Remove LLVM 8.0.1 files.

1 files changed, 0 insertions, 5213 deletions

diff --git a/gnu/llvm/tools/clang/lib/Sema/SemaLookup.cpp b/gnu/llvm/tools/clang/lib/Sema/SemaLookup.cpp
deleted file mode 100644
index effccc2f3d3..00000000000
--- a/gnu/llvm/tools/clang/lib/Sema/SemaLookup.cpp
+++ /dev/null
@@ -1,5213 +0,0 @@
-//===--------------------- SemaLookup.cpp - Name Lookup  ------------------===//
-//
-//                     The LLVM Compiler Infrastructure
-//
-// This file is distributed under the University of Illinois Open Source
-// License. See LICENSE.TXT for details.
-//
-//===----------------------------------------------------------------------===//
-//
-//  This file implements name lookup for C, C++, Objective-C, and
-//  Objective-C++.
-//
-//===----------------------------------------------------------------------===//
-
-#include "clang/AST/ASTContext.h"
-#include "clang/AST/CXXInheritance.h"
-#include "clang/AST/Decl.h"
-#include "clang/AST/DeclCXX.h"
-#include "clang/AST/DeclLookups.h"
-#include "clang/AST/DeclObjC.h"
-#include "clang/AST/DeclTemplate.h"
-#include "clang/AST/Expr.h"
-#include "clang/AST/ExprCXX.h"
-#include "clang/Basic/Builtins.h"
-#include "clang/Basic/LangOptions.h"
-#include "clang/Lex/HeaderSearch.h"
-#include "clang/Lex/ModuleLoader.h"
-#include "clang/Lex/Preprocessor.h"
-#include "clang/Sema/DeclSpec.h"
-#include "clang/Sema/Lookup.h"
-#include "clang/Sema/Overload.h"
-#include "clang/Sema/Scope.h"
-#include "clang/Sema/ScopeInfo.h"
-#include "clang/Sema/Sema.h"
-#include "clang/Sema/SemaInternal.h"
-#include "clang/Sema/TemplateDeduction.h"
-#include "clang/Sema/TypoCorrection.h"
-#include "llvm/ADT/STLExtras.h"
-#include "llvm/ADT/SmallPtrSet.h"
-#include "llvm/ADT/TinyPtrVector.h"
-#include "llvm/ADT/edit_distance.h"
-#include "llvm/Support/ErrorHandling.h"
-#include <algorithm>
-#include <iterator>
-#include <list>
-#include <set>
-#include <utility>
-#include <vector>
-
-using namespace clang;
-using namespace sema;
-
-namespace {
-  class UnqualUsingEntry {
-    const DeclContext *Nominated;
-    const DeclContext *CommonAncestor;
-
-  public:
-    UnqualUsingEntry(const DeclContext *Nominated,
-                     const DeclContext *CommonAncestor)
-      : Nominated(Nominated), CommonAncestor(CommonAncestor) {
-    }
-
-    const DeclContext *getCommonAncestor() const {
-      return CommonAncestor;
-    }
-
-    const DeclContext *getNominatedNamespace() const {
-      return Nominated;
-    }
-
-    // Sort by the pointer value of the common ancestor.
-    struct Comparator {
-      bool operator()(const UnqualUsingEntry &L, const UnqualUsingEntry &R) {
-        return L.getCommonAncestor() < R.getCommonAncestor();
-      }
-
-      bool operator()(const UnqualUsingEntry &E, const DeclContext *DC) {
-        return E.getCommonAncestor() < DC;
-      }
-
-      bool operator()(const DeclContext *DC, const UnqualUsingEntry &E) {
-        return DC < E.getCommonAncestor();
-      }
-    };
-  };
-
-  /// A collection of using directives, as used by C++ unqualified
-  /// lookup.
-  class UnqualUsingDirectiveSet {
-    Sema &SemaRef;
-
-    typedef SmallVector<UnqualUsingEntry, 8> ListTy;
-
-    ListTy list;
-    llvm::SmallPtrSet<DeclContext*, 8> visited;
-
-  public:
-    UnqualUsingDirectiveSet(Sema &SemaRef) : SemaRef(SemaRef) {}
-
-    void visitScopeChain(Scope *S, Scope *InnermostFileScope) {
-      // C++ [namespace.udir]p1:
-      //   During unqualified name lookup, the names appear as if they
-      //   were declared in the nearest enclosing namespace which contains
-      //   both the using-directive and the nominated namespace.
-      DeclContext *InnermostFileDC = InnermostFileScope->getEntity();
-      assert(InnermostFileDC && InnermostFileDC->isFileContext());
-
-      for (; S; S = S->getParent()) {
-        // C++ [namespace.udir]p1:
-        //   A using-directive shall not appear in class scope, but may
-        //   appear in namespace scope or in block scope.
-        DeclContext *Ctx = S->getEntity();
-        if (Ctx && Ctx->isFileContext()) {
-          visit(Ctx, Ctx);
-        } else if (!Ctx || Ctx->isFunctionOrMethod()) {
-          for (auto *I : S->using_directives())
-            if (SemaRef.isVisible(I))
-              visit(I, InnermostFileDC);
-        }
-      }
-    }
-
-    // Visits a context and collect all of its using directives
-    // recursively.  Treats all using directives as if they were
-    // declared in the context.
-    //
-    // A given context is only every visited once, so it is important
-    // that contexts be visited from the inside out in order to get
-    // the effective DCs right.
-    void visit(DeclContext *DC, DeclContext *EffectiveDC) {
-      if (!visited.insert(DC).second)
-        return;
-
-      addUsingDirectives(DC, EffectiveDC);
-    }
-
-    // Visits a using directive and collects all of its using
-    // directives recursively.  Treats all using directives as if they
-    // were declared in the effective DC.
-    void visit(UsingDirectiveDecl *UD, DeclContext *EffectiveDC) {
-      DeclContext *NS = UD->getNominatedNamespace();
-      if (!visited.insert(NS).second)
-        return;
-
-      addUsingDirective(UD, EffectiveDC);
-      addUsingDirectives(NS, EffectiveDC);
-    }
-
-    // Adds all the using directives in a context (and those nominated
-    // by its using directives, transitively) as if they appeared in
-    // the given effective context.
-    void addUsingDirectives(DeclContext *DC, DeclContext *EffectiveDC) {
-      SmallVector<DeclContext*, 4> queue;
-      while (true) {
-        for (auto UD : DC->using_directives()) {
-          DeclContext *NS = UD->getNominatedNamespace();
-          if (SemaRef.isVisible(UD) && visited.insert(NS).second) {
-            addUsingDirective(UD, EffectiveDC);
-            queue.push_back(NS);
-          }
-        }
-
-        if (queue.empty())
-          return;
-
-        DC = queue.pop_back_val();
-      }
-    }
-
-    // Add a using directive as if it had been declared in the given
-    // context.  This helps implement C++ [namespace.udir]p3:
-    //   The using-directive is transitive: if a scope contains a
-    //   using-directive that nominates a second namespace that itself
-    //   contains using-directives, the effect is as if the
-    //   using-directives from the second namespace also appeared in
-    //   the first.
-    void addUsingDirective(UsingDirectiveDecl *UD, DeclContext *EffectiveDC) {
-      // Find the common ancestor between the effective context and
-      // the nominated namespace.
-      DeclContext *Common = UD->getNominatedNamespace();
-      while (!Common->Encloses(EffectiveDC))
-        Common = Common->getParent();
-      Common = Common->getPrimaryContext();
-
-      list.push_back(UnqualUsingEntry(UD->getNominatedNamespace(), Common));
-    }
-
-    void done() { llvm::sort(list, UnqualUsingEntry::Comparator()); }
-
-    typedef ListTy::const_iterator const_iterator;
-
-    const_iterator begin() const { return list.begin(); }
-    const_iterator end() const { return list.end(); }
-
-    llvm::iterator_range<const_iterator>
-    getNamespacesFor(DeclContext *DC) const {
-      return llvm::make_range(std::equal_range(begin(), end(),
-                                               DC->getPrimaryContext(),
-                                               UnqualUsingEntry::Comparator()));
-    }
-  };
-} // end anonymous namespace
-
-// Retrieve the set of identifier namespaces that correspond to a
-// specific kind of name lookup.
-static inline unsigned getIDNS(Sema::LookupNameKind NameKind,
-                               bool CPlusPlus,
-                               bool Redeclaration) {
-  unsigned IDNS = 0;
-  switch (NameKind) {
-  case Sema::LookupObjCImplicitSelfParam:
-  case Sema::LookupOrdinaryName:
-  case Sema::LookupRedeclarationWithLinkage:
-  case Sema::LookupLocalFriendName:
-    IDNS = Decl::IDNS_Ordinary;
-    if (CPlusPlus) {
-      IDNS |= Decl::IDNS_Tag | Decl::IDNS_Member | Decl::IDNS_Namespace;
-      if (Redeclaration)
-        IDNS |= Decl::IDNS_TagFriend | Decl::IDNS_OrdinaryFriend;
-    }
-    if (Redeclaration)
-      IDNS |= Decl::IDNS_LocalExtern;
-    break;
-
-  case Sema::LookupOperatorName:
-    // Operator lookup is its own crazy thing;  it is not the same
-    // as (e.g.) looking up an operator name for redeclaration.
-    assert(!Redeclaration && "cannot do redeclaration operator lookup");
-    IDNS = Decl::IDNS_NonMemberOperator;
-    break;
-
-  case Sema::LookupTagName:
-    if (CPlusPlus) {
-      IDNS = Decl::IDNS_Type;
-
-      // When looking for a redeclaration of a tag name, we add:
-      // 1) TagFriend to find undeclared friend decls
-      // 2) Namespace because they can't "overload" with tag decls.
-      // 3) Tag because it includes class templates, which can't
-      //    "overload" with tag decls.
-      if (Redeclaration)
-        IDNS |= Decl::IDNS_Tag | Decl::IDNS_TagFriend | Decl::IDNS_Namespace;
-    } else {
-      IDNS = Decl::IDNS_Tag;
-    }
-    break;
-
-  case Sema::LookupLabel:
-    IDNS = Decl::IDNS_Label;
-    break;
-
-  case Sema::LookupMemberName:
-    IDNS = Decl::IDNS_Member;
-    if (CPlusPlus)
-      IDNS |= Decl::IDNS_Tag | Decl::IDNS_Ordinary;
-    break;
-
-  case Sema::LookupNestedNameSpecifierName:
-    IDNS = Decl::IDNS_Type | Decl::IDNS_Namespace;
-    break;
-
-  case Sema::LookupNamespaceName:
-    IDNS = Decl::IDNS_Namespace;
-    break;
-
-  case Sema::LookupUsingDeclName:
-    assert(Redeclaration && "should only be used for redecl lookup");
-    IDNS = Decl::IDNS_Ordinary | Decl::IDNS_Tag | Decl::IDNS_Member |
-           Decl::IDNS_Using | Decl::IDNS_TagFriend | Decl::IDNS_OrdinaryFriend |
-           Decl::IDNS_LocalExtern;
-    break;
-
-  case Sema::LookupObjCProtocolName:
-    IDNS = Decl::IDNS_ObjCProtocol;
-    break;
-
-  case Sema::LookupOMPReductionName:
-    IDNS = Decl::IDNS_OMPReduction;
-    break;
-
-  case Sema::LookupAnyName:
-    IDNS = Decl::IDNS_Ordinary | Decl::IDNS_Tag | Decl::IDNS_Member
-      | Decl::IDNS_Using | Decl::IDNS_Namespace | Decl::IDNS_ObjCProtocol
-      | Decl::IDNS_Type;
-    break;
-  }
-  return IDNS;
-}
-
-void LookupResult::configure() {
-  IDNS = getIDNS(LookupKind, getSema().getLangOpts().CPlusPlus,
-                 isForRedeclaration());
-
-  // If we're looking for one of the allocation or deallocation
-  // operators, make sure that the implicitly-declared new and delete
-  // operators can be found.
-  switch (NameInfo.getName().getCXXOverloadedOperator()) {
-  case OO_New:
-  case OO_Delete:
-  case OO_Array_New:
-  case OO_Array_Delete:
-    getSema().DeclareGlobalNewDelete();
-    break;
-
-  default:
-    break;
-  }
-
-  // Compiler builtins are always visible, regardless of where they end
-  // up being declared.
-  if (IdentifierInfo *Id = NameInfo.getName().getAsIdentifierInfo()) {
-    if (unsigned BuiltinID = Id->getBuiltinID()) {
-      if (!getSema().Context.BuiltinInfo.isPredefinedLibFunction(BuiltinID))
-        AllowHidden = true;
-    }
-  }
-}
-
-bool LookupResult::sanity() const {
-  // This function is never called by NDEBUG builds.
-  assert(ResultKind != NotFound || Decls.size() == 0);
-  assert(ResultKind != Found || Decls.size() == 1);
-  assert(ResultKind != FoundOverloaded || Decls.size() > 1 ||
-         (Decls.size() == 1 &&
-          isa<FunctionTemplateDecl>((*begin())->getUnderlyingDecl())));
-  assert(ResultKind != FoundUnresolvedValue || sanityCheckUnresolved());
-  assert(ResultKind != Ambiguous || Decls.size() > 1 ||
-         (Decls.size() == 1 && (Ambiguity == AmbiguousBaseSubobjects ||
-                                Ambiguity == AmbiguousBaseSubobjectTypes)));
-  assert((Paths != nullptr) == (ResultKind == Ambiguous &&
-                                (Ambiguity == AmbiguousBaseSubobjectTypes ||
-                                 Ambiguity == AmbiguousBaseSubobjects)));
-  return true;
-}
-
-// Necessary because CXXBasePaths is not complete in Sema.h
-void LookupResult::deletePaths(CXXBasePaths *Paths) {
-  delete Paths;
-}
-
-/// Get a representative context for a declaration such that two declarations
-/// will have the same context if they were found within the same scope.
-static DeclContext *getContextForScopeMatching(Decl *D) {
-  // For function-local declarations, use that function as the context. This
-  // doesn't account for scopes within the function; the caller must deal with
-  // those.
-  DeclContext *DC = D->getLexicalDeclContext();
-  if (DC->isFunctionOrMethod())
-    return DC;
-
-  // Otherwise, look at the semantic context of the declaration. The
-  // declaration must have been found there.
-  return D->getDeclContext()->getRedeclContext();
-}
-
-/// Determine whether \p D is a better lookup result than \p Existing,
-/// given that they declare the same entity.
-static bool isPreferredLookupResult(Sema &S, Sema::LookupNameKind Kind,
-                                    NamedDecl *D, NamedDecl *Existing) {
-  // When looking up redeclarations of a using declaration, prefer a using
-  // shadow declaration over any other declaration of the same entity.
-  if (Kind == Sema::LookupUsingDeclName && isa<UsingShadowDecl>(D) &&
-      !isa<UsingShadowDecl>(Existing))
-    return true;
-
-  auto *DUnderlying = D->getUnderlyingDecl();
-  auto *EUnderlying = Existing->getUnderlyingDecl();
-
-  // If they have different underlying declarations, prefer a typedef over the
-  // original type (this happens when two type declarations denote the same
-  // type), per a generous reading of C++ [dcl.typedef]p3 and p4. The typedef
-  // might carry additional semantic information, such as an alignment override.
-  // However, per C++ [dcl.typedef]p5, when looking up a tag name, prefer a tag
-  // declaration over a typedef.
-  if (DUnderlying->getCanonicalDecl() != EUnderlying->getCanonicalDecl()) {
-    assert(isa<TypeDecl>(DUnderlying) && isa<TypeDecl>(EUnderlying));
-    bool HaveTag = isa<TagDecl>(EUnderlying);
-    bool WantTag = Kind == Sema::LookupTagName;
-    return HaveTag != WantTag;
-  }
-
-  // Pick the function with more default arguments.
-  // FIXME: In the presence of ambiguous default arguments, we should keep both,
-  //        so we can diagnose the ambiguity if the default argument is needed.
-  //        See C++ [over.match.best]p3.
-  if (auto *DFD = dyn_cast<FunctionDecl>(DUnderlying)) {
-    auto *EFD = cast<FunctionDecl>(EUnderlying);
-    unsigned DMin = DFD->getMinRequiredArguments();
-    unsigned EMin = EFD->getMinRequiredArguments();
-    // If D has more default arguments, it is preferred.
-    if (DMin != EMin)
-      return DMin < EMin;
-    // FIXME: When we track visibility for default function arguments, check
-    // that we pick the declaration with more visible default arguments.
-  }
-
-  // Pick the template with more default template arguments.
-  if (auto *DTD = dyn_cast<TemplateDecl>(DUnderlying)) {
-    auto *ETD = cast<TemplateDecl>(EUnderlying);
-    unsigned DMin = DTD->getTemplateParameters()->getMinRequiredArguments();
-    unsigned EMin = ETD->getTemplateParameters()->getMinRequiredArguments();
-    // If D has more default arguments, it is preferred. Note that default
-    // arguments (and their visibility) is monotonically increasing across the
-    // redeclaration chain, so this is a quick proxy for "is more recent".
-    if (DMin != EMin)
-      return DMin < EMin;
-    // If D has more *visible* default arguments, it is preferred. Note, an
-    // earlier default argument being visible does not imply that a later
-    // default argument is visible, so we can't just check the first one.
-    for (unsigned I = DMin, N = DTD->getTemplateParameters()->size();
-        I != N; ++I) {
-      if (!S.hasVisibleDefaultArgument(
-              ETD->getTemplateParameters()->getParam(I)) &&
-          S.hasVisibleDefaultArgument(
-              DTD->getTemplateParameters()->getParam(I)))
-        return true;
-    }
-  }
-
-  // VarDecl can have incomplete array types, prefer the one with more complete
-  // array type.
-  if (VarDecl *DVD = dyn_cast<VarDecl>(DUnderlying)) {
-    VarDecl *EVD = cast<VarDecl>(EUnderlying);
-    if (EVD->getType()->isIncompleteType() &&
-        !DVD->getType()->isIncompleteType()) {
-      // Prefer the decl with a more complete type if visible.
-      return S.isVisible(DVD);
-    }
-    return false; // Avoid picking up a newer decl, just because it was newer.
-  }
-
-  // For most kinds of declaration, it doesn't really matter which one we pick.
-  if (!isa<FunctionDecl>(DUnderlying) && !isa<VarDecl>(DUnderlying)) {
-    // If the existing declaration is hidden, prefer the new one. Otherwise,
-    // keep what we've got.
-    return !S.isVisible(Existing);
-  }
-
-  // Pick the newer declaration; it might have a more precise type.
-  for (Decl *Prev = DUnderlying->getPreviousDecl(); Prev;
-       Prev = Prev->getPreviousDecl())
-    if (Prev == EUnderlying)
-      return true;
-  return false;
-}
-
-/// Determine whether \p D can hide a tag declaration.
-static bool canHideTag(NamedDecl *D) {
-  // C++ [basic.scope.declarative]p4:
-  //   Given a set of declarations in a single declarative region [...]
-  //   exactly one declaration shall declare a class name or enumeration name
-  //   that is not a typedef name and the other declarations shall all refer to
-  //   the same variable, non-static data member, or enumerator, or all refer
-  //   to functions and function templates; in this case the class name or
-  //   enumeration name is hidden.
-  // C++ [basic.scope.hiding]p2:
-  //   A class name or enumeration name can be hidden by the name of a
-  //   variable, data member, function, or enumerator declared in the same
-  //   scope.
-  // An UnresolvedUsingValueDecl always instantiates to one of these.
-  D = D->getUnderlyingDecl();
-  return isa<VarDecl>(D) || isa<EnumConstantDecl>(D) || isa<FunctionDecl>(D) ||
-         isa<FunctionTemplateDecl>(D) || isa<FieldDecl>(D) ||
-         isa<UnresolvedUsingValueDecl>(D);
-}
-
-/// Resolves the result kind of this lookup.
-void LookupResult::resolveKind() {
-  unsigned N = Decls.size();
-
-  // Fast case: no possible ambiguity.
-  if (N == 0) {
-    assert(ResultKind == NotFound ||
-           ResultKind == NotFoundInCurrentInstantiation);
-    return;
-  }
-
-  // If there's a single decl, we need to examine it to decide what
-  // kind of lookup this is.
-  if (N == 1) {
-    NamedDecl *D = (*Decls.begin())->getUnderlyingDecl();
-    if (isa<FunctionTemplateDecl>(D))
-      ResultKind = FoundOverloaded;
-    else if (isa<UnresolvedUsingValueDecl>(D))
-      ResultKind = FoundUnresolvedValue;
-    return;
-  }
-
-  // Don't do any extra resolution if we've already resolved as ambiguous.
-  if (ResultKind == Ambiguous) return;
-
-  llvm::SmallDenseMap<NamedDecl*, unsigned, 16> Unique;
-  llvm::SmallDenseMap<QualType, unsigned, 16> UniqueTypes;
-
-  bool Ambiguous = false;
-  bool HasTag = false, HasFunction = false;
-  bool HasFunctionTemplate = false, HasUnresolved = false;
-  NamedDecl *HasNonFunction = nullptr;
-
-  llvm::SmallVector<NamedDecl*, 4> EquivalentNonFunctions;
-
-  unsigned UniqueTagIndex = 0;
-
-  unsigned I = 0;
-  while (I < N) {
-    NamedDecl *D = Decls[I]->getUnderlyingDecl();
-    D = cast<NamedDecl>(D->getCanonicalDecl());
-
-    // Ignore an invalid declaration unless it's the only one left.
-    if (D->isInvalidDecl() && !(I == 0 && N == 1)) {
-      Decls[I] = Decls[--N];
-      continue;
-    }
-
-    llvm::Optional<unsigned> ExistingI;
-
-    // Redeclarations of types via typedef can occur both within a scope
-    // and, through using declarations and directives, across scopes. There is
-    // no ambiguity if they all refer to the same type, so unique based on the
-    // canonical type.
-    if (TypeDecl *TD = dyn_cast<TypeDecl>(D)) {
-      QualType T = getSema().Context.getTypeDeclType(TD);
-      auto UniqueResult = UniqueTypes.insert(
-          std::make_pair(getSema().Context.getCanonicalType(T), I));
-      if (!UniqueResult.second) {
-        // The type is not unique.
-        ExistingI = UniqueResult.first->second;
-      }
-    }
-
-    // For non-type declarations, check for a prior lookup result naming this
-    // canonical declaration.
-    if (!ExistingI) {
-      auto UniqueResult = Unique.insert(std::make_pair(D, I));
-      if (!UniqueResult.second) {
-        // We've seen this entity before.
-        ExistingI = UniqueResult.first->second;
-      }
-    }
-
-    if (ExistingI) {
-      // This is not a unique lookup result. Pick one of the results and
-      // discard the other.
-      if (isPreferredLookupResult(getSema(), getLookupKind(), Decls[I],
-                                  Decls[*ExistingI]))
-        Decls[*ExistingI] = Decls[I];
-      Decls[I] = Decls[--N];
-      continue;
-    }
-
-    // Otherwise, do some decl type analysis and then continue.
-
-    if (isa<UnresolvedUsingValueDecl>(D)) {
-      HasUnresolved = true;
-    } else if (isa<TagDecl>(D)) {
-      if (HasTag)
-        Ambiguous = true;
-      UniqueTagIndex = I;
-      HasTag = true;
-    } else if (isa<FunctionTemplateDecl>(D)) {
-      HasFunction = true;
-      HasFunctionTemplate = true;
-    } else if (isa<FunctionDecl>(D)) {
-      HasFunction = true;
-    } else {
-      if (HasNonFunction) {
-        // If we're about to create an ambiguity between two declarations that
-        // are equivalent, but one is an internal linkage declaration from one
-        // module and the other is an internal linkage declaration from another
-        // module, just skip it.
-        if (getSema().isEquivalentInternalLinkageDeclaration(HasNonFunction,
-                                                             D)) {
-          EquivalentNonFunctions.push_back(D);
-          Decls[I] = Decls[--N];
-          continue;
-        }
-
-        Ambiguous = true;
-      }
-      HasNonFunction = D;
-    }
-    I++;
-  }
-
-  // C++ [basic.scope.hiding]p2:
-  //   A class name or enumeration name can be hidden by the name of
-  //   an object, function, or enumerator declared in the same
-  //   scope. If a class or enumeration name and an object, function,
-  //   or enumerator are declared in the same scope (in any order)
-  //   with the same name, the class or enumeration name is hidden
-  //   wherever the object, function, or enumerator name is visible.
-  // But it's still an error if there are distinct tag types found,
-  // even if they're not visible. (ref?)
-  if (N > 1 && HideTags && HasTag && !Ambiguous &&
-      (HasFunction || HasNonFunction || HasUnresolved)) {
-    NamedDecl *OtherDecl = Decls[UniqueTagIndex ? 0 : N - 1];
-    if (isa<TagDecl>(Decls[UniqueTagIndex]->getUnderlyingDecl()) &&
-        getContextForScopeMatching(Decls[UniqueTagIndex])->Equals(
-            getContextForScopeMatching(OtherDecl)) &&
-        canHideTag(OtherDecl))
-      Decls[UniqueTagIndex] = Decls[--N];
-    else
-      Ambiguous = true;
-  }
-
-  // FIXME: This diagnostic should really be delayed until we're done with
-  // the lookup result, in case the ambiguity is resolved by the caller.
-  if (!EquivalentNonFunctions.empty() && !Ambiguous)
-    getSema().diagnoseEquivalentInternalLinkageDeclarations(
-        getNameLoc(), HasNonFunction, EquivalentNonFunctions);
-
-  Decls.set_size(N);
-
-  if (HasNonFunction && (HasFunction || HasUnresolved))
-    Ambiguous = true;
-
-  if (Ambiguous)
-    setAmbiguous(LookupResult::AmbiguousReference);
-  else if (HasUnresolved)
-    ResultKind = LookupResult::FoundUnresolvedValue;
-  else if (N > 1 || HasFunctionTemplate)
-    ResultKind = LookupResult::FoundOverloaded;
-  else
-    ResultKind = LookupResult::Found;
-}
-
-void LookupResult::addDeclsFromBasePaths(const CXXBasePaths &P) {
-  CXXBasePaths::const_paths_iterator I, E;
-  for (I = P.begin(), E = P.end(); I != E; ++I)
-    for (DeclContext::lookup_iterator DI = I->Decls.begin(),
-         DE = I->Decls.end(); DI != DE; ++DI)
-      addDecl(*DI);
-}
-
-void LookupResult::setAmbiguousBaseSubobjects(CXXBasePaths &P) {
-  Paths = new CXXBasePaths;
-  Paths->swap(P);
-  addDeclsFromBasePaths(*Paths);
-  resolveKind();
-  setAmbiguous(AmbiguousBaseSubobjects);
-}
-
-void LookupResult::setAmbiguousBaseSubobjectTypes(CXXBasePaths &P) {
-  Paths = new CXXBasePaths;
-  Paths->swap(P);
-  addDeclsFromBasePaths(*Paths);
-  resolveKind();
-  setAmbiguous(AmbiguousBaseSubobjectTypes);
-}
-
-void LookupResult::print(raw_ostream &Out) {
-  Out << Decls.size() << " result(s)";
-  if (isAmbiguous()) Out << ", ambiguous";
-  if (Paths) Out << ", base paths present";
-
-  for (iterator I = begin(), E = end(); I != E; ++I) {
-    Out << "\n";
-    (*I)->print(Out, 2);
-  }
-}
-
-LLVM_DUMP_METHOD void LookupResult::dump() {
-  llvm::errs() << "lookup results for " << getLookupName().getAsString()
-               << ":\n";
-  for (NamedDecl *D : *this)
-    D->dump();
-}
-
-/// Lookup a builtin function, when name lookup would otherwise
-/// fail.
