Import LLVM 10.0.0 release including clang, lld and lldb.

ok hackroom
tested by plenty

1 files changed, 1433 insertions, 0 deletions

diff --git a/gnu/llvm/clang/lib/AST/DeclTemplate.cpp b/gnu/llvm/clang/lib/AST/DeclTemplate.cpp
new file mode 100755
index 00000000000..b5e4ec2d7f4
--- /dev/null
+++ b/gnu/llvm/clang/lib/AST/DeclTemplate.cpp
@@ -0,0 +1,1433 @@
+//===- DeclTemplate.cpp - Template Declaration AST Node Implementation ----===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements the C++ related Decl classes for templates.
+//
+//===----------------------------------------------------------------------===//
+
+#include "clang/AST/DeclTemplate.h"
+#include "clang/AST/ASTContext.h"
+#include "clang/AST/ASTMutationListener.h"
+#include "clang/AST/DeclCXX.h"
+#include "clang/AST/DeclarationName.h"
+#include "clang/AST/Expr.h"
+#include "clang/AST/ExternalASTSource.h"
+#include "clang/AST/TemplateBase.h"
+#include "clang/AST/TemplateName.h"
+#include "clang/AST/Type.h"
+#include "clang/AST/TypeLoc.h"
+#include "clang/Basic/Builtins.h"
+#include "clang/Basic/LLVM.h"
+#include "clang/Basic/SourceLocation.h"
+#include "llvm/ADT/ArrayRef.h"
+#include "llvm/ADT/FoldingSet.h"
+#include "llvm/ADT/None.h"
+#include "llvm/ADT/PointerUnion.h"
+#include "llvm/ADT/SmallVector.h"
+#include "llvm/Support/Casting.h"
+#include "llvm/Support/ErrorHandling.h"
+#include <algorithm>
+#include <cassert>
+#include <cstdint>
+#include <memory>
+#include <utility>
+
+using namespace clang;
+
+//===----------------------------------------------------------------------===//
+// TemplateParameterList Implementation
+//===----------------------------------------------------------------------===//
+
+
+TemplateParameterList::TemplateParameterList(const ASTContext& C,
+                                             SourceLocation TemplateLoc,
+                                             SourceLocation LAngleLoc,
+                                             ArrayRef<NamedDecl *> Params,
+                                             SourceLocation RAngleLoc,
+                                             Expr *RequiresClause)
+    : TemplateLoc(TemplateLoc), LAngleLoc(LAngleLoc), RAngleLoc(RAngleLoc),
+      NumParams(Params.size()), ContainsUnexpandedParameterPack(false),
+      HasRequiresClause(RequiresClause != nullptr),
+      HasConstrainedParameters(false) {
+  for (unsigned Idx = 0; Idx < NumParams; ++Idx) {
+    NamedDecl *P = Params[Idx];
+    begin()[Idx] = P;
+
+    bool IsPack = P->isTemplateParameterPack();
+    if (const auto *NTTP = dyn_cast<NonTypeTemplateParmDecl>(P)) {
+      if (!IsPack && NTTP->getType()->containsUnexpandedParameterPack())
+        ContainsUnexpandedParameterPack = true;
+      if (NTTP->hasPlaceholderTypeConstraint())
+        HasConstrainedParameters = true;
+    } else if (const auto *TTP = dyn_cast<TemplateTemplateParmDecl>(P)) {
+      if (!IsPack &&
+          TTP->getTemplateParameters()->containsUnexpandedParameterPack())
+        ContainsUnexpandedParameterPack = true;
+    } else if (const TypeConstraint *TC =
+        cast<TemplateTypeParmDecl>(P)->getTypeConstraint()) {
+      if (TC->getImmediatelyDeclaredConstraint()
+          ->containsUnexpandedParameterPack())
+        ContainsUnexpandedParameterPack = true;
+      HasConstrainedParameters = true;
+    }
+    // FIXME: If a default argument contains an unexpanded parameter pack, the
+    // template parameter list does too.
+  }
+
+  if (HasRequiresClause) {
+    if (RequiresClause->containsUnexpandedParameterPack())
+      ContainsUnexpandedParameterPack = true;
+    *getTrailingObjects<Expr *>() = RequiresClause;
+  }
+}
+
+TemplateParameterList *
+TemplateParameterList::Create(const ASTContext &C, SourceLocation TemplateLoc,
+                              SourceLocation LAngleLoc,
+                              ArrayRef<NamedDecl *> Params,
+                              SourceLocation RAngleLoc, Expr *RequiresClause) {
+  void *Mem = C.Allocate(totalSizeToAlloc<NamedDecl *, Expr *>(
+                             Params.size(), RequiresClause ? 1u : 0u),
+                         alignof(TemplateParameterList));
+  return new (Mem) TemplateParameterList(C, TemplateLoc, LAngleLoc, Params,
+                                         RAngleLoc, RequiresClause);
+}
+
+unsigned TemplateParameterList::getMinRequiredArguments() const {
+  unsigned NumRequiredArgs = 0;
+  for (const NamedDecl *P : asArray()) {
+    if (P->isTemplateParameterPack()) {
+      if (const auto *NTTP = dyn_cast<NonTypeTemplateParmDecl>(P)) {
+        if (NTTP->isExpandedParameterPack()) {
+          NumRequiredArgs += NTTP->getNumExpansionTypes();
+          continue;
+        }
+      } else if (const auto *TTP = dyn_cast<TemplateTypeParmDecl>(P)) {
+        if (TTP->isExpandedParameterPack()) {
+          NumRequiredArgs += TTP->getNumExpansionParameters();
+          continue;
+        }
+      } else {
+        const auto *TP = cast<TemplateTemplateParmDecl>(P);
+        if (TP->isExpandedParameterPack()) {
+          NumRequiredArgs += TP->getNumExpansionTemplateParameters();
+          continue;
+        }
+      }
+
+      break;
+    }
+
+    if (const auto *TTP = dyn_cast<TemplateTypeParmDecl>(P)) {
+      if (TTP->hasDefaultArgument())
+        break;
+    } else if (const auto *NTTP = dyn_cast<NonTypeTemplateParmDecl>(P)) {
+      if (NTTP->hasDefaultArgument())
+        break;
+    } else if (cast<TemplateTemplateParmDecl>(P)->hasDefaultArgument())
+      break;
+
+    ++NumRequiredArgs;
+  }
+
+  return NumRequiredArgs;
+}
+
+unsigned TemplateParameterList::getDepth() const {
+  if (size() == 0)
+    return 0;
+
+  const NamedDecl *FirstParm = getParam(0);
+  if (const auto *TTP = dyn_cast<TemplateTypeParmDecl>(FirstParm))
+    return TTP->getDepth();
+  else if (const auto *NTTP = dyn_cast<NonTypeTemplateParmDecl>(FirstParm))
+    return NTTP->getDepth();
+  else
+    return cast<TemplateTemplateParmDecl>(FirstParm)->getDepth();
+}
+
+static void AdoptTemplateParameterList(TemplateParameterList *Params,
+                                       DeclContext *Owner) {
+  for (NamedDecl *P : *Params) {
+    P->setDeclContext(Owner);
+
+    if (const auto *TTP = dyn_cast<TemplateTemplateParmDecl>(P))
+      AdoptTemplateParameterList(TTP->getTemplateParameters(), Owner);
+  }
+}
+
+void TemplateParameterList::
+getAssociatedConstraints(llvm::SmallVectorImpl<const Expr *> &AC) const {
+  if (HasConstrainedParameters)
+    for (const NamedDecl *Param : *this) {
+      if (const auto *TTP = dyn_cast<TemplateTypeParmDecl>(Param)) {
+        if (const auto *TC = TTP->getTypeConstraint())
+          AC.push_back(TC->getImmediatelyDeclaredConstraint());
+      } else if (const auto *NTTP = dyn_cast<NonTypeTemplateParmDecl>(Param)) {
+        if (const Expr *E = NTTP->getPlaceholderTypeConstraint())
+          AC.push_back(E);
+      }
+    }
+  if (HasRequiresClause)
+    AC.push_back(getRequiresClause());
+}
+
+bool TemplateParameterList::hasAssociatedConstraints() const {
+  return HasRequiresClause || HasConstrainedParameters;
+}
+
+namespace clang {
+
+void *allocateDefaultArgStorageChain(const ASTContext &C) {
+  return new (C) char[sizeof(void*) * 2];
+}
+
+} // namespace clang
+
+//===----------------------------------------------------------------------===//
+// TemplateDecl Implementation
