }
-
-  case ovl_fail_trivial_conversion:
-  case ovl_fail_bad_final_conversion:
-  case ovl_fail_final_conversion_not_exact:
-    return S.NoteOverloadCandidate(Cand->FoundDecl, Fn);
-
-  case ovl_fail_bad_conversion: {
-    unsigned I = (Cand->IgnoreObjectArgument ? 1 : 0);
-    for (unsigned N = Cand->Conversions.size(); I != N; ++I)
-      if (Cand->Conversions[I].isBad())
-        return DiagnoseBadConversion(S, Cand, I, TakingCandidateAddress);
-
-    // FIXME: this currently happens when we're called from SemaInit
-    // when user-conversion overload fails.  Figure out how to handle
-    // those conditions and diagnose them well.
-    return S.NoteOverloadCandidate(Cand->FoundDecl, Fn);
-  }
-
-  case ovl_fail_bad_target:
-    return DiagnoseBadTarget(S, Cand);
-
-  case ovl_fail_enable_if:
-    return DiagnoseFailedEnableIfAttr(S, Cand);
-
-  case ovl_fail_ext_disabled:
-    return DiagnoseOpenCLExtensionDisabled(S, Cand);
-
-  case ovl_fail_inhctor_slice:
-    // It's generally not interesting to note copy/move constructors here.
-    if (cast<CXXConstructorDecl>(Fn)->isCopyOrMoveConstructor())
-      return;
-    S.Diag(Fn->getLocation(),
-           diag::note_ovl_candidate_inherited_constructor_slice)
-      << (Fn->getPrimaryTemplate() ? 1 : 0)
-      << Fn->getParamDecl(0)->getType()->isRValueReferenceType();
-    MaybeEmitInheritedConstructorNote(S, Cand->FoundDecl);
-    return;
-
-  case ovl_fail_addr_not_available: {
-    bool Available = checkAddressOfCandidateIsAvailable(S, Cand->Function);
-    (void)Available;
-    assert(!Available);
-    break;
-  }
-  case ovl_non_default_multiversion_function:
-    // Do nothing, these should simply be ignored.
-    break;
-  }
-}
-
-static void NoteSurrogateCandidate(Sema &S, OverloadCandidate *Cand) {
-  // Desugar the type of the surrogate down to a function type,
-  // retaining as many typedefs as possible while still showing
-  // the function type (and, therefore, its parameter types).
-  QualType FnType = Cand->Surrogate->getConversionType();
-  bool isLValueReference = false;
-  bool isRValueReference = false;
-  bool isPointer = false;
-  if (const LValueReferenceType *FnTypeRef =
-        FnType->getAs<LValueReferenceType>()) {
-    FnType = FnTypeRef->getPointeeType();
-    isLValueReference = true;
-  } else if (const RValueReferenceType *FnTypeRef =
-               FnType->getAs<RValueReferenceType>()) {
-    FnType = FnTypeRef->getPointeeType();
-    isRValueReference = true;
-  }
-  if (const PointerType *FnTypePtr = FnType->getAs<PointerType>()) {
-    FnType = FnTypePtr->getPointeeType();
-    isPointer = true;
-  }
-  // Desugar down to a function type.
-  FnType = QualType(FnType->getAs<FunctionType>(), 0);
-  // Reconstruct the pointer/reference as appropriate.
-  if (isPointer) FnType = S.Context.getPointerType(FnType);
-  if (isRValueReference) FnType = S.Context.getRValueReferenceType(FnType);
-  if (isLValueReference) FnType = S.Context.getLValueReferenceType(FnType);
-
-  S.Diag(Cand->Surrogate->getLocation(), diag::note_ovl_surrogate_cand)
-    << FnType;
-}
-
-static void NoteBuiltinOperatorCandidate(Sema &S, StringRef Opc,
-                                         SourceLocation OpLoc,
-                                         OverloadCandidate *Cand) {
-  assert(Cand->Conversions.size() <= 2 && "builtin operator is not binary");
-  std::string TypeStr("operator");
-  TypeStr += Opc;
-  TypeStr += "(";
-  TypeStr += Cand->BuiltinParamTypes[0].getAsString();
-  if (Cand->Conversions.size() == 1) {
-    TypeStr += ")";
-    S.Diag(OpLoc, diag::note_ovl_builtin_unary_candidate) << TypeStr;
-  } else {
-    TypeStr += ", ";
-    TypeStr += Cand->BuiltinParamTypes[1].getAsString();
-    TypeStr += ")";
-    S.Diag(OpLoc, diag::note_ovl_builtin_binary_candidate) << TypeStr;
-  }
-}
-
-static void NoteAmbiguousUserConversions(Sema &S, SourceLocation OpLoc,
-                                         OverloadCandidate *Cand) {
-  for (const ImplicitConversionSequence &ICS : Cand->Conversions) {
-    if (ICS.isBad()) break; // all meaningless after first invalid
-    if (!ICS.isAmbiguous()) continue;
-
-    ICS.DiagnoseAmbiguousConversion(
-        S, OpLoc, S.PDiag(diag::note_ambiguous_type_conversion));
-  }
-}
-
-static SourceLocation GetLocationForCandidate(const OverloadCandidate *Cand) {
-  if (Cand->Function)
-    return Cand->Function->getLocation();
-  if (Cand->IsSurrogate)
-    return Cand->Surrogate->getLocation();
-  return SourceLocation();
-}
-
-static unsigned RankDeductionFailure(const DeductionFailureInfo &DFI) {
-  switch ((Sema::TemplateDeductionResult)DFI.Result) {
-  case Sema::TDK_Success:
-  case Sema::TDK_NonDependentConversionFailure:
-    llvm_unreachable("non-deduction failure while diagnosing bad deduction");
-
-  case Sema::TDK_Invalid:
-  case Sema::TDK_Incomplete:
-  case Sema::TDK_IncompletePack:
-    return 1;
-
-  case Sema::TDK_Underqualified:
-  case Sema::TDK_Inconsistent:
-    return 2;
-
-  case Sema::TDK_SubstitutionFailure:
-  case Sema::TDK_DeducedMismatch:
-  case Sema::TDK_DeducedMismatchNested:
-  case Sema::TDK_NonDeducedMismatch:
-  case Sema::TDK_MiscellaneousDeductionFailure:
-  case Sema::TDK_CUDATargetMismatch:
-    return 3;
-
-  case Sema::TDK_InstantiationDepth:
-    return 4;
-
-  case Sema::TDK_InvalidExplicitArguments:
-    return 5;
-
-  case Sema::TDK_TooManyArguments:
-  case Sema::TDK_TooFewArguments:
-    return 6;
-  }
-  llvm_unreachable("Unhandled deduction result");
-}
-
-namespace {
-struct CompareOverloadCandidatesForDisplay {
-  Sema &S;
-  SourceLocation Loc;
-  size_t NumArgs;
-  OverloadCandidateSet::CandidateSetKind CSK;
-
-  CompareOverloadCandidatesForDisplay(
-      Sema &S, SourceLocation Loc, size_t NArgs,
-      OverloadCandidateSet::CandidateSetKind CSK)
-      : S(S), NumArgs(NArgs), CSK(CSK) {}
-
-  bool operator()(const OverloadCandidate *L,
-                  const OverloadCandidate *R) {
-    // Fast-path this check.
-    if (L == R) return false;
-
-    // Order first by viability.
-    if (L->Viable) {
-      if (!R->Viable) return true;
-
-      // TODO: introduce a tri-valued comparison for overload
-      // candidates.  Would be more worthwhile if we had a sort
-      // that could exploit it.
-      if (isBetterOverloadCandidate(S, *L, *R, SourceLocation(), CSK))
-        return true;
-      if (isBetterOverloadCandidate(S, *R, *L, SourceLocation(), CSK))
-        return false;
-    } else if (R->Viable)
-      return false;
-
-    assert(L->Viable == R->Viable);
-
-    // Criteria by which we can sort non-viable candidates:
-    if (!L->Viable) {
-      // 1. Arity mismatches come after other candidates.
-      if (L->FailureKind == ovl_fail_too_many_arguments ||
-          L->FailureKind == ovl_fail_too_few_arguments) {
-        if (R->FailureKind == ovl_fail_too_many_arguments ||
-            R->FailureKind == ovl_fail_too_few_arguments) {
-          int LDist = std::abs((int)L->getNumParams() - (int)NumArgs);
-          int RDist = std::abs((int)R->getNumParams() - (int)NumArgs);
-          if (LDist == RDist) {
-            if (L->FailureKind == R->FailureKind)
-              // Sort non-surrogates before surrogates.
-              return !L->IsSurrogate && R->IsSurrogate;
-            // Sort candidates requiring fewer parameters than there were
-            // arguments given after candidates requiring more parameters
-            // than there were arguments given.
-            return L->FailureKind == ovl_fail_too_many_arguments;
-          }
-          return LDist < RDist;
-        }
-        return false;
-      }
-      if (R->FailureKind == ovl_fail_too_many_arguments ||
-          R->FailureKind == ovl_fail_too_few_arguments)
-        return true;
-
-      // 2. Bad conversions come first and are ordered by the number
-      // of bad conversions and quality of good conversions.
-      if (L->FailureKind == ovl_fail_bad_conversion) {
-        if (R->FailureKind != ovl_fail_bad_conversion)
-          return true;
-
-        // The conversion that can be fixed with a smaller number of changes,
-        // comes first.
-        unsigned numLFixes = L->Fix.NumConversionsFixed;
-        unsigned numRFixes = R->Fix.NumConversionsFixed;
-        numLFixes = (numLFixes == 0) ? UINT_MAX : numLFixes;
-        numRFixes = (numRFixes == 0) ? UINT_MAX : numRFixes;
-        if (numLFixes != numRFixes) {
-          return numLFixes < numRFixes;
-        }
-
-        // If there's any ordering between the defined conversions...
-        // FIXME: this might not be transitive.
-        assert(L->Conversions.size() == R->Conversions.size());
-
-        int leftBetter = 0;
-        unsigned I = (L->IgnoreObjectArgument || R->IgnoreObjectArgument);
-        for (unsigned E = L->Conversions.size(); I != E; ++I) {
-          switch (CompareImplicitConversionSequences(S, Loc,
-                                                     L->Conversions[I],
-                                                     R->Conversions[I])) {
-          case ImplicitConversionSequence::Better:
-            leftBetter++;
-            break;
-
-          case ImplicitConversionSequence::Worse:
-            leftBetter--;
-            break;
-
-          case ImplicitConversionSequence::Indistinguishable:
-            break;
-          }
-        }
-        if (leftBetter > 0) return true;
-        if (leftBetter < 0) return false;
-
-      } else if (R->FailureKind == ovl_fail_bad_conversion)
-        return false;
-
-      if (L->FailureKind == ovl_fail_bad_deduction) {
-        if (R->FailureKind != ovl_fail_bad_deduction)
-          return true;
-
-        if (L->DeductionFailure.Result != R->DeductionFailure.Result)
-          return RankDeductionFailure(L->DeductionFailure)
-               < RankDeductionFailure(R->DeductionFailure);
-      } else if (R->FailureKind == ovl_fail_bad_deduction)
-        return false;
-
-      // TODO: others?
-    }
-
-    // Sort everything else by location.
-    SourceLocation LLoc = GetLocationForCandidate(L);
-    SourceLocation RLoc = GetLocationForCandidate(R);
-
-    // Put candidates without locations (e.g. builtins) at the end.
-    if (LLoc.isInvalid()) return false;
-    if (RLoc.isInvalid()) return true;
-
-    return S.SourceMgr.isBeforeInTranslationUnit(LLoc, RLoc);
-  }
-};
-}
-
-/// CompleteNonViableCandidate - Normally, overload resolution only
-/// computes up to the first bad conversion. Produces the FixIt set if
-/// possible.
-static void CompleteNonViableCandidate(Sema &S, OverloadCandidate *Cand,
-                                       ArrayRef<Expr *> Args) {
-  assert(!Cand->Viable);
-
-  // Don't do anything on failures other than bad conversion.
-  if (Cand->FailureKind != ovl_fail_bad_conversion) return;
-
-  // We only want the FixIts if all the arguments can be corrected.
-  bool Unfixable = false;
-  // Use a implicit copy initialization to check conversion fixes.
-  Cand->Fix.setConversionChecker(TryCopyInitialization);
-
-  // Attempt to fix the bad conversion.
-  unsigned ConvCount = Cand->Conversions.size();
-  for (unsigned ConvIdx = (Cand->IgnoreObjectArgument ? 1 : 0); /**/;
-       ++ConvIdx) {
-    assert(ConvIdx != ConvCount && "no bad conversion in candidate");
-    if (Cand->Conversions[ConvIdx].isInitialized() &&
-        Cand->Conversions[ConvIdx].isBad()) {
-      Unfixable = !Cand->TryToFixBadConversion(ConvIdx, S);
-      break;
-    }
-  }
-
-  // FIXME: this should probably be preserved from the overload
-  // operation somehow.
-  bool SuppressUserConversions = false;
-
-  unsigned ConvIdx = 0;
-  ArrayRef<QualType> ParamTypes;
-
-  if (Cand->IsSurrogate) {
-    QualType ConvType
-      = Cand->Surrogate->getConversionType().getNonReferenceType();
-    if (const PointerType *ConvPtrType = ConvType->getAs<PointerType>())
-      ConvType = ConvPtrType->getPointeeType();
-    ParamTypes = ConvType->getAs<FunctionProtoType>()->getParamTypes();
-    // Conversion 0 is 'this', which doesn't have a corresponding argument.
-    ConvIdx = 1;
-  } else if (Cand->Function) {
-    ParamTypes =
-        Cand->Function->getType()->getAs<FunctionProtoType>()->getParamTypes();
-    if (isa<CXXMethodDecl>(Cand->Function) &&
-        !isa<CXXConstructorDecl>(Cand->Function)) {
-      // Conversion 0 is 'this', which doesn't have a corresponding argument.
-      ConvIdx = 1;
-    }
-  } else {
-    // Builtin operator.
-    assert(ConvCount <= 3);
-    ParamTypes = Cand->BuiltinParamTypes;
-  }
-
-  // Fill in the rest of the conversions.
-  for (unsigned ArgIdx = 0; ConvIdx != ConvCount; ++ConvIdx, ++ArgIdx) {
-    if (Cand->Conversions[ConvIdx].isInitialized()) {
-      // We've already checked this conversion.
-    } else if (ArgIdx < ParamTypes.size()) {
-      if (ParamTypes[ArgIdx]->isDependentType())
-        Cand->Conversions[ConvIdx].setAsIdentityConversion(
-            Args[ArgIdx]->getType());
-      else {
-        Cand->Conversions[ConvIdx] =
-            TryCopyInitialization(S, Args[ArgIdx], ParamTypes[ArgIdx],
-                                  SuppressUserConversions,
-                                  /*InOverloadResolution=*/true,
-                                  /*AllowObjCWritebackConversion=*/
-                                  S.getLangOpts().ObjCAutoRefCount);
-        // Store the FixIt in the candidate if it exists.
-        if (!Unfixable && Cand->Conversions[ConvIdx].isBad())
-          Unfixable = !Cand->TryToFixBadConversion(ConvIdx, S);
-      }
-    } else
-      Cand->Conversions[ConvIdx].setEllipsis();
-  }
-}
-
-/// When overload resolution fails, prints diagnostic messages containing the
-/// candidates in the candidate set.
-void OverloadCandidateSet::NoteCandidates(
-    Sema &S, OverloadCandidateDisplayKind OCD, ArrayRef<Expr *> Args,
-    StringRef Opc, SourceLocation OpLoc,
-    llvm::function_ref<bool(OverloadCandidate &)> Filter) {
-  // Sort the candidates by viability and position.  Sorting directly would
-  // be prohibitive, so we make a set of pointers and sort those.
-  SmallVector<OverloadCandidate*, 32> Cands;
-  if (OCD == OCD_AllCandidates) Cands.reserve(size());
-  for (iterator Cand = begin(), LastCand = end(); Cand != LastCand; ++Cand) {
-    if (!Filter(*Cand))
-      continue;
-    if (Cand->Viable)
-      Cands.push_back(Cand);
-    else if (OCD == OCD_AllCandidates) {
-      CompleteNonViableCandidate(S, Cand, Args);
-      if (Cand->Function || Cand->IsSurrogate)
-        Cands.push_back(Cand);
-      // Otherwise, this a non-viable builtin candidate.  We do not, in general,
-      // want to list every possible builtin candidate.
-    }
-  }
-
-  std::stable_sort(Cands.begin(), Cands.end(),
-            CompareOverloadCandidatesForDisplay(S, OpLoc, Args.size(), Kind));
-
-  bool ReportedAmbiguousConversions = false;
-
-  SmallVectorImpl<OverloadCandidate*>::iterator I, E;
-  const OverloadsShown ShowOverloads = S.Diags.getShowOverloads();
-  unsigned CandsShown = 0;
-  for (I = Cands.begin(), E = Cands.end(); I != E; ++I) {
-    OverloadCandidate *Cand = *I;
-
-    // Set an arbitrary limit on the number of candidate functions we'll spam
-    // the user with.  FIXME: This limit should depend on details of the
-    // candidate list.
-    if (CandsShown >= 4 && ShowOverloads == Ovl_Best) {
-      break;
-    }
-    ++CandsShown;
-
-    if (Cand->Function)
-      NoteFunctionCandidate(S, Cand, Args.size(),
-                            /*TakingCandidateAddress=*/false);
-    else if (Cand->IsSurrogate)
-      NoteSurrogateCandidate(S, Cand);
-    else {
-      assert(Cand->Viable &&
-             "Non-viable built-in candidates are not added to Cands.");
-      // Generally we only see ambiguities including viable builtin
-      // operators if overload resolution got screwed up by an
-      // ambiguous user-defined conversion.
-      //
-      // FIXME: It's quite possible for different conversions to see
-      // different ambiguities, though.
-      if (!ReportedAmbiguousConversions) {
-        NoteAmbiguousUserConversions(S, OpLoc, Cand);
-        ReportedAmbiguousConversions = true;
-      }
-
-      // If this is a viable builtin, print it.
-      NoteBuiltinOperatorCandidate(S, Opc, OpLoc, Cand);
-    }
-  }
-
-  if (I != E)
-    S.Diag(OpLoc, diag::note_ovl_too_many_candidates) << int(E - I);
-}
-
-static SourceLocation
-GetLocationForCandidate(const TemplateSpecCandidate *Cand) {
-  return Cand->Specialization ? Cand->Specialization->getLocation()
-                              : SourceLocation();
-}
-
-namespace {
-struct CompareTemplateSpecCandidatesForDisplay {
-  Sema &S;
-  CompareTemplateSpecCandidatesForDisplay(Sema &S) : S(S) {}
-
-  bool operator()(const TemplateSpecCandidate *L,
-                  const TemplateSpecCandidate *R) {
-    // Fast-path this check.
-    if (L == R)
-      return false;
-
-    // Assuming that both candidates are not matches...
-
-    // Sort by the ranking of deduction failures.