-static bool LookupBuiltin(Sema &S, LookupResult &R) {
-  Sema::LookupNameKind NameKind = R.getLookupKind();
-
-  // If we didn't find a use of this identifier, and if the identifier
-  // corresponds to a compiler builtin, create the decl object for the builtin
-  // now, injecting it into translation unit scope, and return it.
-  if (NameKind == Sema::LookupOrdinaryName ||
-      NameKind == Sema::LookupRedeclarationWithLinkage) {
-    IdentifierInfo *II = R.getLookupName().getAsIdentifierInfo();
-    if (II) {
-      if (S.getLangOpts().CPlusPlus && NameKind == Sema::LookupOrdinaryName) {
-        if (II == S.getASTContext().getMakeIntegerSeqName()) {
-          R.addDecl(S.getASTContext().getMakeIntegerSeqDecl());
-          return true;
-        } else if (II == S.getASTContext().getTypePackElementName()) {
-          R.addDecl(S.getASTContext().getTypePackElementDecl());
-          return true;
-        }
-      }
-
-      // If this is a builtin on this (or all) targets, create the decl.
-      if (unsigned BuiltinID = II->getBuiltinID()) {
-        // In C++ and OpenCL (spec v1.2 s6.9.f), we don't have any predefined
-        // library functions like 'malloc'. Instead, we'll just error.
-        if ((S.getLangOpts().CPlusPlus || S.getLangOpts().OpenCL) &&
-            S.Context.BuiltinInfo.isPredefinedLibFunction(BuiltinID))
-          return false;
-
-        if (NamedDecl *D = S.LazilyCreateBuiltin((IdentifierInfo *)II,
-                                                 BuiltinID, S.TUScope,
-                                                 R.isForRedeclaration(),
-                                                 R.getNameLoc())) {
-          R.addDecl(D);
-          return true;
-        }
-      }
-    }
-  }
-
-  return false;
-}
-
-/// Determine whether we can declare a special member function within
-/// the class at this point.
-static bool CanDeclareSpecialMemberFunction(const CXXRecordDecl *Class) {
-  // We need to have a definition for the class.
-  if (!Class->getDefinition() || Class->isDependentContext())
-    return false;
-
-  // We can't be in the middle of defining the class.
-  return !Class->isBeingDefined();
-}
-
-void Sema::ForceDeclarationOfImplicitMembers(CXXRecordDecl *Class) {
-  if (!CanDeclareSpecialMemberFunction(Class))
-    return;
-
-  // If the default constructor has not yet been declared, do so now.
-  if (Class->needsImplicitDefaultConstructor())
-    DeclareImplicitDefaultConstructor(Class);
-
-  // If the copy constructor has not yet been declared, do so now.
-  if (Class->needsImplicitCopyConstructor())
-    DeclareImplicitCopyConstructor(Class);
-
-  // If the copy assignment operator has not yet been declared, do so now.
-  if (Class->needsImplicitCopyAssignment())
-    DeclareImplicitCopyAssignment(Class);
-
-  if (getLangOpts().CPlusPlus11) {
-    // If the move constructor has not yet been declared, do so now.
-    if (Class->needsImplicitMoveConstructor())
-      DeclareImplicitMoveConstructor(Class);
-
-    // If the move assignment operator has not yet been declared, do so now.
-    if (Class->needsImplicitMoveAssignment())
-      DeclareImplicitMoveAssignment(Class);
-  }
-
-  // If the destructor has not yet been declared, do so now.
-  if (Class->needsImplicitDestructor())
-    DeclareImplicitDestructor(Class);
-}
-
-/// Determine whether this is the name of an implicitly-declared
-/// special member function.
-static bool isImplicitlyDeclaredMemberFunctionName(DeclarationName Name) {
-  switch (Name.getNameKind()) {
-  case DeclarationName::CXXConstructorName:
-  case DeclarationName::CXXDestructorName:
-    return true;
-
-  case DeclarationName::CXXOperatorName:
-    return Name.getCXXOverloadedOperator() == OO_Equal;
-
-  default:
-    break;
-  }
-
-  return false;
-}
-
-/// If there are any implicit member functions with the given name
-/// that need to be declared in the given declaration context, do so.
-static void DeclareImplicitMemberFunctionsWithName(Sema &S,
-                                                   DeclarationName Name,
-                                                   SourceLocation Loc,
-                                                   const DeclContext *DC) {
-  if (!DC)
-    return;
-
-  switch (Name.getNameKind()) {
-  case DeclarationName::CXXConstructorName:
-    if (const CXXRecordDecl *Record = dyn_cast<CXXRecordDecl>(DC))
-      if (Record->getDefinition() && CanDeclareSpecialMemberFunction(Record)) {
-        CXXRecordDecl *Class = const_cast<CXXRecordDecl *>(Record);
-        if (Record->needsImplicitDefaultConstructor())
-          S.DeclareImplicitDefaultConstructor(Class);
-        if (Record->needsImplicitCopyConstructor())
-          S.DeclareImplicitCopyConstructor(Class);
-        if (S.getLangOpts().CPlusPlus11 &&
-            Record->needsImplicitMoveConstructor())
-          S.DeclareImplicitMoveConstructor(Class);
-      }
-    break;
-
-  case DeclarationName::CXXDestructorName:
-    if (const CXXRecordDecl *Record = dyn_cast<CXXRecordDecl>(DC))
-      if (Record->getDefinition() && Record->needsImplicitDestructor() &&
-          CanDeclareSpecialMemberFunction(Record))
-        S.DeclareImplicitDestructor(const_cast<CXXRecordDecl *>(Record));
-    break;
-
-  case DeclarationName::CXXOperatorName:
-    if (Name.getCXXOverloadedOperator() != OO_Equal)
-      break;
-
-    if (const CXXRecordDecl *Record = dyn_cast<CXXRecordDecl>(DC)) {
-      if (Record->getDefinition() && CanDeclareSpecialMemberFunction(Record)) {
-        CXXRecordDecl *Class = const_cast<CXXRecordDecl *>(Record);
-        if (Record->needsImplicitCopyAssignment())
-          S.DeclareImplicitCopyAssignment(Class);
-        if (S.getLangOpts().CPlusPlus11 &&
-            Record->needsImplicitMoveAssignment())
-          S.DeclareImplicitMoveAssignment(Class);
-      }
-    }
-    break;
-
-  case DeclarationName::CXXDeductionGuideName:
-    S.DeclareImplicitDeductionGuides(Name.getCXXDeductionGuideTemplate(), Loc);
-    break;
-
-  default:
-    break;
-  }
-}
-
-// Adds all qualifying matches for a name within a decl context to the
-// given lookup result.  Returns true if any matches were found.
-static bool LookupDirect(Sema &S, LookupResult &R, const DeclContext *DC) {
-  bool Found = false;
-
-  // Lazily declare C++ special member functions.
-  if (S.getLangOpts().CPlusPlus)
-    DeclareImplicitMemberFunctionsWithName(S, R.getLookupName(), R.getNameLoc(),
-                                           DC);
-
-  // Perform lookup into this declaration context.
-  DeclContext::lookup_result DR = DC->lookup(R.getLookupName());
-  for (NamedDecl *D : DR) {
-    if ((D = R.getAcceptableDecl(D))) {
-      R.addDecl(D);
-      Found = true;
-    }
-  }
-
-  if (!Found && DC->isTranslationUnit() && LookupBuiltin(S, R))
-    return true;
-
-  if (R.getLookupName().getNameKind()
-        != DeclarationName::CXXConversionFunctionName ||
-      R.getLookupName().getCXXNameType()->isDependentType() ||
-      !isa<CXXRecordDecl>(DC))
-    return Found;
-
-  // C++ [temp.mem]p6:
-  //   A specialization of a conversion function template is not found by
-  //   name lookup. Instead, any conversion function templates visible in the
-  //   context of the use are considered. [...]
-  const CXXRecordDecl *Record = cast<CXXRecordDecl>(DC);
-  if (!Record->isCompleteDefinition())
-    return Found;
-
-  // For conversion operators, 'operator auto' should only match
-  // 'operator auto'.  Since 'auto' is not a type, it shouldn't be considered
-  // as a candidate for template substitution.
-  auto *ContainedDeducedType =
-      R.getLookupName().getCXXNameType()->getContainedDeducedType();
-  if (R.getLookupName().getNameKind() ==
-          DeclarationName::CXXConversionFunctionName &&
-      ContainedDeducedType && ContainedDeducedType->isUndeducedType())
-    return Found;
-
-  for (CXXRecordDecl::conversion_iterator U = Record->conversion_begin(),
-         UEnd = Record->conversion_end(); U != UEnd; ++U) {
-    FunctionTemplateDecl *ConvTemplate = dyn_cast<FunctionTemplateDecl>(*U);
-    if (!ConvTemplate)
-      continue;
-
-    // When we're performing lookup for the purposes of redeclaration, just
-    // add the conversion function template. When we deduce template
-    // arguments for specializations, we'll end up unifying the return
-    // type of the new declaration with the type of the function template.
-    if (R.isForRedeclaration()) {
-      R.addDecl(ConvTemplate);
-      Found = true;
-      continue;
-    }
-
-    // C++ [temp.mem]p6:
-    //   [...] For each such operator, if argument deduction succeeds
-    //   (14.9.2.3), the resulting specialization is used as if found by
-    //   name lookup.
-    //
-    // When referencing a conversion function for any purpose other than
-    // a redeclaration (such that we'll be building an expression with the
-    // result), perform template argument deduction and place the
-    // specialization into the result set. We do this to avoid forcing all
-    // callers to perform special deduction for conversion functions.
-    TemplateDeductionInfo Info(R.getNameLoc());
-    FunctionDecl *Specialization = nullptr;
-
-    const FunctionProtoType *ConvProto
-      = ConvTemplate->getTemplatedDecl()->getType()->getAs<FunctionProtoType>();
-    assert(ConvProto && "Nonsensical conversion function template type");
-
-    // Compute the type of the function that we would expect the conversion
-    // function to have, if it were to match the name given.
-    // FIXME: Calling convention!
-    FunctionProtoType::ExtProtoInfo EPI = ConvProto->getExtProtoInfo();
-    EPI.ExtInfo = EPI.ExtInfo.withCallingConv(CC_C);
-    EPI.ExceptionSpec = EST_None;
-    QualType ExpectedType
-      = R.getSema().Context.getFunctionType(R.getLookupName().getCXXNameType(),
-                                            None, EPI);
-
-    // Perform template argument deduction against the type that we would
-    // expect the function to have.
-    if (R.getSema().DeduceTemplateArguments(ConvTemplate, nullptr, ExpectedType,
-                                            Specialization, Info)
-          == Sema::TDK_Success) {
-      R.addDecl(Specialization);
-      Found = true;
-    }
-  }
-
-  return Found;
-}
-
-// Performs C++ unqualified lookup into the given file context.
-static bool
-CppNamespaceLookup(Sema &S, LookupResult &R, ASTContext &Context,
-                   DeclContext *NS, UnqualUsingDirectiveSet &UDirs) {
-
-  assert(NS && NS->isFileContext() && "CppNamespaceLookup() requires namespace!");
-
-  // Perform direct name lookup into the LookupCtx.
-  bool Found = LookupDirect(S, R, NS);
-
-  // Perform direct name lookup into the namespaces nominated by the
-  // using directives whose common ancestor is this namespace.
-  for (const UnqualUsingEntry &UUE : UDirs.getNamespacesFor(NS))
-    if (LookupDirect(S, R, UUE.getNominatedNamespace()))
-      Found = true;
-
-  R.resolveKind();
-
-  return Found;
-}
-
-static bool isNamespaceOrTranslationUnitScope(Scope *S) {
-  if (DeclContext *Ctx = S->getEntity())
-    return Ctx->isFileContext();
-  return false;
-}
-
-// Find the next outer declaration context from this scope. This
-// routine actually returns the semantic outer context, which may
-// differ from the lexical context (encoded directly in the Scope
-// stack) when we are parsing a member of a class template. In this
-// case, the second element of the pair will be true, to indicate that
-// name lookup should continue searching in this semantic context when
-// it leaves the current template parameter scope.
-static std::pair<DeclContext *, bool> findOuterContext(Scope *S) {
-  DeclContext *DC = S->getEntity();
-  DeclContext *Lexical = nullptr;
-  for (Scope *OuterS = S->getParent(); OuterS;
-       OuterS = OuterS->getParent()) {
-    if (OuterS->getEntity()) {
-      Lexical = OuterS->getEntity();
-      break;
-    }
-  }
-
-  // C++ [temp.local]p8:
-  //   In the definition of a member of a class template that appears
-  //   outside of the namespace containing the class template
-  //   definition, the name of a template-parameter hides the name of
-  //   a member of this namespace.
-  //
-  // Example:
-  //
-  //   namespace N {
-  //     class C { };
-  //
-  //     template<class T> class B {
-  //       void f(T);
-  //     };
-  //   }
-  //
-  //   template<class C> void N::B<C>::f(C) {
-  //     C b;  // C is the template parameter, not N::C
-  //   }
-  //
-  // In this example, the lexical context we return is the
-  // TranslationUnit, while the semantic context is the namespace N.
-  if (!Lexical || !DC || !S->getParent() ||
-      !S->getParent()->isTemplateParamScope())
-    return std::make_pair(Lexical, false);
-
-  // Find the outermost template parameter scope.
-  // For the example, this is the scope for the template parameters of
-  // template<class C>.
-  Scope *OutermostTemplateScope = S->getParent();
-  while (OutermostTemplateScope->getParent() &&
-         OutermostTemplateScope->getParent()->isTemplateParamScope())
-    OutermostTemplateScope = OutermostTemplateScope->getParent();
-
-  // Find the namespace context in which the original scope occurs. In
-  // the example, this is namespace N.
-  DeclContext *Semantic = DC;
-  while (!Semantic->isFileContext())
-    Semantic = Semantic->getParent();
-
-  // Find the declaration context just outside of the template
-  // parameter scope. This is the context in which the template is
-  // being lexically declaration (a namespace context). In the
-  // example, this is the global scope.
-  if (Lexical->isFileContext() && !Lexical->Equals(Semantic) &&
-      Lexical->Encloses(Semantic))
-    return std::make_pair(Semantic, true);
-
-  return std::make_pair(Lexical, false);
-}
-
-namespace {
-/// An RAII object to specify that we want to find block scope extern
-/// declarations.
-struct FindLocalExternScope {
-  FindLocalExternScope(LookupResult &R)
-      : R(R), OldFindLocalExtern(R.getIdentifierNamespace() &
-                                 Decl::IDNS_LocalExtern) {
-    R.setFindLocalExtern(R.getIdentifierNamespace() &
-                         (Decl::IDNS_Ordinary | Decl::IDNS_NonMemberOperator));
-  }
-  void restore() {
-    R.setFindLocalExtern(OldFindLocalExtern);
-  }
-  ~FindLocalExternScope() {
-    restore();
-  }
-  LookupResult &R;
-  bool OldFindLocalExtern;
-};
-} // end anonymous namespace
-
-bool Sema::CppLookupName(LookupResult &R, Scope *S) {
-  assert(getLangOpts().CPlusPlus && "Can perform only C++ lookup");
-
-  DeclarationName Name = R.getLookupName();
-  Sema::LookupNameKind NameKind = R.getLookupKind();
-
-  // If this is the name of an implicitly-declared special member function,
-  // go through the scope stack to implicitly declare
-  if (isImplicitlyDeclaredMemberFunctionName(Name)) {
-    for (Scope *PreS = S; PreS; PreS = PreS->getParent())
-      if (DeclContext *DC = PreS->getEntity())
-        DeclareImplicitMemberFunctionsWithName(*this, Name, R.getNameLoc(), DC);
-  }
-
-  // Implicitly declare member functions with the name we're looking for, if in
-  // fact we are in a scope where it matters.
-
-  Scope *Initial = S;
-  IdentifierResolver::iterator
-    I = IdResolver.begin(Name),
-    IEnd = IdResolver.end();
-
-  // First we lookup local scope.
-  // We don't consider using-directives, as per 7.3.4.p1 [namespace.udir]
-  // ...During unqualified name lookup (3.4.1), the names appear as if
-  // they were declared in the nearest enclosing namespace which contains
-  // both the using-directive and the nominated namespace.
-  // [Note: in this context, "contains" means "contains directly or
-  // indirectly".
-  //
-  // For example:
-  // namespace A { int i; }
-  // void foo() {
-  //   int i;
-  //   {
-  //     using namespace A;
-  //     ++i; // finds local 'i', A::i appears at global scope
-  //   }
-  // }
-  //
-  UnqualUsingDirectiveSet UDirs(*this);
-  bool VisitedUsingDirectives = false;
-  bool LeftStartingScope = false;
-  DeclContext *OutsideOfTemplateParamDC = nullptr;
-
-  // When performing a scope lookup, we want to find local extern decls.
-  FindLocalExternScope FindLocals(R);
-
-  for (; S && !isNamespaceOrTranslationUnitScope(S); S = S->getParent()) {
-    DeclContext *Ctx = S->getEntity();
-    bool SearchNamespaceScope = true;
-    // Check whether the IdResolver has anything in this scope.
-    for (; I != IEnd && S->isDeclScope(*I); ++I) {
-      if (NamedDecl *ND = R.getAcceptableDecl(*I)) {
-        if (NameKind == LookupRedeclarationWithLinkage &&
-            !(*I)->isTemplateParameter()) {
-          // If it's a template parameter, we still find it, so we can diagnose
-          // the invalid redeclaration.
-
-          // Determine whether this (or a previous) declaration is
-          // out-of-scope.
-          if (!LeftStartingScope && !Initial->isDeclScope(*I))
-            LeftStartingScope = true;
-
-          // If we found something outside of our starting scope that
-          // does not have linkage, skip it.
-          if (LeftStartingScope && !((*I)->hasLinkage())) {
-            R.setShadowed();
-            continue;
-          }
-        } else {
-          // We found something in this scope, we should not look at the
-          // namespace scope
-          SearchNamespaceScope = false;
-        }
-        R.addDecl(ND);
-      }
-    }
-    if (!SearchNamespaceScope) {
-      R.resolveKind();
-      if (S->isClassScope())
-        if (CXXRecordDecl *Record = dyn_cast_or_null<CXXRecordDecl>(Ctx))
-          R.setNamingClass(Record);
-      return true;
-    }
-
-    if (NameKind == LookupLocalFriendName && !S->isClassScope()) {
-      // C++11 [class.friend]p11:
-      //   If a friend declaration appears in a local class and the name
-      //   specified is an unqualified name, a prior declaration is
-      //   looked up without considering scopes that are outside the
-      //   innermost enclosing non-class scope.
-      return false;
-    }
-
-    if (!Ctx && S->isTemplateParamScope() && OutsideOfTemplateParamDC &&
-        S->getParent() && !S->getParent()->isTemplateParamScope()) {
-      // We've just searched the last template parameter scope and
-      // found nothing, so look into the contexts between the
-      // lexical and semantic declaration contexts returned by
-      // findOuterContext(). This implements the name lookup behavior
-      // of C++ [temp.local]p8.
-      Ctx = OutsideOfTemplateParamDC;
-      OutsideOfTemplateParamDC = nullptr;
-    }
-
-    if (Ctx) {
-      DeclContext *OuterCtx;
-      bool SearchAfterTemplateScope;
-      std::tie(OuterCtx, SearchAfterTemplateScope) = findOuterContext(S);
-      if (SearchAfterTemplateScope)
-        OutsideOfTemplateParamDC = OuterCtx;
-
-      for (; Ctx && !Ctx->Equals(OuterCtx); Ctx = Ctx->getLookupParent()) {
-        // We do not directly look into transparent contexts, since
-        // those entities will be found in the nearest enclosing
-        // non-transparent context.
-        if (Ctx->isTransparentContext())
-          continue;
-
-        // We do not look directly into function or method contexts,
-        // since all of the local variables and parameters of the
-        // function/method are present within the Scope.
-        if (Ctx->isFunctionOrMethod()) {
-          // If we have an Objective-C instance method, look for ivars
-          // in the corresponding interface.
-          if (ObjCMethodDecl *Method = dyn_cast<ObjCMethodDecl>(Ctx)) {
-            if (Method->isInstanceMethod() && Name.getAsIdentifierInfo())
-              if (ObjCInterfaceDecl *Class = Method->getClassInterface()) {
-                ObjCInterfaceDecl *ClassDeclared;
-                if (ObjCIvarDecl *Ivar = Class->lookupInstanceVariable(
-                                                 Name.getAsIdentifierInfo(),
-                                                             ClassDeclared)) {
-                  if (NamedDecl *ND = R.getAcceptableDecl(Ivar)) {
-                    R.addDecl(ND);
-                    R.resolveKind();
-                    return true;
-                  }
-                }
-              }
-          }
-
-          continue;
-        }
-
-        // If this is a file context, we need to perform unqualified name
-        // lookup considering using directives.
-        if (Ctx->isFileContext()) {
-          // If we haven't handled using directives yet, do so now.
-          if (!VisitedUsingDirectives) {
-            // Add using directives from this context up to the top level.
-            for (DeclContext *UCtx = Ctx; UCtx; UCtx = UCtx->getParent()) {
-              if (UCtx->isTransparentContext())
-                continue;
-
-              UDirs.visit(UCtx, UCtx);
-            }
-
-            // Find the innermost file scope, so we can add using directives
-            // from local scopes.
-            Scope *InnermostFileScope = S;
-            while (InnermostFileScope &&
-                   !isNamespaceOrTranslationUnitScope(InnermostFileScope))
-              InnermostFileScope = InnermostFileScope->getParent();
-            UDirs.visitScopeChain(Initial, InnermostFileScope);
-
-            UDirs.done();
-
-            VisitedUsingDirectives = true;
-          }
-
-          if (CppNamespaceLookup(*this, R, Context, Ctx, UDirs)) {
-            R.resolveKind();
-            return true;
-          }
-
-          continue;
-        }
-
-        // Perform qualified name lookup into this context.
-        // FIXME: In some cases, we know that every name that could be found by
-        // this qualified name lookup will also be on the identifier chain. For
-        // example, inside a class without any base classes, we never need to
-        // perform qualified lookup because all of the members are on top of the
-        // identifier chain.
-        if (LookupQualifiedName(R, Ctx, /*InUnqualifiedLookup=*/true))
-          return true;
-      }
-    }
-  }
-
-  // Stop if we ran out of scopes.
-  // FIXME:  This really, really shouldn't be happening.
-  if (!S) return false;
-
-  // If we are looking for members, no need to look into global/namespace scope.
-  if (NameKind == LookupMemberName)
-    return false;
-
-  // Collect UsingDirectiveDecls in all scopes, and recursively all
-  // nominated namespaces by those using-directives.
-  //
-  // FIXME: Cache this sorted list in Scope structure, and DeclContext, so we
-  // don't build it for each lookup!
-  if (!VisitedUsingDirectives) {
-    UDirs.visitScopeChain(Initial, S);
-    UDirs.done();
-  }
-
-  // If we're not performing redeclaration lookup, do not look for local
-  // extern declarations outside of a function scope.
-  if (!R.isForRedeclaration())
-    FindLocals.restore();
-
-  // Lookup namespace scope, and global scope.
-  // Unqualified name lookup in C++ requires looking into scopes
-  // that aren't strictly lexical, and therefore we walk through the
-  // context as well as walking through the scopes.
-  for (; S; S = S->getParent()) {
-    // Check whether the IdResolver has anything in this scope.
-    bool Found = false;
-    for (; I != IEnd && S->isDeclScope(*I); ++I) {
-      if (NamedDecl *ND = R.getAcceptableDecl(*I)) {
-        // We found something.  Look for anything else in our scope
-        // with this same name and in an acceptable identifier
-        // namespace, so that we can construct an overload set if we
-        // need to.
-        Found = true;
-        R.addDecl(ND);
-      }
-    }
-
-    if (Found && S->isTemplateParamScope()) {
-      R.resolveKind();
-      return true;
-    }
-
-    DeclContext *Ctx = S->getEntity();
-    if (!Ctx && S->isTemplateParamScope() && OutsideOfTemplateParamDC &&
-        S->getParent() && !S->getParent()->isTemplateParamScope()) {
-      // We've just searched the last template parameter scope and
-      // found nothing, so look into the contexts between the
-      // lexical and semantic declaration contexts returned by
-      // findOuterContext(). This implements the name lookup behavior
-      // of C++ [temp.local]p8.
-      Ctx = OutsideOfTemplateParamDC;
-      OutsideOfTemplateParamDC = nullptr;
-    }
-
-    if (Ctx) {
-      DeclContext *OuterCtx;
-      bool SearchAfterTemplateScope;
-      std::tie(OuterCtx, SearchAfterTemplateScope) = findOuterContext(S);
-      if (SearchAfterTemplateScope)
-        OutsideOfTemplateParamDC = OuterCtx;
-
-      for (; Ctx && !Ctx->Equals(OuterCtx); Ctx = Ctx->getLookupParent()) {
-        // We do not directly look into transparent contexts, since
-        // those entities will be found in the nearest enclosing
-        // non-transparent context.
-        if (Ctx->isTransparentContext())
-          continue;
-
-        // If we have a context, and it's not a context stashed in the
-        // template parameter scope for an out-of-line definition, also
-        // look into that context.
-        if (!(Found && S->isTemplateParamScope())) {
-          assert(Ctx->isFileContext() &&
-              "We should have been looking only at file context here already.");
-
-          // Look into context considering using-directives.
-          if (CppNamespaceLookup(*this, R, Context, Ctx, UDirs))
-            Found = true;
-        }
-
-        if (Found) {
-          R.resolveKind();
-          return true;
-        }
-
-        if (R.isForRedeclaration() && !Ctx->isTransparentContext())
-          return false;
-      }
-    }
-
-    if (R.isForRedeclaration() && Ctx && !Ctx->isTransparentContext())
-      return false;
-  }
-
-  return !R.empty();
-}
-
-void Sema::makeMergedDefinitionVisible(NamedDecl *ND) {
-  if (auto *M = getCurrentModule())
-    Context.mergeDefinitionIntoModule(ND, M);
-  else
-    // We're not building a module; just make the definition visible.