+//===----------------------------------------------------------------------===//
+
+TemplateDecl::TemplateDecl(Kind DK, DeclContext *DC, SourceLocation L,
+                           DeclarationName Name, TemplateParameterList *Params,
+                           NamedDecl *Decl)
+    : NamedDecl(DK, DC, L, Name), TemplatedDecl(Decl), TemplateParams(Params) {}
+
+void TemplateDecl::anchor() {}
+
+void TemplateDecl::
+getAssociatedConstraints(llvm::SmallVectorImpl<const Expr *> &AC) const {
+  TemplateParams->getAssociatedConstraints(AC);
+  if (auto *FD = dyn_cast_or_null<FunctionDecl>(getTemplatedDecl()))
+    if (const Expr *TRC = FD->getTrailingRequiresClause())
+      AC.push_back(TRC);
+}
+
+bool TemplateDecl::hasAssociatedConstraints() const {
+  if (TemplateParams->hasAssociatedConstraints())
+    return true;
+  if (auto *FD = dyn_cast_or_null<FunctionDecl>(getTemplatedDecl()))
+    return FD->getTrailingRequiresClause();
+  return false;
+}
+
+//===----------------------------------------------------------------------===//
+// RedeclarableTemplateDecl Implementation
+//===----------------------------------------------------------------------===//
+
+void RedeclarableTemplateDecl::anchor() {}
+
+RedeclarableTemplateDecl::CommonBase *RedeclarableTemplateDecl::getCommonPtr() const {
+  if (Common)
+    return Common;
+
+  // Walk the previous-declaration chain until we either find a declaration
+  // with a common pointer or we run out of previous declarations.
+  SmallVector<const RedeclarableTemplateDecl *, 2> PrevDecls;
+  for (const RedeclarableTemplateDecl *Prev = getPreviousDecl(); Prev;
+       Prev = Prev->getPreviousDecl()) {
+    if (Prev->Common) {
+      Common = Prev->Common;
+      break;
+    }
+
+    PrevDecls.push_back(Prev);
+  }
+
+  // If we never found a common pointer, allocate one now.
+  if (!Common) {
+    // FIXME: If any of the declarations is from an AST file, we probably
+    // need an update record to add the common data.
+
+    Common = newCommon(getASTContext());
+  }
+
+  // Update any previous declarations we saw with the common pointer.
+  for (const RedeclarableTemplateDecl *Prev : PrevDecls)
+    Prev->Common = Common;
+
+  return Common;
+}
+
+void RedeclarableTemplateDecl::loadLazySpecializationsImpl() const {
+  // Grab the most recent declaration to ensure we've loaded any lazy
+  // redeclarations of this template.
+  CommonBase *CommonBasePtr = getMostRecentDecl()->getCommonPtr();
+  if (CommonBasePtr->LazySpecializations) {
+    ASTContext &Context = getASTContext();
+    uint32_t *Specs = CommonBasePtr->LazySpecializations;
+    CommonBasePtr->LazySpecializations = nullptr;
+    for (uint32_t I = 0, N = *Specs++; I != N; ++I)
+      (void)Context.getExternalSource()->GetExternalDecl(Specs[I]);
+  }
+}
+
+template<class EntryType, typename... ProfileArguments>
+typename RedeclarableTemplateDecl::SpecEntryTraits<EntryType>::DeclType *
+RedeclarableTemplateDecl::findSpecializationImpl(
+    llvm::FoldingSetVector<EntryType> &Specs, void *&InsertPos,
+    ProfileArguments&&... ProfileArgs) {
+  using SETraits = SpecEntryTraits<EntryType>;
+
+  llvm::FoldingSetNodeID ID;
+  EntryType::Profile(ID, std::forward<ProfileArguments>(ProfileArgs)...,
+                     getASTContext());
+  EntryType *Entry = Specs.FindNodeOrInsertPos(ID, InsertPos);
+  return Entry ? SETraits::getDecl(Entry)->getMostRecentDecl() : nullptr;
+}
+
+template<class Derived, class EntryType>
+void RedeclarableTemplateDecl::addSpecializationImpl(
+    llvm::FoldingSetVector<EntryType> &Specializations, EntryType *Entry,
+    void *InsertPos) {
+  using SETraits = SpecEntryTraits<EntryType>;
+
+  if (InsertPos) {
+#ifndef NDEBUG
+    void *CorrectInsertPos;
+    assert(!findSpecializationImpl(Specializations,
+                                   CorrectInsertPos,
+                                   SETraits::getTemplateArgs(Entry)) &&
+           InsertPos == CorrectInsertPos &&
+           "given incorrect InsertPos for specialization");
+#endif
+    Specializations.InsertNode(Entry, InsertPos);
+  } else {
+    EntryType *Existing = Specializations.GetOrInsertNode(Entry);
+    (void)Existing;
+    assert(SETraits::getDecl(Existing)->isCanonicalDecl() &&
+           "non-canonical specialization?");
+  }
+
+  if (ASTMutationListener *L = getASTMutationListener())
+    L->AddedCXXTemplateSpecialization(cast<Derived>(this),
+                                      SETraits::getDecl(Entry));
+}
+
+//===----------------------------------------------------------------------===//
+// FunctionTemplateDecl Implementation
+//===----------------------------------------------------------------------===//
+
+FunctionTemplateDecl *FunctionTemplateDecl::Create(ASTContext &C,
+                                                   DeclContext *DC,
+                                                   SourceLocation L,
+                                                   DeclarationName Name,
+                                               TemplateParameterList *Params,
+                                                   NamedDecl *Decl) {
+  AdoptTemplateParameterList(Params, cast<DeclContext>(Decl));
+  return new (C, DC) FunctionTemplateDecl(C, DC, L, Name, Params, Decl);
+}
+
+FunctionTemplateDecl *FunctionTemplateDecl::CreateDeserialized(ASTContext &C,
+                                                               unsigned ID) {
+  return new (C, ID) FunctionTemplateDecl(C, nullptr, SourceLocation(),
+                                          DeclarationName(), nullptr, nullptr);
+}
+
+RedeclarableTemplateDecl::CommonBase *
+FunctionTemplateDecl::newCommon(ASTContext &C) const {
+  auto *CommonPtr = new (C) Common;
+  C.addDestruction(CommonPtr);
+  return CommonPtr;
+}
+
+void FunctionTemplateDecl::LoadLazySpecializations() const {
+  loadLazySpecializationsImpl();
+}
+
+llvm::FoldingSetVector<FunctionTemplateSpecializationInfo> &
+FunctionTemplateDecl::getSpecializations() const {
+  LoadLazySpecializations();
+  return getCommonPtr()->Specializations;
+}
+
+FunctionDecl *
+FunctionTemplateDecl::findSpecialization(ArrayRef<TemplateArgument> Args,
+                                         void *&InsertPos) {
+  return findSpecializationImpl(getSpecializations(), InsertPos, Args);
+}
+
+void FunctionTemplateDecl::addSpecialization(
+      FunctionTemplateSpecializationInfo *Info, void *InsertPos) {
+  addSpecializationImpl<FunctionTemplateDecl>(getSpecializations(), Info,
+                                              InsertPos);
+}
+
+ArrayRef<TemplateArgument> FunctionTemplateDecl::getInjectedTemplateArgs() {
+  TemplateParameterList *Params = getTemplateParameters();
+  Common *CommonPtr = getCommonPtr();
+  if (!CommonPtr->InjectedArgs) {
+    auto &Context = getASTContext();
+    SmallVector<TemplateArgument, 16> TemplateArgs;
+    Context.getInjectedTemplateArgs(Params, TemplateArgs);
+    CommonPtr->InjectedArgs =
+        new (Context) TemplateArgument[TemplateArgs.size()];
+    std::copy(TemplateArgs.begin(), TemplateArgs.end(),
+              CommonPtr->InjectedArgs);
+  }
+
+  return llvm::makeArrayRef(CommonPtr->InjectedArgs, Params->size());
+}
+
+void FunctionTemplateDecl::mergePrevDecl(FunctionTemplateDecl *Prev) {
+  using Base = RedeclarableTemplateDecl;
+
+  // If we haven't created a common pointer yet, then it can just be created
+  // with the usual method.