-    if (L->DeductionFailure.Result != R->DeductionFailure.Result)
-      return RankDeductionFailure(L->DeductionFailure) <
-             RankDeductionFailure(R->DeductionFailure);
-
-    // Sort everything else by location.
-    SourceLocation LLoc = GetLocationForCandidate(L);
-    SourceLocation RLoc = GetLocationForCandidate(R);
-
-    // Put candidates without locations (e.g. builtins) at the end.
-    if (LLoc.isInvalid())
-      return false;
-    if (RLoc.isInvalid())
-      return true;
-
-    return S.SourceMgr.isBeforeInTranslationUnit(LLoc, RLoc);
-  }
-};
-}
-
-/// Diagnose a template argument deduction failure.
-/// We are treating these failures as overload failures due to bad
-/// deductions.
-void TemplateSpecCandidate::NoteDeductionFailure(Sema &S,
-                                                 bool ForTakingAddress) {
-  DiagnoseBadDeduction(S, FoundDecl, Specialization, // pattern
-                       DeductionFailure, /*NumArgs=*/0, ForTakingAddress);
-}
-
-void TemplateSpecCandidateSet::destroyCandidates() {
-  for (iterator i = begin(), e = end(); i != e; ++i) {
-    i->DeductionFailure.Destroy();
-  }
-}
-
-void TemplateSpecCandidateSet::clear() {
-  destroyCandidates();
-  Candidates.clear();
-}
-
-/// NoteCandidates - When no template specialization match is found, prints
-/// diagnostic messages containing the non-matching specializations that form
-/// the candidate set.
-/// This is analoguous to OverloadCandidateSet::NoteCandidates() with
-/// OCD == OCD_AllCandidates and Cand->Viable == false.
-void TemplateSpecCandidateSet::NoteCandidates(Sema &S, SourceLocation Loc) {
-  // Sort the candidates by position (assuming no candidate is a match).
-  // Sorting directly would be prohibitive, so we make a set of pointers
-  // and sort those.
-  SmallVector<TemplateSpecCandidate *, 32> Cands;
-  Cands.reserve(size());
-  for (iterator Cand = begin(), LastCand = end(); Cand != LastCand; ++Cand) {
-    if (Cand->Specialization)
-      Cands.push_back(Cand);
-    // Otherwise, this is a non-matching builtin candidate.  We do not,
-    // in general, want to list every possible builtin candidate.
-  }
-
-  llvm::sort(Cands, CompareTemplateSpecCandidatesForDisplay(S));
-
-  // FIXME: Perhaps rename OverloadsShown and getShowOverloads()
-  // for generalization purposes (?).
-  const OverloadsShown ShowOverloads = S.Diags.getShowOverloads();
-
-  SmallVectorImpl<TemplateSpecCandidate *>::iterator I, E;
-  unsigned CandsShown = 0;
-  for (I = Cands.begin(), E = Cands.end(); I != E; ++I) {
-    TemplateSpecCandidate *Cand = *I;
-
-    // Set an arbitrary limit on the number of candidates we'll spam
-    // the user with.  FIXME: This limit should depend on details of the
-    // candidate list.
-    if (CandsShown >= 4 && ShowOverloads == Ovl_Best)
-      break;
-    ++CandsShown;
-
-    assert(Cand->Specialization &&
-           "Non-matching built-in candidates are not added to Cands.");
-    Cand->NoteDeductionFailure(S, ForTakingAddress);
-  }
-
-  if (I != E)
-    S.Diag(Loc, diag::note_ovl_too_many_candidates) << int(E - I);
-}
-
-// [PossiblyAFunctionType]  -->   [Return]
-// NonFunctionType --> NonFunctionType
-// R (A) --> R(A)
-// R (*)(A) --> R (A)
-// R (&)(A) --> R (A)
-// R (S::*)(A) --> R (A)
-QualType Sema::ExtractUnqualifiedFunctionType(QualType PossiblyAFunctionType) {
-  QualType Ret = PossiblyAFunctionType;
-  if (const PointerType *ToTypePtr =
-    PossiblyAFunctionType->getAs<PointerType>())
-    Ret = ToTypePtr->getPointeeType();
-  else if (const ReferenceType *ToTypeRef =
-    PossiblyAFunctionType->getAs<ReferenceType>())
-    Ret = ToTypeRef->getPointeeType();
-  else if (const MemberPointerType *MemTypePtr =
-    PossiblyAFunctionType->getAs<MemberPointerType>())
-    Ret = MemTypePtr->getPointeeType();
-  Ret =
-    Context.getCanonicalType(Ret).getUnqualifiedType();
-  return Ret;
-}
-
-static bool completeFunctionType(Sema &S, FunctionDecl *FD, SourceLocation Loc,
-                                 bool Complain = true) {
-  if (S.getLangOpts().CPlusPlus14 && FD->getReturnType()->isUndeducedType() &&
-      S.DeduceReturnType(FD, Loc, Complain))
-    return true;
-
-  auto *FPT = FD->getType()->castAs<FunctionProtoType>();
-  if (S.getLangOpts().CPlusPlus17 &&
-      isUnresolvedExceptionSpec(FPT->getExceptionSpecType()) &&
-      !S.ResolveExceptionSpec(Loc, FPT))
-    return true;
-
-  return false;
-}
-
-namespace {
-// A helper class to help with address of function resolution
-// - allows us to avoid passing around all those ugly parameters
-class AddressOfFunctionResolver {
-  Sema& S;
-  Expr* SourceExpr;
-  const QualType& TargetType;
-  QualType TargetFunctionType; // Extracted function type from target type
-
-  bool Complain;
-  //DeclAccessPair& ResultFunctionAccessPair;
-  ASTContext& Context;
-
-  bool TargetTypeIsNonStaticMemberFunction;
-  bool FoundNonTemplateFunction;
-  bool StaticMemberFunctionFromBoundPointer;
-  bool HasComplained;
-
-  OverloadExpr::FindResult OvlExprInfo;
-  OverloadExpr *OvlExpr;
-  TemplateArgumentListInfo OvlExplicitTemplateArgs;
-  SmallVector<std::pair<DeclAccessPair, FunctionDecl*>, 4> Matches;
-  TemplateSpecCandidateSet FailedCandidates;
-
-public:
-  AddressOfFunctionResolver(Sema &S, Expr *SourceExpr,
-                            const QualType &TargetType, bool Complain)
-      : S(S), SourceExpr(SourceExpr), TargetType(TargetType),
-        Complain(Complain), Context(S.getASTContext()),
-        TargetTypeIsNonStaticMemberFunction(
-            !!TargetType->getAs<MemberPointerType>()),
-        FoundNonTemplateFunction(false),
-        StaticMemberFunctionFromBoundPointer(false),
-        HasComplained(false),
-        OvlExprInfo(OverloadExpr::find(SourceExpr)),
-        OvlExpr(OvlExprInfo.Expression),
-        FailedCandidates(OvlExpr->getNameLoc(), /*ForTakingAddress=*/true) {
-    ExtractUnqualifiedFunctionTypeFromTargetType();
-
-    if (TargetFunctionType->isFunctionType()) {
-      if (UnresolvedMemberExpr *UME = dyn_cast<UnresolvedMemberExpr>(OvlExpr))
-        if (!UME->isImplicitAccess() &&
-            !S.ResolveSingleFunctionTemplateSpecialization(UME))
-          StaticMemberFunctionFromBoundPointer = true;
-    } else if (OvlExpr->hasExplicitTemplateArgs()) {
-      DeclAccessPair dap;
-      if (FunctionDecl *Fn = S.ResolveSingleFunctionTemplateSpecialization(
-              OvlExpr, false, &dap)) {
-        if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(Fn))
-          if (!Method->isStatic()) {
-            // If the target type is a non-function type and the function found
-            // is a non-static member function, pretend as if that was the
-            // target, it's the only possible type to end up with.
-            TargetTypeIsNonStaticMemberFunction = true;
-
-            // And skip adding the function if its not in the proper form.
-            // We'll diagnose this due to an empty set of functions.
-            if (!OvlExprInfo.HasFormOfMemberPointer)
-              return;
-          }
-
-        Matches.push_back(std::make_pair(dap, Fn));
-      }
-      return;
-    }
-
-    if (OvlExpr->hasExplicitTemplateArgs())
-      OvlExpr->copyTemplateArgumentsInto(OvlExplicitTemplateArgs);
-
-    if (FindAllFunctionsThatMatchTargetTypeExactly()) {
-      // C++ [over.over]p4:
-      //   If more than one function is selected, [...]
-      if (Matches.size() > 1 && !eliminiateSuboptimalOverloadCandidates()) {
-        if (FoundNonTemplateFunction)
-          EliminateAllTemplateMatches();
-        else
-          EliminateAllExceptMostSpecializedTemplate();
-      }
-    }
-
-    if (S.getLangOpts().CUDA && Matches.size() > 1)
-      EliminateSuboptimalCudaMatches();
-  }
-
-  bool hasComplained() const { return HasComplained; }
-
-private:
-  bool candidateHasExactlyCorrectType(const FunctionDecl *FD) {
-    QualType Discard;
-    return Context.hasSameUnqualifiedType(TargetFunctionType, FD->getType()) ||
-           S.IsFunctionConversion(FD->getType(), TargetFunctionType, Discard);
-  }
-
-  /// \return true if A is considered a better overload candidate for the
-  /// desired type than B.
-  bool isBetterCandidate(const FunctionDecl *A, const FunctionDecl *B) {
-    // If A doesn't have exactly the correct type, we don't want to classify it
-    // as "better" than anything else. This way, the user is required to
-    // disambiguate for us if there are multiple candidates and no exact match.
-    return candidateHasExactlyCorrectType(A) &&
-           (!candidateHasExactlyCorrectType(B) ||
-            compareEnableIfAttrs(S, A, B) == Comparison::Better);
-  }
-
-  /// \return true if we were able to eliminate all but one overload candidate,
-  /// false otherwise.
-  bool eliminiateSuboptimalOverloadCandidates() {
-    // Same algorithm as overload resolution -- one pass to pick the "best",
-    // another pass to be sure that nothing is better than the best.
-    auto Best = Matches.begin();
-    for (auto I = Matches.begin()+1, E = Matches.end(); I != E; ++I)
-      if (isBetterCandidate(I->second, Best->second))
-        Best = I;
-
-    const FunctionDecl *BestFn = Best->second;
-    auto IsBestOrInferiorToBest = [this, BestFn](
-        const std::pair<DeclAccessPair, FunctionDecl *> &Pair) {
-      return BestFn == Pair.second || isBetterCandidate(BestFn, Pair.second);
-    };
-
-    // Note: We explicitly leave Matches unmodified if there isn't a clear best
-    // option, so we can potentially give the user a better error
-    if (!llvm::all_of(Matches, IsBestOrInferiorToBest))
-      return false;
-    Matches[0] = *Best;
-    Matches.resize(1);
-    return true;
-  }
-
-  bool isTargetTypeAFunction() const {
-    return TargetFunctionType->isFunctionType();
-  }
-
-  // [ToType]     [Return]
-
-  // R (*)(A) --> R (A), IsNonStaticMemberFunction = false
-  // R (&)(A) --> R (A), IsNonStaticMemberFunction = false
-  // R (S::*)(A) --> R (A), IsNonStaticMemberFunction = true
-  void inline ExtractUnqualifiedFunctionTypeFromTargetType() {
-    TargetFunctionType = S.ExtractUnqualifiedFunctionType(TargetType);
-  }
-
-  // return true if any matching specializations were found
-  bool AddMatchingTemplateFunction(FunctionTemplateDecl* FunctionTemplate,
-                                   const DeclAccessPair& CurAccessFunPair) {
-    if (CXXMethodDecl *Method
-              = dyn_cast<CXXMethodDecl>(FunctionTemplate->getTemplatedDecl())) {
-      // Skip non-static function templates when converting to pointer, and
-      // static when converting to member pointer.
-      if (Method->isStatic() == TargetTypeIsNonStaticMemberFunction)
-        return false;
-    }
-    else if (TargetTypeIsNonStaticMemberFunction)
-      return false;
-
-    // C++ [over.over]p2:
-    //   If the name is a function template, template argument deduction is
-    //   done (14.8.2.2), and if the argument deduction succeeds, the
-    //   resulting template argument list is used to generate a single
-    //   function template specialization, which is added to the set of
-    //   overloaded functions considered.
-    FunctionDecl *Specialization = nullptr;
-    TemplateDeductionInfo Info(FailedCandidates.getLocation());
-    if (Sema::TemplateDeductionResult Result
-          = S.DeduceTemplateArguments(FunctionTemplate,
-                                      &OvlExplicitTemplateArgs,
-                                      TargetFunctionType, Specialization,
-                                      Info, /*IsAddressOfFunction*/true)) {
-      // Make a note of the failed deduction for diagnostics.
-      FailedCandidates.addCandidate()
-          .set(CurAccessFunPair, FunctionTemplate->getTemplatedDecl(),
-               MakeDeductionFailureInfo(Context, Result, Info));
-      return false;
-    }
-
-    // Template argument deduction ensures that we have an exact match or
-    // compatible pointer-to-function arguments that would be adjusted by ICS.
-    // This function template specicalization works.
-    assert(S.isSameOrCompatibleFunctionType(
-              Context.getCanonicalType(Specialization->getType()),
-              Context.getCanonicalType(TargetFunctionType)));
-
-    if (!S.checkAddressOfFunctionIsAvailable(Specialization))
-      return false;
-
-    Matches.push_back(std::make_pair(CurAccessFunPair, Specialization));
-    return true;
-  }
-
-  bool AddMatchingNonTemplateFunction(NamedDecl* Fn,
-                                      const DeclAccessPair& CurAccessFunPair) {
-    if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(Fn)) {
-      // Skip non-static functions when converting to pointer, and static
-      // when converting to member pointer.
-      if (Method->isStatic() == TargetTypeIsNonStaticMemberFunction)
-        return false;
-    }
-    else if (TargetTypeIsNonStaticMemberFunction)
-      return false;
-
-    if (FunctionDecl *FunDecl = dyn_cast<FunctionDecl>(Fn)) {
-      if (S.getLangOpts().CUDA)
-        if (FunctionDecl *Caller = dyn_cast<FunctionDecl>(S.CurContext))
-          if (!Caller->isImplicit() && !S.IsAllowedCUDACall(Caller, FunDecl))
-            return false;
-      if (FunDecl->isMultiVersion()) {
-        const auto *TA = FunDecl->getAttr<TargetAttr>();
-        if (TA && !TA->isDefaultVersion())
-          return false;
-      }
-
-      // If any candidate has a placeholder return type, trigger its deduction
-      // now.
-      if (completeFunctionType(S, FunDecl, SourceExpr->getBeginLoc(),
-                               Complain)) {
-        HasComplained |= Complain;
-        return false;
-      }
-
-      if (!S.checkAddressOfFunctionIsAvailable(FunDecl))
-        return false;
-
-      // If we're in C, we need to support types that aren't exactly identical.
-      if (!S.getLangOpts().CPlusPlus ||
-          candidateHasExactlyCorrectType(FunDecl)) {
-        Matches.push_back(std::make_pair(
-            CurAccessFunPair, cast<FunctionDecl>(FunDecl->getCanonicalDecl())));
-        FoundNonTemplateFunction = true;
-        return true;
-      }
-    }
-
-    return false;
-  }
-
-  bool FindAllFunctionsThatMatchTargetTypeExactly() {
-    bool Ret = false;
-
-    // If the overload expression doesn't have the form of a pointer to
-    // member, don't try to convert it to a pointer-to-member type.
-    if (IsInvalidFormOfPointerToMemberFunction())
-      return false;
-
-    for (UnresolvedSetIterator I = OvlExpr->decls_begin(),
-                               E = OvlExpr->decls_end();
-         I != E; ++I) {
-      // Look through any using declarations to find the underlying function.
-      NamedDecl *Fn = (*I)->getUnderlyingDecl();
-
-      // C++ [over.over]p3:
-      //   Non-member functions and static member functions match
-      //   targets of type "pointer-to-function" or "reference-to-function."
-      //   Nonstatic member functions match targets of
-      //   type "pointer-to-member-function."
-      // Note that according to DR 247, the containing class does not matter.
-      if (FunctionTemplateDecl *FunctionTemplate
-                                        = dyn_cast<FunctionTemplateDecl>(Fn)) {
-        if (AddMatchingTemplateFunction(FunctionTemplate, I.getPair()))
-          Ret = true;
-      }
-      // If we have explicit template arguments supplied, skip non-templates.
-      else if (!OvlExpr->hasExplicitTemplateArgs() &&
-               AddMatchingNonTemplateFunction(Fn, I.getPair()))
-        Ret = true;
-    }
-    assert(Ret || Matches.empty());
-    return Ret;
-  }
-
-  void EliminateAllExceptMostSpecializedTemplate() {
-    //   [...] and any given function template specialization F1 is
-    //   eliminated if the set contains a second function template
-    //   specialization whose function template is more specialized
-    //   than the function template of F1 according to the partial
-    //   ordering rules of 14.5.5.2.
-
-    // The algorithm specified above is quadratic. We instead use a
-    // two-pass algorithm (similar to the one used to identify the
-    // best viable function in an overload set) that identifies the
-    // best function template (if it exists).
-
-    UnresolvedSet<4> MatchesCopy; // TODO: avoid!
-    for (unsigned I = 0, E = Matches.size(); I != E; ++I)
-      MatchesCopy.addDecl(Matches[I].second, Matches[I].first.getAccess());
-
-    // TODO: It looks like FailedCandidates does not serve much purpose
-    // here, since the no_viable diagnostic has index 0.
-    UnresolvedSetIterator Result = S.getMostSpecialized(
-        MatchesCopy.begin(), MatchesCopy.end(), FailedCandidates,
-        SourceExpr->getBeginLoc(), S.PDiag(),
-        S.PDiag(diag::err_addr_ovl_ambiguous)
-            << Matches[0].second->getDeclName(),
-        S.PDiag(diag::note_ovl_candidate)
-            << (unsigned)oc_function << (unsigned)ocs_described_template,
-        Complain, TargetFunctionType);
-
-    if (Result != MatchesCopy.end()) {
-      // Make it the first and only element
-      Matches[0].first = Matches[Result - MatchesCopy.begin()].first;
-      Matches[0].second = cast<FunctionDecl>(*Result);
-      Matches.resize(1);
-    } else
-      HasComplained |= Complain;
-  }
-
-  void EliminateAllTemplateMatches() {
-    //   [...] any function template specializations in the set are
-    //   eliminated if the set also contains a non-template function, [...]