-    ND->setVisibleDespiteOwningModule();
-
-  // If ND is a template declaration, make the template parameters
-  // visible too. They're not (necessarily) within a mergeable DeclContext.
-  if (auto *TD = dyn_cast<TemplateDecl>(ND))
-    for (auto *Param : *TD->getTemplateParameters())
-      makeMergedDefinitionVisible(Param);
-}
-
-/// Find the module in which the given declaration was defined.
-static Module *getDefiningModule(Sema &S, Decl *Entity) {
-  if (FunctionDecl *FD = dyn_cast<FunctionDecl>(Entity)) {
-    // If this function was instantiated from a template, the defining module is
-    // the module containing the pattern.
-    if (FunctionDecl *Pattern = FD->getTemplateInstantiationPattern())
-      Entity = Pattern;
-  } else if (CXXRecordDecl *RD = dyn_cast<CXXRecordDecl>(Entity)) {
-    if (CXXRecordDecl *Pattern = RD->getTemplateInstantiationPattern())
-      Entity = Pattern;
-  } else if (EnumDecl *ED = dyn_cast<EnumDecl>(Entity)) {
-    if (auto *Pattern = ED->getTemplateInstantiationPattern())
-      Entity = Pattern;
-  } else if (VarDecl *VD = dyn_cast<VarDecl>(Entity)) {
-    if (VarDecl *Pattern = VD->getTemplateInstantiationPattern())
-      Entity = Pattern;
-  }
-
-  // Walk up to the containing context. That might also have been instantiated
-  // from a template.
-  DeclContext *Context = Entity->getLexicalDeclContext();
-  if (Context->isFileContext())
-    return S.getOwningModule(Entity);
-  return getDefiningModule(S, cast<Decl>(Context));
-}
-
-llvm::DenseSet<Module*> &Sema::getLookupModules() {
-  unsigned N = CodeSynthesisContexts.size();
-  for (unsigned I = CodeSynthesisContextLookupModules.size();
-       I != N; ++I) {
-    Module *M = getDefiningModule(*this, CodeSynthesisContexts[I].Entity);
-    if (M && !LookupModulesCache.insert(M).second)
-      M = nullptr;
-    CodeSynthesisContextLookupModules.push_back(M);
-  }
-  return LookupModulesCache;
-}
-
-/// Determine whether the module M is part of the current module from the
-/// perspective of a module-private visibility check.
-static bool isInCurrentModule(const Module *M, const LangOptions &LangOpts) {
-  // If M is the global module fragment of a module that we've not yet finished
-  // parsing, then it must be part of the current module.
-  return M->getTopLevelModuleName() == LangOpts.CurrentModule ||
-         (M->Kind == Module::GlobalModuleFragment && !M->Parent);
-}
-
-bool Sema::hasVisibleMergedDefinition(NamedDecl *Def) {
-  for (const Module *Merged : Context.getModulesWithMergedDefinition(Def))
-    if (isModuleVisible(Merged))
-      return true;
-  return false;
-}
-
-bool Sema::hasMergedDefinitionInCurrentModule(NamedDecl *Def) {
-  for (const Module *Merged : Context.getModulesWithMergedDefinition(Def))
-    if (isInCurrentModule(Merged, getLangOpts()))
-      return true;
-  return false;
-}
-
-template<typename ParmDecl>
-static bool
-hasVisibleDefaultArgument(Sema &S, const ParmDecl *D,
-                          llvm::SmallVectorImpl<Module *> *Modules) {
-  if (!D->hasDefaultArgument())
-    return false;
-
-  while (D) {
-    auto &DefaultArg = D->getDefaultArgStorage();
-    if (!DefaultArg.isInherited() && S.isVisible(D))
-      return true;
-
-    if (!DefaultArg.isInherited() && Modules) {
-      auto *NonConstD = const_cast<ParmDecl*>(D);
-      Modules->push_back(S.getOwningModule(NonConstD));
-    }
-
-    // If there was a previous default argument, maybe its parameter is visible.
-    D = DefaultArg.getInheritedFrom();
-  }
-  return false;
-}
-
-bool Sema::hasVisibleDefaultArgument(const NamedDecl *D,
-                                     llvm::SmallVectorImpl<Module *> *Modules) {
-  if (auto *P = dyn_cast<TemplateTypeParmDecl>(D))
-    return ::hasVisibleDefaultArgument(*this, P, Modules);
-  if (auto *P = dyn_cast<NonTypeTemplateParmDecl>(D))
-    return ::hasVisibleDefaultArgument(*this, P, Modules);
-  return ::hasVisibleDefaultArgument(*this, cast<TemplateTemplateParmDecl>(D),
-                                     Modules);
-}
-
-template<typename Filter>
-static bool hasVisibleDeclarationImpl(Sema &S, const NamedDecl *D,
-                                      llvm::SmallVectorImpl<Module *> *Modules,
-                                      Filter F) {
-  bool HasFilteredRedecls = false;
-
-  for (auto *Redecl : D->redecls()) {
-    auto *R = cast<NamedDecl>(Redecl);
-    if (!F(R))
-      continue;
-
-    if (S.isVisible(R))
-      return true;
-
-    HasFilteredRedecls = true;
-
-    if (Modules)
-      Modules->push_back(R->getOwningModule());
-  }
-
-  // Only return false if there is at least one redecl that is not filtered out.
-  if (HasFilteredRedecls)
-    return false;
-
-  return true;
-}
-
-bool Sema::hasVisibleExplicitSpecialization(
-    const NamedDecl *D, llvm::SmallVectorImpl<Module *> *Modules) {
-  return hasVisibleDeclarationImpl(*this, D, Modules, [](const NamedDecl *D) {
-    if (auto *RD = dyn_cast<CXXRecordDecl>(D))
-      return RD->getTemplateSpecializationKind() == TSK_ExplicitSpecialization;
-    if (auto *FD = dyn_cast<FunctionDecl>(D))
-      return FD->getTemplateSpecializationKind() == TSK_ExplicitSpecialization;
-    if (auto *VD = dyn_cast<VarDecl>(D))
-      return VD->getTemplateSpecializationKind() == TSK_ExplicitSpecialization;
-    llvm_unreachable("unknown explicit specialization kind");
-  });
-}
-
-bool Sema::hasVisibleMemberSpecialization(
-    const NamedDecl *D, llvm::SmallVectorImpl<Module *> *Modules) {
-  assert(isa<CXXRecordDecl>(D->getDeclContext()) &&
-         "not a member specialization");
-  return hasVisibleDeclarationImpl(*this, D, Modules, [](const NamedDecl *D) {
-    // If the specialization is declared at namespace scope, then it's a member
-    // specialization declaration. If it's lexically inside the class
-    // definition then it was instantiated.
-    //
-    // FIXME: This is a hack. There should be a better way to determine this.
-    // FIXME: What about MS-style explicit specializations declared within a
-    //        class definition?
-    return D->getLexicalDeclContext()->isFileContext();
-  });
-}
-
-/// Determine whether a declaration is visible to name lookup.
-///
-/// This routine determines whether the declaration D is visible in the current
-/// lookup context, taking into account the current template instantiation
-/// stack. During template instantiation, a declaration is visible if it is
-/// visible from a module containing any entity on the template instantiation
-/// path (by instantiating a template, you allow it to see the declarations that
-/// your module can see, including those later on in your module).
-bool LookupResult::isVisibleSlow(Sema &SemaRef, NamedDecl *D) {
-  assert(D->isHidden() && "should not call this: not in slow case");
-
-  Module *DeclModule = SemaRef.getOwningModule(D);
-  assert(DeclModule && "hidden decl has no owning module");
-
-  // If the owning module is visible, the decl is visible.
-  if (SemaRef.isModuleVisible(DeclModule, D->isModulePrivate()))
-    return true;
-
-  // Determine whether a decl context is a file context for the purpose of
-  // visibility. This looks through some (export and linkage spec) transparent
-  // contexts, but not others (enums).
-  auto IsEffectivelyFileContext = [](const DeclContext *DC) {
-    return DC->isFileContext() || isa<LinkageSpecDecl>(DC) ||
-           isa<ExportDecl>(DC);
-  };
-
-  // If this declaration is not at namespace scope
-  // then it is visible if its lexical parent has a visible definition.
-  DeclContext *DC = D->getLexicalDeclContext();
-  if (DC && !IsEffectivelyFileContext(DC)) {
-    // For a parameter, check whether our current template declaration's
-    // lexical context is visible, not whether there's some other visible
-    // definition of it, because parameters aren't "within" the definition.
-    //
-    // In C++ we need to check for a visible definition due to ODR merging,
-    // and in C we must not because each declaration of a function gets its own
-    // set of declarations for tags in prototype scope.
-    bool VisibleWithinParent;
-    if (D->isTemplateParameter() || isa<ParmVarDecl>(D) ||
-        (isa<FunctionDecl>(DC) && !SemaRef.getLangOpts().CPlusPlus))
-      VisibleWithinParent = isVisible(SemaRef, cast<NamedDecl>(DC));
-    else if (D->isModulePrivate()) {
-      // A module-private declaration is only visible if an enclosing lexical
-      // parent was merged with another definition in the current module.
-      VisibleWithinParent = false;
-      do {
-        if (SemaRef.hasMergedDefinitionInCurrentModule(cast<NamedDecl>(DC))) {
-          VisibleWithinParent = true;
-          break;
-        }
-        DC = DC->getLexicalParent();
-      } while (!IsEffectivelyFileContext(DC));
-    } else {
-      VisibleWithinParent = SemaRef.hasVisibleDefinition(cast<NamedDecl>(DC));
-    }
-
-    if (VisibleWithinParent && SemaRef.CodeSynthesisContexts.empty() &&
-        // FIXME: Do something better in this case.
-        !SemaRef.getLangOpts().ModulesLocalVisibility) {
-      // Cache the fact that this declaration is implicitly visible because
-      // its parent has a visible definition.
-      D->setVisibleDespiteOwningModule();
-    }
-    return VisibleWithinParent;
-  }
-
-  return false;
-}
-
-bool Sema::isModuleVisible(const Module *M, bool ModulePrivate) {
-  // The module might be ordinarily visible. For a module-private query, that
-  // means it is part of the current module. For any other query, that means it
-  // is in our visible module set.
-  if (ModulePrivate) {
-    if (isInCurrentModule(M, getLangOpts()))
-      return true;
-  } else {
-    if (VisibleModules.isVisible(M))
-      return true;
-  }
-
-  // Otherwise, it might be visible by virtue of the query being within a
-  // template instantiation or similar that is permitted to look inside M.
-
-  // Find the extra places where we need to look.
-  const auto &LookupModules = getLookupModules();
-  if (LookupModules.empty())
-    return false;
-
-  // If our lookup set contains the module, it's visible.
-  if (LookupModules.count(M))
-    return true;
-
-  // For a module-private query, that's everywhere we get to look.
-  if (ModulePrivate)
-    return false;
-
-  // Check whether M is transitively exported to an import of the lookup set.
-  return llvm::any_of(LookupModules, [&](const Module *LookupM) {
-    return LookupM->isModuleVisible(M);
-  });
-}
-
-bool Sema::isVisibleSlow(const NamedDecl *D) {
-  return LookupResult::isVisible(*this, const_cast<NamedDecl*>(D));
-}
-
-bool Sema::shouldLinkPossiblyHiddenDecl(LookupResult &R, const NamedDecl *New) {
-  // FIXME: If there are both visible and hidden declarations, we need to take
-  // into account whether redeclaration is possible. Example:
-  //
-  // Non-imported module:
-  //   int f(T);        // #1
-  // Some TU:
-  //   static int f(U); // #2, not a redeclaration of #1
-  //   int f(T);        // #3, finds both, should link with #1 if T != U, but
-  //                    // with #2 if T == U; neither should be ambiguous.
-  for (auto *D : R) {
-    if (isVisible(D))
-      return true;
-    assert(D->isExternallyDeclarable() &&
-           "should not have hidden, non-externally-declarable result here");
-  }
-
-  // This function is called once "New" is essentially complete, but before a
-  // previous declaration is attached. We can't query the linkage of "New" in
-  // general, because attaching the previous declaration can change the
-  // linkage of New to match the previous declaration.
-  //
-  // However, because we've just determined that there is no *visible* prior
-  // declaration, we can compute the linkage here. There are two possibilities:
-  //
-  //  * This is not a redeclaration; it's safe to compute the linkage now.
-  //
-  //  * This is a redeclaration of a prior declaration that is externally
-  //    redeclarable. In that case, the linkage of the declaration is not
-  //    changed by attaching the prior declaration, because both are externally
-  //    declarable (and thus ExternalLinkage or VisibleNoLinkage).
-  //
-  // FIXME: This is subtle and fragile.
-  return New->isExternallyDeclarable();
-}
-
-/// Retrieve the visible declaration corresponding to D, if any.
-///
-/// This routine determines whether the declaration D is visible in the current
-/// module, with the current imports. If not, it checks whether any
-/// redeclaration of D is visible, and if so, returns that declaration.
-///
-/// \returns D, or a visible previous declaration of D, whichever is more recent
-/// and visible. If no declaration of D is visible, returns null.
-static NamedDecl *findAcceptableDecl(Sema &SemaRef, NamedDecl *D,
-                                     unsigned IDNS) {
-  assert(!LookupResult::isVisible(SemaRef, D) && "not in slow case");
-
-  for (auto RD : D->redecls()) {
-    // Don't bother with extra checks if we already know this one isn't visible.
-    if (RD == D)
-      continue;
-
-    auto ND = cast<NamedDecl>(RD);
-    // FIXME: This is wrong in the case where the previous declaration is not
-    // visible in the same scope as D. This needs to be done much more
-    // carefully.
-    if (ND->isInIdentifierNamespace(IDNS) &&
-        LookupResult::isVisible(SemaRef, ND))
-      return ND;
-  }
-
-  return nullptr;
-}
-
-bool Sema::hasVisibleDeclarationSlow(const NamedDecl *D,
-                                     llvm::SmallVectorImpl<Module *> *Modules) {
-  assert(!isVisible(D) && "not in slow case");
-  return hasVisibleDeclarationImpl(*this, D, Modules,
-                                   [](const NamedDecl *) { return true; });
-}
-
-NamedDecl *LookupResult::getAcceptableDeclSlow(NamedDecl *D) const {
-  if (auto *ND = dyn_cast<NamespaceDecl>(D)) {
-    // Namespaces are a bit of a special case: we expect there to be a lot of
-    // redeclarations of some namespaces, all declarations of a namespace are
-    // essentially interchangeable, all declarations are found by name lookup
-    // if any is, and namespaces are never looked up during template
-    // instantiation. So we benefit from caching the check in this case, and
-    // it is correct to do so.
-    auto *Key = ND->getCanonicalDecl();
-    if (auto *Acceptable = getSema().VisibleNamespaceCache.lookup(Key))
-      return Acceptable;
-    auto *Acceptable = isVisible(getSema(), Key)
-                           ? Key
-                           : findAcceptableDecl(getSema(), Key, IDNS);
-    if (Acceptable)
-      getSema().VisibleNamespaceCache.insert(std::make_pair(Key, Acceptable));
-    return Acceptable;
-  }
-
-  return findAcceptableDecl(getSema(), D, IDNS);
-}
-
-/// Perform unqualified name lookup starting from a given
-/// scope.
-///
-/// Unqualified name lookup (C++ [basic.lookup.unqual], C99 6.2.1) is
-/// used to find names within the current scope. For example, 'x' in
-/// @code
-/// int x;
-/// int f() {
-///   return x; // unqualified name look finds 'x' in the global scope
-/// }
-/// @endcode
-///
-/// Different lookup criteria can find different names. For example, a
-/// particular scope can have both a struct and a function of the same
-/// name, and each can be found by certain lookup criteria. For more
-/// information about lookup criteria, see the documentation for the
-/// class LookupCriteria.
-///
-/// @param S        The scope from which unqualified name lookup will
-/// begin. If the lookup criteria permits, name lookup may also search
-/// in the parent scopes.
-///
-/// @param [in,out] R Specifies the lookup to perform (e.g., the name to
-/// look up and the lookup kind), and is updated with the results of lookup
-/// including zero or more declarations and possibly additional information
-/// used to diagnose ambiguities.
-///
-/// @returns \c true if lookup succeeded and false otherwise.
-bool Sema::LookupName(LookupResult &R, Scope *S, bool AllowBuiltinCreation) {
-  DeclarationName Name = R.getLookupName();
-  if (!Name) return false;
-
-  LookupNameKind NameKind = R.getLookupKind();
-
-  if (!getLangOpts().CPlusPlus) {
-    // Unqualified name lookup in C/Objective-C is purely lexical, so
-    // search in the declarations attached to the name.
-    if (NameKind == Sema::LookupRedeclarationWithLinkage) {
-      // Find the nearest non-transparent declaration scope.
-      while (!(S->getFlags() & Scope::DeclScope) ||
-             (S->getEntity() && S->getEntity()->isTransparentContext()))
-        S = S->getParent();
-    }
-
-    // When performing a scope lookup, we want to find local extern decls.
-    FindLocalExternScope FindLocals(R);
-
-    // Scan up the scope chain looking for a decl that matches this
-    // identifier that is in the appropriate namespace.  This search
-    // should not take long, as shadowing of names is uncommon, and
-    // deep shadowing is extremely uncommon.
-    bool LeftStartingScope = false;
-
-    for (IdentifierResolver::iterator I = IdResolver.begin(Name),
-                                   IEnd = IdResolver.end();
-         I != IEnd; ++I)
-      if (NamedDecl *D = R.getAcceptableDecl(*I)) {
-        if (NameKind == LookupRedeclarationWithLinkage) {
-          // Determine whether this (or a previous) declaration is
-          // out-of-scope.
-          if (!LeftStartingScope && !S->isDeclScope(*I))
-            LeftStartingScope = true;
-
-          // If we found something outside of our starting scope that
-          // does not have linkage, skip it.
-          if (LeftStartingScope && !((*I)->hasLinkage())) {
-            R.setShadowed();
-            continue;
-          }
-        }
-        else if (NameKind == LookupObjCImplicitSelfParam &&
-                 !isa<ImplicitParamDecl>(*I))
-          continue;
-
-        R.addDecl(D);
-
-        // Check whether there are any other declarations with the same name
-        // and in the same scope.
-        if (I != IEnd) {
-          // Find the scope in which this declaration was declared (if it
-          // actually exists in a Scope).
-          while (S && !S->isDeclScope(D))
-            S = S->getParent();
-
-          // If the scope containing the declaration is the translation unit,
-          // then we'll need to perform our checks based on the matching
-          // DeclContexts rather than matching scopes.
-          if (S && isNamespaceOrTranslationUnitScope(S))
-            S = nullptr;
-
-          // Compute the DeclContext, if we need it.
-          DeclContext *DC = nullptr;
-          if (!S)
-            DC = (*I)->getDeclContext()->getRedeclContext();
-
-          IdentifierResolver::iterator LastI = I;
-          for (++LastI; LastI != IEnd; ++LastI) {
-            if (S) {
-              // Match based on scope.
-              if (!S->isDeclScope(*LastI))
-                break;
-            } else {
-              // Match based on DeclContext.
-              DeclContext *LastDC
-                = (*LastI)->getDeclContext()->getRedeclContext();
-              if (!LastDC->Equals(DC))
-                break;
-            }
-
-            // If the declaration is in the right namespace and visible, add it.
-            if (NamedDecl *LastD = R.getAcceptableDecl(*LastI))
-              R.addDecl(LastD);
-          }
-
-          R.resolveKind();
-        }
-
-        return true;
-      }
-  } else {
-    // Perform C++ unqualified name lookup.
-    if (CppLookupName(R, S))
-      return true;
-  }
-
-  // If we didn't find a use of this identifier, and if the identifier
-  // corresponds to a compiler builtin, create the decl object for the builtin
-  // now, injecting it into translation unit scope, and return it.
-  if (AllowBuiltinCreation && LookupBuiltin(*this, R))
-    return true;
-
-  // If we didn't find a use of this identifier, the ExternalSource
-  // may be able to handle the situation.
-  // Note: some lookup failures are expected!
-  // See e.g. R.isForRedeclaration().
-  return (ExternalSource && ExternalSource->LookupUnqualified(R, S));
-}
-
-/// Perform qualified name lookup in the namespaces nominated by
-/// using directives by the given context.
-///
-/// C++98 [namespace.qual]p2:
-///   Given X::m (where X is a user-declared namespace), or given \::m
-///   (where X is the global namespace), let S be the set of all
-///   declarations of m in X and in the transitive closure of all
-///   namespaces nominated by using-directives in X and its used
-///   namespaces, except that using-directives are ignored in any
-///   namespace, including X, directly containing one or more
-///   declarations of m. No namespace is searched more than once in
-///   the lookup of a name. If S is the empty set, the program is
-///   ill-formed. Otherwise, if S has exactly one member, or if the
-///   context of the reference is a using-declaration
-///   (namespace.udecl), S is the required set of declarations of
-///   m. Otherwise if the use of m is not one that allows a unique
-///   declaration to be chosen from S, the program is ill-formed.
-///
-/// C++98 [namespace.qual]p5:
-///   During the lookup of a qualified namespace member name, if the
-///   lookup finds more than one declaration of the member, and if one
-///   declaration introduces a class name or enumeration name and the
-///   other declarations either introduce the same object, the same
-///   enumerator or a set of functions, the non-type name hides the
-///   class or enumeration name if and only if the declarations are
-///   from the same namespace; otherwise (the declarations are from
-///   different namespaces), the program is ill-formed.
-static bool LookupQualifiedNameInUsingDirectives(Sema &S, LookupResult &R,
-                                                 DeclContext *StartDC) {
-  assert(StartDC->isFileContext() && "start context is not a file context");
-
-  // We have not yet looked into these namespaces, much less added
-  // their "using-children" to the queue.
-  SmallVector<NamespaceDecl*, 8> Queue;
-
-  // We have at least added all these contexts to the queue.
-  llvm::SmallPtrSet<DeclContext*, 8> Visited;
-  Visited.insert(StartDC);
-
-  // We have already looked into the initial namespace; seed the queue
-  // with its using-children.
-  for (auto *I : StartDC->using_directives()) {
-    NamespaceDecl *ND = I->getNominatedNamespace()->getOriginalNamespace();
-    if (S.isVisible(I) && Visited.insert(ND).second)
-      Queue.push_back(ND);
-  }
-
-  // The easiest way to implement the restriction in [namespace.qual]p5
-  // is to check whether any of the individual results found a tag
-  // and, if so, to declare an ambiguity if the final result is not
-  // a tag.
-  bool FoundTag = false;
-  bool FoundNonTag = false;
-
-  LookupResult LocalR(LookupResult::Temporary, R);
-
-  bool Found = false;
-  while (!Queue.empty()) {
-    NamespaceDecl *ND = Queue.pop_back_val();
-
-    // We go through some convolutions here to avoid copying results
-    // between LookupResults.
-    bool UseLocal = !R.empty();
-    LookupResult &DirectR = UseLocal ? LocalR : R;
-    bool FoundDirect = LookupDirect(S, DirectR, ND);
-
-    if (FoundDirect) {
-      // First do any local hiding.
-      DirectR.resolveKind();
-
-      // If the local result is a tag, remember that.
-      if (DirectR.isSingleTagDecl())
-        FoundTag = true;
-      else
-        FoundNonTag = true;
-
-      // Append the local results to the total results if necessary.
-      if (UseLocal) {
-        R.addAllDecls(LocalR);
-        LocalR.clear();
-      }
-    }
-
-    // If we find names in this namespace, ignore its using directives.
-    if (FoundDirect) {
-      Found = true;
-      continue;
-    }
-
-    for (auto I : ND->using_directives()) {
-      NamespaceDecl *Nom = I->getNominatedNamespace();
-      if (S.isVisible(I) && Visited.insert(Nom).second)
-        Queue.push_back(Nom);
-    }
-  }
-
-  if (Found) {
-    if (FoundTag && FoundNonTag)
-      R.setAmbiguousQualifiedTagHiding();
-    else
-      R.resolveKind();
-  }
-
-  return Found;
-}
-
-/// Callback that looks for any member of a class with the given name.
-static bool LookupAnyMember(const CXXBaseSpecifier *Specifier,
-                            CXXBasePath &Path, DeclarationName Name) {
-  RecordDecl *BaseRecord = Specifier->getType()->getAs<RecordType>()->getDecl();
-
-  Path.Decls = BaseRecord->lookup(Name);
-  return !Path.Decls.empty();
-}
-
-/// Determine whether the given set of member declarations contains only
-/// static members, nested types, and enumerators.
-template<typename InputIterator>
-static bool HasOnlyStaticMembers(InputIterator First, InputIterator Last) {
-  Decl *D = (*First)->getUnderlyingDecl();
-  if (isa<VarDecl>(D) || isa<TypeDecl>(D) || isa<EnumConstantDecl>(D))
-    return true;
-
-  if (isa<CXXMethodDecl>(D)) {
-    // Determine whether all of the methods are static.
-    bool AllMethodsAreStatic = true;
-    for(; First != Last; ++First) {
-      D = (*First)->getUnderlyingDecl();
-
-      if (!isa<CXXMethodDecl>(D)) {
-        assert(isa<TagDecl>(D) && "Non-function must be a tag decl");
-        break;
-      }
-
-      if (!cast<CXXMethodDecl>(D)->isStatic()) {
-        AllMethodsAreStatic = false;
-        break;
-      }
-    }
-
-    if (AllMethodsAreStatic)
-      return true;
-  }
-
-  return false;
-}
-
-/// Perform qualified name lookup into a given context.
-///
-/// Qualified name lookup (C++ [basic.lookup.qual]) is used to find
-/// names when the context of those names is explicit specified, e.g.,
-/// "std::vector" or "x->member", or as part of unqualified name lookup.
-///
-/// Different lookup criteria can find different names. For example, a
-/// particular scope can have both a struct and a function of the same
-/// name, and each can be found by certain lookup criteria. For more
-/// information about lookup criteria, see the documentation for the
-/// class LookupCriteria.
-///
-/// \param R captures both the lookup criteria and any lookup results found.
-///
-/// \param LookupCtx The context in which qualified name lookup will
-/// search. If the lookup criteria permits, name lookup may also search
-/// in the parent contexts or (for C++ classes) base classes.
-///
-/// \param InUnqualifiedLookup true if this is qualified name lookup that
-/// occurs as part of unqualified name lookup.
-///
-/// \returns true if lookup succeeded, false if it failed.
-bool Sema::LookupQualifiedName(LookupResult &R, DeclContext *LookupCtx,
-                               bool InUnqualifiedLookup) {
-  assert(LookupCtx && "Sema::LookupQualifiedName requires a lookup context");
-
-  if (!R.getLookupName())
-    return false;
-
-  // Make sure that the declaration context is complete.