+  if (!Base::Common)
+    return;
+
+  Common *ThisCommon = static_cast<Common *>(Base::Common);
+  Common *PrevCommon = nullptr;
+  SmallVector<FunctionTemplateDecl *, 8> PreviousDecls;
+  for (; Prev; Prev = Prev->getPreviousDecl()) {
+    if (Prev->Base::Common) {
+      PrevCommon = static_cast<Common *>(Prev->Base::Common);
+      break;
+    }
+    PreviousDecls.push_back(Prev);
+  }
+
+  // If the previous redecl chain hasn't created a common pointer yet, then just
+  // use this common pointer.
+  if (!PrevCommon) {
+    for (auto *D : PreviousDecls)
+      D->Base::Common = ThisCommon;
+    return;
+  }
+
+  // Ensure we don't leak any important state.
+  assert(ThisCommon->Specializations.size() == 0 &&
+         "Can't merge incompatible declarations!");
+
+  Base::Common = PrevCommon;
+}
+
+//===----------------------------------------------------------------------===//
+// ClassTemplateDecl Implementation
+//===----------------------------------------------------------------------===//
+
+ClassTemplateDecl *ClassTemplateDecl::Create(ASTContext &C,
+                                             DeclContext *DC,
+                                             SourceLocation L,
+                                             DeclarationName Name,
+                                             TemplateParameterList *Params,
+                                             NamedDecl *Decl) {
+  AdoptTemplateParameterList(Params, cast<DeclContext>(Decl));
+
+  return new (C, DC) ClassTemplateDecl(C, DC, L, Name, Params, Decl);
+}
+
+ClassTemplateDecl *ClassTemplateDecl::CreateDeserialized(ASTContext &C,
+                                                         unsigned ID) {
+  return new (C, ID) ClassTemplateDecl(C, nullptr, SourceLocation(),
+                                       DeclarationName(), nullptr, nullptr);
+}
+
+void ClassTemplateDecl::LoadLazySpecializations() const {
+  loadLazySpecializationsImpl();
+}
+
+llvm::FoldingSetVector<ClassTemplateSpecializationDecl> &
+ClassTemplateDecl::getSpecializations() const {
+  LoadLazySpecializations();
+  return getCommonPtr()->Specializations;
+}
+
+llvm::FoldingSetVector<ClassTemplatePartialSpecializationDecl> &
+ClassTemplateDecl::getPartialSpecializations() {
+  LoadLazySpecializations();
+  return getCommonPtr()->PartialSpecializations;
+}
+
+RedeclarableTemplateDecl::CommonBase *
+ClassTemplateDecl::newCommon(ASTContext &C) const {
+  auto *CommonPtr = new (C) Common;
+  C.addDestruction(CommonPtr);
+  return CommonPtr;
+}
+
+ClassTemplateSpecializationDecl *
+ClassTemplateDecl::findSpecialization(ArrayRef<TemplateArgument> Args,
+                                      void *&InsertPos) {
+  return findSpecializationImpl(getSpecializations(), InsertPos, Args);
+}
+
+void ClassTemplateDecl::AddSpecialization(ClassTemplateSpecializationDecl *D,
+                                          void *InsertPos) {
+  addSpecializationImpl<ClassTemplateDecl>(getSpecializations(), D, InsertPos);
+}
+
+ClassTemplatePartialSpecializationDecl *
+ClassTemplateDecl::findPartialSpecialization(
+    ArrayRef<TemplateArgument> Args,
+    TemplateParameterList *TPL, void *&InsertPos) {
+  return findSpecializationImpl(getPartialSpecializations(), InsertPos, Args,
+                                TPL);
+}
+
+static void ProfileTemplateParameterList(ASTContext &C,
+    llvm::FoldingSetNodeID &ID, const TemplateParameterList *TPL) {
+  const Expr *RC = TPL->getRequiresClause();
+  ID.AddBoolean(RC != nullptr);
+  if (RC)
+    RC->Profile(ID, C, /*Canonical=*/true);
+  ID.AddInteger(TPL->size());
+  for (NamedDecl *D : *TPL) {
+    if (const auto *NTTP = dyn_cast<NonTypeTemplateParmDecl>(D)) {
+      ID.AddInteger(0);
+      ID.AddBoolean(NTTP->isParameterPack());
+      NTTP->getType().getCanonicalType().Profile(ID);
+      continue;
+    }
+    if (const auto *TTP = dyn_cast<TemplateTypeParmDecl>(D)) {
+      ID.AddInteger(1);
+      ID.AddBoolean(TTP->isParameterPack());
+      ID.AddBoolean(TTP->hasTypeConstraint());
+      if (const TypeConstraint *TC = TTP->getTypeConstraint())
+        TC->getImmediatelyDeclaredConstraint()->Profile(ID, C,
+                                                        /*Canonical=*/true);
+      continue;
+    }
+    const auto *TTP = cast<TemplateTemplateParmDecl>(D);
+    ID.AddInteger(2);
+    ID.AddBoolean(TTP->isParameterPack());
+    ProfileTemplateParameterList(C, ID, TTP->getTemplateParameters());
+  }
+}
+
+void
+ClassTemplatePartialSpecializationDecl::Profile(llvm::FoldingSetNodeID &ID,
+    ArrayRef<TemplateArgument> TemplateArgs, TemplateParameterList *TPL,
+    ASTContext &Context) {
+  ID.AddInteger(TemplateArgs.size());
+  for (const TemplateArgument &TemplateArg : TemplateArgs)
+    TemplateArg.Profile(ID, Context);
+  ProfileTemplateParameterList(Context, ID, TPL);
+}
+
+void ClassTemplateDecl::AddPartialSpecialization(
+                                      ClassTemplatePartialSpecializationDecl *D,
+                                      void *InsertPos) {
+  if (InsertPos)
+    getPartialSpecializations().InsertNode(D, InsertPos);
+  else {
+    ClassTemplatePartialSpecializationDecl *Existing
+      = getPartialSpecializations().GetOrInsertNode(D);
+    (void)Existing;
+    assert(Existing->isCanonicalDecl() && "Non-canonical specialization?");
+  }
+
+  if (ASTMutationListener *L = getASTMutationListener())
+    L->AddedCXXTemplateSpecialization(this, D);
+}
+
+void ClassTemplateDecl::getPartialSpecializations(
+          SmallVectorImpl<ClassTemplatePartialSpecializationDecl *> &PS) {
+  llvm::FoldingSetVector<ClassTemplatePartialSpecializationDecl> &PartialSpecs
+    = getPartialSpecializations();
+  PS.clear();
+  PS.reserve(PartialSpecs.size());
+  for (ClassTemplatePartialSpecializationDecl &P : PartialSpecs)
+    PS.push_back(P.getMostRecentDecl());
+}
+
+ClassTemplatePartialSpecializationDecl *
+ClassTemplateDecl::findPartialSpecialization(QualType T) {
+  ASTContext &Context = getASTContext();
+  for (ClassTemplatePartialSpecializationDecl &P :
+       getPartialSpecializations()) {
+    if (Context.hasSameType(P.getInjectedSpecializationType(), T))
+      return P.getMostRecentDecl();
+  }
+