-    for (unsigned I = 0, N = Matches.size(); I != N; ) {
-      if (Matches[I].second->getPrimaryTemplate() == nullptr)
-        ++I;
-      else {
-        Matches[I] = Matches[--N];
-        Matches.resize(N);
-      }
-    }
-  }
-
-  void EliminateSuboptimalCudaMatches() {
-    S.EraseUnwantedCUDAMatches(dyn_cast<FunctionDecl>(S.CurContext), Matches);
-  }
-
-public:
-  void ComplainNoMatchesFound() const {
-    assert(Matches.empty());
-    S.Diag(OvlExpr->getBeginLoc(), diag::err_addr_ovl_no_viable)
-        << OvlExpr->getName() << TargetFunctionType
-        << OvlExpr->getSourceRange();
-    if (FailedCandidates.empty())
-      S.NoteAllOverloadCandidates(OvlExpr, TargetFunctionType,
-                                  /*TakingAddress=*/true);
-    else {
-      // We have some deduction failure messages. Use them to diagnose
-      // the function templates, and diagnose the non-template candidates
-      // normally.
-      for (UnresolvedSetIterator I = OvlExpr->decls_begin(),
-                                 IEnd = OvlExpr->decls_end();
-           I != IEnd; ++I)
-        if (FunctionDecl *Fun =
-                dyn_cast<FunctionDecl>((*I)->getUnderlyingDecl()))
-          if (!functionHasPassObjectSizeParams(Fun))
-            S.NoteOverloadCandidate(*I, Fun, TargetFunctionType,
-                                    /*TakingAddress=*/true);
-      FailedCandidates.NoteCandidates(S, OvlExpr->getBeginLoc());
-    }
-  }
-
-  bool IsInvalidFormOfPointerToMemberFunction() const {
-    return TargetTypeIsNonStaticMemberFunction &&
-      !OvlExprInfo.HasFormOfMemberPointer;
-  }
-
-  void ComplainIsInvalidFormOfPointerToMemberFunction() const {
-      // TODO: Should we condition this on whether any functions might
-      // have matched, or is it more appropriate to do that in callers?
-      // TODO: a fixit wouldn't hurt.
-      S.Diag(OvlExpr->getNameLoc(), diag::err_addr_ovl_no_qualifier)
-        << TargetType << OvlExpr->getSourceRange();
-  }
-
-  bool IsStaticMemberFunctionFromBoundPointer() const {
-    return StaticMemberFunctionFromBoundPointer;
-  }
-
-  void ComplainIsStaticMemberFunctionFromBoundPointer() const {
-    S.Diag(OvlExpr->getBeginLoc(),
-           diag::err_invalid_form_pointer_member_function)
-        << OvlExpr->getSourceRange();
-  }
-
-  void ComplainOfInvalidConversion() const {
-    S.Diag(OvlExpr->getBeginLoc(), diag::err_addr_ovl_not_func_ptrref)
-        << OvlExpr->getName() << TargetType;
-  }
-
-  void ComplainMultipleMatchesFound() const {
-    assert(Matches.size() > 1);
-    S.Diag(OvlExpr->getBeginLoc(), diag::err_addr_ovl_ambiguous)
-        << OvlExpr->getName() << OvlExpr->getSourceRange();
-    S.NoteAllOverloadCandidates(OvlExpr, TargetFunctionType,
-                                /*TakingAddress=*/true);
-  }
-
-  bool hadMultipleCandidates() const { return (OvlExpr->getNumDecls() > 1); }
-
-  int getNumMatches() const { return Matches.size(); }
-
-  FunctionDecl* getMatchingFunctionDecl() const {
-    if (Matches.size() != 1) return nullptr;
-    return Matches[0].second;
-  }
-
-  const DeclAccessPair* getMatchingFunctionAccessPair() const {
-    if (Matches.size() != 1) return nullptr;
-    return &Matches[0].first;
-  }
-};
-}
-
-/// ResolveAddressOfOverloadedFunction - Try to resolve the address of
-/// an overloaded function (C++ [over.over]), where @p From is an
-/// expression with overloaded function type and @p ToType is the type
-/// we're trying to resolve to. For example:
-///
-/// @code
-/// int f(double);
-/// int f(int);
-///
-/// int (*pfd)(double) = f; // selects f(double)
-/// @endcode
-///
-/// This routine returns the resulting FunctionDecl if it could be
-/// resolved, and NULL otherwise. When @p Complain is true, this
-/// routine will emit diagnostics if there is an error.
-FunctionDecl *
-Sema::ResolveAddressOfOverloadedFunction(Expr *AddressOfExpr,
-                                         QualType TargetType,
-                                         bool Complain,
-                                         DeclAccessPair &FoundResult,
-                                         bool *pHadMultipleCandidates) {
-  assert(AddressOfExpr->getType() == Context.OverloadTy);
-
-  AddressOfFunctionResolver Resolver(*this, AddressOfExpr, TargetType,
-                                     Complain);
-  int NumMatches = Resolver.getNumMatches();
-  FunctionDecl *Fn = nullptr;
-  bool ShouldComplain = Complain && !Resolver.hasComplained();
-  if (NumMatches == 0 && ShouldComplain) {
-    if (Resolver.IsInvalidFormOfPointerToMemberFunction())
-      Resolver.ComplainIsInvalidFormOfPointerToMemberFunction();
-    else
-      Resolver.ComplainNoMatchesFound();
-  }
-  else if (NumMatches > 1 && ShouldComplain)
-    Resolver.ComplainMultipleMatchesFound();
-  else if (NumMatches == 1) {
-    Fn = Resolver.getMatchingFunctionDecl();
-    assert(Fn);
-    if (auto *FPT = Fn->getType()->getAs<FunctionProtoType>())
-      ResolveExceptionSpec(AddressOfExpr->getExprLoc(), FPT);
-    FoundResult = *Resolver.getMatchingFunctionAccessPair();
-    if (Complain) {
-      if (Resolver.IsStaticMemberFunctionFromBoundPointer())
-        Resolver.ComplainIsStaticMemberFunctionFromBoundPointer();
-      else
-        CheckAddressOfMemberAccess(AddressOfExpr, FoundResult);
-    }
-  }
-
-  if (pHadMultipleCandidates)
-    *pHadMultipleCandidates = Resolver.hadMultipleCandidates();
-  return Fn;
-}
-
-/// Given an expression that refers to an overloaded function, try to
-/// resolve that function to a single function that can have its address taken.
-/// This will modify `Pair` iff it returns non-null.
-///
-/// This routine can only realistically succeed if all but one candidates in the
-/// overload set for SrcExpr cannot have their addresses taken.
-FunctionDecl *
-Sema::resolveAddressOfOnlyViableOverloadCandidate(Expr *E,
-                                                  DeclAccessPair &Pair) {
-  OverloadExpr::FindResult R = OverloadExpr::find(E);
-  OverloadExpr *Ovl = R.Expression;
-  FunctionDecl *Result = nullptr;
-  DeclAccessPair DAP;
-  // Don't use the AddressOfResolver because we're specifically looking for
-  // cases where we have one overload candidate that lacks
-  // enable_if/pass_object_size/...
-  for (auto I = Ovl->decls_begin(), E = Ovl->decls_end(); I != E; ++I) {
-    auto *FD = dyn_cast<FunctionDecl>(I->getUnderlyingDecl());
-    if (!FD)
-      return nullptr;
-
-    if (!checkAddressOfFunctionIsAvailable(FD))
-      continue;
-
-    // We have more than one result; quit.
-    if (Result)
-      return nullptr;
-    DAP = I.getPair();
-    Result = FD;
-  }
-
-  if (Result)
-    Pair = DAP;
-  return Result;
-}
-
-/// Given an overloaded function, tries to turn it into a non-overloaded
-/// function reference using resolveAddressOfOnlyViableOverloadCandidate. This
-/// will perform access checks, diagnose the use of the resultant decl, and, if
-/// requested, potentially perform a function-to-pointer decay.
-///
-/// Returns false if resolveAddressOfOnlyViableOverloadCandidate fails.
-/// Otherwise, returns true. This may emit diagnostics and return true.
-bool Sema::resolveAndFixAddressOfOnlyViableOverloadCandidate(
-    ExprResult &SrcExpr, bool DoFunctionPointerConverion) {
-  Expr *E = SrcExpr.get();
-  assert(E->getType() == Context.OverloadTy && "SrcExpr must be an overload");
-
-  DeclAccessPair DAP;
-  FunctionDecl *Found = resolveAddressOfOnlyViableOverloadCandidate(E, DAP);
-  if (!Found || Found->isCPUDispatchMultiVersion() ||
-      Found->isCPUSpecificMultiVersion())
-    return false;
-
-  // Emitting multiple diagnostics for a function that is both inaccessible and
-  // unavailable is consistent with our behavior elsewhere. So, always check
-  // for both.
-  DiagnoseUseOfDecl(Found, E->getExprLoc());
-  CheckAddressOfMemberAccess(E, DAP);
-  Expr *Fixed = FixOverloadedFunctionReference(E, DAP, Found);
-  if (DoFunctionPointerConverion && Fixed->getType()->isFunctionType())
-    SrcExpr = DefaultFunctionArrayConversion(Fixed, /*Diagnose=*/false);
-  else
-    SrcExpr = Fixed;
-  return true;
-}
-
-/// Given an expression that refers to an overloaded function, try to
-/// resolve that overloaded function expression down to a single function.
-///
-/// This routine can only resolve template-ids that refer to a single function
-/// template, where that template-id refers to a single template whose template
-/// arguments are either provided by the template-id or have defaults,
-/// as described in C++0x [temp.arg.explicit]p3.
-///
-/// If no template-ids are found, no diagnostics are emitted and NULL is
-/// returned.
-FunctionDecl *
-Sema::ResolveSingleFunctionTemplateSpecialization(OverloadExpr *ovl,
-                                                  bool Complain,
-                                                  DeclAccessPair *FoundResult) {
-  // C++ [over.over]p1:
-  //   [...] [Note: any redundant set of parentheses surrounding the
-  //   overloaded function name is ignored (5.1). ]
-  // C++ [over.over]p1:
-  //   [...] The overloaded function name can be preceded by the &
-  //   operator.
-
-  // If we didn't actually find any template-ids, we're done.
-  if (!ovl->hasExplicitTemplateArgs())
-    return nullptr;
-
-  TemplateArgumentListInfo ExplicitTemplateArgs;
-  ovl->copyTemplateArgumentsInto(ExplicitTemplateArgs);
-  TemplateSpecCandidateSet FailedCandidates(ovl->getNameLoc());
-
-  // Look through all of the overloaded functions, searching for one
-  // whose type matches exactly.
-  FunctionDecl *Matched = nullptr;
-  for (UnresolvedSetIterator I = ovl->decls_begin(),
-         E = ovl->decls_end(); I != E; ++I) {
-    // C++0x [temp.arg.explicit]p3:
-    //   [...] In contexts where deduction is done and fails, or in contexts
-    //   where deduction is not done, if a template argument list is
-    //   specified and it, along with any default template arguments,
-    //   identifies a single function template specialization, then the
-    //   template-id is an lvalue for the function template specialization.
-    FunctionTemplateDecl *FunctionTemplate
-      = cast<FunctionTemplateDecl>((*I)->getUnderlyingDecl());
-
-    // C++ [over.over]p2:
-    //   If the name is a function template, template argument deduction is
-    //   done (14.8.2.2), and if the argument deduction succeeds, the
-    //   resulting template argument list is used to generate a single
-    //   function template specialization, which is added to the set of
-    //   overloaded functions considered.
-    FunctionDecl *Specialization = nullptr;
-    TemplateDeductionInfo Info(FailedCandidates.getLocation());
-    if (TemplateDeductionResult Result
-          = DeduceTemplateArguments(FunctionTemplate, &ExplicitTemplateArgs,
-                                    Specialization, Info,
-                                    /*IsAddressOfFunction*/true)) {
-      // Make a note of the failed deduction for diagnostics.
-      // TODO: Actually use the failed-deduction info?
-      FailedCandidates.addCandidate()
-          .set(I.getPair(), FunctionTemplate->getTemplatedDecl(),
-               MakeDeductionFailureInfo(Context, Result, Info));
-      continue;
-    }
-
-    assert(Specialization && "no specialization and no error?");
-
-    // Multiple matches; we can't resolve to a single declaration.
-    if (Matched) {
-      if (Complain) {
-        Diag(ovl->getExprLoc(), diag::err_addr_ovl_ambiguous)
-          << ovl->getName();
-        NoteAllOverloadCandidates(ovl);
-      }
-      return nullptr;
-    }
-
-    Matched = Specialization;
-    if (FoundResult) *FoundResult = I.getPair();
-  }
-
-  if (Matched &&
-      completeFunctionType(*this, Matched, ovl->getExprLoc(), Complain))
-    return nullptr;
-
-  return Matched;
-}
-
-// Resolve and fix an overloaded expression that can be resolved
-// because it identifies a single function template specialization.
-//
-// Last three arguments should only be supplied if Complain = true
-//
-// Return true if it was logically possible to so resolve the
-// expression, regardless of whether or not it succeeded.  Always
-// returns true if 'complain' is set.
-bool Sema::ResolveAndFixSingleFunctionTemplateSpecialization(
-                      ExprResult &SrcExpr, bool doFunctionPointerConverion,
-                      bool complain, SourceRange OpRangeForComplaining,
-                                           QualType DestTypeForComplaining,
-                                            unsigned DiagIDForComplaining) {
-  assert(SrcExpr.get()->getType() == Context.OverloadTy);
-
-  OverloadExpr::FindResult ovl = OverloadExpr::find(SrcExpr.get());
-
-  DeclAccessPair found;
-  ExprResult SingleFunctionExpression;
-  if (FunctionDecl *fn = ResolveSingleFunctionTemplateSpecialization(
-                           ovl.Expression, /*complain*/ false, &found)) {
-    if (DiagnoseUseOfDecl(fn, SrcExpr.get()->getBeginLoc())) {
-      SrcExpr = ExprError();
-      return true;
-    }
-
-    // It is only correct to resolve to an instance method if we're
-    // resolving a form that's permitted to be a pointer to member.
-    // Otherwise we'll end up making a bound member expression, which
-    // is illegal in all the contexts we resolve like this.
-    if (!ovl.HasFormOfMemberPointer &&
-        isa<CXXMethodDecl>(fn) &&
-        cast<CXXMethodDecl>(fn)->isInstance()) {
-      if (!complain) return false;
-
-      Diag(ovl.Expression->getExprLoc(),
-           diag::err_bound_member_function)
-        << 0 << ovl.Expression->getSourceRange();
-
-      // TODO: I believe we only end up here if there's a mix of
-      // static and non-static candidates (otherwise the expression
-      // would have 'bound member' type, not 'overload' type).
-      // Ideally we would note which candidate was chosen and why
-      // the static candidates were rejected.
-      SrcExpr = ExprError();
-      return true;
-    }
-
-    // Fix the expression to refer to 'fn'.
-    SingleFunctionExpression =
-        FixOverloadedFunctionReference(SrcExpr.get(), found, fn);
-
-    // If desired, do function-to-pointer decay.
-    if (doFunctionPointerConverion) {
-      SingleFunctionExpression =
-        DefaultFunctionArrayLvalueConversion(SingleFunctionExpression.get());
-      if (SingleFunctionExpression.isInvalid()) {
-        SrcExpr = ExprError();
-        return true;
-      }
-    }
-  }
-
-  if (!SingleFunctionExpression.isUsable()) {
-    if (complain) {
-      Diag(OpRangeForComplaining.getBegin(), DiagIDForComplaining)
-        << ovl.Expression->getName()
-        << DestTypeForComplaining
-        << OpRangeForComplaining
-        << ovl.Expression->getQualifierLoc().getSourceRange();
-      NoteAllOverloadCandidates(SrcExpr.get());
-
-      SrcExpr = ExprError();
-      return true;
-    }
-
-    return false;
-  }
-
-  SrcExpr = SingleFunctionExpression;
-  return true;
-}
-
-/// Add a single candidate to the overload set.
-static void AddOverloadedCallCandidate(Sema &S,
-                                       DeclAccessPair FoundDecl,
-                                 TemplateArgumentListInfo *ExplicitTemplateArgs,
-                                       ArrayRef<Expr *> Args,
-                                       OverloadCandidateSet &CandidateSet,
-                                       bool PartialOverloading,
-                                       bool KnownValid) {
-  NamedDecl *Callee = FoundDecl.getDecl();
-  if (isa<UsingShadowDecl>(Callee))
-    Callee = cast<UsingShadowDecl>(Callee)->getTargetDecl();
-
-  if (FunctionDecl *Func = dyn_cast<FunctionDecl>(Callee)) {
-    if (ExplicitTemplateArgs) {
-      assert(!KnownValid && "Explicit template arguments?");
-      return;
-    }
-    // Prevent ill-formed function decls to be added as overload candidates.
-    if (!dyn_cast<FunctionProtoType>(Func->getType()->getAs<FunctionType>()))
-      return;
-
-    S.AddOverloadCandidate(Func, FoundDecl, Args, CandidateSet,
-                           /*SuppressUsedConversions=*/false,
-                           PartialOverloading);
-    return;
-  }
-
-  if (FunctionTemplateDecl *FuncTemplate
-      = dyn_cast<FunctionTemplateDecl>(Callee)) {
-    S.AddTemplateOverloadCandidate(FuncTemplate, FoundDecl,
-                                   ExplicitTemplateArgs, Args, CandidateSet,
-                                   /*SuppressUsedConversions=*/false,
-                                   PartialOverloading);
-    return;
-  }
-
-  assert(!KnownValid && "unhandled case in overloaded call candidate");
-}
-
-/// Add the overload candidates named by callee and/or found by argument
-/// dependent lookup to the given overload set.
-void Sema::AddOverloadedCallCandidates(UnresolvedLookupExpr *ULE,
-                                       ArrayRef<Expr *> Args,
-                                       OverloadCandidateSet &CandidateSet,
-                                       bool PartialOverloading) {
-
-#ifndef NDEBUG
-  // Verify that ArgumentDependentLookup is consistent with the rules
-  // in C++0x [basic.lookup.argdep]p3:
-  //
-  //   Let X be the lookup set produced by unqualified lookup (3.4.1)
-  //   and let Y be the lookup set produced by argument dependent
-  //   lookup (defined as follows). If X contains
-  //
-  //     -- a declaration of a class member, or
-  //
-  //     -- a block-scope function declaration that is not a
-  //        using-declaration, or
-  //
-  //     -- a declaration that is neither a function or a function
-  //        template
-  //
-  //   then Y is empty.
-
-  if (ULE->requiresADL()) {
-    for (UnresolvedLookupExpr::decls_iterator I = ULE->decls_begin(),
-           E = ULE->decls_end(); I != E; ++I) {
-      assert(!(*I)->getDeclContext()->isRecord());
-      assert(isa<UsingShadowDecl>(*I) ||
-             !(*I)->getDeclContext()->isFunctionOrMethod());
-      assert((*I)->getUnderlyingDecl()->isFunctionOrFunctionTemplate());
-    }
-  }
-#endif
-
-  // It would be nice to avoid this copy.