-  assert((!isa<TagDecl>(LookupCtx) ||
-          LookupCtx->isDependentContext() ||
-          cast<TagDecl>(LookupCtx)->isCompleteDefinition() ||
-          cast<TagDecl>(LookupCtx)->isBeingDefined()) &&
-         "Declaration context must already be complete!");
-
-  struct QualifiedLookupInScope {
-    bool oldVal;
-    DeclContext *Context;
-    // Set flag in DeclContext informing debugger that we're looking for qualified name
-    QualifiedLookupInScope(DeclContext *ctx) : Context(ctx) {
-      oldVal = ctx->setUseQualifiedLookup();
-    }
-    ~QualifiedLookupInScope() {
-      Context->setUseQualifiedLookup(oldVal);
-    }
-  } QL(LookupCtx);
-
-  if (LookupDirect(*this, R, LookupCtx)) {
-    R.resolveKind();
-    if (isa<CXXRecordDecl>(LookupCtx))
-      R.setNamingClass(cast<CXXRecordDecl>(LookupCtx));
-    return true;
-  }
-
-  // Don't descend into implied contexts for redeclarations.
-  // C++98 [namespace.qual]p6:
-  //   In a declaration for a namespace member in which the
-  //   declarator-id is a qualified-id, given that the qualified-id
-  //   for the namespace member has the form
-  //     nested-name-specifier unqualified-id
-  //   the unqualified-id shall name a member of the namespace
-  //   designated by the nested-name-specifier.
-  // See also [class.mfct]p5 and [class.static.data]p2.
-  if (R.isForRedeclaration())
-    return false;
-
-  // If this is a namespace, look it up in the implied namespaces.
-  if (LookupCtx->isFileContext())
-    return LookupQualifiedNameInUsingDirectives(*this, R, LookupCtx);
-
-  // If this isn't a C++ class, we aren't allowed to look into base
-  // classes, we're done.
-  CXXRecordDecl *LookupRec = dyn_cast<CXXRecordDecl>(LookupCtx);
-  if (!LookupRec || !LookupRec->getDefinition())
-    return false;
-
-  // If we're performing qualified name lookup into a dependent class,
-  // then we are actually looking into a current instantiation. If we have any
-  // dependent base classes, then we either have to delay lookup until
-  // template instantiation time (at which point all bases will be available)
-  // or we have to fail.
-  if (!InUnqualifiedLookup && LookupRec->isDependentContext() &&
-      LookupRec->hasAnyDependentBases()) {
-    R.setNotFoundInCurrentInstantiation();
-    return false;
-  }
-
-  // Perform lookup into our base classes.
-  CXXBasePaths Paths;
-  Paths.setOrigin(LookupRec);
-
-  // Look for this member in our base classes
-  bool (*BaseCallback)(const CXXBaseSpecifier *Specifier, CXXBasePath &Path,
-                       DeclarationName Name) = nullptr;
-  switch (R.getLookupKind()) {
-    case LookupObjCImplicitSelfParam:
-    case LookupOrdinaryName:
-    case LookupMemberName:
-    case LookupRedeclarationWithLinkage:
-    case LookupLocalFriendName:
-      BaseCallback = &CXXRecordDecl::FindOrdinaryMember;
-      break;
-
-    case LookupTagName:
-      BaseCallback = &CXXRecordDecl::FindTagMember;
-      break;
-
-    case LookupAnyName:
-      BaseCallback = &LookupAnyMember;
-      break;
-
-    case LookupOMPReductionName:
-      BaseCallback = &CXXRecordDecl::FindOMPReductionMember;
-      break;
-
-    case LookupUsingDeclName:
-      // This lookup is for redeclarations only.
-
-    case LookupOperatorName:
-    case LookupNamespaceName:
-    case LookupObjCProtocolName:
-    case LookupLabel:
-      // These lookups will never find a member in a C++ class (or base class).
-      return false;
-
-    case LookupNestedNameSpecifierName:
-      BaseCallback = &CXXRecordDecl::FindNestedNameSpecifierMember;
-      break;
-  }
-
-  DeclarationName Name = R.getLookupName();
-  if (!LookupRec->lookupInBases(
-          [=](const CXXBaseSpecifier *Specifier, CXXBasePath &Path) {
-            return BaseCallback(Specifier, Path, Name);
-          },
-          Paths))
-    return false;
-
-  R.setNamingClass(LookupRec);
-
-  // C++ [class.member.lookup]p2:
-  //   [...] If the resulting set of declarations are not all from
-  //   sub-objects of the same type, or the set has a nonstatic member
-  //   and includes members from distinct sub-objects, there is an
-  //   ambiguity and the program is ill-formed. Otherwise that set is
-  //   the result of the lookup.
-  QualType SubobjectType;
-  int SubobjectNumber = 0;
-  AccessSpecifier SubobjectAccess = AS_none;
-
-  for (CXXBasePaths::paths_iterator Path = Paths.begin(), PathEnd = Paths.end();
-       Path != PathEnd; ++Path) {
-    const CXXBasePathElement &PathElement = Path->back();
-
-    // Pick the best (i.e. most permissive i.e. numerically lowest) access
-    // across all paths.
-    SubobjectAccess = std::min(SubobjectAccess, Path->Access);
-
-    // Determine whether we're looking at a distinct sub-object or not.
-    if (SubobjectType.isNull()) {
-      // This is the first subobject we've looked at. Record its type.
-      SubobjectType = Context.getCanonicalType(PathElement.Base->getType());
-      SubobjectNumber = PathElement.SubobjectNumber;
-      continue;
-    }
-
-    if (SubobjectType
-                 != Context.getCanonicalType(PathElement.Base->getType())) {
-      // We found members of the given name in two subobjects of
-      // different types. If the declaration sets aren't the same, this
-      // lookup is ambiguous.
-      if (HasOnlyStaticMembers(Path->Decls.begin(), Path->Decls.end())) {
-        CXXBasePaths::paths_iterator FirstPath = Paths.begin();
-        DeclContext::lookup_iterator FirstD = FirstPath->Decls.begin();
-        DeclContext::lookup_iterator CurrentD = Path->Decls.begin();
-
-        while (FirstD != FirstPath->Decls.end() &&
-               CurrentD != Path->Decls.end()) {
-         if ((*FirstD)->getUnderlyingDecl()->getCanonicalDecl() !=
-             (*CurrentD)->getUnderlyingDecl()->getCanonicalDecl())
-           break;
-
-          ++FirstD;
-          ++CurrentD;
-        }
-
-        if (FirstD == FirstPath->Decls.end() &&
-            CurrentD == Path->Decls.end())
-          continue;
-      }
-
-      R.setAmbiguousBaseSubobjectTypes(Paths);
-      return true;
-    }
-
-    if (SubobjectNumber != PathElement.SubobjectNumber) {
-      // We have a different subobject of the same type.
-
-      // C++ [class.member.lookup]p5:
-      //   A static member, a nested type or an enumerator defined in
-      //   a base class T can unambiguously be found even if an object
-      //   has more than one base class subobject of type T.
-      if (HasOnlyStaticMembers(Path->Decls.begin(), Path->Decls.end()))
-        continue;
-
-      // We have found a nonstatic member name in multiple, distinct
-      // subobjects. Name lookup is ambiguous.
-      R.setAmbiguousBaseSubobjects(Paths);
-      return true;
-    }
-  }
-
-  // Lookup in a base class succeeded; return these results.
-
-  for (auto *D : Paths.front().Decls) {
-    AccessSpecifier AS = CXXRecordDecl::MergeAccess(SubobjectAccess,
-                                                    D->getAccess());
-    R.addDecl(D, AS);
-  }
-  R.resolveKind();
-  return true;
-}
-
-/// Performs qualified name lookup or special type of lookup for
-/// "__super::" scope specifier.
-///
-/// This routine is a convenience overload meant to be called from contexts
-/// that need to perform a qualified name lookup with an optional C++ scope
-/// specifier that might require special kind of lookup.
-///
-/// \param R captures both the lookup criteria and any lookup results found.
-///
-/// \param LookupCtx The context in which qualified name lookup will
-/// search.
-///
-/// \param SS An optional C++ scope-specifier.
-///
-/// \returns true if lookup succeeded, false if it failed.
-bool Sema::LookupQualifiedName(LookupResult &R, DeclContext *LookupCtx,
-                               CXXScopeSpec &SS) {
-  auto *NNS = SS.getScopeRep();
-  if (NNS && NNS->getKind() == NestedNameSpecifier::Super)
-    return LookupInSuper(R, NNS->getAsRecordDecl());
-  else
-
-    return LookupQualifiedName(R, LookupCtx);
-}
-
-/// Performs name lookup for a name that was parsed in the
-/// source code, and may contain a C++ scope specifier.
-///
-/// This routine is a convenience routine meant to be called from
-/// contexts that receive a name and an optional C++ scope specifier
-/// (e.g., "N::M::x"). It will then perform either qualified or
-/// unqualified name lookup (with LookupQualifiedName or LookupName,
-/// respectively) on the given name and return those results. It will
-/// perform a special type of lookup for "__super::" scope specifier.
-///
-/// @param S        The scope from which unqualified name lookup will
-/// begin.
-///
-/// @param SS       An optional C++ scope-specifier, e.g., "::N::M".
-///
-/// @param EnteringContext Indicates whether we are going to enter the
-/// context of the scope-specifier SS (if present).
-///
-/// @returns True if any decls were found (but possibly ambiguous)
-bool Sema::LookupParsedName(LookupResult &R, Scope *S, CXXScopeSpec *SS,
-                            bool AllowBuiltinCreation, bool EnteringContext) {
-  if (SS && SS->isInvalid()) {
-    // When the scope specifier is invalid, don't even look for
-    // anything.
-    return false;
-  }
-
-  if (SS && SS->isSet()) {
-    NestedNameSpecifier *NNS = SS->getScopeRep();
-    if (NNS->getKind() == NestedNameSpecifier::Super)
-      return LookupInSuper(R, NNS->getAsRecordDecl());
-
-    if (DeclContext *DC = computeDeclContext(*SS, EnteringContext)) {
-      // We have resolved the scope specifier to a particular declaration
-      // contex, and will perform name lookup in that context.
-      if (!DC->isDependentContext() && RequireCompleteDeclContext(*SS, DC))
-        return false;
-
-      R.setContextRange(SS->getRange());
-      return LookupQualifiedName(R, DC);
-    }
-
-    // We could not resolve the scope specified to a specific declaration
-    // context, which means that SS refers to an unknown specialization.
-    // Name lookup can't find anything in this case.
-    R.setNotFoundInCurrentInstantiation();
-    R.setContextRange(SS->getRange());
-    return false;
-  }
-
-  // Perform unqualified name lookup starting in the given scope.
-  return LookupName(R, S, AllowBuiltinCreation);
-}
-
-/// Perform qualified name lookup into all base classes of the given
-/// class.
-///
-/// \param R captures both the lookup criteria and any lookup results found.
-///
-/// \param Class The context in which qualified name lookup will
-/// search. Name lookup will search in all base classes merging the results.
-///
-/// @returns True if any decls were found (but possibly ambiguous)
-bool Sema::LookupInSuper(LookupResult &R, CXXRecordDecl *Class) {
-  // The access-control rules we use here are essentially the rules for
-  // doing a lookup in Class that just magically skipped the direct
-  // members of Class itself.  That is, the naming class is Class, and the
-  // access includes the access of the base.
-  for (const auto &BaseSpec : Class->bases()) {
-    CXXRecordDecl *RD = cast<CXXRecordDecl>(
-        BaseSpec.getType()->castAs<RecordType>()->getDecl());
-    LookupResult Result(*this, R.getLookupNameInfo(), R.getLookupKind());
-    Result.setBaseObjectType(Context.getRecordType(Class));
-    LookupQualifiedName(Result, RD);
-
-    // Copy the lookup results into the target, merging the base's access into
-    // the path access.
-    for (auto I = Result.begin(), E = Result.end(); I != E; ++I) {
-      R.addDecl(I.getDecl(),
-                CXXRecordDecl::MergeAccess(BaseSpec.getAccessSpecifier(),
-                                           I.getAccess()));
-    }
-
-    Result.suppressDiagnostics();
-  }
-
-  R.resolveKind();
-  R.setNamingClass(Class);
-
-  return !R.empty();
-}
-
-/// Produce a diagnostic describing the ambiguity that resulted
-/// from name lookup.
-///
-/// \param Result The result of the ambiguous lookup to be diagnosed.
-void Sema::DiagnoseAmbiguousLookup(LookupResult &Result) {
-  assert(Result.isAmbiguous() && "Lookup result must be ambiguous");
-
-  DeclarationName Name = Result.getLookupName();
-  SourceLocation NameLoc = Result.getNameLoc();
-  SourceRange LookupRange = Result.getContextRange();
-
-  switch (Result.getAmbiguityKind()) {
-  case LookupResult::AmbiguousBaseSubobjects: {
-    CXXBasePaths *Paths = Result.getBasePaths();
-    QualType SubobjectType = Paths->front().back().Base->getType();
-    Diag(NameLoc, diag::err_ambiguous_member_multiple_subobjects)
-      << Name << SubobjectType << getAmbiguousPathsDisplayString(*Paths)
-      << LookupRange;
-
-    DeclContext::lookup_iterator Found = Paths->front().Decls.begin();
-    while (isa<CXXMethodDecl>(*Found) &&
-           cast<CXXMethodDecl>(*Found)->isStatic())
-      ++Found;
-
-    Diag((*Found)->getLocation(), diag::note_ambiguous_member_found);
-    break;
-  }
-
-  case LookupResult::AmbiguousBaseSubobjectTypes: {
-    Diag(NameLoc, diag::err_ambiguous_member_multiple_subobject_types)
-      << Name << LookupRange;
-
-    CXXBasePaths *Paths = Result.getBasePaths();
-    std::set<Decl *> DeclsPrinted;
-    for (CXXBasePaths::paths_iterator Path = Paths->begin(),
-                                      PathEnd = Paths->end();
-         Path != PathEnd; ++Path) {
-      Decl *D = Path->Decls.front();
-      if (DeclsPrinted.insert(D).second)
-        Diag(D->getLocation(), diag::note_ambiguous_member_found);
-    }
-    break;
-  }
-
-  case LookupResult::AmbiguousTagHiding: {
-    Diag(NameLoc, diag::err_ambiguous_tag_hiding) << Name << LookupRange;
-
-    llvm::SmallPtrSet<NamedDecl*, 8> TagDecls;
-
-    for (auto *D : Result)
-      if (TagDecl *TD = dyn_cast<TagDecl>(D)) {
-        TagDecls.insert(TD);
-        Diag(TD->getLocation(), diag::note_hidden_tag);
-      }
-
-    for (auto *D : Result)
-      if (!isa<TagDecl>(D))
-        Diag(D->getLocation(), diag::note_hiding_object);
-
-    // For recovery purposes, go ahead and implement the hiding.
-    LookupResult::Filter F = Result.makeFilter();
-    while (F.hasNext()) {
-      if (TagDecls.count(F.next()))
-        F.erase();
-    }
-    F.done();
-    break;
-  }
-
-  case LookupResult::AmbiguousReference: {
-    Diag(NameLoc, diag::err_ambiguous_reference) << Name << LookupRange;
-
-    for (auto *D : Result)
-      Diag(D->getLocation(), diag::note_ambiguous_candidate) << D;
-    break;
-  }
-  }
-}
-
-namespace {
-  struct AssociatedLookup {
-    AssociatedLookup(Sema &S, SourceLocation InstantiationLoc,
-                     Sema::AssociatedNamespaceSet &Namespaces,
-                     Sema::AssociatedClassSet &Classes)
-      : S(S), Namespaces(Namespaces), Classes(Classes),
-        InstantiationLoc(InstantiationLoc) {
-    }
-
-    Sema &S;
-    Sema::AssociatedNamespaceSet &Namespaces;
-    Sema::AssociatedClassSet &Classes;
-    SourceLocation InstantiationLoc;
-  };
-} // end anonymous namespace
-
-static void
-addAssociatedClassesAndNamespaces(AssociatedLookup &Result, QualType T);
-
-static void CollectEnclosingNamespace(Sema::AssociatedNamespaceSet &Namespaces,
-                                      DeclContext *Ctx) {
-  // Add the associated namespace for this class.
-
-  // We don't use DeclContext::getEnclosingNamespaceContext() as this may
-  // be a locally scoped record.
-
-  // We skip out of inline namespaces. The innermost non-inline namespace
-  // contains all names of all its nested inline namespaces anyway, so we can
-  // replace the entire inline namespace tree with its root.
-  while (Ctx->isRecord() || Ctx->isTransparentContext() ||
-         Ctx->isInlineNamespace())
-    Ctx = Ctx->getParent();
-
-  if (Ctx->isFileContext())
-    Namespaces.insert(Ctx->getPrimaryContext());
-}
-
-// Add the associated classes and namespaces for argument-dependent
-// lookup that involves a template argument (C++ [basic.lookup.koenig]p2).
-static void
-addAssociatedClassesAndNamespaces(AssociatedLookup &Result,
-                                  const TemplateArgument &Arg) {
-  // C++ [basic.lookup.koenig]p2, last bullet:
-  //   -- [...] ;
-  switch (Arg.getKind()) {
-    case TemplateArgument::Null:
-      break;
-
-    case TemplateArgument::Type:
-      // [...] the namespaces and classes associated with the types of the
-      // template arguments provided for template type parameters (excluding
-      // template template parameters)
-      addAssociatedClassesAndNamespaces(Result, Arg.getAsType());
-      break;
-
-    case TemplateArgument::Template:
-    case TemplateArgument::TemplateExpansion: {
-      // [...] the namespaces in which any template template arguments are
-      // defined; and the classes in which any member templates used as
-      // template template arguments are defined.
-      TemplateName Template = Arg.getAsTemplateOrTemplatePattern();
-      if (ClassTemplateDecl *ClassTemplate
-                 = dyn_cast<ClassTemplateDecl>(Template.getAsTemplateDecl())) {
-        DeclContext *Ctx = ClassTemplate->getDeclContext();
-        if (CXXRecordDecl *EnclosingClass = dyn_cast<CXXRecordDecl>(Ctx))
-          Result.Classes.insert(EnclosingClass);
-        // Add the associated namespace for this class.
-        CollectEnclosingNamespace(Result.Namespaces, Ctx);
-      }
-      break;
-    }
-
-    case TemplateArgument::Declaration:
-    case TemplateArgument::Integral:
-    case TemplateArgument::Expression:
-    case TemplateArgument::NullPtr:
-      // [Note: non-type template arguments do not contribute to the set of
-      //  associated namespaces. ]
-      break;
-
-    case TemplateArgument::Pack:
-      for (const auto &P : Arg.pack_elements())
-        addAssociatedClassesAndNamespaces(Result, P);
-      break;
-  }
-}
-
-// Add the associated classes and namespaces for
-// argument-dependent lookup with an argument of class type
-// (C++ [basic.lookup.koenig]p2).
-static void
-addAssociatedClassesAndNamespaces(AssociatedLookup &Result,
-                                  CXXRecordDecl *Class) {
-
-  // Just silently ignore anything whose name is __va_list_tag.
-  if (Class->getDeclName() == Result.S.VAListTagName)
-    return;
-
-  // C++ [basic.lookup.koenig]p2:
-  //   [...]
-  //     -- If T is a class type (including unions), its associated
-  //        classes are: the class itself; the class of which it is a
-  //        member, if any; and its direct and indirect base
-  //        classes. Its associated namespaces are the namespaces in
-  //        which its associated classes are defined.
-
-  // Add the class of which it is a member, if any.
-  DeclContext *Ctx = Class->getDeclContext();
-  if (CXXRecordDecl *EnclosingClass = dyn_cast<CXXRecordDecl>(Ctx))
-    Result.Classes.insert(EnclosingClass);
-  // Add the associated namespace for this class.
-  CollectEnclosingNamespace(Result.Namespaces, Ctx);
-
-  // Add the class itself. If we've already seen this class, we don't
-  // need to visit base classes.
-  //
-  // FIXME: That's not correct, we may have added this class only because it
-  // was the enclosing class of another class, and in that case we won't have
-  // added its base classes yet.
-  if (!Result.Classes.insert(Class))
-    return;
-
-  // -- If T is a template-id, its associated namespaces and classes are
-  //    the namespace in which the template is defined; for member
-  //    templates, the member template's class; the namespaces and classes
-  //    associated with the types of the template arguments provided for
-  //    template type parameters (excluding template template parameters); the
-  //    namespaces in which any template template arguments are defined; and
-  //    the classes in which any member templates used as template template
-  //    arguments are defined. [Note: non-type template arguments do not
-  //    contribute to the set of associated namespaces. ]
-  if (ClassTemplateSpecializationDecl *Spec
-        = dyn_cast<ClassTemplateSpecializationDecl>(Class)) {
-    DeclContext *Ctx = Spec->getSpecializedTemplate()->getDeclContext();
-    if (CXXRecordDecl *EnclosingClass = dyn_cast<CXXRecordDecl>(Ctx))
-      Result.Classes.insert(EnclosingClass);
-    // Add the associated namespace for this class.
-    CollectEnclosingNamespace(Result.Namespaces, Ctx);
-
-    const TemplateArgumentList &TemplateArgs = Spec->getTemplateArgs();
-    for (unsigned I = 0, N = TemplateArgs.size(); I != N; ++I)
-      addAssociatedClassesAndNamespaces(Result, TemplateArgs[I]);
-  }
-
-  // Only recurse into base classes for complete types.
-  if (!Result.S.isCompleteType(Result.InstantiationLoc,
-                               Result.S.Context.getRecordType(Class)))
-    return;
-
-  // Add direct and indirect base classes along with their associated
-  // namespaces.
-  SmallVector<CXXRecordDecl *, 32> Bases;
-  Bases.push_back(Class);
-  while (!Bases.empty()) {
-    // Pop this class off the stack.
-    Class = Bases.pop_back_val();
-
-    // Visit the base classes.
-    for (const auto &Base : Class->bases()) {
-      const RecordType *BaseType = Base.getType()->getAs<RecordType>();
-      // In dependent contexts, we do ADL twice, and the first time around,
-      // the base type might be a dependent TemplateSpecializationType, or a
-      // TemplateTypeParmType. If that happens, simply ignore it.
-      // FIXME: If we want to support export, we probably need to add the
-      // namespace of the template in a TemplateSpecializationType, or even
-      // the classes and namespaces of known non-dependent arguments.
-      if (!BaseType)
-        continue;
-      CXXRecordDecl *BaseDecl = cast<CXXRecordDecl>(BaseType->getDecl());
-      if (Result.Classes.insert(BaseDecl)) {
-        // Find the associated namespace for this base class.
-        DeclContext *BaseCtx = BaseDecl->getDeclContext();
-        CollectEnclosingNamespace(Result.Namespaces, BaseCtx);
-
-        // Make sure we visit the bases of this base class.
-        if (BaseDecl->bases_begin() != BaseDecl->bases_end())
-          Bases.push_back(BaseDecl);
-      }
-    }
-  }
-}
-
-// Add the associated classes and namespaces for
-// argument-dependent lookup with an argument of type T
-// (C++ [basic.lookup.koenig]p2).
-static void
-addAssociatedClassesAndNamespaces(AssociatedLookup &Result, QualType Ty) {
-  // C++ [basic.lookup.koenig]p2:
-  //
-  //   For each argument type T in the function call, there is a set
-  //   of zero or more associated namespaces and a set of zero or more
-  //   associated classes to be considered. The sets of namespaces and
-  //   classes is determined entirely by the types of the function
-  //   arguments (and the namespace of any template template
-  //   argument). Typedef names and using-declarations used to specify
-  //   the types do not contribute to this set. The sets of namespaces
-  //   and classes are determined in the following way:
-
-  SmallVector<const Type *, 16> Queue;
-  const Type *T = Ty->getCanonicalTypeInternal().getTypePtr();
-
-  while (true) {
-    switch (T->getTypeClass()) {
-
-#define TYPE(Class, Base)
-#define DEPENDENT_TYPE(Class, Base) case Type::Class:
-#define NON_CANONICAL_TYPE(Class, Base) case Type::Class:
-#define NON_CANONICAL_UNLESS_DEPENDENT_TYPE(Class, Base) case Type::Class:
-#define ABSTRACT_TYPE(Class, Base)
-#include "clang/AST/TypeNodes.def"
-      // T is canonical.  We can also ignore dependent types because
-      // we don't need to do ADL at the definition point, but if we
-      // wanted to implement template export (or if we find some other
-      // use for associated classes and namespaces...) this would be
-      // wrong.
-      break;
-
-    //    -- If T is a pointer to U or an array of U, its associated
-    //       namespaces and classes are those associated with U.
-    case Type::Pointer:
-      T = cast<PointerType>(T)->getPointeeType().getTypePtr();
-      continue;
-    case Type::ConstantArray:
-    case Type::IncompleteArray:
-    case Type::VariableArray:
-      T = cast<ArrayType>(T)->getElementType().getTypePtr();
-      continue;
-
-    //     -- If T is a fundamental type, its associated sets of
-    //        namespaces and classes are both empty.
-    case Type::Builtin:
-      break;
-
-    //     -- If T is a class type (including unions), its associated
-    //        classes are: the class itself; the class of which it is a
-    //        member, if any; and its direct and indirect base
-    //        classes. Its associated namespaces are the namespaces in
-    //        which its associated classes are defined.
-    case Type::Record: {
-      CXXRecordDecl *Class =
-          cast<CXXRecordDecl>(cast<RecordType>(T)->getDecl());
-      addAssociatedClassesAndNamespaces(Result, Class);
-      break;
-    }
-
-    //     -- If T is an enumeration type, its associated namespace is
-    //        the namespace in which it is defined. If it is class
-    //        member, its associated class is the member's class; else
-    //        it has no associated class.
-    case Type::Enum: {
-      EnumDecl *Enum = cast<EnumType>(T)->getDecl();
-
-      DeclContext *Ctx = Enum->getDeclContext();
-      if (CXXRecordDecl *EnclosingClass = dyn_cast<CXXRecordDecl>(Ctx))
-        Result.Classes.insert(EnclosingClass);
-
-      // Add the associated namespace for this class.
-      CollectEnclosingNamespace(Result.Namespaces, Ctx);
-
-      break;
-    }
-
-    //     -- If T is a function type, its associated namespaces and
-    //        classes are those associated with the function parameter
-    //        types and those associated with the return type.
-    case Type::FunctionProto: {
-      const FunctionProtoType *Proto = cast<FunctionProtoType>(T);
-      for (const auto &Arg : Proto->param_types())
-        Queue.push_back(Arg.getTypePtr());
-      // fallthrough
-      LLVM_FALLTHROUGH;
-    }
-    case Type::FunctionNoProto: {
-      const FunctionType *FnType = cast<FunctionType>(T);
-      T = FnType->getReturnType().getTypePtr();
-      continue;
-    }
-
-    //     -- If T is a pointer to a member function of a class X, its
-    //        associated namespaces and classes are those associated
-    //        with the function parameter types and return type,
-    //        together with those associated with X.