+  return nullptr;
+}
+
+ClassTemplatePartialSpecializationDecl *
+ClassTemplateDecl::findPartialSpecInstantiatedFromMember(
+                                    ClassTemplatePartialSpecializationDecl *D) {
+  Decl *DCanon = D->getCanonicalDecl();
+  for (ClassTemplatePartialSpecializationDecl &P : getPartialSpecializations()) {
+    if (P.getInstantiatedFromMember()->getCanonicalDecl() == DCanon)
+      return P.getMostRecentDecl();
+  }
+
+  return nullptr;
+}
+
+QualType
+ClassTemplateDecl::getInjectedClassNameSpecialization() {
+  Common *CommonPtr = getCommonPtr();
+  if (!CommonPtr->InjectedClassNameType.isNull())
+    return CommonPtr->InjectedClassNameType;
+
+  // C++0x [temp.dep.type]p2:
+  //  The template argument list of a primary template is a template argument
+  //  list in which the nth template argument has the value of the nth template
+  //  parameter of the class template. If the nth template parameter is a
+  //  template parameter pack (14.5.3), the nth template argument is a pack
+  //  expansion (14.5.3) whose pattern is the name of the template parameter
+  //  pack.
+  ASTContext &Context = getASTContext();
+  TemplateParameterList *Params = getTemplateParameters();
+  SmallVector<TemplateArgument, 16> TemplateArgs;
+  Context.getInjectedTemplateArgs(Params, TemplateArgs);
+  CommonPtr->InjectedClassNameType
+    = Context.getTemplateSpecializationType(TemplateName(this),
+                                            TemplateArgs);
+  return CommonPtr->InjectedClassNameType;
+}
+
+//===----------------------------------------------------------------------===//
+// TemplateTypeParm Allocation/Deallocation Method Implementations
+//===----------------------------------------------------------------------===//
+
+TemplateTypeParmDecl *
+TemplateTypeParmDecl::Create(const ASTContext &C, DeclContext *DC,
+                             SourceLocation KeyLoc, SourceLocation NameLoc,
+                             unsigned D, unsigned P, IdentifierInfo *Id,
+                             bool Typename, bool ParameterPack,
+                             bool HasTypeConstraint,
+                             Optional<unsigned> NumExpanded) {
+  auto *TTPDecl =
+      new (C, DC,
+           additionalSizeToAlloc<TypeConstraint>(HasTypeConstraint ? 1 : 0))
+      TemplateTypeParmDecl(DC, KeyLoc, NameLoc, Id, Typename,
+                           HasTypeConstraint, NumExpanded);
+  QualType TTPType = C.getTemplateTypeParmType(D, P, ParameterPack, TTPDecl);
+  TTPDecl->setTypeForDecl(TTPType.getTypePtr());
+  return TTPDecl;
+}
+
+TemplateTypeParmDecl *
+TemplateTypeParmDecl::CreateDeserialized(const ASTContext &C, unsigned ID) {
+  return new (C, ID) TemplateTypeParmDecl(nullptr, SourceLocation(),
+                                          SourceLocation(), nullptr, false,
+                                          false, None);
+}
+
+TemplateTypeParmDecl *
+TemplateTypeParmDecl::CreateDeserialized(const ASTContext &C, unsigned ID,
+                                         bool HasTypeConstraint) {
+  return new (C, ID,
+              additionalSizeToAlloc<TypeConstraint>(HasTypeConstraint ? 1 : 0))
+         TemplateTypeParmDecl(nullptr, SourceLocation(), SourceLocation(),
+                              nullptr, false, HasTypeConstraint, None);
+}
+
+SourceLocation TemplateTypeParmDecl::getDefaultArgumentLoc() const {
+  return hasDefaultArgument()
+             ? getDefaultArgumentInfo()->getTypeLoc().getBeginLoc()
+             : SourceLocation();
+}
+
+SourceRange TemplateTypeParmDecl::getSourceRange() const {
+  if (hasDefaultArgument() && !defaultArgumentWasInherited())
+    return SourceRange(getBeginLoc(),
+                       getDefaultArgumentInfo()->getTypeLoc().getEndLoc());
+  // TypeDecl::getSourceRange returns a range containing name location, which is
+  // wrong for unnamed template parameters. e.g:
+  // it will return <[[typename>]] instead of <[[typename]]>
+  else if (getDeclName().isEmpty())
+    return SourceRange(getBeginLoc());
+  return TypeDecl::getSourceRange();
+}
+
+unsigned TemplateTypeParmDecl::getDepth() const {
+  return getTypeForDecl()->castAs<TemplateTypeParmType>()->getDepth();
+}
+
+unsigned TemplateTypeParmDecl::getIndex() const {
+  return getTypeForDecl()->castAs<TemplateTypeParmType>()->getIndex();
+}
+
+bool TemplateTypeParmDecl::isParameterPack() const {
+  return getTypeForDecl()->castAs<TemplateTypeParmType>()->isParameterPack();
+}
+
+void TemplateTypeParmDecl::setTypeConstraint(NestedNameSpecifierLoc NNS,
+    DeclarationNameInfo NameInfo, NamedDecl *FoundDecl, ConceptDecl *CD,
+    const ASTTemplateArgumentListInfo *ArgsAsWritten,
+    Expr *ImmediatelyDeclaredConstraint) {
+  assert(HasTypeConstraint &&
+         "HasTypeConstraint=true must be passed at construction in order to "
+         "call setTypeConstraint");
+  assert(!TypeConstraintInitialized &&
+         "TypeConstraint was already initialized!");
+  new (getTrailingObjects<TypeConstraint>()) TypeConstraint(NNS, NameInfo,
+      FoundDecl, CD, ArgsAsWritten, ImmediatelyDeclaredConstraint);
+  TypeConstraintInitialized = true;
+}
+
+//===----------------------------------------------------------------------===//
+// NonTypeTemplateParmDecl Method Implementations
+//===----------------------------------------------------------------------===//
+
+NonTypeTemplateParmDecl::NonTypeTemplateParmDecl(
+    DeclContext *DC, SourceLocation StartLoc, SourceLocation IdLoc, unsigned D,
+    unsigned P, IdentifierInfo *Id, QualType T, TypeSourceInfo *TInfo,
+    ArrayRef<QualType> ExpandedTypes, ArrayRef<TypeSourceInfo *> ExpandedTInfos)
+    : DeclaratorDecl(NonTypeTemplateParm, DC, IdLoc, Id, T, TInfo, StartLoc),
+      TemplateParmPosition(D, P), ParameterPack(true),
+      ExpandedParameterPack(true), NumExpandedTypes(ExpandedTypes.size()) {
+  if (!ExpandedTypes.empty() && !ExpandedTInfos.empty()) {
+    auto TypesAndInfos =
+        getTrailingObjects<std::pair<QualType, TypeSourceInfo *>>();
+    for (unsigned I = 0; I != NumExpandedTypes; ++I) {
+      new (&TypesAndInfos[I].first) QualType(ExpandedTypes[I]);
+      TypesAndInfos[I].second = ExpandedTInfos[I];
+    }
+  }
+}
+