-  TemplateArgumentListInfo TABuffer;
-  TemplateArgumentListInfo *ExplicitTemplateArgs = nullptr;
-  if (ULE->hasExplicitTemplateArgs()) {
-    ULE->copyTemplateArgumentsInto(TABuffer);
-    ExplicitTemplateArgs = &TABuffer;
-  }
-
-  for (UnresolvedLookupExpr::decls_iterator I = ULE->decls_begin(),
-         E = ULE->decls_end(); I != E; ++I)
-    AddOverloadedCallCandidate(*this, I.getPair(), ExplicitTemplateArgs, Args,
-                               CandidateSet, PartialOverloading,
-                               /*KnownValid*/ true);
-
-  if (ULE->requiresADL())
-    AddArgumentDependentLookupCandidates(ULE->getName(), ULE->getExprLoc(),
-                                         Args, ExplicitTemplateArgs,
-                                         CandidateSet, PartialOverloading);
-}
-
-/// Determine whether a declaration with the specified name could be moved into
-/// a different namespace.
-static bool canBeDeclaredInNamespace(const DeclarationName &Name) {
-  switch (Name.getCXXOverloadedOperator()) {
-  case OO_New: case OO_Array_New:
-  case OO_Delete: case OO_Array_Delete:
-    return false;
-
-  default:
-    return true;
-  }
-}
-
-/// Attempt to recover from an ill-formed use of a non-dependent name in a
-/// template, where the non-dependent name was declared after the template
-/// was defined. This is common in code written for a compilers which do not
-/// correctly implement two-stage name lookup.
-///
-/// Returns true if a viable candidate was found and a diagnostic was issued.
-static bool
-DiagnoseTwoPhaseLookup(Sema &SemaRef, SourceLocation FnLoc,
-                       const CXXScopeSpec &SS, LookupResult &R,
-                       OverloadCandidateSet::CandidateSetKind CSK,
-                       TemplateArgumentListInfo *ExplicitTemplateArgs,
-                       ArrayRef<Expr *> Args,
-                       bool *DoDiagnoseEmptyLookup = nullptr) {
-  if (!SemaRef.inTemplateInstantiation() || !SS.isEmpty())
-    return false;
-
-  for (DeclContext *DC = SemaRef.CurContext; DC; DC = DC->getParent()) {
-    if (DC->isTransparentContext())
-      continue;
-
-    SemaRef.LookupQualifiedName(R, DC);
-
-    if (!R.empty()) {
-      R.suppressDiagnostics();
-
-      if (isa<CXXRecordDecl>(DC)) {
-        // Don't diagnose names we find in classes; we get much better
-        // diagnostics for these from DiagnoseEmptyLookup.
-        R.clear();
-        if (DoDiagnoseEmptyLookup)
-          *DoDiagnoseEmptyLookup = true;
-        return false;
-      }
-
-      OverloadCandidateSet Candidates(FnLoc, CSK);
-      for (LookupResult::iterator I = R.begin(), E = R.end(); I != E; ++I)
-        AddOverloadedCallCandidate(SemaRef, I.getPair(),
-                                   ExplicitTemplateArgs, Args,
-                                   Candidates, false, /*KnownValid*/ false);
-
-      OverloadCandidateSet::iterator Best;
-      if (Candidates.BestViableFunction(SemaRef, FnLoc, Best) != OR_Success) {
-        // No viable functions. Don't bother the user with notes for functions
-        // which don't work and shouldn't be found anyway.
-        R.clear();
-        return false;
-      }
-
-      // Find the namespaces where ADL would have looked, and suggest
-      // declaring the function there instead.
-      Sema::AssociatedNamespaceSet AssociatedNamespaces;
-      Sema::AssociatedClassSet AssociatedClasses;
-      SemaRef.FindAssociatedClassesAndNamespaces(FnLoc, Args,
-                                                 AssociatedNamespaces,
-                                                 AssociatedClasses);
-      Sema::AssociatedNamespaceSet SuggestedNamespaces;
-      if (canBeDeclaredInNamespace(R.getLookupName())) {
-        DeclContext *Std = SemaRef.getStdNamespace();
-        for (Sema::AssociatedNamespaceSet::iterator
-               it = AssociatedNamespaces.begin(),
-               end = AssociatedNamespaces.end(); it != end; ++it) {
-          // Never suggest declaring a function within namespace 'std'.
-          if (Std && Std->Encloses(*it))
-            continue;
-
-          // Never suggest declaring a function within a namespace with a
-          // reserved name, like __gnu_cxx.
-          NamespaceDecl *NS = dyn_cast<NamespaceDecl>(*it);
-          if (NS &&
-              NS->getQualifiedNameAsString().find("__") != std::string::npos)
-            continue;
-
-          SuggestedNamespaces.insert(*it);
-        }
-      }
-
-      SemaRef.Diag(R.getNameLoc(), diag::err_not_found_by_two_phase_lookup)
-        << R.getLookupName();
-      if (SuggestedNamespaces.empty()) {
-        SemaRef.Diag(Best->Function->getLocation(),
-                     diag::note_not_found_by_two_phase_lookup)
-          << R.getLookupName() << 0;
-      } else if (SuggestedNamespaces.size() == 1) {
-        SemaRef.Diag(Best->Function->getLocation(),
-                     diag::note_not_found_by_two_phase_lookup)
-          << R.getLookupName() << 1 << *SuggestedNamespaces.begin();
-      } else {
-        // FIXME: It would be useful to list the associated namespaces here,
-        // but the diagnostics infrastructure doesn't provide a way to produce
-        // a localized representation of a list of items.
-        SemaRef.Diag(Best->Function->getLocation(),
-                     diag::note_not_found_by_two_phase_lookup)
-          << R.getLookupName() << 2;
-      }
-
-      // Try to recover by calling this function.
-      return true;
-    }
-
-    R.clear();
-  }
-
-  return false;
-}
-
-/// Attempt to recover from ill-formed use of a non-dependent operator in a
-/// template, where the non-dependent operator was declared after the template
-/// was defined.
-///
-/// Returns true if a viable candidate was found and a diagnostic was issued.
-static bool
-DiagnoseTwoPhaseOperatorLookup(Sema &SemaRef, OverloadedOperatorKind Op,
-                               SourceLocation OpLoc,
-                               ArrayRef<Expr *> Args) {
-  DeclarationName OpName =
-    SemaRef.Context.DeclarationNames.getCXXOperatorName(Op);
-  LookupResult R(SemaRef, OpName, OpLoc, Sema::LookupOperatorName);
-  return DiagnoseTwoPhaseLookup(SemaRef, OpLoc, CXXScopeSpec(), R,
-                                OverloadCandidateSet::CSK_Operator,
-                                /*ExplicitTemplateArgs=*/nullptr, Args);
-}
-
-namespace {
-class BuildRecoveryCallExprRAII {
-  Sema &SemaRef;
-public:
-  BuildRecoveryCallExprRAII(Sema &S) : SemaRef(S) {
-    assert(SemaRef.IsBuildingRecoveryCallExpr == false);
-    SemaRef.IsBuildingRecoveryCallExpr = true;
-  }
-
-  ~BuildRecoveryCallExprRAII() {
-    SemaRef.IsBuildingRecoveryCallExpr = false;
-  }
-};
-
-}
-
-static std::unique_ptr<CorrectionCandidateCallback>
-MakeValidator(Sema &SemaRef, MemberExpr *ME, size_t NumArgs,
-              bool HasTemplateArgs, bool AllowTypoCorrection) {
-  if (!AllowTypoCorrection)
-    return llvm::make_unique<NoTypoCorrectionCCC>();
-  return llvm::make_unique<FunctionCallFilterCCC>(SemaRef, NumArgs,
-                                                  HasTemplateArgs, ME);
-}
-
-/// Attempts to recover from a call where no functions were found.
-///
-/// Returns true if new candidates were found.
-static ExprResult
-BuildRecoveryCallExpr(Sema &SemaRef, Scope *S, Expr *Fn,
-                      UnresolvedLookupExpr *ULE,
-                      SourceLocation LParenLoc,
-                      MutableArrayRef<Expr *> Args,
-                      SourceLocation RParenLoc,
-                      bool EmptyLookup, bool AllowTypoCorrection) {
-  // Do not try to recover if it is already building a recovery call.
-  // This stops infinite loops for template instantiations like
-  //
-  // template <typename T> auto foo(T t) -> decltype(foo(t)) {}
-  // template <typename T> auto foo(T t) -> decltype(foo(&t)) {}
-  //
-  if (SemaRef.IsBuildingRecoveryCallExpr)
-    return ExprError();
-  BuildRecoveryCallExprRAII RCE(SemaRef);
-
-  CXXScopeSpec SS;
-  SS.Adopt(ULE->getQualifierLoc());
-  SourceLocation TemplateKWLoc = ULE->getTemplateKeywordLoc();
-
-  TemplateArgumentListInfo TABuffer;
-  TemplateArgumentListInfo *ExplicitTemplateArgs = nullptr;
-  if (ULE->hasExplicitTemplateArgs()) {
-    ULE->copyTemplateArgumentsInto(TABuffer);
-    ExplicitTemplateArgs = &TABuffer;
-  }
-
-  LookupResult R(SemaRef, ULE->getName(), ULE->getNameLoc(),
-                 Sema::LookupOrdinaryName);
-  bool DoDiagnoseEmptyLookup = EmptyLookup;
-  if (!DiagnoseTwoPhaseLookup(SemaRef, Fn->getExprLoc(), SS, R,
-                              OverloadCandidateSet::CSK_Normal,
-                              ExplicitTemplateArgs, Args,
-                              &DoDiagnoseEmptyLookup) &&
-    (!DoDiagnoseEmptyLookup || SemaRef.DiagnoseEmptyLookup(
-        S, SS, R,
-        MakeValidator(SemaRef, dyn_cast<MemberExpr>(Fn), Args.size(),
-                      ExplicitTemplateArgs != nullptr, AllowTypoCorrection),
-        ExplicitTemplateArgs, Args)))
-    return ExprError();
-
-  assert(!R.empty() && "lookup results empty despite recovery");
-
-  // If recovery created an ambiguity, just bail out.
-  if (R.isAmbiguous()) {
-    R.suppressDiagnostics();
-    return ExprError();
-  }
-
-  // Build an implicit member call if appropriate.  Just drop the
-  // casts and such from the call, we don't really care.
-  ExprResult NewFn = ExprError();
-  if ((*R.begin())->isCXXClassMember())
-    NewFn = SemaRef.BuildPossibleImplicitMemberExpr(SS, TemplateKWLoc, R,
-                                                    ExplicitTemplateArgs, S);
-  else if (ExplicitTemplateArgs || TemplateKWLoc.isValid())
-    NewFn = SemaRef.BuildTemplateIdExpr(SS, TemplateKWLoc, R, false,
-                                        ExplicitTemplateArgs);
-  else
-    NewFn = SemaRef.BuildDeclarationNameExpr(SS, R, false);
-
-  if (NewFn.isInvalid())
-    return ExprError();
-
-  // This shouldn't cause an infinite loop because we're giving it
-  // an expression with viable lookup results, which should never
-  // end up here.
-  return SemaRef.ActOnCallExpr(/*Scope*/ nullptr, NewFn.get(), LParenLoc,
-                               MultiExprArg(Args.data(), Args.size()),
-                               RParenLoc);
-}
-
-/// Constructs and populates an OverloadedCandidateSet from
-/// the given function.
-/// \returns true when an the ExprResult output parameter has been set.
-bool Sema::buildOverloadedCallSet(Scope *S, Expr *Fn,
-                                  UnresolvedLookupExpr *ULE,
-                                  MultiExprArg Args,
-                                  SourceLocation RParenLoc,
-                                  OverloadCandidateSet *CandidateSet,
-                                  ExprResult *Result) {
-#ifndef NDEBUG
-  if (ULE->requiresADL()) {
-    // To do ADL, we must have found an unqualified name.
-    assert(!ULE->getQualifier() && "qualified name with ADL");
-
-    // We don't perform ADL for implicit declarations of builtins.
-    // Verify that this was correctly set up.
-    FunctionDecl *F;
-    if (ULE->decls_begin() + 1 == ULE->decls_end() &&
-        (F = dyn_cast<FunctionDecl>(*ULE->decls_begin())) &&
-        F->getBuiltinID() && F->isImplicit())
-      llvm_unreachable("performing ADL for builtin");
-
-    // We don't perform ADL in C.
-    assert(getLangOpts().CPlusPlus && "ADL enabled in C");
-  }
-#endif
-
-  UnbridgedCastsSet UnbridgedCasts;
-  if (checkArgPlaceholdersForOverload(*this, Args, UnbridgedCasts)) {
-    *Result = ExprError();
-    return true;
-  }
-
-  // Add the functions denoted by the callee to the set of candidate
-  // functions, including those from argument-dependent lookup.
-  AddOverloadedCallCandidates(ULE, Args, *CandidateSet);
-
-  if (getLangOpts().MSVCCompat &&
-      CurContext->isDependentContext() && !isSFINAEContext() &&
-      (isa<FunctionDecl>(CurContext) || isa<CXXRecordDecl>(CurContext))) {
-
-    OverloadCandidateSet::iterator Best;
-    if (CandidateSet->empty() ||
-        CandidateSet->BestViableFunction(*this, Fn->getBeginLoc(), Best) ==
-            OR_No_Viable_Function) {
-      // In Microsoft mode, if we are inside a template class member function
-      // then create a type dependent CallExpr. The goal is to postpone name
-      // lookup to instantiation time to be able to search into type dependent
-      // base classes.
-      CallExpr *CE = CallExpr::Create(Context, Fn, Args, Context.DependentTy,
-                                      VK_RValue, RParenLoc);
-      CE->setTypeDependent(true);
-      CE->setValueDependent(true);
-      CE->setInstantiationDependent(true);
-      *Result = CE;
-      return true;
-    }
-  }
-
-  if (CandidateSet->empty())
-    return false;
-
-  UnbridgedCasts.restore();
-  return false;
-}
-
-/// FinishOverloadedCallExpr - given an OverloadCandidateSet, builds and returns
-/// the completed call expression. If overload resolution fails, emits
-/// diagnostics and returns ExprError()
-static ExprResult FinishOverloadedCallExpr(Sema &SemaRef, Scope *S, Expr *Fn,
-                                           UnresolvedLookupExpr *ULE,
-                                           SourceLocation LParenLoc,
-                                           MultiExprArg Args,
-                                           SourceLocation RParenLoc,
-                                           Expr *ExecConfig,
-                                           OverloadCandidateSet *CandidateSet,
-                                           OverloadCandidateSet::iterator *Best,
-                                           OverloadingResult OverloadResult,
-                                           bool AllowTypoCorrection) {
-  if (CandidateSet->empty())
-    return BuildRecoveryCallExpr(SemaRef, S, Fn, ULE, LParenLoc, Args,
-                                 RParenLoc, /*EmptyLookup=*/true,
-                                 AllowTypoCorrection);
-
-  switch (OverloadResult) {
-  case OR_Success: {
-    FunctionDecl *FDecl = (*Best)->Function;
-    SemaRef.CheckUnresolvedLookupAccess(ULE, (*Best)->FoundDecl);
-    if (SemaRef.DiagnoseUseOfDecl(FDecl, ULE->getNameLoc()))
-      return ExprError();
-    Fn = SemaRef.FixOverloadedFunctionReference(Fn, (*Best)->FoundDecl, FDecl);
-    return SemaRef.BuildResolvedCallExpr(Fn, FDecl, LParenLoc, Args, RParenLoc,
-                                         ExecConfig, /*IsExecConfig=*/false,
-                                         (*Best)->IsADLCandidate);
-  }
-
-  case OR_No_Viable_Function: {
-    // Try to recover by looking for viable functions which the user might
-    // have meant to call.
-    ExprResult Recovery = BuildRecoveryCallExpr(SemaRef, S, Fn, ULE, LParenLoc,
-                                                Args, RParenLoc,
-                                                /*EmptyLookup=*/false,
-                                                AllowTypoCorrection);
-    if (!Recovery.isInvalid())
-      return Recovery;
-
-    // If the user passes in a function that we can't take the address of, we
-    // generally end up emitting really bad error messages. Here, we attempt to
-    // emit better ones.
-    for (const Expr *Arg : Args) {
-      if (!Arg->getType()->isFunctionType())
-        continue;
-      if (auto *DRE = dyn_cast<DeclRefExpr>(Arg->IgnoreParenImpCasts())) {
-        auto *FD = dyn_cast<FunctionDecl>(DRE->getDecl());
-        if (FD &&
-            !SemaRef.checkAddressOfFunctionIsAvailable(FD, /*Complain=*/true,
-                                                       Arg->getExprLoc()))
-          return ExprError();
-      }
-    }
-
-    SemaRef.Diag(Fn->getBeginLoc(), diag::err_ovl_no_viable_function_in_call)
-        << ULE->getName() << Fn->getSourceRange();
-    CandidateSet->NoteCandidates(SemaRef, OCD_AllCandidates, Args);
-    break;
-  }
-
-  case OR_Ambiguous:
-    SemaRef.Diag(Fn->getBeginLoc(), diag::err_ovl_ambiguous_call)
-        << ULE->getName() << Fn->getSourceRange();
-    CandidateSet->NoteCandidates(SemaRef, OCD_ViableCandidates, Args);
-    break;
-
-  case OR_Deleted: {
-    SemaRef.Diag(Fn->getBeginLoc(), diag::err_ovl_deleted_call)
-        << (*Best)->Function->isDeleted() << ULE->getName()
-        << SemaRef.getDeletedOrUnavailableSuffix((*Best)->Function)
-        << Fn->getSourceRange();
-    CandidateSet->NoteCandidates(SemaRef, OCD_AllCandidates, Args);
-
-    // We emitted an error for the unavailable/deleted function call but keep
-    // the call in the AST.
-    FunctionDecl *FDecl = (*Best)->Function;
-    Fn = SemaRef.FixOverloadedFunctionReference(Fn, (*Best)->FoundDecl, FDecl);
-    return SemaRef.BuildResolvedCallExpr(Fn, FDecl, LParenLoc, Args, RParenLoc,
-                                         ExecConfig, /*IsExecConfig=*/false,
-                                         (*Best)->IsADLCandidate);
-  }
-  }
-
-  // Overload resolution failed.
-  return ExprError();
-}
-
-static void markUnaddressableCandidatesUnviable(Sema &S,
-                                                OverloadCandidateSet &CS) {
-  for (auto I = CS.begin(), E = CS.end(); I != E; ++I) {
-    if (I->Viable &&
-        !S.checkAddressOfFunctionIsAvailable(I->Function, /*Complain=*/false)) {
-      I->Viable = false;
-      I->FailureKind = ovl_fail_addr_not_available;
-    }
-  }
-}
-
-/// BuildOverloadedCallExpr - Given the call expression that calls Fn
-/// (which eventually refers to the declaration Func) and the call
-/// arguments Args/NumArgs, attempt to resolve the function call down
-/// to a specific function. If overload resolution succeeds, returns
-/// the call expression produced by overload resolution.
-/// Otherwise, emits diagnostics and returns ExprError.