-    //
-    //     -- If T is a pointer to a data member of class X, its
-    //        associated namespaces and classes are those associated
-    //        with the member type together with those associated with
-    //        X.
-    case Type::MemberPointer: {
-      const MemberPointerType *MemberPtr = cast<MemberPointerType>(T);
-
-      // Queue up the class type into which this points.
-      Queue.push_back(MemberPtr->getClass());
-
-      // And directly continue with the pointee type.
-      T = MemberPtr->getPointeeType().getTypePtr();
-      continue;
-    }
-
-    // As an extension, treat this like a normal pointer.
-    case Type::BlockPointer:
-      T = cast<BlockPointerType>(T)->getPointeeType().getTypePtr();
-      continue;
-
-    // References aren't covered by the standard, but that's such an
-    // obvious defect that we cover them anyway.
-    case Type::LValueReference:
-    case Type::RValueReference:
-      T = cast<ReferenceType>(T)->getPointeeType().getTypePtr();
-      continue;
-
-    // These are fundamental types.
-    case Type::Vector:
-    case Type::ExtVector:
-    case Type::Complex:
-      break;
-
-    // Non-deduced auto types only get here for error cases.
-    case Type::Auto:
-    case Type::DeducedTemplateSpecialization:
-      break;
-
-    // If T is an Objective-C object or interface type, or a pointer to an
-    // object or interface type, the associated namespace is the global
-    // namespace.
-    case Type::ObjCObject:
-    case Type::ObjCInterface:
-    case Type::ObjCObjectPointer:
-      Result.Namespaces.insert(Result.S.Context.getTranslationUnitDecl());
-      break;
-
-    // Atomic types are just wrappers; use the associations of the
-    // contained type.
-    case Type::Atomic:
-      T = cast<AtomicType>(T)->getValueType().getTypePtr();
-      continue;
-    case Type::Pipe:
-      T = cast<PipeType>(T)->getElementType().getTypePtr();
-      continue;
-    }
-
-    if (Queue.empty())
-      break;
-    T = Queue.pop_back_val();
-  }
-}
-
-/// Find the associated classes and namespaces for
-/// argument-dependent lookup for a call with the given set of
-/// arguments.
-///
-/// This routine computes the sets of associated classes and associated
-/// namespaces searched by argument-dependent lookup
-/// (C++ [basic.lookup.argdep]) for a given set of arguments.
-void Sema::FindAssociatedClassesAndNamespaces(
-    SourceLocation InstantiationLoc, ArrayRef<Expr *> Args,
-    AssociatedNamespaceSet &AssociatedNamespaces,
-    AssociatedClassSet &AssociatedClasses) {
-  AssociatedNamespaces.clear();
-  AssociatedClasses.clear();
-
-  AssociatedLookup Result(*this, InstantiationLoc,
-                          AssociatedNamespaces, AssociatedClasses);
-
-  // C++ [basic.lookup.koenig]p2:
-  //   For each argument type T in the function call, there is a set
-  //   of zero or more associated namespaces and a set of zero or more
-  //   associated classes to be considered. The sets of namespaces and
-  //   classes is determined entirely by the types of the function
-  //   arguments (and the namespace of any template template
-  //   argument).
-  for (unsigned ArgIdx = 0; ArgIdx != Args.size(); ++ArgIdx) {
-    Expr *Arg = Args[ArgIdx];
-
-    if (Arg->getType() != Context.OverloadTy) {
-      addAssociatedClassesAndNamespaces(Result, Arg->getType());
-      continue;
-    }
-
-    // [...] In addition, if the argument is the name or address of a
-    // set of overloaded functions and/or function templates, its
-    // associated classes and namespaces are the union of those
-    // associated with each of the members of the set: the namespace
-    // in which the function or function template is defined and the
-    // classes and namespaces associated with its (non-dependent)
-    // parameter types and return type.
-    Arg = Arg->IgnoreParens();
-    if (UnaryOperator *unaryOp = dyn_cast<UnaryOperator>(Arg))
-      if (unaryOp->getOpcode() == UO_AddrOf)
-        Arg = unaryOp->getSubExpr();
-
-    UnresolvedLookupExpr *ULE = dyn_cast<UnresolvedLookupExpr>(Arg);
-    if (!ULE) continue;
-
-    for (const auto *D : ULE->decls()) {
-      // Look through any using declarations to find the underlying function.
-      const FunctionDecl *FDecl = D->getUnderlyingDecl()->getAsFunction();
-
-      // Add the classes and namespaces associated with the parameter
-      // types and return type of this function.
-      addAssociatedClassesAndNamespaces(Result, FDecl->getType());
-    }
-  }
-}
-
-NamedDecl *Sema::LookupSingleName(Scope *S, DeclarationName Name,
-                                  SourceLocation Loc,
-                                  LookupNameKind NameKind,
-                                  RedeclarationKind Redecl) {
-  LookupResult R(*this, Name, Loc, NameKind, Redecl);
-  LookupName(R, S);
-  return R.getAsSingle<NamedDecl>();
-}
-
-/// Find the protocol with the given name, if any.
-ObjCProtocolDecl *Sema::LookupProtocol(IdentifierInfo *II,
-                                       SourceLocation IdLoc,
-                                       RedeclarationKind Redecl) {
-  Decl *D = LookupSingleName(TUScope, II, IdLoc,
-                             LookupObjCProtocolName, Redecl);
-  return cast_or_null<ObjCProtocolDecl>(D);
-}
-
-void Sema::LookupOverloadedOperatorName(OverloadedOperatorKind Op, Scope *S,
-                                        QualType T1, QualType T2,
-                                        UnresolvedSetImpl &Functions) {
-  // C++ [over.match.oper]p3:
-  //     -- The set of non-member candidates is the result of the
-  //        unqualified lookup of operator@ in the context of the
-  //        expression according to the usual rules for name lookup in
-  //        unqualified function calls (3.4.2) except that all member
-  //        functions are ignored.
-  DeclarationName OpName = Context.DeclarationNames.getCXXOperatorName(Op);
-  LookupResult Operators(*this, OpName, SourceLocation(), LookupOperatorName);
-  LookupName(Operators, S);
-
-  assert(!Operators.isAmbiguous() && "Operator lookup cannot be ambiguous");
-  Functions.append(Operators.begin(), Operators.end());
-}
-
-Sema::SpecialMemberOverloadResult Sema::LookupSpecialMember(CXXRecordDecl *RD,
-                                                           CXXSpecialMember SM,
-                                                           bool ConstArg,
-                                                           bool VolatileArg,
-                                                           bool RValueThis,
-                                                           bool ConstThis,
-                                                           bool VolatileThis) {
-  assert(CanDeclareSpecialMemberFunction(RD) &&
-         "doing special member lookup into record that isn't fully complete");
-  RD = RD->getDefinition();
-  if (RValueThis || ConstThis || VolatileThis)
-    assert((SM == CXXCopyAssignment || SM == CXXMoveAssignment) &&
-           "constructors and destructors always have unqualified lvalue this");
-  if (ConstArg || VolatileArg)
-    assert((SM != CXXDefaultConstructor && SM != CXXDestructor) &&
-           "parameter-less special members can't have qualified arguments");
-
-  // FIXME: Get the caller to pass in a location for the lookup.
-  SourceLocation LookupLoc = RD->getLocation();
-
-  llvm::FoldingSetNodeID ID;
-  ID.AddPointer(RD);
-  ID.AddInteger(SM);
-  ID.AddInteger(ConstArg);
-  ID.AddInteger(VolatileArg);
-  ID.AddInteger(RValueThis);
-  ID.AddInteger(ConstThis);
-  ID.AddInteger(VolatileThis);
-
-  void *InsertPoint;
-  SpecialMemberOverloadResultEntry *Result =
-    SpecialMemberCache.FindNodeOrInsertPos(ID, InsertPoint);
-
-  // This was already cached
-  if (Result)
-    return *Result;
-
-  Result = BumpAlloc.Allocate<SpecialMemberOverloadResultEntry>();
-  Result = new (Result) SpecialMemberOverloadResultEntry(ID);
-  SpecialMemberCache.InsertNode(Result, InsertPoint);
-
-  if (SM == CXXDestructor) {
-    if (RD->needsImplicitDestructor())
-      DeclareImplicitDestructor(RD);
-    CXXDestructorDecl *DD = RD->getDestructor();
-    assert(DD && "record without a destructor");
-    Result->setMethod(DD);
-    Result->setKind(DD->isDeleted() ?
-                    SpecialMemberOverloadResult::NoMemberOrDeleted :
-                    SpecialMemberOverloadResult::Success);
-    return *Result;
-  }
-
-  // Prepare for overload resolution. Here we construct a synthetic argument
-  // if necessary and make sure that implicit functions are declared.
-  CanQualType CanTy = Context.getCanonicalType(Context.getTagDeclType(RD));
-  DeclarationName Name;
-  Expr *Arg = nullptr;
-  unsigned NumArgs;
-
-  QualType ArgType = CanTy;
-  ExprValueKind VK = VK_LValue;
-
-  if (SM == CXXDefaultConstructor) {
-    Name = Context.DeclarationNames.getCXXConstructorName(CanTy);
-    NumArgs = 0;
-    if (RD->needsImplicitDefaultConstructor())
-      DeclareImplicitDefaultConstructor(RD);
-  } else {
-    if (SM == CXXCopyConstructor || SM == CXXMoveConstructor) {
-      Name = Context.DeclarationNames.getCXXConstructorName(CanTy);
-      if (RD->needsImplicitCopyConstructor())
-        DeclareImplicitCopyConstructor(RD);
-      if (getLangOpts().CPlusPlus11 && RD->needsImplicitMoveConstructor())
-        DeclareImplicitMoveConstructor(RD);
-    } else {
-      Name = Context.DeclarationNames.getCXXOperatorName(OO_Equal);
-      if (RD->needsImplicitCopyAssignment())
-        DeclareImplicitCopyAssignment(RD);
-      if (getLangOpts().CPlusPlus11 && RD->needsImplicitMoveAssignment())
-        DeclareImplicitMoveAssignment(RD);
-    }
-
-    if (ConstArg)
-      ArgType.addConst();
-    if (VolatileArg)
-      ArgType.addVolatile();
-
-    // This isn't /really/ specified by the standard, but it's implied
-    // we should be working from an RValue in the case of move to ensure
-    // that we prefer to bind to rvalue references, and an LValue in the
-    // case of copy to ensure we don't bind to rvalue references.
-    // Possibly an XValue is actually correct in the case of move, but
-    // there is no semantic difference for class types in this restricted
-    // case.
-    if (SM == CXXCopyConstructor || SM == CXXCopyAssignment)
-      VK = VK_LValue;
-    else
-      VK = VK_RValue;
-  }
-
-  OpaqueValueExpr FakeArg(LookupLoc, ArgType, VK);
-
-  if (SM != CXXDefaultConstructor) {
-    NumArgs = 1;
-    Arg = &FakeArg;
-  }
-
-  // Create the object argument
-  QualType ThisTy = CanTy;
-  if (ConstThis)
-    ThisTy.addConst();
-  if (VolatileThis)
-    ThisTy.addVolatile();
-  Expr::Classification Classification =
-    OpaqueValueExpr(LookupLoc, ThisTy,
-                    RValueThis ? VK_RValue : VK_LValue).Classify(Context);
-
-  // Now we perform lookup on the name we computed earlier and do overload
-  // resolution. Lookup is only performed directly into the class since there
-  // will always be a (possibly implicit) declaration to shadow any others.
-  OverloadCandidateSet OCS(LookupLoc, OverloadCandidateSet::CSK_Normal);
-  DeclContext::lookup_result R = RD->lookup(Name);
-
-  if (R.empty()) {
-    // We might have no default constructor because we have a lambda's closure
-    // type, rather than because there's some other declared constructor.
-    // Every class has a copy/move constructor, copy/move assignment, and
-    // destructor.
-    assert(SM == CXXDefaultConstructor &&
-           "lookup for a constructor or assignment operator was empty");
-    Result->setMethod(nullptr);
-    Result->setKind(SpecialMemberOverloadResult::NoMemberOrDeleted);
-    return *Result;
-  }
-
-  // Copy the candidates as our processing of them may load new declarations
-  // from an external source and invalidate lookup_result.
-  SmallVector<NamedDecl *, 8> Candidates(R.begin(), R.end());
-
-  for (NamedDecl *CandDecl : Candidates) {
-    if (CandDecl->isInvalidDecl())
-      continue;
-
-    DeclAccessPair Cand = DeclAccessPair::make(CandDecl, AS_public);
-    auto CtorInfo = getConstructorInfo(Cand);
-    if (CXXMethodDecl *M = dyn_cast<CXXMethodDecl>(Cand->getUnderlyingDecl())) {
-      if (SM == CXXCopyAssignment || SM == CXXMoveAssignment)
-        AddMethodCandidate(M, Cand, RD, ThisTy, Classification,
-                           llvm::makeArrayRef(&Arg, NumArgs), OCS, true);
-      else if (CtorInfo)
-        AddOverloadCandidate(CtorInfo.Constructor, CtorInfo.FoundDecl,
-                             llvm::makeArrayRef(&Arg, NumArgs), OCS, true);
-      else
-        AddOverloadCandidate(M, Cand, llvm::makeArrayRef(&Arg, NumArgs), OCS,
-                             true);
-    } else if (FunctionTemplateDecl *Tmpl =
-                 dyn_cast<FunctionTemplateDecl>(Cand->getUnderlyingDecl())) {
-      if (SM == CXXCopyAssignment || SM == CXXMoveAssignment)
-        AddMethodTemplateCandidate(
-            Tmpl, Cand, RD, nullptr, ThisTy, Classification,
-            llvm::makeArrayRef(&Arg, NumArgs), OCS, true);
-      else if (CtorInfo)
-        AddTemplateOverloadCandidate(
-            CtorInfo.ConstructorTmpl, CtorInfo.FoundDecl, nullptr,
-            llvm::makeArrayRef(&Arg, NumArgs), OCS, true);
-      else
-        AddTemplateOverloadCandidate(
-            Tmpl, Cand, nullptr, llvm::makeArrayRef(&Arg, NumArgs), OCS, true);
-    } else {
-      assert(isa<UsingDecl>(Cand.getDecl()) &&
-             "illegal Kind of operator = Decl");
-    }
-  }
-
-  OverloadCandidateSet::iterator Best;
-  switch (OCS.BestViableFunction(*this, LookupLoc, Best)) {
-    case OR_Success:
-      Result->setMethod(cast<CXXMethodDecl>(Best->Function));
-      Result->setKind(SpecialMemberOverloadResult::Success);
-      break;
-
-    case OR_Deleted:
-      Result->setMethod(cast<CXXMethodDecl>(Best->Function));
-      Result->setKind(SpecialMemberOverloadResult::NoMemberOrDeleted);
-      break;
-
-    case OR_Ambiguous:
-      Result->setMethod(nullptr);
-      Result->setKind(SpecialMemberOverloadResult::Ambiguous);
-      break;
-
-    case OR_No_Viable_Function:
-      Result->setMethod(nullptr);
-      Result->setKind(SpecialMemberOverloadResult::NoMemberOrDeleted);
-      break;
-  }
-
-  return *Result;
-}
-
-/// Look up the default constructor for the given class.
-CXXConstructorDecl *Sema::LookupDefaultConstructor(CXXRecordDecl *Class) {
-  SpecialMemberOverloadResult Result =
-    LookupSpecialMember(Class, CXXDefaultConstructor, false, false, false,
-                        false, false);
-
-  return cast_or_null<CXXConstructorDecl>(Result.getMethod());
-}
-
-/// Look up the copying constructor for the given class.
-CXXConstructorDecl *Sema::LookupCopyingConstructor(CXXRecordDecl *Class,
-                                                   unsigned Quals) {
-  assert(!(Quals & ~(Qualifiers::Const | Qualifiers::Volatile)) &&
-         "non-const, non-volatile qualifiers for copy ctor arg");
-  SpecialMemberOverloadResult Result =
-    LookupSpecialMember(Class, CXXCopyConstructor, Quals & Qualifiers::Const,
-                        Quals & Qualifiers::Volatile, false, false, false);
-
-  return cast_or_null<CXXConstructorDecl>(Result.getMethod());
-}
-
-/// Look up the moving constructor for the given class.
-CXXConstructorDecl *Sema::LookupMovingConstructor(CXXRecordDecl *Class,
-                                                  unsigned Quals) {
-  SpecialMemberOverloadResult Result =
-    LookupSpecialMember(Class, CXXMoveConstructor, Quals & Qualifiers::Const,
-                        Quals & Qualifiers::Volatile, false, false, false);
-
-  return cast_or_null<CXXConstructorDecl>(Result.getMethod());
-}
-
-/// Look up the constructors for the given class.
-DeclContext::lookup_result Sema::LookupConstructors(CXXRecordDecl *Class) {
-  // If the implicit constructors have not yet been declared, do so now.
-  if (CanDeclareSpecialMemberFunction(Class)) {
-    if (Class->needsImplicitDefaultConstructor())
-      DeclareImplicitDefaultConstructor(Class);
-    if (Class->needsImplicitCopyConstructor())
-      DeclareImplicitCopyConstructor(Class);
-    if (getLangOpts().CPlusPlus11 && Class->needsImplicitMoveConstructor())
-      DeclareImplicitMoveConstructor(Class);
-  }
-
-  CanQualType T = Context.getCanonicalType(Context.getTypeDeclType(Class));
-  DeclarationName Name = Context.DeclarationNames.getCXXConstructorName(T);
-  return Class->lookup(Name);
-}
-
-/// Look up the copying assignment operator for the given class.
-CXXMethodDecl *Sema::LookupCopyingAssignment(CXXRecordDecl *Class,
-                                             unsigned Quals, bool RValueThis,
-                                             unsigned ThisQuals) {
-  assert(!(Quals & ~(Qualifiers::Const | Qualifiers::Volatile)) &&
-         "non-const, non-volatile qualifiers for copy assignment arg");
-  assert(!(ThisQuals & ~(Qualifiers::Const | Qualifiers::Volatile)) &&
-         "non-const, non-volatile qualifiers for copy assignment this");
-  SpecialMemberOverloadResult Result =
-    LookupSpecialMember(Class, CXXCopyAssignment, Quals & Qualifiers::Const,
-                        Quals & Qualifiers::Volatile, RValueThis,
-                        ThisQuals & Qualifiers::Const,
-                        ThisQuals & Qualifiers::Volatile);
-
-  return Result.getMethod();
-}
-
-/// Look up the moving assignment operator for the given class.
-CXXMethodDecl *Sema::LookupMovingAssignment(CXXRecordDecl *Class,
-                                            unsigned Quals,
-                                            bool RValueThis,
-                                            unsigned ThisQuals) {
-  assert(!(ThisQuals & ~(Qualifiers::Const | Qualifiers::Volatile)) &&
-         "non-const, non-volatile qualifiers for copy assignment this");
-  SpecialMemberOverloadResult Result =
-    LookupSpecialMember(Class, CXXMoveAssignment, Quals & Qualifiers::Const,
-                        Quals & Qualifiers::Volatile, RValueThis,
-                        ThisQuals & Qualifiers::Const,
-                        ThisQuals & Qualifiers::Volatile);
-
-  return Result.getMethod();
-}
-
-/// Look for the destructor of the given class.
-///
-/// During semantic analysis, this routine should be used in lieu of
-/// CXXRecordDecl::getDestructor().
-///
-/// \returns The destructor for this class.
-CXXDestructorDecl *Sema::LookupDestructor(CXXRecordDecl *Class) {
-  return cast<CXXDestructorDecl>(LookupSpecialMember(Class, CXXDestructor,
-                                                     false, false, false,
-                                                     false, false).getMethod());
-}
-
-/// LookupLiteralOperator - Determine which literal operator should be used for
-/// a user-defined literal, per C++11 [lex.ext].
-///
-/// Normal overload resolution is not used to select which literal operator to
-/// call for a user-defined literal. Look up the provided literal operator name,
-/// and filter the results to the appropriate set for the given argument types.
-Sema::LiteralOperatorLookupResult
-Sema::LookupLiteralOperator(Scope *S, LookupResult &R,
-                            ArrayRef<QualType> ArgTys,
-                            bool AllowRaw, bool AllowTemplate,
-                            bool AllowStringTemplate, bool DiagnoseMissing) {
-  LookupName(R, S);
-  assert(R.getResultKind() != LookupResult::Ambiguous &&
-         "literal operator lookup can't be ambiguous");
-
-  // Filter the lookup results appropriately.
-  LookupResult::Filter F = R.makeFilter();
-
-  bool FoundRaw = false;
-  bool FoundTemplate = false;
-  bool FoundStringTemplate = false;
-  bool FoundExactMatch = false;
-
-  while (F.hasNext()) {
-    Decl *D = F.next();
-    if (UsingShadowDecl *USD = dyn_cast<UsingShadowDecl>(D))
-      D = USD->getTargetDecl();
-
-    // If the declaration we found is invalid, skip it.
-    if (D->isInvalidDecl()) {
-      F.erase();
-      continue;
-    }
-
-    bool IsRaw = false;
-    bool IsTemplate = false;
-    bool IsStringTemplate = false;
-    bool IsExactMatch = false;
-
-    if (FunctionDecl *FD = dyn_cast<FunctionDecl>(D)) {
-      if (FD->getNumParams() == 1 &&
-          FD->getParamDecl(0)->getType()->getAs<PointerType>())
-        IsRaw = true;
-      else if (FD->getNumParams() == ArgTys.size()) {
-        IsExactMatch = true;
-        for (unsigned ArgIdx = 0; ArgIdx != ArgTys.size(); ++ArgIdx) {
-          QualType ParamTy = FD->getParamDecl(ArgIdx)->getType();
-          if (!Context.hasSameUnqualifiedType(ArgTys[ArgIdx], ParamTy)) {
-            IsExactMatch = false;
-            break;
-          }
-        }
-      }
-    }
-    if (FunctionTemplateDecl *FD = dyn_cast<FunctionTemplateDecl>(D)) {
-      TemplateParameterList *Params = FD->getTemplateParameters();
-      if (Params->size() == 1)
-        IsTemplate = true;
-      else
-        IsStringTemplate = true;
-    }
-
-    if (IsExactMatch) {
-      FoundExactMatch = true;
-      AllowRaw = false;
-      AllowTemplate = false;
-      AllowStringTemplate = false;
-      if (FoundRaw || FoundTemplate || FoundStringTemplate) {
-        // Go through again and remove the raw and template decls we've
-        // already found.
-        F.restart();
-        FoundRaw = FoundTemplate = FoundStringTemplate = false;
-      }
-    } else if (AllowRaw && IsRaw) {
-      FoundRaw = true;
-    } else if (AllowTemplate && IsTemplate) {
-      FoundTemplate = true;
-    } else if (AllowStringTemplate && IsStringTemplate) {
-      FoundStringTemplate = true;
-    } else {
-      F.erase();
-    }
-  }
-
-  F.done();
-
-  // C++11 [lex.ext]p3, p4: If S contains a literal operator with a matching
-  // parameter type, that is used in preference to a raw literal operator
-  // or literal operator template.
-  if (FoundExactMatch)
-    return LOLR_Cooked;
-
-  // C++11 [lex.ext]p3, p4: S shall contain a raw literal operator or a literal
-  // operator template, but not both.
-  if (FoundRaw && FoundTemplate) {
-    Diag(R.getNameLoc(), diag::err_ovl_ambiguous_call) << R.getLookupName();
-    for (LookupResult::iterator I = R.begin(), E = R.end(); I != E; ++I)
-      NoteOverloadCandidate(*I, (*I)->getUnderlyingDecl()->getAsFunction());
-    return LOLR_Error;
-  }
-
-  if (FoundRaw)
-    return LOLR_Raw;
-
-  if (FoundTemplate)
-    return LOLR_Template;
-
-  if (FoundStringTemplate)
-    return LOLR_StringTemplate;
-
-  // Didn't find anything we could use.
-  if (DiagnoseMissing) {
-    Diag(R.getNameLoc(), diag::err_ovl_no_viable_literal_operator)
-        << R.getLookupName() << (int)ArgTys.size() << ArgTys[0]
-        << (ArgTys.size() == 2 ? ArgTys[1] : QualType()) << AllowRaw
-        << (AllowTemplate || AllowStringTemplate);
-    return LOLR_Error;
-  }
-
-  return LOLR_ErrorNoDiagnostic;
-}
-
-void ADLResult::insert(NamedDecl *New) {
-  NamedDecl *&Old = Decls[cast<NamedDecl>(New->getCanonicalDecl())];
-
-  // If we haven't yet seen a decl for this key, or the last decl
-  // was exactly this one, we're done.
-  if (Old == nullptr || Old == New) {
-    Old = New;
-    return;
-  }
-
-  // Otherwise, decide which is a more recent redeclaration.
-  FunctionDecl *OldFD = Old->getAsFunction();
-  FunctionDecl *NewFD = New->getAsFunction();
-
-  FunctionDecl *Cursor = NewFD;
-  while (true) {
-    Cursor = Cursor->getPreviousDecl();
-
-    // If we got to the end without finding OldFD, OldFD is the newer
-    // declaration;  leave things as they are.
-    if (!Cursor) return;
-
-    // If we do find OldFD, then NewFD is newer.
-    if (Cursor == OldFD) break;
-
-    // Otherwise, keep looking.
-  }
-
-  Old = New;
-}
-
-void Sema::ArgumentDependentLookup(DeclarationName Name, SourceLocation Loc,
-                                   ArrayRef<Expr *> Args, ADLResult &Result) {
-  // Find all of the associated namespaces and classes based on the
-  // arguments we have.
-  AssociatedNamespaceSet AssociatedNamespaces;
-  AssociatedClassSet AssociatedClasses;
-  FindAssociatedClassesAndNamespaces(Loc, Args,
-                                     AssociatedNamespaces,
-                                     AssociatedClasses);
-
-  // C++ [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 [...] then Y is
-  //   empty. Otherwise Y is the set of declarations found in the
-  //   namespaces associated with the argument types as described
-  //   below. The set of declarations found by the lookup of the name
-  //   is the union of X and Y.
-  //
-  // Here, we compute Y and add its members to the overloaded
-  // candidate set.
-  for (auto *NS : AssociatedNamespaces) {
-    //   When considering an associated namespace, the lookup is the
-    //   same as the lookup performed when the associated namespace is
-    //   used as a qualifier (3.4.3.2) except that:
-    //
-    //     -- Any using-directives in the associated namespace are
-    //        ignored.
-    //
-    //     -- Any namespace-scope friend functions declared in
-    //        associated classes are visible within their respective
-    //        namespaces even if they are not visible during an ordinary
-    //        lookup (11.4).