+NonTypeTemplateParmDecl *
+NonTypeTemplateParmDecl::Create(const ASTContext &C, DeclContext *DC,
+                                SourceLocation StartLoc, SourceLocation IdLoc,
+                                unsigned D, unsigned P, IdentifierInfo *Id,
+                                QualType T, bool ParameterPack,
+                                TypeSourceInfo *TInfo) {
+  AutoType *AT =
+      C.getLangOpts().CPlusPlus2a ? T->getContainedAutoType() : nullptr;
+  return new (C, DC,
+              additionalSizeToAlloc<std::pair<QualType, TypeSourceInfo *>,
+                                    Expr *>(0,
+                                            AT && AT->isConstrained() ? 1 : 0))
+      NonTypeTemplateParmDecl(DC, StartLoc, IdLoc, D, P, Id, T, ParameterPack,
+                              TInfo);
+}
+
+NonTypeTemplateParmDecl *NonTypeTemplateParmDecl::Create(
+    const ASTContext &C, DeclContext *DC, SourceLocation StartLoc,
+    SourceLocation IdLoc, unsigned D, unsigned P, IdentifierInfo *Id,
+    QualType T, TypeSourceInfo *TInfo, ArrayRef<QualType> ExpandedTypes,
+    ArrayRef<TypeSourceInfo *> ExpandedTInfos) {
+  AutoType *AT = TInfo->getType()->getContainedAutoType();
+  return new (C, DC,
+              additionalSizeToAlloc<std::pair<QualType, TypeSourceInfo *>,
+                                    Expr *>(
+                  ExpandedTypes.size(), AT && AT->isConstrained() ? 1 : 0))
+      NonTypeTemplateParmDecl(DC, StartLoc, IdLoc, D, P, Id, T, TInfo,
+                              ExpandedTypes, ExpandedTInfos);
+}
+
+NonTypeTemplateParmDecl *
+NonTypeTemplateParmDecl::CreateDeserialized(ASTContext &C, unsigned ID,
+                                            bool HasTypeConstraint) {
+  return new (C, ID, additionalSizeToAlloc<std::pair<QualType,
+                                                     TypeSourceInfo *>,
+                                           Expr *>(0,
+                                                   HasTypeConstraint ? 1 : 0))
+          NonTypeTemplateParmDecl(nullptr, SourceLocation(), SourceLocation(),
+                                  0, 0, nullptr, QualType(), false, nullptr);
+}
+
+NonTypeTemplateParmDecl *
+NonTypeTemplateParmDecl::CreateDeserialized(ASTContext &C, unsigned ID,
+                                            unsigned NumExpandedTypes,
+                                            bool HasTypeConstraint) {
+  auto *NTTP =
+      new (C, ID, additionalSizeToAlloc<std::pair<QualType, TypeSourceInfo *>,
+                                        Expr *>(
+                      NumExpandedTypes, HasTypeConstraint ? 1 : 0))
+          NonTypeTemplateParmDecl(nullptr, SourceLocation(), SourceLocation(),
+                                  0, 0, nullptr, QualType(), nullptr, None,
+                                  None);
+  NTTP->NumExpandedTypes = NumExpandedTypes;
+  return NTTP;
+}
+
+SourceRange NonTypeTemplateParmDecl::getSourceRange() const {
+  if (hasDefaultArgument() && !defaultArgumentWasInherited())
+    return SourceRange(getOuterLocStart(),
+                       getDefaultArgument()->getSourceRange().getEnd());
+  return DeclaratorDecl::getSourceRange();
+}
+
+SourceLocation NonTypeTemplateParmDecl::getDefaultArgumentLoc() const {
+  return hasDefaultArgument()
+    ? getDefaultArgument()->getSourceRange().getBegin()
+    : SourceLocation();
+}
+
+//===----------------------------------------------------------------------===//
+// TemplateTemplateParmDecl Method Implementations
+//===----------------------------------------------------------------------===//
+
+void TemplateTemplateParmDecl::anchor() {}
+
+TemplateTemplateParmDecl::TemplateTemplateParmDecl(
+    DeclContext *DC, SourceLocation L, unsigned D, unsigned P,
+    IdentifierInfo *Id, TemplateParameterList *Params,
+    ArrayRef<TemplateParameterList *> Expansions)
+    : TemplateDecl(TemplateTemplateParm, DC, L, Id, Params),
+      TemplateParmPosition(D, P), ParameterPack(true),
+      ExpandedParameterPack(true), NumExpandedParams(Expansions.size()) {
+  if (!Expansions.empty())
+    std::uninitialized_copy(Expansions.begin(), Expansions.end(),
+                            getTrailingObjects<TemplateParameterList *>());
+}
+
+TemplateTemplateParmDecl *
+TemplateTemplateParmDecl::Create(const ASTContext &C, DeclContext *DC,
+                                 SourceLocation L, unsigned D, unsigned P,
+                                 bool ParameterPack, IdentifierInfo *Id,
+                                 TemplateParameterList *Params) {
+  return new (C, DC) TemplateTemplateParmDecl(DC, L, D, P, ParameterPack, Id,
+                                              Params);
+}
+
+TemplateTemplateParmDecl *
+TemplateTemplateParmDecl::Create(const ASTContext &C, DeclContext *DC,
+                                 SourceLocation L, unsigned D, unsigned P,
+                                 IdentifierInfo *Id,
+                                 TemplateParameterList *Params,
+                                 ArrayRef<TemplateParameterList *> Expansions) {
+  return new (C, DC,
+              additionalSizeToAlloc<TemplateParameterList *>(Expansions.size()))
+      TemplateTemplateParmDecl(DC, L, D, P, Id, Params, Expansions);
+}
+
+TemplateTemplateParmDecl *
+TemplateTemplateParmDecl::CreateDeserialized(ASTContext &C, unsigned ID) {
+  return new (C, ID) TemplateTemplateParmDecl(nullptr, SourceLocation(), 0, 0,
+                                              false, nullptr, nullptr);
+}
+
+TemplateTemplateParmDecl *
+TemplateTemplateParmDecl::CreateDeserialized(ASTContext &C, unsigned ID,
+                                             unsigned NumExpansions) {
+  auto *TTP =
+      new (C, ID, additionalSizeToAlloc<TemplateParameterList *>(NumExpansions))
+          TemplateTemplateParmDecl(nullptr, SourceLocation(), 0, 0, nullptr,
+                                   nullptr, None);
+  TTP->NumExpandedParams = NumExpansions;
+  return TTP;
+}
+
+SourceLocation TemplateTemplateParmDecl::getDefaultArgumentLoc() const {
+  return hasDefaultArgument() ? getDefaultArgument().getLocation()
+                              : SourceLocation();
+}
+
+void TemplateTemplateParmDecl::setDefaultArgument(