-ExprResult Sema::BuildOverloadedCallExpr(Scope *S, Expr *Fn,
-                                         UnresolvedLookupExpr *ULE,
-                                         SourceLocation LParenLoc,
-                                         MultiExprArg Args,
-                                         SourceLocation RParenLoc,
-                                         Expr *ExecConfig,
-                                         bool AllowTypoCorrection,
-                                         bool CalleesAddressIsTaken) {
-  OverloadCandidateSet CandidateSet(Fn->getExprLoc(),
-                                    OverloadCandidateSet::CSK_Normal);
-  ExprResult result;
-
-  if (buildOverloadedCallSet(S, Fn, ULE, Args, LParenLoc, &CandidateSet,
-                             &result))
-    return result;
-
-  // If the user handed us something like `(&Foo)(Bar)`, we need to ensure that
-  // functions that aren't addressible are considered unviable.
-  if (CalleesAddressIsTaken)
-    markUnaddressableCandidatesUnviable(*this, CandidateSet);
-
-  OverloadCandidateSet::iterator Best;
-  OverloadingResult OverloadResult =
-      CandidateSet.BestViableFunction(*this, Fn->getBeginLoc(), Best);
-
-  return FinishOverloadedCallExpr(*this, S, Fn, ULE, LParenLoc, Args,
-                                  RParenLoc, ExecConfig, &CandidateSet,
-                                  &Best, OverloadResult,
-                                  AllowTypoCorrection);
-}
-
-static bool IsOverloaded(const UnresolvedSetImpl &Functions) {
-  return Functions.size() > 1 ||
-    (Functions.size() == 1 && isa<FunctionTemplateDecl>(*Functions.begin()));
-}
-
-/// Create a unary operation that may resolve to an overloaded
-/// operator.
-///
-/// \param OpLoc The location of the operator itself (e.g., '*').
-///
-/// \param Opc The UnaryOperatorKind that describes this operator.
-///
-/// \param Fns The set of non-member functions that will be
-/// considered by overload resolution. The caller needs to build this
-/// set based on the context using, e.g.,
-/// LookupOverloadedOperatorName() and ArgumentDependentLookup(). This
-/// set should not contain any member functions; those will be added
-/// by CreateOverloadedUnaryOp().
-///
-/// \param Input The input argument.
-ExprResult
-Sema::CreateOverloadedUnaryOp(SourceLocation OpLoc, UnaryOperatorKind Opc,
-                              const UnresolvedSetImpl &Fns,
-                              Expr *Input, bool PerformADL) {
-  OverloadedOperatorKind Op = UnaryOperator::getOverloadedOperator(Opc);
-  assert(Op != OO_None && "Invalid opcode for overloaded unary operator");
-  DeclarationName OpName = Context.DeclarationNames.getCXXOperatorName(Op);
-  // TODO: provide better source location info.
-  DeclarationNameInfo OpNameInfo(OpName, OpLoc);
-
-  if (checkPlaceholderForOverload(*this, Input))
-    return ExprError();
-
-  Expr *Args[2] = { Input, nullptr };
-  unsigned NumArgs = 1;
-
-  // For post-increment and post-decrement, add the implicit '0' as
-  // the second argument, so that we know this is a post-increment or
-  // post-decrement.
-  if (Opc == UO_PostInc || Opc == UO_PostDec) {
-    llvm::APSInt Zero(Context.getTypeSize(Context.IntTy), false);
-    Args[1] = IntegerLiteral::Create(Context, Zero, Context.IntTy,
-                                     SourceLocation());
-    NumArgs = 2;
-  }
-
-  ArrayRef<Expr *> ArgsArray(Args, NumArgs);
-
-  if (Input->isTypeDependent()) {
-    if (Fns.empty())
-      return new (Context) UnaryOperator(Input, Opc, Context.DependentTy,
-                                         VK_RValue, OK_Ordinary, OpLoc, false);
-
-    CXXRecordDecl *NamingClass = nullptr; // lookup ignores member operators
-    UnresolvedLookupExpr *Fn = UnresolvedLookupExpr::Create(
-        Context, NamingClass, NestedNameSpecifierLoc(), OpNameInfo,
-        /*ADL*/ true, IsOverloaded(Fns), Fns.begin(), Fns.end());
-    return CXXOperatorCallExpr::Create(Context, Op, Fn, ArgsArray,
-                                       Context.DependentTy, VK_RValue, OpLoc,
-                                       FPOptions());
-  }
-
-  // Build an empty overload set.
-  OverloadCandidateSet CandidateSet(OpLoc, OverloadCandidateSet::CSK_Operator);
-
-  // Add the candidates from the given function set.
-  AddFunctionCandidates(Fns, ArgsArray, CandidateSet);
-
-  // Add operator candidates that are member functions.
-  AddMemberOperatorCandidates(Op, OpLoc, ArgsArray, CandidateSet);
-
-  // Add candidates from ADL.
-  if (PerformADL) {
-    AddArgumentDependentLookupCandidates(OpName, OpLoc, ArgsArray,
-                                         /*ExplicitTemplateArgs*/nullptr,
-                                         CandidateSet);
-  }
-
-  // Add builtin operator candidates.
-  AddBuiltinOperatorCandidates(Op, OpLoc, ArgsArray, CandidateSet);
-
-  bool HadMultipleCandidates = (CandidateSet.size() > 1);
-
-  // Perform overload resolution.
-  OverloadCandidateSet::iterator Best;
-  switch (CandidateSet.BestViableFunction(*this, OpLoc, Best)) {
-  case OR_Success: {
-    // We found a built-in operator or an overloaded operator.
-    FunctionDecl *FnDecl = Best->Function;
-
-    if (FnDecl) {
-      Expr *Base = nullptr;
-      // We matched an overloaded operator. Build a call to that
-      // operator.
-
-      // Convert the arguments.
-      if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(FnDecl)) {
-        CheckMemberOperatorAccess(OpLoc, Args[0], nullptr, Best->FoundDecl);
-
-        ExprResult InputRes =
-          PerformObjectArgumentInitialization(Input, /*Qualifier=*/nullptr,
-                                              Best->FoundDecl, Method);
-        if (InputRes.isInvalid())
-          return ExprError();
-        Base = Input = InputRes.get();
-      } else {
-        // Convert the arguments.
-        ExprResult InputInit
-          = PerformCopyInitialization(InitializedEntity::InitializeParameter(
-                                                      Context,
-                                                      FnDecl->getParamDecl(0)),
-                                      SourceLocation(),
-                                      Input);
-        if (InputInit.isInvalid())
-          return ExprError();
-        Input = InputInit.get();
-      }
-
-      // Build the actual expression node.
-      ExprResult FnExpr = CreateFunctionRefExpr(*this, FnDecl, Best->FoundDecl,
-                                                Base, HadMultipleCandidates,
-                                                OpLoc);
-      if (FnExpr.isInvalid())
-        return ExprError();
-
-      // Determine the result type.
-      QualType ResultTy = FnDecl->getReturnType();
-      ExprValueKind VK = Expr::getValueKindForType(ResultTy);
-      ResultTy = ResultTy.getNonLValueExprType(Context);
-
-      Args[0] = Input;
-      CallExpr *TheCall = CXXOperatorCallExpr::Create(
-          Context, Op, FnExpr.get(), ArgsArray, ResultTy, VK, OpLoc,
-          FPOptions(), Best->IsADLCandidate);
-
-      if (CheckCallReturnType(FnDecl->getReturnType(), OpLoc, TheCall, FnDecl))
-        return ExprError();
-
-      if (CheckFunctionCall(FnDecl, TheCall,
-                            FnDecl->getType()->castAs<FunctionProtoType>()))
-        return ExprError();
-
-      return MaybeBindToTemporary(TheCall);
-    } else {
-      // We matched a built-in operator. Convert the arguments, then
-      // break out so that we will build the appropriate built-in
-      // operator node.
-      ExprResult InputRes = PerformImplicitConversion(
-          Input, Best->BuiltinParamTypes[0], Best->Conversions[0], AA_Passing,
-          CCK_ForBuiltinOverloadedOp);
-      if (InputRes.isInvalid())
-        return ExprError();
-      Input = InputRes.get();
-      break;
-    }
-  }
-
-  case OR_No_Viable_Function:
-    // This is an erroneous use of an operator which can be overloaded by
-    // a non-member function. Check for non-member operators which were
-    // defined too late to be candidates.
-    if (DiagnoseTwoPhaseOperatorLookup(*this, Op, OpLoc, ArgsArray))
-      // FIXME: Recover by calling the found function.
-      return ExprError();
-
-    // No viable function; fall through to handling this as a
-    // built-in operator, which will produce an error message for us.
-    break;
-
-  case OR_Ambiguous:
-    Diag(OpLoc,  diag::err_ovl_ambiguous_oper_unary)
-        << UnaryOperator::getOpcodeStr(Opc)
-        << Input->getType()
-        << Input->getSourceRange();
-    CandidateSet.NoteCandidates(*this, OCD_ViableCandidates, ArgsArray,
-                                UnaryOperator::getOpcodeStr(Opc), OpLoc);
-    return ExprError();
-
-  case OR_Deleted:
-    Diag(OpLoc, diag::err_ovl_deleted_oper)
-      << Best->Function->isDeleted()
-      << UnaryOperator::getOpcodeStr(Opc)
-      << getDeletedOrUnavailableSuffix(Best->Function)
-      << Input->getSourceRange();
-    CandidateSet.NoteCandidates(*this, OCD_AllCandidates, ArgsArray,
-                                UnaryOperator::getOpcodeStr(Opc), OpLoc);
-    return ExprError();
-  }
-
-  // Either we found no viable overloaded operator or we matched a
-  // built-in operator. In either case, fall through to trying to
-  // build a built-in operation.
-  return CreateBuiltinUnaryOp(OpLoc, Opc, Input);
-}
-
-/// Create a binary operation that may resolve to an overloaded
-/// operator.
-///
-/// \param OpLoc The location of the operator itself (e.g., '+').
-///
-/// \param Opc The BinaryOperatorKind that describes this operator.
-///
-/// \param Fns The set of non-member functions that will be
-/// considered by overload resolution. The caller needs to build this
-/// set based on the context using, e.g.,
-/// LookupOverloadedOperatorName() and ArgumentDependentLookup(). This
-/// set should not contain any member functions; those will be added
-/// by CreateOverloadedBinOp().
-///
-/// \param LHS Left-hand argument.
-/// \param RHS Right-hand argument.
-ExprResult
-Sema::CreateOverloadedBinOp(SourceLocation OpLoc,
-                            BinaryOperatorKind Opc,
-                            const UnresolvedSetImpl &Fns,
-                            Expr *LHS, Expr *RHS, bool PerformADL) {
-  Expr *Args[2] = { LHS, RHS };
-  LHS=RHS=nullptr; // Please use only Args instead of LHS/RHS couple
-
-  OverloadedOperatorKind Op = BinaryOperator::getOverloadedOperator(Opc);
-  DeclarationName OpName = Context.DeclarationNames.getCXXOperatorName(Op);
-
-  // If either side is type-dependent, create an appropriate dependent
-  // expression.
-  if (Args[0]->isTypeDependent() || Args[1]->isTypeDependent()) {
-    if (Fns.empty()) {
-      // If there are no functions to store, just build a dependent
-      // BinaryOperator or CompoundAssignment.
-      if (Opc <= BO_Assign || Opc > BO_OrAssign)
-        return new (Context) BinaryOperator(
-            Args[0], Args[1], Opc, Context.DependentTy, VK_RValue, OK_Ordinary,
-            OpLoc, FPFeatures);
-
-      return new (Context) CompoundAssignOperator(
-          Args[0], Args[1], Opc, Context.DependentTy, VK_LValue, OK_Ordinary,
-          Context.DependentTy, Context.DependentTy, OpLoc,
-          FPFeatures);
-    }
-
-    // FIXME: save results of ADL from here?
-    CXXRecordDecl *NamingClass = nullptr; // lookup ignores member operators
-    // TODO: provide better source location info in DNLoc component.
-    DeclarationNameInfo OpNameInfo(OpName, OpLoc);
-    UnresolvedLookupExpr *Fn = UnresolvedLookupExpr::Create(
-        Context, NamingClass, NestedNameSpecifierLoc(), OpNameInfo,
-        /*ADL*/ PerformADL, IsOverloaded(Fns), Fns.begin(), Fns.end());
-    return CXXOperatorCallExpr::Create(Context, Op, Fn, Args,
-                                       Context.DependentTy, VK_RValue, OpLoc,
-                                       FPFeatures);
-  }
-
-  // Always do placeholder-like conversions on the RHS.
-  if (checkPlaceholderForOverload(*this, Args[1]))
-    return ExprError();
-
-  // Do placeholder-like conversion on the LHS; note that we should
-  // not get here with a PseudoObject LHS.
-  assert(Args[0]->getObjectKind() != OK_ObjCProperty);
-  if (checkPlaceholderForOverload(*this, Args[0]))
-    return ExprError();
-
-  // If this is the assignment operator, we only perform overload resolution
-  // if the left-hand side is a class or enumeration type. This is actually
-  // a hack. The standard requires that we do overload resolution between the
-  // various built-in candidates, but as DR507 points out, this can lead to
-  // problems. So we do it this way, which pretty much follows what GCC does.
-  // Note that we go the traditional code path for compound assignment forms.
-  if (Opc == BO_Assign && !Args[0]->getType()->isOverloadableType())
-    return CreateBuiltinBinOp(OpLoc, Opc, Args[0], Args[1]);
-
-  // If this is the .* operator, which is not overloadable, just
-  // create a built-in binary operator.
-  if (Opc == BO_PtrMemD)
-    return CreateBuiltinBinOp(OpLoc, Opc, Args[0], Args[1]);
-
-  // Build an empty overload set.
-  OverloadCandidateSet CandidateSet(OpLoc, OverloadCandidateSet::CSK_Operator);
-
-  // Add the candidates from the given function set.
-  AddFunctionCandidates(Fns, Args, CandidateSet);
-
-  // Add operator candidates that are member functions.
-  AddMemberOperatorCandidates(Op, OpLoc, Args, CandidateSet);
-
-  // Add candidates from ADL. Per [over.match.oper]p2, this lookup is not
-  // performed for an assignment operator (nor for operator[] nor operator->,
-  // which don't get here).
-  if (Opc != BO_Assign && PerformADL)
-    AddArgumentDependentLookupCandidates(OpName, OpLoc, Args,
-                                         /*ExplicitTemplateArgs*/ nullptr,
-                                         CandidateSet);
-
-  // Add builtin operator candidates.
-  AddBuiltinOperatorCandidates(Op, OpLoc, Args, CandidateSet);
-
-  bool HadMultipleCandidates = (CandidateSet.size() > 1);
-
-  // Perform overload resolution.
-  OverloadCandidateSet::iterator Best;
-  switch (CandidateSet.BestViableFunction(*this, OpLoc, Best)) {
-    case OR_Success: {
-      // We found a built-in operator or an overloaded operator.
-      FunctionDecl *FnDecl = Best->Function;
-
-      if (FnDecl) {
-        Expr *Base = nullptr;
-        // We matched an overloaded operator. Build a call to that
-        // operator.
-
-        // Convert the arguments.
-        if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(FnDecl)) {
-          // Best->Access is only meaningful for class members.
-          CheckMemberOperatorAccess(OpLoc, Args[0], Args[1], Best->FoundDecl);
-
-          ExprResult Arg1 =
-            PerformCopyInitialization(
-              InitializedEntity::InitializeParameter(Context,
-                                                     FnDecl->getParamDecl(0)),
-              SourceLocation(), Args[1]);
-          if (Arg1.isInvalid())
-            return ExprError();
-
-          ExprResult Arg0 =
-            PerformObjectArgumentInitialization(Args[0], /*Qualifier=*/nullptr,
-                                                Best->FoundDecl, Method);
-          if (Arg0.isInvalid())
-            return ExprError();
-          Base = Args[0] = Arg0.getAs<Expr>();
-          Args[1] = RHS = Arg1.getAs<Expr>();
-        } else {
-          // Convert the arguments.
-          ExprResult Arg0 = PerformCopyInitialization(
-            InitializedEntity::InitializeParameter(Context,
-                                                   FnDecl->getParamDecl(0)),
-            SourceLocation(), Args[0]);
-          if (Arg0.isInvalid())
-            return ExprError();
-
-          ExprResult Arg1 =
-            PerformCopyInitialization(
-              InitializedEntity::InitializeParameter(Context,
-                                                     FnDecl->getParamDecl(1)),
-              SourceLocation(), Args[1]);
-          if (Arg1.isInvalid())
-            return ExprError();
-          Args[0] = LHS = Arg0.getAs<Expr>();
-          Args[1] = RHS = Arg1.getAs<Expr>();
-        }
-
-        // Build the actual expression node.
-        ExprResult FnExpr = CreateFunctionRefExpr(*this, FnDecl,
-                                                  Best->FoundDecl, Base,
-                                                  HadMultipleCandidates, OpLoc);
-        if (FnExpr.isInvalid())
-          return ExprError();
-
-        // Determine the result type.
-        QualType ResultTy = FnDecl->getReturnType();
-        ExprValueKind VK = Expr::getValueKindForType(ResultTy);
-        ResultTy = ResultTy.getNonLValueExprType(Context);
-
-        CXXOperatorCallExpr *TheCall = CXXOperatorCallExpr::Create(
-            Context, Op, FnExpr.get(), Args, ResultTy, VK, OpLoc, FPFeatures,
-            Best->IsADLCandidate);
-
-        if (CheckCallReturnType(FnDecl->getReturnType(), OpLoc, TheCall,
-                                FnDecl))
-          return ExprError();
-
-        ArrayRef<const Expr *> ArgsArray(Args, 2);
-        const Expr *ImplicitThis = nullptr;
-        // Cut off the implicit 'this'.
-        if (isa<CXXMethodDecl>(FnDecl)) {
-          ImplicitThis = ArgsArray[0];
-          ArgsArray = ArgsArray.slice(1);
-        }
-
-        // Check for a self move.
-        if (Op == OO_Equal)
-          DiagnoseSelfMove(Args[0], Args[1], OpLoc);
-
-        checkCall(FnDecl, nullptr, ImplicitThis, ArgsArray,
-                  isa<CXXMethodDecl>(FnDecl), OpLoc, TheCall->getSourceRange(),
-                  VariadicDoesNotApply);
-
-        return MaybeBindToTemporary(TheCall);
-      } else {
-        // We matched a built-in operator. Convert the arguments, then
-        // break out so that we will build the appropriate built-in
-        // operator node.
-        ExprResult ArgsRes0 = PerformImplicitConversion(
-            Args[0], Best->BuiltinParamTypes[0], Best->Conversions[0],
-            AA_Passing, CCK_ForBuiltinOverloadedOp);
-        if (ArgsRes0.isInvalid())
-          return ExprError();
-        Args[0] = ArgsRes0.get();
-
-        ExprResult ArgsRes1 = PerformImplicitConversion(
-            Args[1], Best->BuiltinParamTypes[1], Best->Conversions[1],
-            AA_Passing, CCK_ForBuiltinOverloadedOp);
-        if (ArgsRes1.isInvalid())
-          return ExprError();
-        Args[1] = ArgsRes1.get();
-        break;
-      }
-    }
-
-    case OR_No_Viable_Function: {
-      // C++ [over.match.oper]p9:
-      //   If the operator is the operator , [...] and there are no
-      //   viable functions, then the operator is assumed to be the
-      //   built-in operator and interpreted according to clause 5.