-    DeclContext::lookup_result R = NS->lookup(Name);
-    for (auto *D : R) {
-      auto *Underlying = D;
-      if (auto *USD = dyn_cast<UsingShadowDecl>(D))
-        Underlying = USD->getTargetDecl();
-
-      if (!isa<FunctionDecl>(Underlying) &&
-          !isa<FunctionTemplateDecl>(Underlying))
-        continue;
-
-      // The declaration is visible to argument-dependent lookup if either
-      // it's ordinarily visible or declared as a friend in an associated
-      // class.
-      bool Visible = false;
-      for (D = D->getMostRecentDecl(); D;
-           D = cast_or_null<NamedDecl>(D->getPreviousDecl())) {
-        if (D->getIdentifierNamespace() & Decl::IDNS_Ordinary) {
-          if (isVisible(D)) {
-            Visible = true;
-            break;
-          }
-        } else if (D->getFriendObjectKind()) {
-          auto *RD = cast<CXXRecordDecl>(D->getLexicalDeclContext());
-          if (AssociatedClasses.count(RD) && isVisible(D)) {
-            Visible = true;
-            break;
-          }
-        }
-      }
-
-      // FIXME: Preserve D as the FoundDecl.
-      if (Visible)
-        Result.insert(Underlying);
-    }
-  }
-}
-
-//----------------------------------------------------------------------------
-// Search for all visible declarations.
-//----------------------------------------------------------------------------
-VisibleDeclConsumer::~VisibleDeclConsumer() { }
-
-bool VisibleDeclConsumer::includeHiddenDecls() const { return false; }
-
-namespace {
-
-class ShadowContextRAII;
-
-class VisibleDeclsRecord {
-public:
-  /// An entry in the shadow map, which is optimized to store a
-  /// single declaration (the common case) but can also store a list
-  /// of declarations.
-  typedef llvm::TinyPtrVector<NamedDecl*> ShadowMapEntry;
-
-private:
-  /// A mapping from declaration names to the declarations that have
-  /// this name within a particular scope.
-  typedef llvm::DenseMap<DeclarationName, ShadowMapEntry> ShadowMap;
-
-  /// A list of shadow maps, which is used to model name hiding.
-  std::list<ShadowMap> ShadowMaps;
-
-  /// The declaration contexts we have already visited.
-  llvm::SmallPtrSet<DeclContext *, 8> VisitedContexts;
-
-  friend class ShadowContextRAII;
-
-public:
-  /// Determine whether we have already visited this context
-  /// (and, if not, note that we are going to visit that context now).
-  bool visitedContext(DeclContext *Ctx) {
-    return !VisitedContexts.insert(Ctx).second;
-  }
-
-  bool alreadyVisitedContext(DeclContext *Ctx) {
-    return VisitedContexts.count(Ctx);
-  }
-
-  /// Determine whether the given declaration is hidden in the
-  /// current scope.
-  ///
-  /// \returns the declaration that hides the given declaration, or
-  /// NULL if no such declaration exists.
-  NamedDecl *checkHidden(NamedDecl *ND);
-
-  /// Add a declaration to the current shadow map.
-  void add(NamedDecl *ND) {
-    ShadowMaps.back()[ND->getDeclName()].push_back(ND);
-  }
-};
-
-/// RAII object that records when we've entered a shadow context.
-class ShadowContextRAII {
-  VisibleDeclsRecord &Visible;
-
-  typedef VisibleDeclsRecord::ShadowMap ShadowMap;
-
-public:
-  ShadowContextRAII(VisibleDeclsRecord &Visible) : Visible(Visible) {
-    Visible.ShadowMaps.emplace_back();
-  }
-
-  ~ShadowContextRAII() {
-    Visible.ShadowMaps.pop_back();
-  }
-};
-
-} // end anonymous namespace
-
-NamedDecl *VisibleDeclsRecord::checkHidden(NamedDecl *ND) {
-  unsigned IDNS = ND->getIdentifierNamespace();
-  std::list<ShadowMap>::reverse_iterator SM = ShadowMaps.rbegin();
-  for (std::list<ShadowMap>::reverse_iterator SMEnd = ShadowMaps.rend();
-       SM != SMEnd; ++SM) {
-    ShadowMap::iterator Pos = SM->find(ND->getDeclName());
-    if (Pos == SM->end())
-      continue;
-
-    for (auto *D : Pos->second) {
-      // A tag declaration does not hide a non-tag declaration.
-      if (D->hasTagIdentifierNamespace() &&
-          (IDNS & (Decl::IDNS_Member | Decl::IDNS_Ordinary |
-                   Decl::IDNS_ObjCProtocol)))
-        continue;
-
-      // Protocols are in distinct namespaces from everything else.
-      if (((D->getIdentifierNamespace() & Decl::IDNS_ObjCProtocol)
-           || (IDNS & Decl::IDNS_ObjCProtocol)) &&
-          D->getIdentifierNamespace() != IDNS)
-        continue;
-
-      // Functions and function templates in the same scope overload
-      // rather than hide.  FIXME: Look for hiding based on function
-      // signatures!
-      if (D->getUnderlyingDecl()->isFunctionOrFunctionTemplate() &&
-          ND->getUnderlyingDecl()->isFunctionOrFunctionTemplate() &&
-          SM == ShadowMaps.rbegin())
-        continue;
-
-      // A shadow declaration that's created by a resolved using declaration
-      // is not hidden by the same using declaration.
-      if (isa<UsingShadowDecl>(ND) && isa<UsingDecl>(D) &&
-          cast<UsingShadowDecl>(ND)->getUsingDecl() == D)
-        continue;
-
-      // We've found a declaration that hides this one.
-      return D;
-    }
-  }
-
-  return nullptr;
-}
-
-static void LookupVisibleDecls(DeclContext *Ctx, LookupResult &Result,
-                               bool QualifiedNameLookup,
-                               bool InBaseClass,
-                               VisibleDeclConsumer &Consumer,
-                               VisibleDeclsRecord &Visited,
-                               bool IncludeDependentBases,
-                               bool LoadExternal) {
-  if (!Ctx)
-    return;
-
-  // Make sure we don't visit the same context twice.
-  if (Visited.visitedContext(Ctx->getPrimaryContext()))
-    return;
-
-  Consumer.EnteredContext(Ctx);
-
-  // Outside C++, lookup results for the TU live on identifiers.
-  if (isa<TranslationUnitDecl>(Ctx) &&
-      !Result.getSema().getLangOpts().CPlusPlus) {
-    auto &S = Result.getSema();
-    auto &Idents = S.Context.Idents;
-
-    // Ensure all external identifiers are in the identifier table.
-    if (LoadExternal)
-      if (IdentifierInfoLookup *External = Idents.getExternalIdentifierLookup()) {
-        std::unique_ptr<IdentifierIterator> Iter(External->getIdentifiers());
-        for (StringRef Name = Iter->Next(); !Name.empty(); Name = Iter->Next())
-          Idents.get(Name);
-      }
-
-    // Walk all lookup results in the TU for each identifier.
-    for (const auto &Ident : Idents) {
-      for (auto I = S.IdResolver.begin(Ident.getValue()),
-                E = S.IdResolver.end();
-           I != E; ++I) {
-        if (S.IdResolver.isDeclInScope(*I, Ctx)) {
-          if (NamedDecl *ND = Result.getAcceptableDecl(*I)) {
-            Consumer.FoundDecl(ND, Visited.checkHidden(ND), Ctx, InBaseClass);
-            Visited.add(ND);
-          }
-        }
-      }
-    }
-
-    return;
-  }
-
-  if (CXXRecordDecl *Class = dyn_cast<CXXRecordDecl>(Ctx))
-    Result.getSema().ForceDeclarationOfImplicitMembers(Class);
-
-  // We sometimes skip loading namespace-level results (they tend to be huge).
-  bool Load = LoadExternal ||
-              !(isa<TranslationUnitDecl>(Ctx) || isa<NamespaceDecl>(Ctx));
-  // Enumerate all of the results in this context.
-  for (DeclContextLookupResult R :
-       Load ? Ctx->lookups()
-            : Ctx->noload_lookups(/*PreserveInternalState=*/false)) {
-    for (auto *D : R) {
-      if (auto *ND = Result.getAcceptableDecl(D)) {
-        Consumer.FoundDecl(ND, Visited.checkHidden(ND), Ctx, InBaseClass);
-        Visited.add(ND);
-      }
-    }
-  }
-
-  // Traverse using directives for qualified name lookup.
-  if (QualifiedNameLookup) {
-    ShadowContextRAII Shadow(Visited);
-    for (auto I : Ctx->using_directives()) {
-      if (!Result.getSema().isVisible(I))
-        continue;
-      LookupVisibleDecls(I->getNominatedNamespace(), Result,
-                         QualifiedNameLookup, InBaseClass, Consumer, Visited,
-                         IncludeDependentBases, LoadExternal);
-    }
-  }
-
-  // Traverse the contexts of inherited C++ classes.
-  if (CXXRecordDecl *Record = dyn_cast<CXXRecordDecl>(Ctx)) {
-    if (!Record->hasDefinition())
-      return;
-
-    for (const auto &B : Record->bases()) {
-      QualType BaseType = B.getType();
-
-      RecordDecl *RD;
-      if (BaseType->isDependentType()) {
-        if (!IncludeDependentBases) {
-          // Don't look into dependent bases, because name lookup can't look
-          // there anyway.
-          continue;
-        }
-        const auto *TST = BaseType->getAs<TemplateSpecializationType>();
-        if (!TST)
-          continue;
-        TemplateName TN = TST->getTemplateName();
-        const auto *TD =
-            dyn_cast_or_null<ClassTemplateDecl>(TN.getAsTemplateDecl());
-        if (!TD)
-          continue;
-        RD = TD->getTemplatedDecl();
-      } else {
-        const auto *Record = BaseType->getAs<RecordType>();
-        if (!Record)
-          continue;
-        RD = Record->getDecl();
-      }
-
-      // FIXME: It would be nice to be able to determine whether referencing
-      // a particular member would be ambiguous. For example, given
-      //
-      //   struct A { int member; };
-      //   struct B { int member; };
-      //   struct C : A, B { };
-      //
-      //   void f(C *c) { c->### }
-      //
-      // accessing 'member' would result in an ambiguity. However, we
-      // could be smart enough to qualify the member with the base
-      // class, e.g.,
-      //
-      //   c->B::member
-      //
-      // or
-      //
-      //   c->A::member
-
-      // Find results in this base class (and its bases).
-      ShadowContextRAII Shadow(Visited);
-      LookupVisibleDecls(RD, Result, QualifiedNameLookup, /*InBaseClass=*/true,
-                         Consumer, Visited, IncludeDependentBases,
-                         LoadExternal);
-    }
-  }
-
-  // Traverse the contexts of Objective-C classes.
-  if (ObjCInterfaceDecl *IFace = dyn_cast<ObjCInterfaceDecl>(Ctx)) {
-    // Traverse categories.
-    for (auto *Cat : IFace->visible_categories()) {
-      ShadowContextRAII Shadow(Visited);
-      LookupVisibleDecls(Cat, Result, QualifiedNameLookup, false, Consumer,
-                         Visited, IncludeDependentBases, LoadExternal);
-    }
-
-    // Traverse protocols.
-    for (auto *I : IFace->all_referenced_protocols()) {
-      ShadowContextRAII Shadow(Visited);
-      LookupVisibleDecls(I, Result, QualifiedNameLookup, false, Consumer,
-                         Visited, IncludeDependentBases, LoadExternal);
-    }
-
-    // Traverse the superclass.
-    if (IFace->getSuperClass()) {
-      ShadowContextRAII Shadow(Visited);
-      LookupVisibleDecls(IFace->getSuperClass(), Result, QualifiedNameLookup,
-                         true, Consumer, Visited, IncludeDependentBases,
-                         LoadExternal);
-    }
-
-    // If there is an implementation, traverse it. We do this to find
-    // synthesized ivars.
-    if (IFace->getImplementation()) {
-      ShadowContextRAII Shadow(Visited);
-      LookupVisibleDecls(IFace->getImplementation(), Result,
-                         QualifiedNameLookup, InBaseClass, Consumer, Visited,
-                         IncludeDependentBases, LoadExternal);
-    }
-  } else if (ObjCProtocolDecl *Protocol = dyn_cast<ObjCProtocolDecl>(Ctx)) {
-    for (auto *I : Protocol->protocols()) {
-      ShadowContextRAII Shadow(Visited);
-      LookupVisibleDecls(I, Result, QualifiedNameLookup, false, Consumer,
-                         Visited, IncludeDependentBases, LoadExternal);
-    }
-  } else if (ObjCCategoryDecl *Category = dyn_cast<ObjCCategoryDecl>(Ctx)) {
-    for (auto *I : Category->protocols()) {
-      ShadowContextRAII Shadow(Visited);
-      LookupVisibleDecls(I, Result, QualifiedNameLookup, false, Consumer,
-                         Visited, IncludeDependentBases, LoadExternal);
-    }
-
-    // If there is an implementation, traverse it.
-    if (Category->getImplementation()) {
-      ShadowContextRAII Shadow(Visited);
-      LookupVisibleDecls(Category->getImplementation(), Result,
-                         QualifiedNameLookup, true, Consumer, Visited,
-                         IncludeDependentBases, LoadExternal);
-    }
-  }
-}
-
-static void LookupVisibleDecls(Scope *S, LookupResult &Result,
-                               UnqualUsingDirectiveSet &UDirs,
-                               VisibleDeclConsumer &Consumer,
-                               VisibleDeclsRecord &Visited,
-                               bool LoadExternal) {
-  if (!S)
-    return;
-
-  if (!S->getEntity() ||
-      (!S->getParent() &&
-       !Visited.alreadyVisitedContext(S->getEntity())) ||
-      (S->getEntity())->isFunctionOrMethod()) {
-    FindLocalExternScope FindLocals(Result);
-    // Walk through the declarations in this Scope. The consumer might add new
-    // decls to the scope as part of deserialization, so make a copy first.
-    SmallVector<Decl *, 8> ScopeDecls(S->decls().begin(), S->decls().end());
-    for (Decl *D : ScopeDecls) {
-      if (NamedDecl *ND = dyn_cast<NamedDecl>(D))
-        if ((ND = Result.getAcceptableDecl(ND))) {
-          Consumer.FoundDecl(ND, Visited.checkHidden(ND), nullptr, false);
-          Visited.add(ND);
-        }
-    }
-  }
-
-  // FIXME: C++ [temp.local]p8
-  DeclContext *Entity = nullptr;
-  if (S->getEntity()) {
-    // Look into this scope's declaration context, along with any of its
-    // parent lookup contexts (e.g., enclosing classes), up to the point
-    // where we hit the context stored in the next outer scope.
-    Entity = S->getEntity();
-    DeclContext *OuterCtx = findOuterContext(S).first; // FIXME
-
-    for (DeclContext *Ctx = Entity; Ctx && !Ctx->Equals(OuterCtx);
-         Ctx = Ctx->getLookupParent()) {
-      if (ObjCMethodDecl *Method = dyn_cast<ObjCMethodDecl>(Ctx)) {
-        if (Method->isInstanceMethod()) {
-          // For instance methods, look for ivars in the method's interface.
-          LookupResult IvarResult(Result.getSema(), Result.getLookupName(),
-                                  Result.getNameLoc(), Sema::LookupMemberName);
-          if (ObjCInterfaceDecl *IFace = Method->getClassInterface()) {
-            LookupVisibleDecls(IFace, IvarResult, /*QualifiedNameLookup=*/false,
-                               /*InBaseClass=*/false, Consumer, Visited,
-                               /*IncludeDependentBases=*/false, LoadExternal);
-          }
-        }
-
-        // We've already performed all of the name lookup that we need
-        // to for Objective-C methods; the next context will be the
-        // outer scope.
-        break;
-      }
-
-      if (Ctx->isFunctionOrMethod())
-        continue;
-
-      LookupVisibleDecls(Ctx, Result, /*QualifiedNameLookup=*/false,
-                         /*InBaseClass=*/false, Consumer, Visited,
-                         /*IncludeDependentBases=*/false, LoadExternal);
-    }
-  } else if (!S->getParent()) {
-    // Look into the translation unit scope. We walk through the translation
-    // unit's declaration context, because the Scope itself won't have all of
-    // the declarations if we loaded a precompiled header.
-    // FIXME: We would like the translation unit's Scope object to point to the
-    // translation unit, so we don't need this special "if" branch. However,
-    // doing so would force the normal C++ name-lookup code to look into the
-    // translation unit decl when the IdentifierInfo chains would suffice.
-    // Once we fix that problem (which is part of a more general "don't look
-    // in DeclContexts unless we have to" optimization), we can eliminate this.
-    Entity = Result.getSema().Context.getTranslationUnitDecl();
-    LookupVisibleDecls(Entity, Result, /*QualifiedNameLookup=*/false,
-                       /*InBaseClass=*/false, Consumer, Visited,
-                       /*IncludeDependentBases=*/false, LoadExternal);
-  }
-
-  if (Entity) {
-    // Lookup visible declarations in any namespaces found by using
-    // directives.
-    for (const UnqualUsingEntry &UUE : UDirs.getNamespacesFor(Entity))
-      LookupVisibleDecls(const_cast<DeclContext *>(UUE.getNominatedNamespace()),
-                         Result, /*QualifiedNameLookup=*/false,
-                         /*InBaseClass=*/false, Consumer, Visited,
-                         /*IncludeDependentBases=*/false, LoadExternal);
-  }
-
-  // Lookup names in the parent scope.
-  ShadowContextRAII Shadow(Visited);
-  LookupVisibleDecls(S->getParent(), Result, UDirs, Consumer, Visited,
-                     LoadExternal);
-}
-
-void Sema::LookupVisibleDecls(Scope *S, LookupNameKind Kind,
-                              VisibleDeclConsumer &Consumer,
-                              bool IncludeGlobalScope, bool LoadExternal) {
-  // Determine the set of using directives available during
-  // unqualified name lookup.
-  Scope *Initial = S;
-  UnqualUsingDirectiveSet UDirs(*this);
-  if (getLangOpts().CPlusPlus) {
-    // Find the first namespace or translation-unit scope.
-    while (S && !isNamespaceOrTranslationUnitScope(S))
-      S = S->getParent();
-
-    UDirs.visitScopeChain(Initial, S);
-  }
-  UDirs.done();
-
-  // Look for visible declarations.
-  LookupResult Result(*this, DeclarationName(), SourceLocation(), Kind);
-  Result.setAllowHidden(Consumer.includeHiddenDecls());
-  VisibleDeclsRecord Visited;
-  if (!IncludeGlobalScope)
-    Visited.visitedContext(Context.getTranslationUnitDecl());
-  ShadowContextRAII Shadow(Visited);
-  ::LookupVisibleDecls(Initial, Result, UDirs, Consumer, Visited, LoadExternal);
-}
-
-void Sema::LookupVisibleDecls(DeclContext *Ctx, LookupNameKind Kind,
-                              VisibleDeclConsumer &Consumer,
-                              bool IncludeGlobalScope,
-                              bool IncludeDependentBases, bool LoadExternal) {
-  LookupResult Result(*this, DeclarationName(), SourceLocation(), Kind);
-  Result.setAllowHidden(Consumer.includeHiddenDecls());
-  VisibleDeclsRecord Visited;
-  if (!IncludeGlobalScope)
-    Visited.visitedContext(Context.getTranslationUnitDecl());
-  ShadowContextRAII Shadow(Visited);
-  ::LookupVisibleDecls(Ctx, Result, /*QualifiedNameLookup=*/true,
-                       /*InBaseClass=*/false, Consumer, Visited,
-                       IncludeDependentBases, LoadExternal);
-}
-
-/// LookupOrCreateLabel - Do a name lookup of a label with the specified name.
-/// If GnuLabelLoc is a valid source location, then this is a definition
-/// of an __label__ label name, otherwise it is a normal label definition
-/// or use.
-LabelDecl *Sema::LookupOrCreateLabel(IdentifierInfo *II, SourceLocation Loc,
-                                     SourceLocation GnuLabelLoc) {
-  // Do a lookup to see if we have a label with this name already.
-  NamedDecl *Res = nullptr;
-
-  if (GnuLabelLoc.isValid()) {
-    // Local label definitions always shadow existing labels.
-    Res = LabelDecl::Create(Context, CurContext, Loc, II, GnuLabelLoc);
-    Scope *S = CurScope;
-    PushOnScopeChains(Res, S, true);
-    return cast<LabelDecl>(Res);
-  }
-
-  // Not a GNU local label.
-  Res = LookupSingleName(CurScope, II, Loc, LookupLabel, NotForRedeclaration);
-  // If we found a label, check to see if it is in the same context as us.
-  // When in a Block, we don't want to reuse a label in an enclosing function.
-  if (Res && Res->getDeclContext() != CurContext)
-    Res = nullptr;
-  if (!Res) {
-    // If not forward referenced or defined already, create the backing decl.
-    Res = LabelDecl::Create(Context, CurContext, Loc, II);
-    Scope *S = CurScope->getFnParent();
-    assert(S && "Not in a function?");
-    PushOnScopeChains(Res, S, true);
-  }
-  return cast<LabelDecl>(Res);
-}
-
-//===----------------------------------------------------------------------===//
-// Typo correction
-//===----------------------------------------------------------------------===//
-
-static bool isCandidateViable(CorrectionCandidateCallback &CCC,
-                              TypoCorrection &Candidate) {
-  Candidate.setCallbackDistance(CCC.RankCandidate(Candidate));
-  return Candidate.getEditDistance(false) != TypoCorrection::InvalidDistance;
-}
-
-static void LookupPotentialTypoResult(Sema &SemaRef,
-                                      LookupResult &Res,
-                                      IdentifierInfo *Name,
-                                      Scope *S, CXXScopeSpec *SS,
-                                      DeclContext *MemberContext,
-                                      bool EnteringContext,
-                                      bool isObjCIvarLookup,
-                                      bool FindHidden);
-
-/// Check whether the declarations found for a typo correction are
-/// visible. Set the correction's RequiresImport flag to true if none of the
-/// declarations are visible, false otherwise.
-static void checkCorrectionVisibility(Sema &SemaRef, TypoCorrection &TC) {
-  TypoCorrection::decl_iterator DI = TC.begin(), DE = TC.end();
-
-  for (/**/; DI != DE; ++DI)
-    if (!LookupResult::isVisible(SemaRef, *DI))
-      break;
-  // No filtering needed if all decls are visible.
-  if (DI == DE) {
-    TC.setRequiresImport(false);
-    return;
-  }
-
-  llvm::SmallVector<NamedDecl*, 4> NewDecls(TC.begin(), DI);
-  bool AnyVisibleDecls = !NewDecls.empty();
-
-  for (/**/; DI != DE; ++DI) {
-    if (LookupResult::isVisible(SemaRef, *DI)) {
-      if (!AnyVisibleDecls) {
-        // Found a visible decl, discard all hidden ones.
-        AnyVisibleDecls = true;
-        NewDecls.clear();
-      }
-      NewDecls.push_back(*DI);
-    } else if (!AnyVisibleDecls && !(*DI)->isModulePrivate())
-      NewDecls.push_back(*DI);
-  }
-
-  if (NewDecls.empty())
-    TC = TypoCorrection();
-  else {
-    TC.setCorrectionDecls(NewDecls);
-    TC.setRequiresImport(!AnyVisibleDecls);
-  }
-}
-
-// Fill the supplied vector with the IdentifierInfo pointers for each piece of
-// the given NestedNameSpecifier (i.e. given a NestedNameSpecifier "foo::bar::",
-// fill the vector with the IdentifierInfo pointers for "foo" and "bar").
-static void getNestedNameSpecifierIdentifiers(
-    NestedNameSpecifier *NNS,
-    SmallVectorImpl<const IdentifierInfo*> &Identifiers) {
-  if (NestedNameSpecifier *Prefix = NNS->getPrefix())
-    getNestedNameSpecifierIdentifiers(Prefix, Identifiers);
-  else
-    Identifiers.clear();
-
-  const IdentifierInfo *II = nullptr;
-
-  switch (NNS->getKind()) {
-  case NestedNameSpecifier::Identifier:
-    II = NNS->getAsIdentifier();
-    break;
-
-  case NestedNameSpecifier::Namespace:
-    if (NNS->getAsNamespace()->isAnonymousNamespace())
-      return;
-    II = NNS->getAsNamespace()->getIdentifier();
-    break;
-
-  case NestedNameSpecifier::NamespaceAlias:
-    II = NNS->getAsNamespaceAlias()->getIdentifier();
-    break;
-
-  case NestedNameSpecifier::TypeSpecWithTemplate:
-  case NestedNameSpecifier::TypeSpec:
-    II = QualType(NNS->getAsType(), 0).getBaseTypeIdentifier();
-    break;
-
-  case NestedNameSpecifier::Global:
-  case NestedNameSpecifier::Super:
-    return;
-  }
-
-  if (II)
-    Identifiers.push_back(II);
-}
-
-void TypoCorrectionConsumer::FoundDecl(NamedDecl *ND, NamedDecl *Hiding,
-                                       DeclContext *Ctx, bool InBaseClass) {
-  // Don't consider hidden names for typo correction.
-  if (Hiding)
-    return;
-
-  // Only consider entities with identifiers for names, ignoring
-  // special names (constructors, overloaded operators, selectors,
-  // etc.).
-  IdentifierInfo *Name = ND->getIdentifier();
-  if (!Name)
-    return;
-
-  // Only consider visible declarations and declarations from modules with
-  // names that exactly match.
-  if (!LookupResult::isVisible(SemaRef, ND) && Name != Typo)
-    return;
-
-  FoundName(Name->getName());
-}
-
-void TypoCorrectionConsumer::FoundName(StringRef Name) {
-  // Compute the edit distance between the typo and the name of this
-  // entity, and add the identifier to the list of results.
-  addName(Name, nullptr);
-}
-
-void TypoCorrectionConsumer::addKeywordResult(StringRef Keyword) {
-  // Compute the edit distance between the typo and this keyword,
-  // and add the keyword to the list of results.
-  addName(Keyword, nullptr, nullptr, true);
-}
-
-void TypoCorrectionConsumer::addName(StringRef Name, NamedDecl *ND,
-                                     NestedNameSpecifier *NNS, bool isKeyword) {
-  // Use a simple length-based heuristic to determine the minimum possible
-  // edit distance. If the minimum isn't good enough, bail out early.
-  StringRef TypoStr = Typo->getName();
-  unsigned MinED = abs((int)Name.size() - (int)TypoStr.size());
-  if (MinED && TypoStr.size() / MinED < 3)
-    return;
-
-  // Compute an upper bound on the allowable edit distance, so that the
-  // edit-distance algorithm can short-circuit.