+    const ASTContext &C, const TemplateArgumentLoc &DefArg) {
+  if (DefArg.getArgument().isNull())
+    DefaultArgument.set(nullptr);
+  else
+    DefaultArgument.set(new (C) TemplateArgumentLoc(DefArg));
+}
+
+//===----------------------------------------------------------------------===//
+// TemplateArgumentList Implementation
+//===----------------------------------------------------------------------===//
+TemplateArgumentList::TemplateArgumentList(ArrayRef<TemplateArgument> Args)
+    : Arguments(getTrailingObjects<TemplateArgument>()),
+      NumArguments(Args.size()) {
+  std::uninitialized_copy(Args.begin(), Args.end(),
+                          getTrailingObjects<TemplateArgument>());
+}
+
+TemplateArgumentList *
+TemplateArgumentList::CreateCopy(ASTContext &Context,
+                                 ArrayRef<TemplateArgument> Args) {
+  void *Mem = Context.Allocate(totalSizeToAlloc<TemplateArgument>(Args.size()));
+  return new (Mem) TemplateArgumentList(Args);
+}
+
+FunctionTemplateSpecializationInfo *FunctionTemplateSpecializationInfo::Create(
+    ASTContext &C, FunctionDecl *FD, FunctionTemplateDecl *Template,
+    TemplateSpecializationKind TSK, const TemplateArgumentList *TemplateArgs,
+    const TemplateArgumentListInfo *TemplateArgsAsWritten, SourceLocation POI,
+    MemberSpecializationInfo *MSInfo) {
+  const ASTTemplateArgumentListInfo *ArgsAsWritten = nullptr;
+  if (TemplateArgsAsWritten)
+    ArgsAsWritten = ASTTemplateArgumentListInfo::Create(C,
+                                                        *TemplateArgsAsWritten);
+
+  void *Mem =
+      C.Allocate(totalSizeToAlloc<MemberSpecializationInfo *>(MSInfo ? 1 : 0));
+  return new (Mem) FunctionTemplateSpecializationInfo(
+      FD, Template, TSK, TemplateArgs, ArgsAsWritten, POI, MSInfo);
+}
+
+//===----------------------------------------------------------------------===//
+// ClassTemplateSpecializationDecl Implementation
+//===----------------------------------------------------------------------===//
+
+ClassTemplateSpecializationDecl::
+ClassTemplateSpecializationDecl(ASTContext &Context, Kind DK, TagKind TK,
+                                DeclContext *DC, SourceLocation StartLoc,
+                                SourceLocation IdLoc,
+                                ClassTemplateDecl *SpecializedTemplate,
+                                ArrayRef<TemplateArgument> Args,
+                                ClassTemplateSpecializationDecl *PrevDecl)
+    : CXXRecordDecl(DK, TK, Context, DC, StartLoc, IdLoc,
+                    SpecializedTemplate->getIdentifier(), PrevDecl),
+    SpecializedTemplate(SpecializedTemplate),
+    TemplateArgs(TemplateArgumentList::CreateCopy(Context, Args)),
+    SpecializationKind(TSK_Undeclared) {
+}
+
+ClassTemplateSpecializationDecl::ClassTemplateSpecializationDecl(ASTContext &C,
+                                                                 Kind DK)
+    : CXXRecordDecl(DK, TTK_Struct, C, nullptr, SourceLocation(),
+                    SourceLocation(), nullptr, nullptr),
+      SpecializationKind(TSK_Undeclared) {}
+
+ClassTemplateSpecializationDecl *
+ClassTemplateSpecializationDecl::Create(ASTContext &Context, TagKind TK,
+                                        DeclContext *DC,
+                                        SourceLocation StartLoc,
+                                        SourceLocation IdLoc,
+                                        ClassTemplateDecl *SpecializedTemplate,
+                                        ArrayRef<TemplateArgument> Args,
+                                   ClassTemplateSpecializationDecl *PrevDecl) {
+  auto *Result =
+      new (Context, DC) ClassTemplateSpecializationDecl(
+          Context, ClassTemplateSpecialization, TK, DC, StartLoc, IdLoc,
+          SpecializedTemplate, Args, PrevDecl);
+  Result->setMayHaveOutOfDateDef(false);
+
+  Context.getTypeDeclType(Result, PrevDecl);
+  return Result;
+}
+
+ClassTemplateSpecializationDecl *
+ClassTemplateSpecializationDecl::CreateDeserialized(ASTContext &C,
+                                                    unsigned ID) {
+  auto *Result =
+    new (C, ID) ClassTemplateSpecializationDecl(C, ClassTemplateSpecialization);
+  Result->setMayHaveOutOfDateDef(false);
+  return Result;
+}
+
+void ClassTemplateSpecializationDecl::getNameForDiagnostic(
+    raw_ostream &OS, const PrintingPolicy &Policy, bool Qualified) const {
+  NamedDecl::getNameForDiagnostic(OS, Policy, Qualified);
+
+  const auto *PS = dyn_cast<ClassTemplatePartialSpecializationDecl>(this);
+  if (const ASTTemplateArgumentListInfo *ArgsAsWritten =
+          PS ? PS->getTemplateArgsAsWritten() : nullptr) {
+    printTemplateArgumentList(OS, ArgsAsWritten->arguments(), Policy);
+  } else {
+    const TemplateArgumentList &TemplateArgs = getTemplateArgs();
+    printTemplateArgumentList(OS, TemplateArgs.asArray(), Policy);
+  }
+}
+
+ClassTemplateDecl *
+ClassTemplateSpecializationDecl::getSpecializedTemplate() const {
+  if (const auto *PartialSpec =
+          SpecializedTemplate.dyn_cast<SpecializedPartialSpecialization*>())
+    return PartialSpec->PartialSpecialization->getSpecializedTemplate();
+  return SpecializedTemplate.get<ClassTemplateDecl*>();
+}
+
+SourceRange
+ClassTemplateSpecializationDecl::getSourceRange() const {
+  if (ExplicitInfo) {
+    SourceLocation Begin = getTemplateKeywordLoc();
+    if (Begin.isValid()) {
+      // Here we have an explicit (partial) specialization or instantiation.
+      assert(getSpecializationKind() == TSK_ExplicitSpecialization ||
+             getSpecializationKind() == TSK_ExplicitInstantiationDeclaration ||
+             getSpecializationKind() == TSK_ExplicitInstantiationDefinition);
+      if (getExternLoc().isValid())
+        Begin = getExternLoc();
+      SourceLocation End = getBraceRange().getEnd();
+      if (End.isInvalid())
+        End = getTypeAsWritten()->getTypeLoc().getEndLoc();
+      return SourceRange(Begin, End);
+    }
+    // An implicit instantiation of a class template partial specialization
+    // uses ExplicitInfo to record the TypeAsWritten, but the source
+    // locations should be retrieved from the instantiation pattern.