-      if (Opc == BO_Comma)
-        break;
-
-      // For class as left operand for assignment or compound assignment
-      // operator do not fall through to handling in built-in, but report that
-      // no overloaded assignment operator found
-      ExprResult Result = ExprError();
-      if (Args[0]->getType()->isRecordType() &&
-          Opc >= BO_Assign && Opc <= BO_OrAssign) {
-        Diag(OpLoc,  diag::err_ovl_no_viable_oper)
-             << BinaryOperator::getOpcodeStr(Opc)
-             << Args[0]->getSourceRange() << Args[1]->getSourceRange();
-        if (Args[0]->getType()->isIncompleteType()) {
-          Diag(OpLoc, diag::note_assign_lhs_incomplete)
-            << Args[0]->getType()
-            << Args[0]->getSourceRange() << Args[1]->getSourceRange();
-        }
-      } else {
-        // This is an erroneous use of an operator which can be overloaded by
-        // a non-member function. Check for non-member operators which were
-        // defined too late to be candidates.
-        if (DiagnoseTwoPhaseOperatorLookup(*this, Op, OpLoc, Args))
-          // FIXME: Recover by calling the found function.
-          return ExprError();
-
-        // No viable function; try to create a built-in operation, which will
-        // produce an error. Then, show the non-viable candidates.
-        Result = CreateBuiltinBinOp(OpLoc, Opc, Args[0], Args[1]);
-      }
-      assert(Result.isInvalid() &&
-             "C++ binary operator overloading is missing candidates!");
-      if (Result.isInvalid())
-        CandidateSet.NoteCandidates(*this, OCD_AllCandidates, Args,
-                                    BinaryOperator::getOpcodeStr(Opc), OpLoc);
-      return Result;
-    }
-
-    case OR_Ambiguous:
-      Diag(OpLoc,  diag::err_ovl_ambiguous_oper_binary)
-          << BinaryOperator::getOpcodeStr(Opc)
-          << Args[0]->getType() << Args[1]->getType()
-          << Args[0]->getSourceRange() << Args[1]->getSourceRange();
-      CandidateSet.NoteCandidates(*this, OCD_ViableCandidates, Args,
-                                  BinaryOperator::getOpcodeStr(Opc), OpLoc);
-      return ExprError();
-
-    case OR_Deleted:
-      if (isImplicitlyDeleted(Best->Function)) {
-        CXXMethodDecl *Method = cast<CXXMethodDecl>(Best->Function);
-        Diag(OpLoc, diag::err_ovl_deleted_special_oper)
-          << Context.getRecordType(Method->getParent())
-          << getSpecialMember(Method);
-
-        // The user probably meant to call this special member. Just
-        // explain why it's deleted.
-        NoteDeletedFunction(Method);
-        return ExprError();
-      } else {
-        Diag(OpLoc, diag::err_ovl_deleted_oper)
-          << Best->Function->isDeleted()
-          << BinaryOperator::getOpcodeStr(Opc)
-          << getDeletedOrUnavailableSuffix(Best->Function)
-          << Args[0]->getSourceRange() << Args[1]->getSourceRange();
-      }
-      CandidateSet.NoteCandidates(*this, OCD_AllCandidates, Args,
-                                  BinaryOperator::getOpcodeStr(Opc), OpLoc);
-      return ExprError();
-  }
-
-  // We matched a built-in operator; build it.
-  return CreateBuiltinBinOp(OpLoc, Opc, Args[0], Args[1]);
-}
-
-ExprResult
-Sema::CreateOverloadedArraySubscriptExpr(SourceLocation LLoc,
-                                         SourceLocation RLoc,
-                                         Expr *Base, Expr *Idx) {
-  Expr *Args[2] = { Base, Idx };
-  DeclarationName OpName =
-      Context.DeclarationNames.getCXXOperatorName(OO_Subscript);
-
-  // If either side is type-dependent, create an appropriate dependent
-  // expression.
-  if (Args[0]->isTypeDependent() || Args[1]->isTypeDependent()) {
-
-    CXXRecordDecl *NamingClass = nullptr; // lookup ignores member operators
-    // CHECKME: no 'operator' keyword?
-    DeclarationNameInfo OpNameInfo(OpName, LLoc);
-    OpNameInfo.setCXXOperatorNameRange(SourceRange(LLoc, RLoc));
-    UnresolvedLookupExpr *Fn
-      = UnresolvedLookupExpr::Create(Context, NamingClass,
-                                     NestedNameSpecifierLoc(), OpNameInfo,
-                                     /*ADL*/ true, /*Overloaded*/ false,
-                                     UnresolvedSetIterator(),
-                                     UnresolvedSetIterator());
-    // Can't add any actual overloads yet
-
-    return CXXOperatorCallExpr::Create(Context, OO_Subscript, Fn, Args,
-                                       Context.DependentTy, VK_RValue, RLoc,
-                                       FPOptions());
-  }
-
-  // Handle placeholders on both operands.
-  if (checkPlaceholderForOverload(*this, Args[0]))
-    return ExprError();
-  if (checkPlaceholderForOverload(*this, Args[1]))
-    return ExprError();
-
-  // Build an empty overload set.
-  OverloadCandidateSet CandidateSet(LLoc, OverloadCandidateSet::CSK_Operator);
-
-  // Subscript can only be overloaded as a member function.
-
-  // Add operator candidates that are member functions.
-  AddMemberOperatorCandidates(OO_Subscript, LLoc, Args, CandidateSet);
-
-  // Add builtin operator candidates.
-  AddBuiltinOperatorCandidates(OO_Subscript, LLoc, Args, CandidateSet);
-
-  bool HadMultipleCandidates = (CandidateSet.size() > 1);
-
-  // Perform overload resolution.
-  OverloadCandidateSet::iterator Best;
-  switch (CandidateSet.BestViableFunction(*this, LLoc, Best)) {
-    case OR_Success: {
-      // We found a built-in operator or an overloaded operator.
-      FunctionDecl *FnDecl = Best->Function;
-
-      if (FnDecl) {
-        // We matched an overloaded operator. Build a call to that
-        // operator.
-
-        CheckMemberOperatorAccess(LLoc, Args[0], Args[1], Best->FoundDecl);
-
-        // Convert the arguments.
-        CXXMethodDecl *Method = cast<CXXMethodDecl>(FnDecl);
-        ExprResult Arg0 =
-          PerformObjectArgumentInitialization(Args[0], /*Qualifier=*/nullptr,
-                                              Best->FoundDecl, Method);
-        if (Arg0.isInvalid())
-          return ExprError();
-        Args[0] = Arg0.get();
-
-        // Convert the arguments.
-        ExprResult InputInit
-          = PerformCopyInitialization(InitializedEntity::InitializeParameter(
-                                                      Context,
-                                                      FnDecl->getParamDecl(0)),
-                                      SourceLocation(),
-                                      Args[1]);
-        if (InputInit.isInvalid())
-          return ExprError();
-
-        Args[1] = InputInit.getAs<Expr>();
-
-        // Build the actual expression node.
-        DeclarationNameInfo OpLocInfo(OpName, LLoc);
-        OpLocInfo.setCXXOperatorNameRange(SourceRange(LLoc, RLoc));
-        ExprResult FnExpr = CreateFunctionRefExpr(*this, FnDecl,
-                                                  Best->FoundDecl,
-                                                  Base,
-                                                  HadMultipleCandidates,
-                                                  OpLocInfo.getLoc(),
-                                                  OpLocInfo.getInfo());
-        if (FnExpr.isInvalid())
-          return ExprError();
-
-        // Determine the result type
-        QualType ResultTy = FnDecl->getReturnType();
-        ExprValueKind VK = Expr::getValueKindForType(ResultTy);
-        ResultTy = ResultTy.getNonLValueExprType(Context);
-
-        CXXOperatorCallExpr *TheCall =
-            CXXOperatorCallExpr::Create(Context, OO_Subscript, FnExpr.get(),
-                                        Args, ResultTy, VK, RLoc, FPOptions());
-
-        if (CheckCallReturnType(FnDecl->getReturnType(), LLoc, TheCall, FnDecl))
-          return ExprError();
-
-        if (CheckFunctionCall(Method, TheCall,
-                              Method->getType()->castAs<FunctionProtoType>()))
-          return ExprError();
-
-        return MaybeBindToTemporary(TheCall);
-      } else {
-        // We matched a built-in operator. Convert the arguments, then
-        // break out so that we will build the appropriate built-in
-        // operator node.
-        ExprResult ArgsRes0 = PerformImplicitConversion(
-            Args[0], Best->BuiltinParamTypes[0], Best->Conversions[0],
-            AA_Passing, CCK_ForBuiltinOverloadedOp);
-        if (ArgsRes0.isInvalid())
-          return ExprError();
-        Args[0] = ArgsRes0.get();
-
-        ExprResult ArgsRes1 = PerformImplicitConversion(
-            Args[1], Best->BuiltinParamTypes[1], Best->Conversions[1],
-            AA_Passing, CCK_ForBuiltinOverloadedOp);
-        if (ArgsRes1.isInvalid())
-          return ExprError();
-        Args[1] = ArgsRes1.get();
-
-        break;
-      }
-    }
-
-    case OR_No_Viable_Function: {
-      if (CandidateSet.empty())
-        Diag(LLoc, diag::err_ovl_no_oper)
-          << Args[0]->getType() << /*subscript*/ 0
-          << Args[0]->getSourceRange() << Args[1]->getSourceRange();
-      else
-        Diag(LLoc, diag::err_ovl_no_viable_subscript)
-          << Args[0]->getType()
-          << Args[0]->getSourceRange() << Args[1]->getSourceRange();
-      CandidateSet.NoteCandidates(*this, OCD_AllCandidates, Args,
-                                  "[]", LLoc);
-      return ExprError();
-    }
-
-    case OR_Ambiguous:
-      Diag(LLoc,  diag::err_ovl_ambiguous_oper_binary)
-          << "[]"
-          << Args[0]->getType() << Args[1]->getType()
-          << Args[0]->getSourceRange() << Args[1]->getSourceRange();
-      CandidateSet.NoteCandidates(*this, OCD_ViableCandidates, Args,
-                                  "[]", LLoc);
-      return ExprError();
-
-    case OR_Deleted:
-      Diag(LLoc, diag::err_ovl_deleted_oper)
-        << Best->Function->isDeleted() << "[]"
-        << getDeletedOrUnavailableSuffix(Best->Function)
-        << Args[0]->getSourceRange() << Args[1]->getSourceRange();
-      CandidateSet.NoteCandidates(*this, OCD_AllCandidates, Args,
-                                  "[]", LLoc);
-      return ExprError();
-    }
-
-  // We matched a built-in operator; build it.
-  return CreateBuiltinArraySubscriptExpr(Args[0], LLoc, Args[1], RLoc);
-}
-
-/// BuildCallToMemberFunction - Build a call to a member
-/// function. MemExpr is the expression that refers to the member
-/// function (and includes the object parameter), Args/NumArgs are the
-/// arguments to the function call (not including the object
-/// parameter). The caller needs to validate that the member
-/// expression refers to a non-static member function or an overloaded
-/// member function.
-ExprResult
-Sema::BuildCallToMemberFunction(Scope *S, Expr *MemExprE,
-                                SourceLocation LParenLoc,
-                                MultiExprArg Args,
-                                SourceLocation RParenLoc) {
-  assert(MemExprE->getType() == Context.BoundMemberTy ||
-         MemExprE->getType() == Context.OverloadTy);
-
-  // Dig out the member expression. This holds both the object
-  // argument and the member function we're referring to.
-  Expr *NakedMemExpr = MemExprE->IgnoreParens();
-
-  // Determine whether this is a call to a pointer-to-member function.
-  if (BinaryOperator *op = dyn_cast<BinaryOperator>(NakedMemExpr)) {
-    assert(op->getType() == Context.BoundMemberTy);
-    assert(op->getOpcode() == BO_PtrMemD || op->getOpcode() == BO_PtrMemI);
-
-    QualType fnType =
-      op->getRHS()->getType()->castAs<MemberPointerType>()->getPointeeType();
-
-    const FunctionProtoType *proto = fnType->castAs<FunctionProtoType>();
-    QualType resultType = proto->getCallResultType(Context);
-    ExprValueKind valueKind = Expr::getValueKindForType(proto->getReturnType());
-
-    // Check that the object type isn't more qualified than the
-    // member function we're calling.
-    Qualifiers funcQuals = proto->getTypeQuals();
-
-    QualType objectType = op->getLHS()->getType();
-    if (op->getOpcode() == BO_PtrMemI)
-      objectType = objectType->castAs<PointerType>()->getPointeeType();
-    Qualifiers objectQuals = objectType.getQualifiers();
-
-    Qualifiers difference = objectQuals - funcQuals;
-    difference.removeObjCGCAttr();
-    difference.removeAddressSpace();
-    if (difference) {
-      std::string qualsString = difference.getAsString();
-      Diag(LParenLoc, diag::err_pointer_to_member_call_drops_quals)
-        << fnType.getUnqualifiedType()
-        << qualsString
-        << (qualsString.find(' ') == std::string::npos ? 1 : 2);
-    }
-
-    CXXMemberCallExpr *call =
-        CXXMemberCallExpr::Create(Context, MemExprE, Args, resultType,
-                                  valueKind, RParenLoc, proto->getNumParams());
-
-    if (CheckCallReturnType(proto->getReturnType(), op->getRHS()->getBeginLoc(),
-                            call, nullptr))
-      return ExprError();
-
-    if (ConvertArgumentsForCall(call, op, nullptr, proto, Args, RParenLoc))
-      return ExprError();
-
-    if (CheckOtherCall(call, proto))
-      return ExprError();
-
-    return MaybeBindToTemporary(call);
-  }
-
-  if (isa<CXXPseudoDestructorExpr>(NakedMemExpr))
-    return CallExpr::Create(Context, MemExprE, Args, Context.VoidTy, VK_RValue,
-                            RParenLoc);
-
-  UnbridgedCastsSet UnbridgedCasts;
-  if (checkArgPlaceholdersForOverload(*this, Args, UnbridgedCasts))
-    return ExprError();
-
-  MemberExpr *MemExpr;
-  CXXMethodDecl *Method = nullptr;
-  DeclAccessPair FoundDecl = DeclAccessPair::make(nullptr, AS_public);
-  NestedNameSpecifier *Qualifier = nullptr;
-  if (isa<MemberExpr>(NakedMemExpr)) {
-    MemExpr = cast<MemberExpr>(NakedMemExpr);
-    Method = cast<CXXMethodDecl>(MemExpr->getMemberDecl());
-    FoundDecl = MemExpr->getFoundDecl();
-    Qualifier = MemExpr->getQualifier();
-    UnbridgedCasts.restore();
-  } else {
-    UnresolvedMemberExpr *UnresExpr = cast<UnresolvedMemberExpr>(NakedMemExpr);
-    Qualifier = UnresExpr->getQualifier();
-
-    QualType ObjectType = UnresExpr->getBaseType();
-    Expr::Classification ObjectClassification
-      = UnresExpr->isArrow()? Expr::Classification::makeSimpleLValue()
-                            : UnresExpr->getBase()->Classify(Context);
-
-    // Add overload candidates
-    OverloadCandidateSet CandidateSet(UnresExpr->getMemberLoc(),
-                                      OverloadCandidateSet::CSK_Normal);
-
-    // FIXME: avoid copy.
-    TemplateArgumentListInfo TemplateArgsBuffer, *TemplateArgs = nullptr;
-    if (UnresExpr->hasExplicitTemplateArgs()) {
-      UnresExpr->copyTemplateArgumentsInto(TemplateArgsBuffer);
-      TemplateArgs = &TemplateArgsBuffer;
-    }
-
-    for (UnresolvedMemberExpr::decls_iterator I = UnresExpr->decls_begin(),
-           E = UnresExpr->decls_end(); I != E; ++I) {
-
-      NamedDecl *Func = *I;
-      CXXRecordDecl *ActingDC = cast<CXXRecordDecl>(Func->getDeclContext());
-      if (isa<UsingShadowDecl>(Func))
-        Func = cast<UsingShadowDecl>(Func)->getTargetDecl();
-
-
-      // Microsoft supports direct constructor calls.
-      if (getLangOpts().MicrosoftExt && isa<CXXConstructorDecl>(Func)) {
-        AddOverloadCandidate(cast<CXXConstructorDecl>(Func), I.getPair(),
-                             Args, CandidateSet);
-      } else if ((Method = dyn_cast<CXXMethodDecl>(Func))) {
-        // If explicit template arguments were provided, we can't call a
-        // non-template member function.
-        if (TemplateArgs)
-          continue;
-
-        AddMethodCandidate(Method, I.getPair(), ActingDC, ObjectType,
-                           ObjectClassification, Args, CandidateSet,
-                           /*SuppressUserConversions=*/false);
-      } else {
-        AddMethodTemplateCandidate(
-            cast<FunctionTemplateDecl>(Func), I.getPair(), ActingDC,
-            TemplateArgs, ObjectType, ObjectClassification, Args, CandidateSet,
-            /*SuppressUsedConversions=*/false);
-      }
-    }
-
-    DeclarationName DeclName = UnresExpr->getMemberName();
-
-    UnbridgedCasts.restore();
-
-    OverloadCandidateSet::iterator Best;
-    switch (CandidateSet.BestViableFunction(*this, UnresExpr->getBeginLoc(),
-                                            Best)) {
-    case OR_Success:
-      Method = cast<CXXMethodDecl>(Best->Function);
-      FoundDecl = Best->FoundDecl;
-      CheckUnresolvedMemberAccess(UnresExpr, Best->FoundDecl);
-      if (DiagnoseUseOfDecl(Best->FoundDecl, UnresExpr->getNameLoc()))
-        return ExprError();
-      // If FoundDecl is different from Method (such as if one is a template
-      // and the other a specialization), make sure DiagnoseUseOfDecl is
-      // called on both.
-      // FIXME: This would be more comprehensively addressed by modifying
-      // DiagnoseUseOfDecl to accept both the FoundDecl and the decl
-      // being used.
-      if (Method != FoundDecl.getDecl() &&
-                      DiagnoseUseOfDecl(Method, UnresExpr->getNameLoc()))
-        return ExprError();
-      break;
-
-    case OR_No_Viable_Function:
-      Diag(UnresExpr->getMemberLoc(),
-           diag::err_ovl_no_viable_member_function_in_call)
-        << DeclName << MemExprE->getSourceRange();
-      CandidateSet.NoteCandidates(*this, OCD_AllCandidates, Args);
-      // FIXME: Leaking incoming expressions!