-  unsigned UpperBound = (TypoStr.size() + 2) / 3;
-  unsigned ED = TypoStr.edit_distance(Name, true, UpperBound);
-  if (ED > UpperBound) return;
-
-  TypoCorrection TC(&SemaRef.Context.Idents.get(Name), ND, NNS, ED);
-  if (isKeyword) TC.makeKeyword();
-  TC.setCorrectionRange(nullptr, Result.getLookupNameInfo());
-  addCorrection(TC);
-}
-
-static const unsigned MaxTypoDistanceResultSets = 5;
-
-void TypoCorrectionConsumer::addCorrection(TypoCorrection Correction) {
-  StringRef TypoStr = Typo->getName();
-  StringRef Name = Correction.getCorrectionAsIdentifierInfo()->getName();
-
-  // For very short typos, ignore potential corrections that have a different
-  // base identifier from the typo or which have a normalized edit distance
-  // longer than the typo itself.
-  if (TypoStr.size() < 3 &&
-      (Name != TypoStr || Correction.getEditDistance(true) > TypoStr.size()))
-    return;
-
-  // If the correction is resolved but is not viable, ignore it.
-  if (Correction.isResolved()) {
-    checkCorrectionVisibility(SemaRef, Correction);
-    if (!Correction || !isCandidateViable(*CorrectionValidator, Correction))
-      return;
-  }
-
-  TypoResultList &CList =
-      CorrectionResults[Correction.getEditDistance(false)][Name];
-
-  if (!CList.empty() && !CList.back().isResolved())
-    CList.pop_back();
-  if (NamedDecl *NewND = Correction.getCorrectionDecl()) {
-    std::string CorrectionStr = Correction.getAsString(SemaRef.getLangOpts());
-    for (TypoResultList::iterator RI = CList.begin(), RIEnd = CList.end();
-         RI != RIEnd; ++RI) {
-      // If the Correction refers to a decl already in the result list,
-      // replace the existing result if the string representation of Correction
-      // comes before the current result alphabetically, then stop as there is
-      // nothing more to be done to add Correction to the candidate set.
-      if (RI->getCorrectionDecl() == NewND) {
-        if (CorrectionStr < RI->getAsString(SemaRef.getLangOpts()))
-          *RI = Correction;
-        return;
-      }
-    }
-  }
-  if (CList.empty() || Correction.isResolved())
-    CList.push_back(Correction);
-
-  while (CorrectionResults.size() > MaxTypoDistanceResultSets)
-    CorrectionResults.erase(std::prev(CorrectionResults.end()));
-}
-
-void TypoCorrectionConsumer::addNamespaces(
-    const llvm::MapVector<NamespaceDecl *, bool> &KnownNamespaces) {
-  SearchNamespaces = true;
-
-  for (auto KNPair : KnownNamespaces)
-    Namespaces.addNameSpecifier(KNPair.first);
-
-  bool SSIsTemplate = false;
-  if (NestedNameSpecifier *NNS =
-          (SS && SS->isValid()) ? SS->getScopeRep() : nullptr) {
-    if (const Type *T = NNS->getAsType())
-      SSIsTemplate = T->getTypeClass() == Type::TemplateSpecialization;
-  }
-  // Do not transform this into an iterator-based loop. The loop body can
-  // trigger the creation of further types (through lazy deserialization) and
-  // invalid iterators into this list.
-  auto &Types = SemaRef.getASTContext().getTypes();
-  for (unsigned I = 0; I != Types.size(); ++I) {
-    const auto *TI = Types[I];
-    if (CXXRecordDecl *CD = TI->getAsCXXRecordDecl()) {
-      CD = CD->getCanonicalDecl();
-      if (!CD->isDependentType() && !CD->isAnonymousStructOrUnion() &&
-          !CD->isUnion() && CD->getIdentifier() &&
-          (SSIsTemplate || !isa<ClassTemplateSpecializationDecl>(CD)) &&
-          (CD->isBeingDefined() || CD->isCompleteDefinition()))
-        Namespaces.addNameSpecifier(CD);
-    }
-  }
-}
-
-const TypoCorrection &TypoCorrectionConsumer::getNextCorrection() {
-  if (++CurrentTCIndex < ValidatedCorrections.size())
-    return ValidatedCorrections[CurrentTCIndex];
-
-  CurrentTCIndex = ValidatedCorrections.size();
-  while (!CorrectionResults.empty()) {
-    auto DI = CorrectionResults.begin();
-    if (DI->second.empty()) {
-      CorrectionResults.erase(DI);
-      continue;
-    }
-
-    auto RI = DI->second.begin();
-    if (RI->second.empty()) {
-      DI->second.erase(RI);
-      performQualifiedLookups();
-      continue;
-    }
-
-    TypoCorrection TC = RI->second.pop_back_val();
-    if (TC.isResolved() || TC.requiresImport() || resolveCorrection(TC)) {
-      ValidatedCorrections.push_back(TC);
-      return ValidatedCorrections[CurrentTCIndex];
-    }
-  }
-  return ValidatedCorrections[0];  // The empty correction.
-}
-
-bool TypoCorrectionConsumer::resolveCorrection(TypoCorrection &Candidate) {
-  IdentifierInfo *Name = Candidate.getCorrectionAsIdentifierInfo();
-  DeclContext *TempMemberContext = MemberContext;
-  CXXScopeSpec *TempSS = SS.get();
-retry_lookup:
-  LookupPotentialTypoResult(SemaRef, Result, Name, S, TempSS, TempMemberContext,
-                            EnteringContext,
-                            CorrectionValidator->IsObjCIvarLookup,
-                            Name == Typo && !Candidate.WillReplaceSpecifier());
-  switch (Result.getResultKind()) {
-  case LookupResult::NotFound:
-  case LookupResult::NotFoundInCurrentInstantiation:
-  case LookupResult::FoundUnresolvedValue:
-    if (TempSS) {
-      // Immediately retry the lookup without the given CXXScopeSpec
-      TempSS = nullptr;
-      Candidate.WillReplaceSpecifier(true);
-      goto retry_lookup;
-    }
-    if (TempMemberContext) {
-      if (SS && !TempSS)
-        TempSS = SS.get();
-      TempMemberContext = nullptr;
-      goto retry_lookup;
-    }
-    if (SearchNamespaces)
-      QualifiedResults.push_back(Candidate);
-    break;
-
-  case LookupResult::Ambiguous:
-    // We don't deal with ambiguities.
-    break;
-
-  case LookupResult::Found:
-  case LookupResult::FoundOverloaded:
-    // Store all of the Decls for overloaded symbols
-    for (auto *TRD : Result)
-      Candidate.addCorrectionDecl(TRD);
-    checkCorrectionVisibility(SemaRef, Candidate);
-    if (!isCandidateViable(*CorrectionValidator, Candidate)) {
-      if (SearchNamespaces)
-        QualifiedResults.push_back(Candidate);
-      break;
-    }
-    Candidate.setCorrectionRange(SS.get(), Result.getLookupNameInfo());
-    return true;
-  }
-  return false;
-}
-
-void TypoCorrectionConsumer::performQualifiedLookups() {
-  unsigned TypoLen = Typo->getName().size();
-  for (const TypoCorrection &QR : QualifiedResults) {
-    for (const auto &NSI : Namespaces) {
-      DeclContext *Ctx = NSI.DeclCtx;
-      const Type *NSType = NSI.NameSpecifier->getAsType();
-
-      // If the current NestedNameSpecifier refers to a class and the
-      // current correction candidate is the name of that class, then skip
-      // it as it is unlikely a qualified version of the class' constructor
-      // is an appropriate correction.
-      if (CXXRecordDecl *NSDecl = NSType ? NSType->getAsCXXRecordDecl() :
-                                           nullptr) {
-        if (NSDecl->getIdentifier() == QR.getCorrectionAsIdentifierInfo())
-          continue;
-      }
-
-      TypoCorrection TC(QR);
-      TC.ClearCorrectionDecls();
-      TC.setCorrectionSpecifier(NSI.NameSpecifier);
-      TC.setQualifierDistance(NSI.EditDistance);
-      TC.setCallbackDistance(0); // Reset the callback distance
-
-      // If the current correction candidate and namespace combination are
-      // too far away from the original typo based on the normalized edit
-      // distance, then skip performing a qualified name lookup.
-      unsigned TmpED = TC.getEditDistance(true);
-      if (QR.getCorrectionAsIdentifierInfo() != Typo && TmpED &&
-          TypoLen / TmpED < 3)
-        continue;
-
-      Result.clear();
-      Result.setLookupName(QR.getCorrectionAsIdentifierInfo());
-      if (!SemaRef.LookupQualifiedName(Result, Ctx))
-        continue;
-
-      // Any corrections added below will be validated in subsequent
-      // iterations of the main while() loop over the Consumer's contents.
-      switch (Result.getResultKind()) {
-      case LookupResult::Found:
-      case LookupResult::FoundOverloaded: {
-        if (SS && SS->isValid()) {
-          std::string NewQualified = TC.getAsString(SemaRef.getLangOpts());
-          std::string OldQualified;
-          llvm::raw_string_ostream OldOStream(OldQualified);
-          SS->getScopeRep()->print(OldOStream, SemaRef.getPrintingPolicy());
-          OldOStream << Typo->getName();
-          // If correction candidate would be an identical written qualified
-          // identifier, then the existing CXXScopeSpec probably included a
-          // typedef that didn't get accounted for properly.
-          if (OldOStream.str() == NewQualified)
-            break;
-        }
-        for (LookupResult::iterator TRD = Result.begin(), TRDEnd = Result.end();
-             TRD != TRDEnd; ++TRD) {
-          if (SemaRef.CheckMemberAccess(TC.getCorrectionRange().getBegin(),
-                                        NSType ? NSType->getAsCXXRecordDecl()
-                                               : nullptr,
-                                        TRD.getPair()) == Sema::AR_accessible)
-            TC.addCorrectionDecl(*TRD);
-        }
-        if (TC.isResolved()) {
-          TC.setCorrectionRange(SS.get(), Result.getLookupNameInfo());
-          addCorrection(TC);
-        }
-        break;
-      }
-      case LookupResult::NotFound:
-      case LookupResult::NotFoundInCurrentInstantiation:
-      case LookupResult::Ambiguous:
-      case LookupResult::FoundUnresolvedValue:
-        break;
-      }
-    }
-  }
-  QualifiedResults.clear();
-}
-
-TypoCorrectionConsumer::NamespaceSpecifierSet::NamespaceSpecifierSet(
-    ASTContext &Context, DeclContext *CurContext, CXXScopeSpec *CurScopeSpec)
-    : Context(Context), CurContextChain(buildContextChain(CurContext)) {
-  if (NestedNameSpecifier *NNS =
-          CurScopeSpec ? CurScopeSpec->getScopeRep() : nullptr) {
-    llvm::raw_string_ostream SpecifierOStream(CurNameSpecifier);
-    NNS->print(SpecifierOStream, Context.getPrintingPolicy());
-
-    getNestedNameSpecifierIdentifiers(NNS, CurNameSpecifierIdentifiers);
-  }
-  // Build the list of identifiers that would be used for an absolute
-  // (from the global context) NestedNameSpecifier referring to the current
-  // context.
-  for (DeclContext *C : llvm::reverse(CurContextChain)) {
-    if (auto *ND = dyn_cast_or_null<NamespaceDecl>(C))
-      CurContextIdentifiers.push_back(ND->getIdentifier());
-  }
-
-  // Add the global context as a NestedNameSpecifier
-  SpecifierInfo SI = {cast<DeclContext>(Context.getTranslationUnitDecl()),
-                      NestedNameSpecifier::GlobalSpecifier(Context), 1};
-  DistanceMap[1].push_back(SI);
-}
-
-auto TypoCorrectionConsumer::NamespaceSpecifierSet::buildContextChain(
-    DeclContext *Start) -> DeclContextList {
-  assert(Start && "Building a context chain from a null context");
-  DeclContextList Chain;
-  for (DeclContext *DC = Start->getPrimaryContext(); DC != nullptr;
-       DC = DC->getLookupParent()) {
-    NamespaceDecl *ND = dyn_cast_or_null<NamespaceDecl>(DC);
-    if (!DC->isInlineNamespace() && !DC->isTransparentContext() &&
-        !(ND && ND->isAnonymousNamespace()))
-      Chain.push_back(DC->getPrimaryContext());
-  }
-  return Chain;
-}
-
-unsigned
-TypoCorrectionConsumer::NamespaceSpecifierSet::buildNestedNameSpecifier(
-    DeclContextList &DeclChain, NestedNameSpecifier *&NNS) {
-  unsigned NumSpecifiers = 0;
-  for (DeclContext *C : llvm::reverse(DeclChain)) {
-    if (auto *ND = dyn_cast_or_null<NamespaceDecl>(C)) {
-      NNS = NestedNameSpecifier::Create(Context, NNS, ND);
-      ++NumSpecifiers;
-    } else if (auto *RD = dyn_cast_or_null<RecordDecl>(C)) {
-      NNS = NestedNameSpecifier::Create(Context, NNS, RD->isTemplateDecl(),
-                                        RD->getTypeForDecl());
-      ++NumSpecifiers;
-    }
-  }
-  return NumSpecifiers;
-}
-
-void TypoCorrectionConsumer::NamespaceSpecifierSet::addNameSpecifier(
-    DeclContext *Ctx) {
-  NestedNameSpecifier *NNS = nullptr;
-  unsigned NumSpecifiers = 0;
-  DeclContextList NamespaceDeclChain(buildContextChain(Ctx));
-  DeclContextList FullNamespaceDeclChain(NamespaceDeclChain);
-
-  // Eliminate common elements from the two DeclContext chains.
-  for (DeclContext *C : llvm::reverse(CurContextChain)) {
-    if (NamespaceDeclChain.empty() || NamespaceDeclChain.back() != C)
-      break;
-    NamespaceDeclChain.pop_back();
-  }
-
-  // Build the NestedNameSpecifier from what is left of the NamespaceDeclChain
-  NumSpecifiers = buildNestedNameSpecifier(NamespaceDeclChain, NNS);
-
-  // Add an explicit leading '::' specifier if needed.
-  if (NamespaceDeclChain.empty()) {
-    // Rebuild the NestedNameSpecifier as a globally-qualified specifier.
-    NNS = NestedNameSpecifier::GlobalSpecifier(Context);
-    NumSpecifiers =
-        buildNestedNameSpecifier(FullNamespaceDeclChain, NNS);
-  } else if (NamedDecl *ND =
-                 dyn_cast_or_null<NamedDecl>(NamespaceDeclChain.back())) {
-    IdentifierInfo *Name = ND->getIdentifier();
-    bool SameNameSpecifier = false;
-    if (std::find(CurNameSpecifierIdentifiers.begin(),
-                  CurNameSpecifierIdentifiers.end(),
-                  Name) != CurNameSpecifierIdentifiers.end()) {
-      std::string NewNameSpecifier;
-      llvm::raw_string_ostream SpecifierOStream(NewNameSpecifier);
-      SmallVector<const IdentifierInfo *, 4> NewNameSpecifierIdentifiers;
-      getNestedNameSpecifierIdentifiers(NNS, NewNameSpecifierIdentifiers);
-      NNS->print(SpecifierOStream, Context.getPrintingPolicy());
-      SpecifierOStream.flush();
-      SameNameSpecifier = NewNameSpecifier == CurNameSpecifier;
-    }
-    if (SameNameSpecifier ||
-        std::find(CurContextIdentifiers.begin(), CurContextIdentifiers.end(),
-                  Name) != CurContextIdentifiers.end()) {
-      // Rebuild the NestedNameSpecifier as a globally-qualified specifier.
-      NNS = NestedNameSpecifier::GlobalSpecifier(Context);
-      NumSpecifiers =
-          buildNestedNameSpecifier(FullNamespaceDeclChain, NNS);
-    }
-  }
-
-  // If the built NestedNameSpecifier would be replacing an existing
-  // NestedNameSpecifier, use the number of component identifiers that
-  // would need to be changed as the edit distance instead of the number
-  // of components in the built NestedNameSpecifier.
-  if (NNS && !CurNameSpecifierIdentifiers.empty()) {
-    SmallVector<const IdentifierInfo*, 4> NewNameSpecifierIdentifiers;
-    getNestedNameSpecifierIdentifiers(NNS, NewNameSpecifierIdentifiers);
-    NumSpecifiers = llvm::ComputeEditDistance(
-        llvm::makeArrayRef(CurNameSpecifierIdentifiers),
-        llvm::makeArrayRef(NewNameSpecifierIdentifiers));
-  }
-
-  SpecifierInfo SI = {Ctx, NNS, NumSpecifiers};
-  DistanceMap[NumSpecifiers].push_back(SI);
-}
-
-/// Perform name lookup for a possible result for typo correction.
-static void LookupPotentialTypoResult(Sema &SemaRef,
-                                      LookupResult &Res,
-                                      IdentifierInfo *Name,
-                                      Scope *S, CXXScopeSpec *SS,
-                                      DeclContext *MemberContext,
-                                      bool EnteringContext,
-                                      bool isObjCIvarLookup,
-                                      bool FindHidden) {
-  Res.suppressDiagnostics();
-  Res.clear();
-  Res.setLookupName(Name);
-  Res.setAllowHidden(FindHidden);
-  if (MemberContext) {
-    if (ObjCInterfaceDecl *Class = dyn_cast<ObjCInterfaceDecl>(MemberContext)) {
-      if (isObjCIvarLookup) {
-        if (ObjCIvarDecl *Ivar = Class->lookupInstanceVariable(Name)) {
-          Res.addDecl(Ivar);
-          Res.resolveKind();
-          return;
-        }
-      }
-
-      if (ObjCPropertyDecl *Prop = Class->FindPropertyDeclaration(
-              Name, ObjCPropertyQueryKind::OBJC_PR_query_instance)) {
-        Res.addDecl(Prop);
-        Res.resolveKind();
-        return;
-      }
-    }
-
-    SemaRef.LookupQualifiedName(Res, MemberContext);
-    return;
-  }
-
-  SemaRef.LookupParsedName(Res, S, SS, /*AllowBuiltinCreation=*/false,
-                           EnteringContext);
-
-  // Fake ivar lookup; this should really be part of
-  // LookupParsedName.
-  if (ObjCMethodDecl *Method = SemaRef.getCurMethodDecl()) {
-    if (Method->isInstanceMethod() && Method->getClassInterface() &&
-        (Res.empty() ||
-         (Res.isSingleResult() &&
-          Res.getFoundDecl()->isDefinedOutsideFunctionOrMethod()))) {
-       if (ObjCIvarDecl *IV
-             = Method->getClassInterface()->lookupInstanceVariable(Name)) {
-         Res.addDecl(IV);
-         Res.resolveKind();
-       }
-     }
-  }
-}
-
-/// Add keywords to the consumer as possible typo corrections.
-static void AddKeywordsToConsumer(Sema &SemaRef,
-                                  TypoCorrectionConsumer &Consumer,
-                                  Scope *S, CorrectionCandidateCallback &CCC,
-                                  bool AfterNestedNameSpecifier) {
-  if (AfterNestedNameSpecifier) {
-    // For 'X::', we know exactly which keywords can appear next.
-    Consumer.addKeywordResult("template");
-    if (CCC.WantExpressionKeywords)
-      Consumer.addKeywordResult("operator");
-    return;
-  }
-
-  if (CCC.WantObjCSuper)
-    Consumer.addKeywordResult("super");
-
-  if (CCC.WantTypeSpecifiers) {
-    // Add type-specifier keywords to the set of results.
-    static const char *const CTypeSpecs[] = {
-      "char", "const", "double", "enum", "float", "int", "long", "short",
-      "signed", "struct", "union", "unsigned", "void", "volatile",
-      "_Complex", "_Imaginary",
-      // storage-specifiers as well
-      "extern", "inline", "static", "typedef"
-    };
-
-    const unsigned NumCTypeSpecs = llvm::array_lengthof(CTypeSpecs);
-    for (unsigned I = 0; I != NumCTypeSpecs; ++I)
-      Consumer.addKeywordResult(CTypeSpecs[I]);
-
-    if (SemaRef.getLangOpts().C99)
-      Consumer.addKeywordResult("restrict");
-    if (SemaRef.getLangOpts().Bool || SemaRef.getLangOpts().CPlusPlus)
-      Consumer.addKeywordResult("bool");
-    else if (SemaRef.getLangOpts().C99)
-      Consumer.addKeywordResult("_Bool");
-
-    if (SemaRef.getLangOpts().CPlusPlus) {
-      Consumer.addKeywordResult("class");
-      Consumer.addKeywordResult("typename");
-      Consumer.addKeywordResult("wchar_t");
-
-      if (SemaRef.getLangOpts().CPlusPlus11) {
-        Consumer.addKeywordResult("char16_t");
-        Consumer.addKeywordResult("char32_t");
-        Consumer.addKeywordResult("constexpr");
-        Consumer.addKeywordResult("decltype");
-        Consumer.addKeywordResult("thread_local");
-      }
-    }
-
-    if (SemaRef.getLangOpts().GNUKeywords)
-      Consumer.addKeywordResult("typeof");
-  } else if (CCC.WantFunctionLikeCasts) {
-    static const char *const CastableTypeSpecs[] = {
-      "char", "double", "float", "int", "long", "short",
-      "signed", "unsigned", "void"
-    };
-    for (auto *kw : CastableTypeSpecs)
-      Consumer.addKeywordResult(kw);
-  }
-
-  if (CCC.WantCXXNamedCasts && SemaRef.getLangOpts().CPlusPlus) {
-    Consumer.addKeywordResult("const_cast");
-    Consumer.addKeywordResult("dynamic_cast");
-    Consumer.addKeywordResult("reinterpret_cast");
-    Consumer.addKeywordResult("static_cast");
-  }
-
-  if (CCC.WantExpressionKeywords) {
-    Consumer.addKeywordResult("sizeof");
-    if (SemaRef.getLangOpts().Bool || SemaRef.getLangOpts().CPlusPlus) {
-      Consumer.addKeywordResult("false");
-      Consumer.addKeywordResult("true");
-    }
-
-    if (SemaRef.getLangOpts().CPlusPlus) {
-      static const char *const CXXExprs[] = {
-        "delete", "new", "operator", "throw", "typeid"
-      };
-      const unsigned NumCXXExprs = llvm::array_lengthof(CXXExprs);
-      for (unsigned I = 0; I != NumCXXExprs; ++I)
-        Consumer.addKeywordResult(CXXExprs[I]);
-
-      if (isa<CXXMethodDecl>(SemaRef.CurContext) &&
-          cast<CXXMethodDecl>(SemaRef.CurContext)->isInstance())
-        Consumer.addKeywordResult("this");
-
-      if (SemaRef.getLangOpts().CPlusPlus11) {
-        Consumer.addKeywordResult("alignof");
-        Consumer.addKeywordResult("nullptr");
-      }
-    }
-
-    if (SemaRef.getLangOpts().C11) {
-      // FIXME: We should not suggest _Alignof if the alignof macro
-      // is present.
-      Consumer.addKeywordResult("_Alignof");
-    }
-  }
-
-  if (CCC.WantRemainingKeywords) {
-    if (SemaRef.getCurFunctionOrMethodDecl() || SemaRef.getCurBlock()) {
-      // Statements.
-      static const char *const CStmts[] = {
-        "do", "else", "for", "goto", "if", "return", "switch", "while" };
-      const unsigned NumCStmts = llvm::array_lengthof(CStmts);
-      for (unsigned I = 0; I != NumCStmts; ++I)
-        Consumer.addKeywordResult(CStmts[I]);
-
-      if (SemaRef.getLangOpts().CPlusPlus) {
-        Consumer.addKeywordResult("catch");
-        Consumer.addKeywordResult("try");
-      }
-
-      if (S && S->getBreakParent())
-        Consumer.addKeywordResult("break");
-
-      if (S && S->getContinueParent())
-        Consumer.addKeywordResult("continue");
-
-      if (SemaRef.getCurFunction() &&
-          !SemaRef.getCurFunction()->SwitchStack.empty()) {
-        Consumer.addKeywordResult("case");
-        Consumer.addKeywordResult("default");
-      }
-    } else {
-      if (SemaRef.getLangOpts().CPlusPlus) {
-        Consumer.addKeywordResult("namespace");
-        Consumer.addKeywordResult("template");
-      }
-
-      if (S && S->isClassScope()) {
-        Consumer.addKeywordResult("explicit");
-        Consumer.addKeywordResult("friend");
-        Consumer.addKeywordResult("mutable");
-        Consumer.addKeywordResult("private");
-        Consumer.addKeywordResult("protected");
-        Consumer.addKeywordResult("public");
-        Consumer.addKeywordResult("virtual");
-      }
-    }
-
-    if (SemaRef.getLangOpts().CPlusPlus) {
-      Consumer.addKeywordResult("using");
-
-      if (SemaRef.getLangOpts().CPlusPlus11)
-        Consumer.addKeywordResult("static_assert");
-    }
-  }
-}
-
-std::unique_ptr<TypoCorrectionConsumer> Sema::makeTypoCorrectionConsumer(
-    const DeclarationNameInfo &TypoName, Sema::LookupNameKind LookupKind,
-    Scope *S, CXXScopeSpec *SS,
-    std::unique_ptr<CorrectionCandidateCallback> CCC,
-    DeclContext *MemberContext, bool EnteringContext,
-    const ObjCObjectPointerType *OPT, bool ErrorRecovery) {
-
-  if (Diags.hasFatalErrorOccurred() || !getLangOpts().SpellChecking ||
-      DisableTypoCorrection)
-    return nullptr;
-
-  // In Microsoft mode, don't perform typo correction in a template member
-  // function dependent context because it interferes with the "lookup into
-  // dependent bases of class templates" feature.
-  if (getLangOpts().MSVCCompat && CurContext->isDependentContext() &&
-      isa<CXXMethodDecl>(CurContext))
-    return nullptr;
-
-  // We only attempt to correct typos for identifiers.
-  IdentifierInfo *Typo = TypoName.getName().getAsIdentifierInfo();
-  if (!Typo)
-    return nullptr;
-
-  // If the scope specifier itself was invalid, don't try to correct
-  // typos.
-  if (SS && SS->isInvalid())
-    return nullptr;
-
-  // Never try to correct typos during any kind of code synthesis.
-  if (!CodeSynthesisContexts.empty())
-    return nullptr;
-
-  // Don't try to correct 'super'.
-  if (S && S->isInObjcMethodScope() && Typo == getSuperIdentifier())
-    return nullptr;
-
-  // Abort if typo correction already failed for this specific typo.
-  IdentifierSourceLocations::iterator locs = TypoCorrectionFailures.find(Typo);
-  if (locs != TypoCorrectionFailures.end() &&
-      locs->second.count(TypoName.getLoc()))
-    return nullptr;
-
-  // Don't try to correct the identifier "vector" when in AltiVec mode.
-  // TODO: Figure out why typo correction misbehaves in this case, fix it, and
-  // remove this workaround.