+    using CTPSDecl = ClassTemplatePartialSpecializationDecl;
+    auto *ctpsd = const_cast<CTPSDecl *>(cast<CTPSDecl>(this));
+    CTPSDecl *inst_from = ctpsd->getInstantiatedFromMember();
+    assert(inst_from != nullptr);
+    return inst_from->getSourceRange();
+  }
+  else {
+    // No explicit info available.
+    llvm::PointerUnion<ClassTemplateDecl *,
+                       ClassTemplatePartialSpecializationDecl *>
+      inst_from = getInstantiatedFrom();
+    if (inst_from.isNull())
+      return getSpecializedTemplate()->getSourceRange();
+    if (const auto *ctd = inst_from.dyn_cast<ClassTemplateDecl *>())
+      return ctd->getSourceRange();
+    return inst_from.get<ClassTemplatePartialSpecializationDecl *>()
+      ->getSourceRange();
+  }
+}
+
+//===----------------------------------------------------------------------===//
+// ConceptDecl Implementation
+//===----------------------------------------------------------------------===//
+ConceptDecl *ConceptDecl::Create(ASTContext &C, DeclContext *DC,
+                                 SourceLocation L, DeclarationName Name,
+                                 TemplateParameterList *Params,
+                                 Expr *ConstraintExpr) {
+  AdoptTemplateParameterList(Params, DC);
+  return new (C, DC) ConceptDecl(DC, L, Name, Params, ConstraintExpr);
+}
+
+ConceptDecl *ConceptDecl::CreateDeserialized(ASTContext &C,
+                                             unsigned ID) {
+  ConceptDecl *Result = new (C, ID) ConceptDecl(nullptr, SourceLocation(),
+                                                DeclarationName(),
+                                                nullptr, nullptr);
+
+  return Result;
+}
+
+//===----------------------------------------------------------------------===//
+// ClassTemplatePartialSpecializationDecl Implementation
+//===----------------------------------------------------------------------===//
+void ClassTemplatePartialSpecializationDecl::anchor() {}
+
+ClassTemplatePartialSpecializationDecl::
+ClassTemplatePartialSpecializationDecl(ASTContext &Context, TagKind TK,
+                                       DeclContext *DC,
+                                       SourceLocation StartLoc,
+                                       SourceLocation IdLoc,
+                                       TemplateParameterList *Params,
+                                       ClassTemplateDecl *SpecializedTemplate,
+                                       ArrayRef<TemplateArgument> Args,
+                               const ASTTemplateArgumentListInfo *ArgInfos,
+                               ClassTemplatePartialSpecializationDecl *PrevDecl)
+    : ClassTemplateSpecializationDecl(Context,
+                                      ClassTemplatePartialSpecialization,
+                                      TK, DC, StartLoc, IdLoc,
+                                      SpecializedTemplate, Args, PrevDecl),
+      TemplateParams(Params), ArgsAsWritten(ArgInfos),
+      InstantiatedFromMember(nullptr, false) {
+  AdoptTemplateParameterList(Params, this);
+}
+
+ClassTemplatePartialSpecializationDecl *
+ClassTemplatePartialSpecializationDecl::
+Create(ASTContext &Context, TagKind TK,DeclContext *DC,
+       SourceLocation StartLoc, SourceLocation IdLoc,
+       TemplateParameterList *Params,
+       ClassTemplateDecl *SpecializedTemplate,
+       ArrayRef<TemplateArgument> Args,
+       const TemplateArgumentListInfo &ArgInfos,
+       QualType CanonInjectedType,
+       ClassTemplatePartialSpecializationDecl *PrevDecl) {
+  const ASTTemplateArgumentListInfo *ASTArgInfos =
+    ASTTemplateArgumentListInfo::Create(Context, ArgInfos);
+
+  auto *Result = new (Context, DC)
+      ClassTemplatePartialSpecializationDecl(Context, TK, DC, StartLoc, IdLoc,
+                                             Params, SpecializedTemplate, Args,
+                                             ASTArgInfos, PrevDecl);
+  Result->setSpecializationKind(TSK_ExplicitSpecialization);
+  Result->setMayHaveOutOfDateDef(false);
+
+  Context.getInjectedClassNameType(Result, CanonInjectedType);
+  return Result;
+}
+
+ClassTemplatePartialSpecializationDecl *
+ClassTemplatePartialSpecializationDecl::CreateDeserialized(ASTContext &C,
+                                                           unsigned ID) {
+  auto *Result = new (C, ID) ClassTemplatePartialSpecializationDecl(C);
+  Result->setMayHaveOutOfDateDef(false);
+  return Result;
+}
+
+//===----------------------------------------------------------------------===//
+// FriendTemplateDecl Implementation
+//===----------------------------------------------------------------------===//
+
+void FriendTemplateDecl::anchor() {}
+
+FriendTemplateDecl *
+FriendTemplateDecl::Create(ASTContext &Context, DeclContext *DC,
+                           SourceLocation L,
+                           MutableArrayRef<TemplateParameterList *> Params,
+                           FriendUnion Friend, SourceLocation FLoc) {
+  return new (Context, DC) FriendTemplateDecl(DC, L, Params, Friend, FLoc);
+}
+
+FriendTemplateDecl *FriendTemplateDecl::CreateDeserialized(ASTContext &C,
+                                                           unsigned ID) {
+  return new (C, ID) FriendTemplateDecl(EmptyShell());
+}
+
+//===----------------------------------------------------------------------===//
+// TypeAliasTemplateDecl Implementation
+//===----------------------------------------------------------------------===//
+
+TypeAliasTemplateDecl *TypeAliasTemplateDecl::Create(ASTContext &C,
+                                                     DeclContext *DC,
+                                                     SourceLocation L,
+                                                     DeclarationName Name,
+                                                  TemplateParameterList *Params,
+                                                     NamedDecl *Decl) {
+  AdoptTemplateParameterList(Params, DC);
+  return new (C, DC) TypeAliasTemplateDecl(C, DC, L, Name, Params, Decl);
+}
+
+TypeAliasTemplateDecl *TypeAliasTemplateDecl::CreateDeserialized(ASTContext &C,
+                                                                 unsigned ID) {
+  return new (C, ID) TypeAliasTemplateDecl(C, nullptr, SourceLocation(),
+                                           DeclarationName(), nullptr, nullptr);
+}
+
+RedeclarableTemplateDecl::CommonBase *
+TypeAliasTemplateDecl::newCommon(ASTContext &C) const {
+  auto *CommonPtr = new (C) Common;
+  C.addDestruction(CommonPtr);
+  return CommonPtr;
+}
+
+//===----------------------------------------------------------------------===//
+// ClassScopeFunctionSpecializationDecl Implementation