-      return ExprError();
-
-    case OR_Ambiguous:
-      Diag(UnresExpr->getMemberLoc(), diag::err_ovl_ambiguous_member_call)
-        << DeclName << MemExprE->getSourceRange();
-      CandidateSet.NoteCandidates(*this, OCD_AllCandidates, Args);
-      // FIXME: Leaking incoming expressions!
-      return ExprError();
-
-    case OR_Deleted:
-      Diag(UnresExpr->getMemberLoc(), diag::err_ovl_deleted_member_call)
-        << Best->Function->isDeleted()
-        << DeclName
-        << getDeletedOrUnavailableSuffix(Best->Function)
-        << MemExprE->getSourceRange();
-      CandidateSet.NoteCandidates(*this, OCD_AllCandidates, Args);
-      // FIXME: Leaking incoming expressions!
-      return ExprError();
-    }
-
-    MemExprE = FixOverloadedFunctionReference(MemExprE, FoundDecl, Method);
-
-    // If overload resolution picked a static member, build a
-    // non-member call based on that function.
-    if (Method->isStatic()) {
-      return BuildResolvedCallExpr(MemExprE, Method, LParenLoc, Args,
-                                   RParenLoc);
-    }
-
-    MemExpr = cast<MemberExpr>(MemExprE->IgnoreParens());
-  }
-
-  QualType ResultType = Method->getReturnType();
-  ExprValueKind VK = Expr::getValueKindForType(ResultType);
-  ResultType = ResultType.getNonLValueExprType(Context);
-
-  assert(Method && "Member call to something that isn't a method?");
-  const auto *Proto = Method->getType()->getAs<FunctionProtoType>();
-  CXXMemberCallExpr *TheCall =
-      CXXMemberCallExpr::Create(Context, MemExprE, Args, ResultType, VK,
-                                RParenLoc, Proto->getNumParams());
-
-  // Check for a valid return type.
-  if (CheckCallReturnType(Method->getReturnType(), MemExpr->getMemberLoc(),
-                          TheCall, Method))
-    return ExprError();
-
-  // Convert the object argument (for a non-static member function call).
-  // We only need to do this if there was actually an overload; otherwise
-  // it was done at lookup.
-  if (!Method->isStatic()) {
-    ExprResult ObjectArg =
-      PerformObjectArgumentInitialization(MemExpr->getBase(), Qualifier,
-                                          FoundDecl, Method);
-    if (ObjectArg.isInvalid())
-      return ExprError();
-    MemExpr->setBase(ObjectArg.get());
-  }
-
-  // Convert the rest of the arguments
-  if (ConvertArgumentsForCall(TheCall, MemExpr, Method, Proto, Args,
-                              RParenLoc))
-    return ExprError();
-
-  DiagnoseSentinelCalls(Method, LParenLoc, Args);
-
-  if (CheckFunctionCall(Method, TheCall, Proto))
-    return ExprError();
-
-  // In the case the method to call was not selected by the overloading
-  // resolution process, we still need to handle the enable_if attribute. Do
-  // that here, so it will not hide previous -- and more relevant -- errors.
-  if (auto *MemE = dyn_cast<MemberExpr>(NakedMemExpr)) {
-    if (const EnableIfAttr *Attr = CheckEnableIf(Method, Args, true)) {
-      Diag(MemE->getMemberLoc(),
-           diag::err_ovl_no_viable_member_function_in_call)
-          << Method << Method->getSourceRange();
-      Diag(Method->getLocation(),
-           diag::note_ovl_candidate_disabled_by_function_cond_attr)
-          << Attr->getCond()->getSourceRange() << Attr->getMessage();
-      return ExprError();
-    }
-  }
-
-  if ((isa<CXXConstructorDecl>(CurContext) ||
-       isa<CXXDestructorDecl>(CurContext)) &&
-      TheCall->getMethodDecl()->isPure()) {
-    const CXXMethodDecl *MD = TheCall->getMethodDecl();
-
-    if (isa<CXXThisExpr>(MemExpr->getBase()->IgnoreParenCasts()) &&
-        MemExpr->performsVirtualDispatch(getLangOpts())) {
-      Diag(MemExpr->getBeginLoc(),
-           diag::warn_call_to_pure_virtual_member_function_from_ctor_dtor)
-          << MD->getDeclName() << isa<CXXDestructorDecl>(CurContext)
-          << MD->getParent()->getDeclName();
-
-      Diag(MD->getBeginLoc(), diag::note_previous_decl) << MD->getDeclName();
-      if (getLangOpts().AppleKext)
-        Diag(MemExpr->getBeginLoc(), diag::note_pure_qualified_call_kext)
-            << MD->getParent()->getDeclName() << MD->getDeclName();
-    }
-  }
-
-  if (CXXDestructorDecl *DD =
-          dyn_cast<CXXDestructorDecl>(TheCall->getMethodDecl())) {
-    // a->A::f() doesn't go through the vtable, except in AppleKext mode.
-    bool CallCanBeVirtual = !MemExpr->hasQualifier() || getLangOpts().AppleKext;
-    CheckVirtualDtorCall(DD, MemExpr->getBeginLoc(), /*IsDelete=*/false,
-                         CallCanBeVirtual, /*WarnOnNonAbstractTypes=*/true,
-                         MemExpr->getMemberLoc());
-  }
-
-  return MaybeBindToTemporary(TheCall);
-}
-
-/// BuildCallToObjectOfClassType - Build a call to an object of class
-/// type (C++ [over.call.object]), which can end up invoking an
-/// overloaded function call operator (@c operator()) or performing a
-/// user-defined conversion on the object argument.
-ExprResult
-Sema::BuildCallToObjectOfClassType(Scope *S, Expr *Obj,
-                                   SourceLocation LParenLoc,
-                                   MultiExprArg Args,
-                                   SourceLocation RParenLoc) {
-  if (checkPlaceholderForOverload(*this, Obj))
-    return ExprError();
-  ExprResult Object = Obj;
-
-  UnbridgedCastsSet UnbridgedCasts;
-  if (checkArgPlaceholdersForOverload(*this, Args, UnbridgedCasts))
-    return ExprError();
-
-  assert(Object.get()->getType()->isRecordType() &&
-         "Requires object type argument");
-  const RecordType *Record = Object.get()->getType()->getAs<RecordType>();
-
-  // C++ [over.call.object]p1:
-  //  If the primary-expression E in the function call syntax
-  //  evaluates to a class object of type "cv T", then the set of
-  //  candidate functions includes at least the function call
-  //  operators of T. The function call operators of T are obtained by
-  //  ordinary lookup of the name operator() in the context of
-  //  (E).operator().
-  OverloadCandidateSet CandidateSet(LParenLoc,
-                                    OverloadCandidateSet::CSK_Operator);
-  DeclarationName OpName = Context.DeclarationNames.getCXXOperatorName(OO_Call);
-
-  if (RequireCompleteType(LParenLoc, Object.get()->getType(),
-                          diag::err_incomplete_object_call, Object.get()))
-    return true;
-
-  LookupResult R(*this, OpName, LParenLoc, LookupOrdinaryName);
-  LookupQualifiedName(R, Record->getDecl());
-  R.suppressDiagnostics();
-
-  for (LookupResult::iterator Oper = R.begin(), OperEnd = R.end();
-       Oper != OperEnd; ++Oper) {
-    AddMethodCandidate(Oper.getPair(), Object.get()->getType(),
-                       Object.get()->Classify(Context), Args, CandidateSet,
-                       /*SuppressUserConversions=*/false);
-  }
-
-  // C++ [over.call.object]p2:
-  //   In addition, for each (non-explicit in C++0x) conversion function
-  //   declared in T of the form
-  //
-  //        operator conversion-type-id () cv-qualifier;
-  //
-  //   where cv-qualifier is the same cv-qualification as, or a
-  //   greater cv-qualification than, cv, and where conversion-type-id
-  //   denotes the type "pointer to function of (P1,...,Pn) returning
-  //   R", or the type "reference to pointer to function of
-  //   (P1,...,Pn) returning R", or the type "reference to function
-  //   of (P1,...,Pn) returning R", a surrogate call function [...]
-  //   is also considered as a candidate function. Similarly,
-  //   surrogate call functions are added to the set of candidate
-  //   functions for each conversion function declared in an
-  //   accessible base class provided the function is not hidden
-  //   within T by another intervening declaration.
-  const auto &Conversions =
-      cast<CXXRecordDecl>(Record->getDecl())->getVisibleConversionFunctions();
-  for (auto I = Conversions.begin(), E = Conversions.end(); I != E; ++I) {
-    NamedDecl *D = *I;
-    CXXRecordDecl *ActingContext = cast<CXXRecordDecl>(D->getDeclContext());
-    if (isa<UsingShadowDecl>(D))
-      D = cast<UsingShadowDecl>(D)->getTargetDecl();
-
-    // Skip over templated conversion functions; they aren't
-    // surrogates.
-    if (isa<FunctionTemplateDecl>(D))
-      continue;
-
-    CXXConversionDecl *Conv = cast<CXXConversionDecl>(D);
-    if (!Conv->isExplicit()) {
-      // Strip the reference type (if any) and then the pointer type (if
-      // any) to get down to what might be a function type.
-      QualType ConvType = Conv->getConversionType().getNonReferenceType();
-      if (const PointerType *ConvPtrType = ConvType->getAs<PointerType>())
-        ConvType = ConvPtrType->getPointeeType();
-
-      if (const FunctionProtoType *Proto = ConvType->getAs<FunctionProtoType>())
-      {
-        AddSurrogateCandidate(Conv, I.getPair(), ActingContext, Proto,
-                              Object.get(), Args, CandidateSet);
-      }
-    }
-  }
-
-  bool HadMultipleCandidates = (CandidateSet.size() > 1);
-
-  // Perform overload resolution.
-  OverloadCandidateSet::iterator Best;
-  switch (CandidateSet.BestViableFunction(*this, Object.get()->getBeginLoc(),
-                                          Best)) {
-  case OR_Success:
-    // Overload resolution succeeded; we'll build the appropriate call
-    // below.
-    break;
-
-  case OR_No_Viable_Function:
-    if (CandidateSet.empty())
-      Diag(Object.get()->getBeginLoc(), diag::err_ovl_no_oper)
-          << Object.get()->getType() << /*call*/ 1
-          << Object.get()->getSourceRange();
-    else
-      Diag(Object.get()->getBeginLoc(), diag::err_ovl_no_viable_object_call)
-          << Object.get()->getType() << Object.get()->getSourceRange();
-    CandidateSet.NoteCandidates(*this, OCD_AllCandidates, Args);
-    break;
-
-  case OR_Ambiguous:
-    Diag(Object.get()->getBeginLoc(), diag::err_ovl_ambiguous_object_call)
-        << Object.get()->getType() << Object.get()->getSourceRange();
-    CandidateSet.NoteCandidates(*this, OCD_ViableCandidates, Args);
-    break;
-
-  case OR_Deleted:
-    Diag(Object.get()->getBeginLoc(), diag::err_ovl_deleted_object_call)
-        << Best->Function->isDeleted() << Object.get()->getType()
-        << getDeletedOrUnavailableSuffix(Best->Function)
-        << Object.get()->getSourceRange();
-    CandidateSet.NoteCandidates(*this, OCD_AllCandidates, Args);
-    break;
-  }
-
-  if (Best == CandidateSet.end())
-    return true;
-
-  UnbridgedCasts.restore();
-
-  if (Best->Function == nullptr) {
-    // Since there is no function declaration, this is one of the
-    // surrogate candidates. Dig out the conversion function.
-    CXXConversionDecl *Conv
-      = cast<CXXConversionDecl>(
-                         Best->Conversions[0].UserDefined.ConversionFunction);
-
-    CheckMemberOperatorAccess(LParenLoc, Object.get(), nullptr,
-                              Best->FoundDecl);
-    if (DiagnoseUseOfDecl(Best->FoundDecl, LParenLoc))
-      return ExprError();
-    assert(Conv == Best->FoundDecl.getDecl() &&
-             "Found Decl & conversion-to-functionptr should be same, right?!");
-    // We selected one of the surrogate functions that converts the
-    // object parameter to a function pointer. Perform the conversion
-    // on the object argument, then let ActOnCallExpr finish the job.
-
-    // Create an implicit member expr to refer to the conversion operator.
-    // and then call it.
-    ExprResult Call = BuildCXXMemberCallExpr(Object.get(), Best->FoundDecl,
-                                             Conv, HadMultipleCandidates);
-    if (Call.isInvalid())
-      return ExprError();
-    // Record usage of conversion in an implicit cast.
-    Call = ImplicitCastExpr::Create(Context, Call.get()->getType(),
-                                    CK_UserDefinedConversion, Call.get(),
-                                    nullptr, VK_RValue);
-
-    return ActOnCallExpr(S, Call.get(), LParenLoc, Args, RParenLoc);
-  }
-
-  CheckMemberOperatorAccess(LParenLoc, Object.get(), nullptr, Best->FoundDecl);
-
-  // We found an overloaded operator(). Build a CXXOperatorCallExpr
-  // that calls this method, using Object for the implicit object
-  // parameter and passing along the remaining arguments.
-  CXXMethodDecl *Method = cast<CXXMethodDecl>(Best->Function);
-
-  // An error diagnostic has already been printed when parsing the declaration.
-  if (Method->isInvalidDecl())
-    return ExprError();
-
-  const FunctionProtoType *Proto =
-    Method->getType()->getAs<FunctionProtoType>();
-
-  unsigned NumParams = Proto->getNumParams();
-
-  DeclarationNameInfo OpLocInfo(
-               Context.DeclarationNames.getCXXOperatorName(OO_Call), LParenLoc);
-  OpLocInfo.setCXXOperatorNameRange(SourceRange(LParenLoc, RParenLoc));
-  ExprResult NewFn = CreateFunctionRefExpr(*this, Method, Best->FoundDecl,
-                                           Obj, HadMultipleCandidates,
-                                           OpLocInfo.getLoc(),
-                                           OpLocInfo.getInfo());
-  if (NewFn.isInvalid())
-    return true;
-
-  // The number of argument slots to allocate in the call. If we have default
-  // arguments we need to allocate space for them as well. We additionally
-  // need one more slot for the object parameter.
-  unsigned NumArgsSlots = 1 + std::max<unsigned>(Args.size(), NumParams);
-
-  // Build the full argument list for the method call (the implicit object
-  // parameter is placed at the beginning of the list).
-  SmallVector<Expr *, 8> MethodArgs(NumArgsSlots);
-
-  bool IsError = false;
-
-  // Initialize the implicit object parameter.
-  ExprResult ObjRes =
-    PerformObjectArgumentInitialization(Object.get(), /*Qualifier=*/nullptr,
-                                        Best->FoundDecl, Method);
-  if (ObjRes.isInvalid())
-    IsError = true;
-  else
-    Object = ObjRes;
-  MethodArgs[0] = Object.get();
-
-  // Check the argument types.
-  for (unsigned i = 0; i != NumParams; i++) {
-    Expr *Arg;
-    if (i < Args.size()) {
-      Arg = Args[i];
-
-      // Pass the argument.
-
-      ExprResult InputInit
-        = PerformCopyInitialization(InitializedEntity::InitializeParameter(
-                                                    Context,
-                                                    Method->getParamDecl(i)),
-                                    SourceLocation(), Arg);
-
-      IsError |= InputInit.isInvalid();
-      Arg = InputInit.getAs<Expr>();
-    } else {
-      ExprResult DefArg
-        = BuildCXXDefaultArgExpr(LParenLoc, Method, Method->getParamDecl(i));
-      if (DefArg.isInvalid()) {
-        IsError = true;
-        break;
-      }
-
-      Arg = DefArg.getAs<Expr>();
-    }
-
-    MethodArgs[i + 1] = Arg;
-  }
-
-  // If this is a variadic call, handle args passed through "...".
-  if (Proto->isVariadic()) {
-    // Promote the arguments (C99 6.5.2.2p7).
-    for (unsigned i = NumParams, e = Args.size(); i < e; i++) {
-      ExprResult Arg = DefaultVariadicArgumentPromotion(Args[i], VariadicMethod,
-                                                        nullptr);
-      IsError |= Arg.isInvalid();
-      MethodArgs[i + 1] = Arg.get();
-    }
-  }
-
-  if (IsError)
-    return true;
-
-  DiagnoseSentinelCalls(Method, LParenLoc, Args);
-
-  // Once we've built TheCall, all of the expressions are properly owned.
-  QualType ResultTy = Method->getReturnType();
-  ExprValueKind VK = Expr::getValueKindForType(ResultTy);
-  ResultTy = ResultTy.getNonLValueExprType(Context);
-
-  CXXOperatorCallExpr *TheCall =
-      CXXOperatorCallExpr::Create(Context, OO_Call, NewFn.get(), MethodArgs,
-                                  ResultTy, VK, RParenLoc, FPOptions());
-
-  if (CheckCallReturnType(Method->getReturnType(), LParenLoc, TheCall, Method))
-    return true;
-
-  if (CheckFunctionCall(Method, TheCall, Proto))
-    return true;
-
-  return MaybeBindToTemporary(TheCall);
-}
-
-/// BuildOverloadedArrowExpr - Build a call to an overloaded @c operator->
-///  (if one exists), where @c Base is an expression of class type and
-/// @c Member is the name of the member we're trying to find.
-ExprResult
-Sema::BuildOverloadedArrowExpr(Scope *S, Expr *Base, SourceLocation OpLoc,
-                               bool *NoArrowOperatorFound) {
-  assert(Base->getType()->isRecordType() &&
-         "left-hand side must have class type");
-
-  if (checkPlaceholderForOverload(*this, Base))
-    return ExprError();
-
-  SourceLocation Loc = Base->getExprLoc();
-
-  // C++ [over.ref]p1:
-  //
-  //   [...] An expression x->m is interpreted as (x.operator->())->m
-  //   for a class object x of type T if T::operator->() exists and if
-  //   the operator is selected as the best match function by the
-  //   overload resolution mechanism (13.3).
-  DeclarationName OpName =
-    Context.DeclarationNames.getCXXOperatorName(OO_Arrow);
-  OverloadCandidateSet CandidateSet(Loc, OverloadCandidateSet::CSK_Operator);
-  const RecordType *BaseRecord = Base->getType()->getAs<RecordType>();
-
-  if (RequireCompleteType(Loc, Base->getType(),
-                          diag::err_typecheck_incomplete_tag, Base))
-    return ExprError();
-
-  LookupResult R(*this, OpName, OpLoc, LookupOrdinaryName);
-  LookupQualifiedName(R, BaseRecord->getDecl());
-  R.suppressDiagnostics();
-
-  for (LookupResult::iterator Oper = R.begin(), OperEnd = R.end();
-       Oper != OperEnd; ++Oper) {
-    AddMethodCandidate(Oper.getPair(), Base->getType(), Base->Classify(Context),
-                       None, CandidateSet, /*SuppressUserConversions=*/false);
-  }
-
-  bool HadMultipleCandidates = (CandidateSet.size() > 1);
-
-  // Perform overload resolution.
-  OverloadCandidateSet::iterator Best;
-  switch (CandidateSet.BestViableFunction(*this, OpLoc, Best)) {
-  case OR_Success:
-    // Overload resolution succeeded; we'll build the call below.