-  if ((getLangOpts().AltiVec || getLangOpts().ZVector) && Typo->isStr("vector"))
-    return nullptr;
-
-  // Provide a stop gap for files that are just seriously broken.  Trying
-  // to correct all typos can turn into a HUGE performance penalty, causing
-  // some files to take minutes to get rejected by the parser.
-  unsigned Limit = getDiagnostics().getDiagnosticOptions().SpellCheckingLimit;
-  if (Limit && TyposCorrected >= Limit)
-    return nullptr;
-  ++TyposCorrected;
-
-  // If we're handling a missing symbol error, using modules, and the
-  // special search all modules option is used, look for a missing import.
-  if (ErrorRecovery && getLangOpts().Modules &&
-      getLangOpts().ModulesSearchAll) {
-    // The following has the side effect of loading the missing module.
-    getModuleLoader().lookupMissingImports(Typo->getName(),
-                                           TypoName.getBeginLoc());
-  }
-
-  CorrectionCandidateCallback &CCCRef = *CCC;
-  auto Consumer = llvm::make_unique<TypoCorrectionConsumer>(
-      *this, TypoName, LookupKind, S, SS, std::move(CCC), MemberContext,
-      EnteringContext);
-
-  // Perform name lookup to find visible, similarly-named entities.
-  bool IsUnqualifiedLookup = false;
-  DeclContext *QualifiedDC = MemberContext;
-  if (MemberContext) {
-    LookupVisibleDecls(MemberContext, LookupKind, *Consumer);
-
-    // Look in qualified interfaces.
-    if (OPT) {
-      for (auto *I : OPT->quals())
-        LookupVisibleDecls(I, LookupKind, *Consumer);
-    }
-  } else if (SS && SS->isSet()) {
-    QualifiedDC = computeDeclContext(*SS, EnteringContext);
-    if (!QualifiedDC)
-      return nullptr;
-
-    LookupVisibleDecls(QualifiedDC, LookupKind, *Consumer);
-  } else {
-    IsUnqualifiedLookup = true;
-  }
-
-  // Determine whether we are going to search in the various namespaces for
-  // corrections.
-  bool SearchNamespaces
-    = getLangOpts().CPlusPlus &&
-      (IsUnqualifiedLookup || (SS && SS->isSet()));
-
-  if (IsUnqualifiedLookup || SearchNamespaces) {
-    // For unqualified lookup, look through all of the names that we have
-    // seen in this translation unit.
-    // FIXME: Re-add the ability to skip very unlikely potential corrections.
-    for (const auto &I : Context.Idents)
-      Consumer->FoundName(I.getKey());
-
-    // Walk through identifiers in external identifier sources.
-    // FIXME: Re-add the ability to skip very unlikely potential corrections.
-    if (IdentifierInfoLookup *External
-                            = Context.Idents.getExternalIdentifierLookup()) {
-      std::unique_ptr<IdentifierIterator> Iter(External->getIdentifiers());
-      do {
-        StringRef Name = Iter->Next();
-        if (Name.empty())
-          break;
-
-        Consumer->FoundName(Name);
-      } while (true);
-    }
-  }
-
-  AddKeywordsToConsumer(*this, *Consumer, S, CCCRef, SS && SS->isNotEmpty());
-
-  // Build the NestedNameSpecifiers for the KnownNamespaces, if we're going
-  // to search those namespaces.
-  if (SearchNamespaces) {
-    // Load any externally-known namespaces.
-    if (ExternalSource && !LoadedExternalKnownNamespaces) {
-      SmallVector<NamespaceDecl *, 4> ExternalKnownNamespaces;
-      LoadedExternalKnownNamespaces = true;
-      ExternalSource->ReadKnownNamespaces(ExternalKnownNamespaces);
-      for (auto *N : ExternalKnownNamespaces)
-        KnownNamespaces[N] = true;
-    }
-
-    Consumer->addNamespaces(KnownNamespaces);
-  }
-
-  return Consumer;
-}
-
-/// Try to "correct" a typo in the source code by finding
-/// visible declarations whose names are similar to the name that was
-/// present in the source code.
-///
-/// \param TypoName the \c DeclarationNameInfo structure that contains
-/// the name that was present in the source code along with its location.
-///
-/// \param LookupKind the name-lookup criteria used to search for the name.
-///
-/// \param S the scope in which name lookup occurs.
-///
-/// \param SS the nested-name-specifier that precedes the name we're
-/// looking for, if present.
-///
-/// \param CCC A CorrectionCandidateCallback object that provides further
-/// validation of typo correction candidates. It also provides flags for
-/// determining the set of keywords permitted.
-///
-/// \param MemberContext if non-NULL, the context in which to look for
-/// a member access expression.
-///
-/// \param EnteringContext whether we're entering the context described by
-/// the nested-name-specifier SS.
-///
-/// \param OPT when non-NULL, the search for visible declarations will
-/// also walk the protocols in the qualified interfaces of \p OPT.
-///
-/// \returns a \c TypoCorrection containing the corrected name if the typo
-/// along with information such as the \c NamedDecl where the corrected name
-/// was declared, and any additional \c NestedNameSpecifier needed to access
-/// it (C++ only). The \c TypoCorrection is empty if there is no correction.
-TypoCorrection Sema::CorrectTypo(const DeclarationNameInfo &TypoName,
-                                 Sema::LookupNameKind LookupKind,
-                                 Scope *S, CXXScopeSpec *SS,
-                                 std::unique_ptr<CorrectionCandidateCallback> CCC,
-                                 CorrectTypoKind Mode,
-                                 DeclContext *MemberContext,
-                                 bool EnteringContext,
-                                 const ObjCObjectPointerType *OPT,
-                                 bool RecordFailure) {
-  assert(CCC && "CorrectTypo requires a CorrectionCandidateCallback");
-
-  // Always let the ExternalSource have the first chance at correction, even
-  // if we would otherwise have given up.
-  if (ExternalSource) {
-    if (TypoCorrection Correction = ExternalSource->CorrectTypo(
-        TypoName, LookupKind, S, SS, *CCC, MemberContext, EnteringContext, OPT))
-      return Correction;
-  }
-
-  // Ugly hack equivalent to CTC == CTC_ObjCMessageReceiver;
-  // WantObjCSuper is only true for CTC_ObjCMessageReceiver and for
-  // some instances of CTC_Unknown, while WantRemainingKeywords is true
-  // for CTC_Unknown but not for CTC_ObjCMessageReceiver.
-  bool ObjCMessageReceiver = CCC->WantObjCSuper && !CCC->WantRemainingKeywords;
-
-  IdentifierInfo *Typo = TypoName.getName().getAsIdentifierInfo();
-  auto Consumer = makeTypoCorrectionConsumer(
-      TypoName, LookupKind, S, SS, std::move(CCC), MemberContext,
-      EnteringContext, OPT, Mode == CTK_ErrorRecovery);
-
-  if (!Consumer)
-    return TypoCorrection();
-
-  // If we haven't found anything, we're done.
-  if (Consumer->empty())
-    return FailedCorrection(Typo, TypoName.getLoc(), RecordFailure);
-
-  // Make sure the best edit distance (prior to adding any namespace qualifiers)
-  // is not more that about a third of the length of the typo's identifier.
-  unsigned ED = Consumer->getBestEditDistance(true);
-  unsigned TypoLen = Typo->getName().size();
-  if (ED > 0 && TypoLen / ED < 3)
-    return FailedCorrection(Typo, TypoName.getLoc(), RecordFailure);
-
-  TypoCorrection BestTC = Consumer->getNextCorrection();
-  TypoCorrection SecondBestTC = Consumer->getNextCorrection();
-  if (!BestTC)
-    return FailedCorrection(Typo, TypoName.getLoc(), RecordFailure);
-
-  ED = BestTC.getEditDistance();
-
-  if (TypoLen >= 3 && ED > 0 && TypoLen / ED < 3) {
-    // If this was an unqualified lookup and we believe the callback
-    // object wouldn't have filtered out possible corrections, note
-    // that no correction was found.
-    return FailedCorrection(Typo, TypoName.getLoc(), RecordFailure);
-  }
-
-  // If only a single name remains, return that result.
-  if (!SecondBestTC ||
-      SecondBestTC.getEditDistance(false) > BestTC.getEditDistance(false)) {
-    const TypoCorrection &Result = BestTC;
-
-    // Don't correct to a keyword that's the same as the typo; the keyword
-    // wasn't actually in scope.
-    if (ED == 0 && Result.isKeyword())
-      return FailedCorrection(Typo, TypoName.getLoc(), RecordFailure);
-
-    TypoCorrection TC = Result;
-    TC.setCorrectionRange(SS, TypoName);
-    checkCorrectionVisibility(*this, TC);
-    return TC;
-  } else if (SecondBestTC && ObjCMessageReceiver) {
-    // Prefer 'super' when we're completing in a message-receiver
-    // context.
-
-    if (BestTC.getCorrection().getAsString() != "super") {
-      if (SecondBestTC.getCorrection().getAsString() == "super")
-        BestTC = SecondBestTC;
-      else if ((*Consumer)["super"].front().isKeyword())
-        BestTC = (*Consumer)["super"].front();
-    }
-    // Don't correct to a keyword that's the same as the typo; the keyword
-    // wasn't actually in scope.
-    if (BestTC.getEditDistance() == 0 ||
-        BestTC.getCorrection().getAsString() != "super")
-      return FailedCorrection(Typo, TypoName.getLoc(), RecordFailure);
-
-    BestTC.setCorrectionRange(SS, TypoName);
-    return BestTC;
-  }
-
-  // Record the failure's location if needed and return an empty correction. If
-  // this was an unqualified lookup and we believe the callback object did not
-  // filter out possible corrections, also cache the failure for the typo.
-  return FailedCorrection(Typo, TypoName.getLoc(), RecordFailure && !SecondBestTC);
-}
-
-/// Try to "correct" a typo in the source code by finding
-/// visible declarations whose names are similar to the name that was
-/// present in the source code.
-///
-/// \param TypoName the \c DeclarationNameInfo structure that contains
-/// the name that was present in the source code along with its location.
-///
-/// \param LookupKind the name-lookup criteria used to search for the name.
-///
-/// \param S the scope in which name lookup occurs.
-///
-/// \param SS the nested-name-specifier that precedes the name we're
-/// looking for, if present.
-///
-/// \param CCC A CorrectionCandidateCallback object that provides further
-/// validation of typo correction candidates. It also provides flags for
-/// determining the set of keywords permitted.
-///
-/// \param TDG A TypoDiagnosticGenerator functor that will be used to print
-/// diagnostics when the actual typo correction is attempted.
-///
-/// \param TRC A TypoRecoveryCallback functor that will be used to build an
-/// Expr from a typo correction candidate.
-///
-/// \param MemberContext if non-NULL, the context in which to look for
-/// a member access expression.
-///
-/// \param EnteringContext whether we're entering the context described by
-/// the nested-name-specifier SS.
-///
-/// \param OPT when non-NULL, the search for visible declarations will
-/// also walk the protocols in the qualified interfaces of \p OPT.
-///
-/// \returns a new \c TypoExpr that will later be replaced in the AST with an
-/// Expr representing the result of performing typo correction, or nullptr if
-/// typo correction is not possible. If nullptr is returned, no diagnostics will
-/// be emitted and it is the responsibility of the caller to emit any that are
-/// needed.
-TypoExpr *Sema::CorrectTypoDelayed(
-    const DeclarationNameInfo &TypoName, Sema::LookupNameKind LookupKind,
-    Scope *S, CXXScopeSpec *SS,
-    std::unique_ptr<CorrectionCandidateCallback> CCC,
-    TypoDiagnosticGenerator TDG, TypoRecoveryCallback TRC, CorrectTypoKind Mode,
-    DeclContext *MemberContext, bool EnteringContext,
-    const ObjCObjectPointerType *OPT) {
-  assert(CCC && "CorrectTypoDelayed requires a CorrectionCandidateCallback");
-
-  auto Consumer = makeTypoCorrectionConsumer(
-      TypoName, LookupKind, S, SS, std::move(CCC), MemberContext,
-      EnteringContext, OPT, Mode == CTK_ErrorRecovery);
-
-  // Give the external sema source a chance to correct the typo.
-  TypoCorrection ExternalTypo;
-  if (ExternalSource && Consumer) {
-    ExternalTypo = ExternalSource->CorrectTypo(
-        TypoName, LookupKind, S, SS, *Consumer->getCorrectionValidator(),
-        MemberContext, EnteringContext, OPT);
-    if (ExternalTypo)
-      Consumer->addCorrection(ExternalTypo);
-  }
-
-  if (!Consumer || Consumer->empty())
-    return nullptr;
-
-  // Make sure the best edit distance (prior to adding any namespace qualifiers)
-  // is not more that about a third of the length of the typo's identifier.
-  unsigned ED = Consumer->getBestEditDistance(true);
-  IdentifierInfo *Typo = TypoName.getName().getAsIdentifierInfo();
-  if (!ExternalTypo && ED > 0 && Typo->getName().size() / ED < 3)
-    return nullptr;
-
-  ExprEvalContexts.back().NumTypos++;
-  return createDelayedTypo(std::move(Consumer), std::move(TDG), std::move(TRC));
-}
-
-void TypoCorrection::addCorrectionDecl(NamedDecl *CDecl) {
-  if (!CDecl) return;
-
-  if (isKeyword())
-    CorrectionDecls.clear();
-
-  CorrectionDecls.push_back(CDecl);
-
-  if (!CorrectionName)
-    CorrectionName = CDecl->getDeclName();
-}
-
-std::string TypoCorrection::getAsString(const LangOptions &LO) const {
-  if (CorrectionNameSpec) {
-    std::string tmpBuffer;
-    llvm::raw_string_ostream PrefixOStream(tmpBuffer);
-    CorrectionNameSpec->print(PrefixOStream, PrintingPolicy(LO));
-    PrefixOStream << CorrectionName;
-    return PrefixOStream.str();
-  }
-
-  return CorrectionName.getAsString();
-}
-
-bool CorrectionCandidateCallback::ValidateCandidate(
-    const TypoCorrection &candidate) {
-  if (!candidate.isResolved())
-    return true;
-
-  if (candidate.isKeyword())
-    return WantTypeSpecifiers || WantExpressionKeywords || WantCXXNamedCasts ||
-           WantRemainingKeywords || WantObjCSuper;
-
-  bool HasNonType = false;
-  bool HasStaticMethod = false;
-  bool HasNonStaticMethod = false;
-  for (Decl *D : candidate) {
-    if (FunctionTemplateDecl *FTD = dyn_cast<FunctionTemplateDecl>(D))
-      D = FTD->getTemplatedDecl();
-    if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(D)) {
-      if (Method->isStatic())
-        HasStaticMethod = true;
-      else
-        HasNonStaticMethod = true;
-    }
-    if (!isa<TypeDecl>(D))
-      HasNonType = true;
-  }
-
-  if (IsAddressOfOperand && HasNonStaticMethod && !HasStaticMethod &&
-      !candidate.getCorrectionSpecifier())
-    return false;
-
-  return WantTypeSpecifiers || HasNonType;
-}
-
-FunctionCallFilterCCC::FunctionCallFilterCCC(Sema &SemaRef, unsigned NumArgs,
-                                             bool HasExplicitTemplateArgs,
-                                             MemberExpr *ME)
-    : NumArgs(NumArgs), HasExplicitTemplateArgs(HasExplicitTemplateArgs),
-      CurContext(SemaRef.CurContext), MemberFn(ME) {
-  WantTypeSpecifiers = false;
-  WantFunctionLikeCasts = SemaRef.getLangOpts().CPlusPlus && NumArgs == 1;
-  WantRemainingKeywords = false;
-}
-
-bool FunctionCallFilterCCC::ValidateCandidate(const TypoCorrection &candidate) {
-  if (!candidate.getCorrectionDecl())
-    return candidate.isKeyword();
-
-  for (auto *C : candidate) {
-    FunctionDecl *FD = nullptr;
-    NamedDecl *ND = C->getUnderlyingDecl();
-    if (FunctionTemplateDecl *FTD = dyn_cast<FunctionTemplateDecl>(ND))
-      FD = FTD->getTemplatedDecl();
-    if (!HasExplicitTemplateArgs && !FD) {
-      if (!(FD = dyn_cast<FunctionDecl>(ND)) && isa<ValueDecl>(ND)) {
-        // If the Decl is neither a function nor a template function,
-        // determine if it is a pointer or reference to a function. If so,
-        // check against the number of arguments expected for the pointee.
-        QualType ValType = cast<ValueDecl>(ND)->getType();
-        if (ValType.isNull())
-          continue;
-        if (ValType->isAnyPointerType() || ValType->isReferenceType())
-          ValType = ValType->getPointeeType();
-        if (const FunctionProtoType *FPT = ValType->getAs<FunctionProtoType>())
-          if (FPT->getNumParams() == NumArgs)
-            return true;
-      }
-    }
-
-    // Skip the current candidate if it is not a FunctionDecl or does not accept
-    // the current number of arguments.
-    if (!FD || !(FD->getNumParams() >= NumArgs &&
-                 FD->getMinRequiredArguments() <= NumArgs))
-      continue;
-
-    // If the current candidate is a non-static C++ method, skip the candidate
-    // unless the method being corrected--or the current DeclContext, if the
-    // function being corrected is not a method--is a method in the same class
-    // or a descendent class of the candidate's parent class.
-    if (CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(FD)) {
-      if (MemberFn || !MD->isStatic()) {
-        CXXMethodDecl *CurMD =
-            MemberFn
-                ? dyn_cast_or_null<CXXMethodDecl>(MemberFn->getMemberDecl())
-                : dyn_cast_or_null<CXXMethodDecl>(CurContext);
-        CXXRecordDecl *CurRD =
-            CurMD ? CurMD->getParent()->getCanonicalDecl() : nullptr;
-        CXXRecordDecl *RD = MD->getParent()->getCanonicalDecl();
-        if (!CurRD || (CurRD != RD && !CurRD->isDerivedFrom(RD)))
-          continue;
-      }
-    }
-    return true;
-  }
-  return false;
-}
-
-void Sema::diagnoseTypo(const TypoCorrection &Correction,
-                        const PartialDiagnostic &TypoDiag,
-                        bool ErrorRecovery) {
-  diagnoseTypo(Correction, TypoDiag, PDiag(diag::note_previous_decl),
-               ErrorRecovery);
-}
-
-/// Find which declaration we should import to provide the definition of
-/// the given declaration.
-static NamedDecl *getDefinitionToImport(NamedDecl *D) {
-  if (VarDecl *VD = dyn_cast<VarDecl>(D))
-    return VD->getDefinition();
-  if (FunctionDecl *FD = dyn_cast<FunctionDecl>(D))
-    return FD->getDefinition();
-  if (TagDecl *TD = dyn_cast<TagDecl>(D))
-    return TD->getDefinition();
-  if (ObjCInterfaceDecl *ID = dyn_cast<ObjCInterfaceDecl>(D))
-    return ID->getDefinition();
-  if (ObjCProtocolDecl *PD = dyn_cast<ObjCProtocolDecl>(D))
-    return PD->getDefinition();
-  if (TemplateDecl *TD = dyn_cast<TemplateDecl>(D))
-    return getDefinitionToImport(TD->getTemplatedDecl());
-  return nullptr;
-}
-
-void Sema::diagnoseMissingImport(SourceLocation Loc, NamedDecl *Decl,
-                                 MissingImportKind MIK, bool Recover) {
-  // Suggest importing a module providing the definition of this entity, if
-  // possible.
-  NamedDecl *Def = getDefinitionToImport(Decl);
-  if (!Def)
-    Def = Decl;
-
-  Module *Owner = getOwningModule(Def);
-  assert(Owner && "definition of hidden declaration is not in a module");
-
-  llvm::SmallVector<Module*, 8> OwningModules;
-  OwningModules.push_back(Owner);
-  auto Merged = Context.getModulesWithMergedDefinition(Def);
-  OwningModules.insert(OwningModules.end(), Merged.begin(), Merged.end());
-
-  diagnoseMissingImport(Loc, Decl, Decl->getLocation(), OwningModules, MIK,
-                        Recover);
-}
-
-/// Get a "quoted.h" or <angled.h> include path to use in a diagnostic
-/// suggesting the addition of a #include of the specified file.
-static std::string getIncludeStringForHeader(Preprocessor &PP,
-                                             const FileEntry *E) {
-  bool IsSystem;
-  auto Path =
-      PP.getHeaderSearchInfo().suggestPathToFileForDiagnostics(E, &IsSystem);
-  return (IsSystem ? '<' : '"') + Path + (IsSystem ? '>' : '"');
-}
-
-void Sema::diagnoseMissingImport(SourceLocation UseLoc, NamedDecl *Decl,
-                                 SourceLocation DeclLoc,
-                                 ArrayRef<Module *> Modules,
-                                 MissingImportKind MIK, bool Recover) {
-  assert(!Modules.empty());
-
-  // Weed out duplicates from module list.
-  llvm::SmallVector<Module*, 8> UniqueModules;
-  llvm::SmallDenseSet<Module*, 8> UniqueModuleSet;
-  for (auto *M : Modules)
-    if (UniqueModuleSet.insert(M).second)
-      UniqueModules.push_back(M);
-  Modules = UniqueModules;
-
-  if (Modules.size() > 1) {
-    std::string ModuleList;
-    unsigned N = 0;
-    for (Module *M : Modules) {
-      ModuleList += "\n        ";
-      if (++N == 5 && N != Modules.size()) {
-        ModuleList += "[...]";
-        break;
-      }
-      ModuleList += M->getFullModuleName();
-    }
-
-    Diag(UseLoc, diag::err_module_unimported_use_multiple)
-      << (int)MIK << Decl << ModuleList;
-  } else if (const FileEntry *E = PP.getModuleHeaderToIncludeForDiagnostics(
-                 UseLoc, Modules[0], DeclLoc)) {
-    // The right way to make the declaration visible is to include a header;
-    // suggest doing so.
-    //
-    // FIXME: Find a smart place to suggest inserting a #include, and add
-    // a FixItHint there.
-    Diag(UseLoc, diag::err_module_unimported_use_header)
-      << (int)MIK << Decl << Modules[0]->getFullModuleName()
-      << getIncludeStringForHeader(PP, E);
-  } else {
-    // FIXME: Add a FixItHint that imports the corresponding module.
-    Diag(UseLoc, diag::err_module_unimported_use)
-      << (int)MIK << Decl << Modules[0]->getFullModuleName();
-  }
-
-  unsigned DiagID;
-  switch (MIK) {
-  case MissingImportKind::Declaration:
-    DiagID = diag::note_previous_declaration;
-    break;
-  case MissingImportKind::Definition:
-    DiagID = diag::note_previous_definition;
-    break;
-  case MissingImportKind::DefaultArgument:
-    DiagID = diag::note_default_argument_declared_here;
-    break;
-  case MissingImportKind::ExplicitSpecialization:
-    DiagID = diag::note_explicit_specialization_declared_here;
-    break;
-  case MissingImportKind::PartialSpecialization:
-    DiagID = diag::note_partial_specialization_declared_here;
-    break;
-  }
-  Diag(DeclLoc, DiagID);
-
-  // Try to recover by implicitly importing this module.
-  if (Recover)
-    createImplicitModuleImportForErrorRecovery(UseLoc, Modules[0]);
-}
-
-/// Diagnose a successfully-corrected typo. Separated from the correction
-/// itself to allow external validation of the result, etc.
-///
-/// \param Correction The result of performing typo correction.
-/// \param TypoDiag The diagnostic to produce. This will have the corrected
-///        string added to it (and usually also a fixit).
-/// \param PrevNote A note to use when indicating the location of the entity to
-///        which we are correcting. Will have the correction string added to it.
-/// \param ErrorRecovery If \c true (the default), the caller is going to
-///        recover from the typo as if the corrected string had been typed.
-///        In this case, \c PDiag must be an error, and we will attach a fixit
-///        to it.
-void Sema::diagnoseTypo(const TypoCorrection &Correction,
-                        const PartialDiagnostic &TypoDiag,
-                        const PartialDiagnostic &PrevNote,
-                        bool ErrorRecovery) {
-  std::string CorrectedStr = Correction.getAsString(getLangOpts());
-  std::string CorrectedQuotedStr = Correction.getQuoted(getLangOpts());
-  FixItHint FixTypo = FixItHint::CreateReplacement(
-      Correction.getCorrectionRange(), CorrectedStr);
-
-  // Maybe we're just missing a module import.
-  if (Correction.requiresImport()) {
-    NamedDecl *Decl = Correction.getFoundDecl();
-    assert(Decl && "import required but no declaration to import");
-
-    diagnoseMissingImport(Correction.getCorrectionRange().getBegin(), Decl,
-                          MissingImportKind::Declaration, ErrorRecovery);
-    return;
-  }
-
-  Diag(Correction.getCorrectionRange().getBegin(), TypoDiag)
-    << CorrectedQuotedStr << (ErrorRecovery ? FixTypo : FixItHint());
-
-  NamedDecl *ChosenDecl =
-      Correction.isKeyword() ? nullptr : Correction.getFoundDecl();
-  if (PrevNote.getDiagID() && ChosenDecl)
-    Diag(ChosenDecl->getLocation(), PrevNote)
-      << CorrectedQuotedStr << (ErrorRecovery ? FixItHint() : FixTypo);
-
-  // Add any extra diagnostics.
-  for (const PartialDiagnostic &PD : Correction.getExtraDiagnostics())
-    Diag(Correction.getCorrectionRange().getBegin(), PD);
-}
-
-TypoExpr *Sema::createDelayedTypo(std::unique_ptr<TypoCorrectionConsumer> TCC,
-                                  TypoDiagnosticGenerator TDG,
-                                  TypoRecoveryCallback TRC) {
-  assert(TCC && "createDelayedTypo requires a valid TypoCorrectionConsumer");
-  auto TE = new (Context) TypoExpr(Context.DependentTy);
-  auto &State = DelayedTypos[TE];
-  State.Consumer = std::move(TCC);
-  State.DiagHandler = std::move(TDG);
-  State.RecoveryHandler = std::move(TRC);
-  return TE;
-}
-
-const Sema::TypoExprState &Sema::getTypoExprState(TypoExpr *TE) const {
-  auto Entry = DelayedTypos.find(TE);
-  assert(Entry != DelayedTypos.end() &&
-         "Failed to get the state for a TypoExpr!");
-  return Entry->second;
-}
-
-void Sema::clearDelayedTypo(TypoExpr *TE) {
-  DelayedTypos.erase(TE);
-}
-
-void Sema::ActOnPragmaDump(Scope *S, SourceLocation IILoc, IdentifierInfo *II) {
-  DeclarationNameInfo Name(II, IILoc);
-  LookupResult R(*this, Name, LookupAnyName, Sema::NotForRedeclaration);
-  R.suppressDiagnostics();
-  R.setHideTags(false);
-  LookupName(R, S);
-  R.dump();
-}