-    break;
-
-  case OR_No_Viable_Function:
-    if (CandidateSet.empty()) {
-      QualType BaseType = Base->getType();
-      if (NoArrowOperatorFound) {
-        // Report this specific error to the caller instead of emitting a
-        // diagnostic, as requested.
-        *NoArrowOperatorFound = true;
-        return ExprError();
-      }
-      Diag(OpLoc, diag::err_typecheck_member_reference_arrow)
-        << BaseType << Base->getSourceRange();
-      if (BaseType->isRecordType() && !BaseType->isPointerType()) {
-        Diag(OpLoc, diag::note_typecheck_member_reference_suggestion)
-          << FixItHint::CreateReplacement(OpLoc, ".");
-      }
-    } else
-      Diag(OpLoc, diag::err_ovl_no_viable_oper)
-        << "operator->" << Base->getSourceRange();
-    CandidateSet.NoteCandidates(*this, OCD_AllCandidates, Base);
-    return ExprError();
-
-  case OR_Ambiguous:
-    Diag(OpLoc,  diag::err_ovl_ambiguous_oper_unary)
-      << "->" << Base->getType() << Base->getSourceRange();
-    CandidateSet.NoteCandidates(*this, OCD_ViableCandidates, Base);
-    return ExprError();
-
-  case OR_Deleted:
-    Diag(OpLoc,  diag::err_ovl_deleted_oper)
-      << Best->Function->isDeleted()
-      << "->"
-      << getDeletedOrUnavailableSuffix(Best->Function)
-      << Base->getSourceRange();
-    CandidateSet.NoteCandidates(*this, OCD_AllCandidates, Base);
-    return ExprError();
-  }
-
-  CheckMemberOperatorAccess(OpLoc, Base, nullptr, Best->FoundDecl);
-
-  // Convert the object parameter.
-  CXXMethodDecl *Method = cast<CXXMethodDecl>(Best->Function);
-  ExprResult BaseResult =
-    PerformObjectArgumentInitialization(Base, /*Qualifier=*/nullptr,
-                                        Best->FoundDecl, Method);
-  if (BaseResult.isInvalid())
-    return ExprError();
-  Base = BaseResult.get();
-
-  // Build the operator call.
-  ExprResult FnExpr = CreateFunctionRefExpr(*this, Method, Best->FoundDecl,
-                                            Base, HadMultipleCandidates, OpLoc);
-  if (FnExpr.isInvalid())
-    return ExprError();
-
-  QualType ResultTy = Method->getReturnType();
-  ExprValueKind VK = Expr::getValueKindForType(ResultTy);
-  ResultTy = ResultTy.getNonLValueExprType(Context);
-  CXXOperatorCallExpr *TheCall = CXXOperatorCallExpr::Create(
-      Context, OO_Arrow, FnExpr.get(), Base, ResultTy, VK, OpLoc, FPOptions());
-
-  if (CheckCallReturnType(Method->getReturnType(), OpLoc, TheCall, Method))
-    return ExprError();
-
-  if (CheckFunctionCall(Method, TheCall,
-                        Method->getType()->castAs<FunctionProtoType>()))
-    return ExprError();
-
-  return MaybeBindToTemporary(TheCall);
-}
-
-/// BuildLiteralOperatorCall - Build a UserDefinedLiteral by creating a call to
-/// a literal operator described by the provided lookup results.
-ExprResult Sema::BuildLiteralOperatorCall(LookupResult &R,
-                                          DeclarationNameInfo &SuffixInfo,
-                                          ArrayRef<Expr*> Args,
-                                          SourceLocation LitEndLoc,
-                                       TemplateArgumentListInfo *TemplateArgs) {
-  SourceLocation UDSuffixLoc = SuffixInfo.getCXXLiteralOperatorNameLoc();
-
-  OverloadCandidateSet CandidateSet(UDSuffixLoc,
-                                    OverloadCandidateSet::CSK_Normal);
-  AddFunctionCandidates(R.asUnresolvedSet(), Args, CandidateSet, TemplateArgs,
-                        /*SuppressUserConversions=*/true);
-
-  bool HadMultipleCandidates = (CandidateSet.size() > 1);
-
-  // Perform overload resolution. This will usually be trivial, but might need
-  // to perform substitutions for a literal operator template.
-  OverloadCandidateSet::iterator Best;
-  switch (CandidateSet.BestViableFunction(*this, UDSuffixLoc, Best)) {
-  case OR_Success:
-  case OR_Deleted:
-    break;
-
-  case OR_No_Viable_Function:
-    Diag(UDSuffixLoc, diag::err_ovl_no_viable_function_in_call)
-      << R.getLookupName();
-    CandidateSet.NoteCandidates(*this, OCD_AllCandidates, Args);
-    return ExprError();
-
-  case OR_Ambiguous:
-    Diag(R.getNameLoc(), diag::err_ovl_ambiguous_call) << R.getLookupName();
-    CandidateSet.NoteCandidates(*this, OCD_ViableCandidates, Args);
-    return ExprError();
-  }
-
-  FunctionDecl *FD = Best->Function;
-  ExprResult Fn = CreateFunctionRefExpr(*this, FD, Best->FoundDecl,
-                                        nullptr, HadMultipleCandidates,
-                                        SuffixInfo.getLoc(),
-                                        SuffixInfo.getInfo());
-  if (Fn.isInvalid())
-    return true;
-
-  // Check the argument types. This should almost always be a no-op, except
-  // that array-to-pointer decay is applied to string literals.
-  Expr *ConvArgs[2];
-  for (unsigned ArgIdx = 0, N = Args.size(); ArgIdx != N; ++ArgIdx) {
-    ExprResult InputInit = PerformCopyInitialization(
-      InitializedEntity::InitializeParameter(Context, FD->getParamDecl(ArgIdx)),
-      SourceLocation(), Args[ArgIdx]);
-    if (InputInit.isInvalid())
-      return true;
-    ConvArgs[ArgIdx] = InputInit.get();
-  }
-
-  QualType ResultTy = FD->getReturnType();
-  ExprValueKind VK = Expr::getValueKindForType(ResultTy);
-  ResultTy = ResultTy.getNonLValueExprType(Context);
-
-  UserDefinedLiteral *UDL = UserDefinedLiteral::Create(
-      Context, Fn.get(), llvm::makeArrayRef(ConvArgs, Args.size()), ResultTy,
-      VK, LitEndLoc, UDSuffixLoc);
-
-  if (CheckCallReturnType(FD->getReturnType(), UDSuffixLoc, UDL, FD))
-    return ExprError();
-
-  if (CheckFunctionCall(FD, UDL, nullptr))
-    return ExprError();
-
-  return MaybeBindToTemporary(UDL);
-}
-
-/// Build a call to 'begin' or 'end' for a C++11 for-range statement. If the
-/// given LookupResult is non-empty, it is assumed to describe a member which
-/// will be invoked. Otherwise, the function will be found via argument
-/// dependent lookup.
-/// CallExpr is set to a valid expression and FRS_Success returned on success,
-/// otherwise CallExpr is set to ExprError() and some non-success value
-/// is returned.
-Sema::ForRangeStatus
-Sema::BuildForRangeBeginEndCall(SourceLocation Loc,
-                                SourceLocation RangeLoc,
-                                const DeclarationNameInfo &NameInfo,
-                                LookupResult &MemberLookup,
-                                OverloadCandidateSet *CandidateSet,
-                                Expr *Range, ExprResult *CallExpr) {
-  Scope *S = nullptr;
-
-  CandidateSet->clear(OverloadCandidateSet::CSK_Normal);
-  if (!MemberLookup.empty()) {
-    ExprResult MemberRef =
-        BuildMemberReferenceExpr(Range, Range->getType(), Loc,
-                                 /*IsPtr=*/false, CXXScopeSpec(),
-                                 /*TemplateKWLoc=*/SourceLocation(),
-                                 /*FirstQualifierInScope=*/nullptr,
-                                 MemberLookup,
-                                 /*TemplateArgs=*/nullptr, S);
-    if (MemberRef.isInvalid()) {
-      *CallExpr = ExprError();
-      return FRS_DiagnosticIssued;
-    }
-    *CallExpr = ActOnCallExpr(S, MemberRef.get(), Loc, None, Loc, nullptr);
-    if (CallExpr->isInvalid()) {
-      *CallExpr = ExprError();
-      return FRS_DiagnosticIssued;
-    }
-  } else {
-    UnresolvedSet<0> FoundNames;
-    UnresolvedLookupExpr *Fn =
-      UnresolvedLookupExpr::Create(Context, /*NamingClass=*/nullptr,
-                                   NestedNameSpecifierLoc(), NameInfo,
-                                   /*NeedsADL=*/true, /*Overloaded=*/false,
-                                   FoundNames.begin(), FoundNames.end());
-
-    bool CandidateSetError = buildOverloadedCallSet(S, Fn, Fn, Range, Loc,
-                                                    CandidateSet, CallExpr);
-    if (CandidateSet->empty() || CandidateSetError) {
-      *CallExpr = ExprError();
-      return FRS_NoViableFunction;
-    }
-    OverloadCandidateSet::iterator Best;
-    OverloadingResult OverloadResult =
-        CandidateSet->BestViableFunction(*this, Fn->getBeginLoc(), Best);
-
-    if (OverloadResult == OR_No_Viable_Function) {
-      *CallExpr = ExprError();
-      return FRS_NoViableFunction;
-    }
-    *CallExpr = FinishOverloadedCallExpr(*this, S, Fn, Fn, Loc, Range,
-                                         Loc, nullptr, CandidateSet, &Best,
-                                         OverloadResult,
-                                         /*AllowTypoCorrection=*/false);
-    if (CallExpr->isInvalid() || OverloadResult != OR_Success) {
-      *CallExpr = ExprError();
-      return FRS_DiagnosticIssued;
-    }
-  }
-  return FRS_Success;
-}
-
-
-/// FixOverloadedFunctionReference - E is an expression that refers to
-/// a C++ overloaded function (possibly with some parentheses and
-/// perhaps a '&' around it). We have resolved the overloaded function
-/// to the function declaration Fn, so patch up the expression E to
-/// refer (possibly indirectly) to Fn. Returns the new expr.
-Expr *Sema::FixOverloadedFunctionReference(Expr *E, DeclAccessPair Found,
-                                           FunctionDecl *Fn) {
-  if (ParenExpr *PE = dyn_cast<ParenExpr>(E)) {
-    Expr *SubExpr = FixOverloadedFunctionReference(PE->getSubExpr(),
-                                                   Found, Fn);
-    if (SubExpr == PE->getSubExpr())
-      return PE;
-
-    return new (Context) ParenExpr(PE->getLParen(), PE->getRParen(), SubExpr);
-  }
-
-  if (ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(E)) {
-    Expr *SubExpr = FixOverloadedFunctionReference(ICE->getSubExpr(),
-                                                   Found, Fn);
-    assert(Context.hasSameType(ICE->getSubExpr()->getType(),
-                               SubExpr->getType()) &&
-           "Implicit cast type cannot be determined from overload");
-    assert(ICE->path_empty() && "fixing up hierarchy conversion?");
-    if (SubExpr == ICE->getSubExpr())
-      return ICE;
-
-    return ImplicitCastExpr::Create(Context, ICE->getType(),
-                                    ICE->getCastKind(),
-                                    SubExpr, nullptr,
-                                    ICE->getValueKind());
-  }
-
-  if (auto *GSE = dyn_cast<GenericSelectionExpr>(E)) {
-    if (!GSE->isResultDependent()) {
-      Expr *SubExpr =
-          FixOverloadedFunctionReference(GSE->getResultExpr(), Found, Fn);
-      if (SubExpr == GSE->getResultExpr())
-        return GSE;
-
-      // Replace the resulting type information before rebuilding the generic
-      // selection expression.
-      ArrayRef<Expr *> A = GSE->getAssocExprs();
-      SmallVector<Expr *, 4> AssocExprs(A.begin(), A.end());
-      unsigned ResultIdx = GSE->getResultIndex();
-      AssocExprs[ResultIdx] = SubExpr;
-
-      return new (Context) GenericSelectionExpr(
-          Context, GSE->getGenericLoc(), GSE->getControllingExpr(),
-          GSE->getAssocTypeSourceInfos(), AssocExprs, GSE->getDefaultLoc(),
-          GSE->getRParenLoc(), GSE->containsUnexpandedParameterPack(),
-          ResultIdx);
-    }
-    // Rather than fall through to the unreachable, return the original generic
-    // selection expression.
-    return GSE;
-  }
-
-  if (UnaryOperator *UnOp = dyn_cast<UnaryOperator>(E)) {
-    assert(UnOp->getOpcode() == UO_AddrOf &&
-           "Can only take the address of an overloaded function");
-    if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(Fn)) {
-      if (Method->isStatic()) {
-        // Do nothing: static member functions aren't any different
-        // from non-member functions.
-      } else {
-        // Fix the subexpression, which really has to be an
-        // UnresolvedLookupExpr holding an overloaded member function
-        // or template.
-        Expr *SubExpr = FixOverloadedFunctionReference(UnOp->getSubExpr(),
-                                                       Found, Fn);
-        if (SubExpr == UnOp->getSubExpr())
-          return UnOp;
-
-        assert(isa<DeclRefExpr>(SubExpr)
-               && "fixed to something other than a decl ref");
-        assert(cast<DeclRefExpr>(SubExpr)->getQualifier()
-               && "fixed to a member ref with no nested name qualifier");
-
-        // We have taken the address of a pointer to member
-        // function. Perform the computation here so that we get the
-        // appropriate pointer to member type.
-        QualType ClassType
-          = Context.getTypeDeclType(cast<RecordDecl>(Method->getDeclContext()));
-        QualType MemPtrType
-          = Context.getMemberPointerType(Fn->getType(), ClassType.getTypePtr());
-        // Under the MS ABI, lock down the inheritance model now.
-        if (Context.getTargetInfo().getCXXABI().isMicrosoft())
-          (void)isCompleteType(UnOp->getOperatorLoc(), MemPtrType);
-
-        return new (Context) UnaryOperator(SubExpr, UO_AddrOf, MemPtrType,
-                                           VK_RValue, OK_Ordinary,
-                                           UnOp->getOperatorLoc(), false);
-      }
-    }
-    Expr *SubExpr = FixOverloadedFunctionReference(UnOp->getSubExpr(),
-                                                   Found, Fn);
-    if (SubExpr == UnOp->getSubExpr())
-      return UnOp;
-
-    return new (Context) UnaryOperator(SubExpr, UO_AddrOf,
-                                     Context.getPointerType(SubExpr->getType()),
-                                       VK_RValue, OK_Ordinary,
-                                       UnOp->getOperatorLoc(), false);
-  }
-
-  // C++ [except.spec]p17:
-  //   An exception-specification is considered to be needed when:
-  //   - in an expression the function is the unique lookup result or the
-  //     selected member of a set of overloaded functions
-  if (auto *FPT = Fn->getType()->getAs<FunctionProtoType>())
-    ResolveExceptionSpec(E->getExprLoc(), FPT);
-
-  if (UnresolvedLookupExpr *ULE = dyn_cast<UnresolvedLookupExpr>(E)) {
-    // FIXME: avoid copy.
-    TemplateArgumentListInfo TemplateArgsBuffer, *TemplateArgs = nullptr;
-    if (ULE->hasExplicitTemplateArgs()) {
-      ULE->copyTemplateArgumentsInto(TemplateArgsBuffer);
-      TemplateArgs = &TemplateArgsBuffer;
-    }
-
-    DeclRefExpr *DRE = DeclRefExpr::Create(Context,
-                                           ULE->getQualifierLoc(),
-                                           ULE->getTemplateKeywordLoc(),
-                                           Fn,
-                                           /*enclosing*/ false, // FIXME?
-                                           ULE->getNameLoc(),
-                                           Fn->getType(),
-                                           VK_LValue,
-                                           Found.getDecl(),
-                                           TemplateArgs);
-    MarkDeclRefReferenced(DRE);
-    DRE->setHadMultipleCandidates(ULE->getNumDecls() > 1);
-    return DRE;
-  }
-
-  if (UnresolvedMemberExpr *MemExpr = dyn_cast<UnresolvedMemberExpr>(E)) {
-    // FIXME: avoid copy.
-    TemplateArgumentListInfo TemplateArgsBuffer, *TemplateArgs = nullptr;
-    if (MemExpr->hasExplicitTemplateArgs()) {
-      MemExpr->copyTemplateArgumentsInto(TemplateArgsBuffer);
-      TemplateArgs = &TemplateArgsBuffer;
-    }
-
-    Expr *Base;
-
-    // If we're filling in a static method where we used to have an
-    // implicit member access, rewrite to a simple decl ref.
-    if (MemExpr->isImplicitAccess()) {
-      if (cast<CXXMethodDecl>(Fn)->isStatic()) {
-        DeclRefExpr *DRE = DeclRefExpr::Create(Context,
-                                               MemExpr->getQualifierLoc(),
-                                               MemExpr->getTemplateKeywordLoc(),
-                                               Fn,
-                                               /*enclosing*/ false,
-                                               MemExpr->getMemberLoc(),
-                                               Fn->getType(),
-                                               VK_LValue,
-                                               Found.getDecl(),
-                                               TemplateArgs);
-        MarkDeclRefReferenced(DRE);
-        DRE->setHadMultipleCandidates(MemExpr->getNumDecls() > 1);
-        return DRE;
-      } else {
-        SourceLocation Loc = MemExpr->getMemberLoc();
-        if (MemExpr->getQualifier())
-          Loc = MemExpr->getQualifierLoc().getBeginLoc();
-        CheckCXXThisCapture(Loc);
-        Base = new (Context) CXXThisExpr(Loc,
-                                         MemExpr->getBaseType(),
-                                         /*isImplicit=*/true);
-      }
-    } else
-      Base = MemExpr->getBase();
-
-    ExprValueKind valueKind;
-    QualType type;
-    if (cast<CXXMethodDecl>(Fn)->isStatic()) {
-      valueKind = VK_LValue;
-      type = Fn->getType();
-    } else {
-      valueKind = VK_RValue;
-      type = Context.BoundMemberTy;
-    }
-
-    MemberExpr *ME = MemberExpr::Create(
-        Context, Base, MemExpr->isArrow(), MemExpr->getOperatorLoc(),
-        MemExpr->getQualifierLoc(), MemExpr->getTemplateKeywordLoc(), Fn, Found,
-        MemExpr->getMemberNameInfo(), TemplateArgs, type, valueKind,
-        OK_Ordinary);
-    ME->setHadMultipleCandidates(true);
-    MarkMemberReferenced(ME);
-    return ME;
-  }
-
-  llvm_unreachable("Invalid reference to overloaded function");
-}
-
-ExprResult Sema::FixOverloadedFunctionReference(ExprResult E,
-                                                DeclAccessPair Found,
-                                                FunctionDecl *Fn) {
-  return FixOverloadedFunctionReference(E.get(), Found, Fn);
-}