+//===----------------------------------------------------------------------===//
+
+void ClassScopeFunctionSpecializationDecl::anchor() {}
+
+ClassScopeFunctionSpecializationDecl *
+ClassScopeFunctionSpecializationDecl::CreateDeserialized(ASTContext &C,
+                                                         unsigned ID) {
+  return new (C, ID) ClassScopeFunctionSpecializationDecl(
+      nullptr, SourceLocation(), nullptr, nullptr);
+}
+
+//===----------------------------------------------------------------------===//
+// VarTemplateDecl Implementation
+//===----------------------------------------------------------------------===//
+
+VarTemplateDecl *VarTemplateDecl::getDefinition() {
+  VarTemplateDecl *CurD = this;
+  while (CurD) {
+    if (CurD->isThisDeclarationADefinition())
+      return CurD;
+    CurD = CurD->getPreviousDecl();
+  }
+  return nullptr;
+}
+
+VarTemplateDecl *VarTemplateDecl::Create(ASTContext &C, DeclContext *DC,
+                                         SourceLocation L, DeclarationName Name,
+                                         TemplateParameterList *Params,
+                                         VarDecl *Decl) {
+  AdoptTemplateParameterList(Params, DC);
+  return new (C, DC) VarTemplateDecl(C, DC, L, Name, Params, Decl);
+}
+
+VarTemplateDecl *VarTemplateDecl::CreateDeserialized(ASTContext &C,
+                                                     unsigned ID) {
+  return new (C, ID) VarTemplateDecl(C, nullptr, SourceLocation(),
+                                     DeclarationName(), nullptr, nullptr);
+}
+
+void VarTemplateDecl::LoadLazySpecializations() const {
+  loadLazySpecializationsImpl();
+}
+
+llvm::FoldingSetVector<VarTemplateSpecializationDecl> &
+VarTemplateDecl::getSpecializations() const {
+  LoadLazySpecializations();
+  return getCommonPtr()->Specializations;
+}
+
+llvm::FoldingSetVector<VarTemplatePartialSpecializationDecl> &
+VarTemplateDecl::getPartialSpecializations() {
+  LoadLazySpecializations();
+  return getCommonPtr()->PartialSpecializations;
+}
+
+RedeclarableTemplateDecl::CommonBase *
+VarTemplateDecl::newCommon(ASTContext &C) const {
+  auto *CommonPtr = new (C) Common;
+  C.addDestruction(CommonPtr);
+  return CommonPtr;
+}
+
+VarTemplateSpecializationDecl *
+VarTemplateDecl::findSpecialization(ArrayRef<TemplateArgument> Args,
+                                    void *&InsertPos) {
+  return findSpecializationImpl(getSpecializations(), InsertPos, Args);
+}
+
+void VarTemplateDecl::AddSpecialization(VarTemplateSpecializationDecl *D,
+                                        void *InsertPos) {
+  addSpecializationImpl<VarTemplateDecl>(getSpecializations(), D, InsertPos);
+}
+
+VarTemplatePartialSpecializationDecl *
+VarTemplateDecl::findPartialSpecialization(ArrayRef<TemplateArgument> Args,
+     TemplateParameterList *TPL, void *&InsertPos) {
+  return findSpecializationImpl(getPartialSpecializations(), InsertPos, Args,
+                                TPL);
+}
+
+void
+VarTemplatePartialSpecializationDecl::Profile(llvm::FoldingSetNodeID &ID,
+    ArrayRef<TemplateArgument> TemplateArgs, TemplateParameterList *TPL,
+    ASTContext &Context) {
+  ID.AddInteger(TemplateArgs.size());
+  for (const TemplateArgument &TemplateArg : TemplateArgs)
+    TemplateArg.Profile(ID, Context);
+  ProfileTemplateParameterList(Context, ID, TPL);
+}
+
+void VarTemplateDecl::AddPartialSpecialization(
+    VarTemplatePartialSpecializationDecl *D, void *InsertPos) {
+  if (InsertPos)
+    getPartialSpecializations().InsertNode(D, InsertPos);
+  else {
+    VarTemplatePartialSpecializationDecl *Existing =
+        getPartialSpecializations().GetOrInsertNode(D);
+    (void)Existing;
+    assert(Existing->isCanonicalDecl() && "Non-canonical specialization?");
+  }
+
+  if (ASTMutationListener *L = getASTMutationListener())
+    L->AddedCXXTemplateSpecialization(this, D);
+}
+
+void VarTemplateDecl::getPartialSpecializations(
+    SmallVectorImpl<VarTemplatePartialSpecializationDecl *> &PS) {
+  llvm::FoldingSetVector<VarTemplatePartialSpecializationDecl> &PartialSpecs =
+      getPartialSpecializations();
+  PS.clear();
+  PS.reserve(PartialSpecs.size());
+  for (VarTemplatePartialSpecializationDecl &P : PartialSpecs)
+    PS.push_back(P.getMostRecentDecl());
+}
+
+VarTemplatePartialSpecializationDecl *
+VarTemplateDecl::findPartialSpecInstantiatedFromMember(
+    VarTemplatePartialSpecializationDecl *D) {
+  Decl *DCanon = D->getCanonicalDecl();
+  for (VarTemplatePartialSpecializationDecl &P : getPartialSpecializations()) {
+    if (P.getInstantiatedFromMember()->getCanonicalDecl() == DCanon)
+      return P.getMostRecentDecl();
+  }
+
+  return nullptr;
+}
+
+//===----------------------------------------------------------------------===//
+// VarTemplateSpecializationDecl Implementation
+//===----------------------------------------------------------------------===//
+
+VarTemplateSpecializationDecl::VarTemplateSpecializationDecl(
+    Kind DK, ASTContext &Context, DeclContext *DC, SourceLocation StartLoc,
+    SourceLocation IdLoc, VarTemplateDecl *SpecializedTemplate, QualType T,
+    TypeSourceInfo *TInfo, StorageClass S, ArrayRef<TemplateArgument> Args)
+    : VarDecl(DK, Context, DC, StartLoc, IdLoc,
+              SpecializedTemplate->getIdentifier(), T, TInfo, S),
+      SpecializedTemplate(SpecializedTemplate),
+      TemplateArgs(TemplateArgumentList::CreateCopy(Context, Args)),
+      SpecializationKind(TSK_Undeclared), IsCompleteDefinition(false) {}
+
+VarTemplateSpecializationDecl::VarTemplateSpecializationDecl(Kind DK,
+                                                             ASTContext &C)
+    : VarDecl(DK, C, nullptr, SourceLocation(), SourceLocation(), nullptr,
+              QualType(), nullptr, SC_None),
+      SpecializationKind(TSK_Undeclared), IsCompleteDefinition(false) {}
+
+VarTemplateSpecializationDecl *VarTemplateSpecializationDecl::Create(
+    ASTContext &Context, DeclContext *DC, SourceLocation StartLoc,
+    SourceLocation IdLoc, VarTemplateDecl *SpecializedTemplate, QualType T,
+    TypeSourceInfo *TInfo, StorageClass S, ArrayRef<TemplateArgument> Args) {
+  return new (Context, DC) VarTemplateSpecializationDecl(
+      VarTemplateSpecialization, Context, DC, StartLoc, IdLoc,
+      SpecializedTemplate, T, TInfo, S, Args);
+}
+
+VarTemplateSpecializationDecl *
+VarTemplateSpecializationDecl::CreateDeserialized(ASTContext &C, unsigned ID) {
+  return new (C, ID)
+      VarTemplateSpecializationDecl(VarTemplateSpecialization, C);
+}
+
+void VarTemplateSpecializationDecl::getNameForDiagnostic(
+    raw_ostream &OS, const PrintingPolicy &Policy, bool Qualified) const {
+  NamedDecl::getNameForDiagnostic(OS, Policy, Qualified);
+
+  const auto *PS = dyn_cast<VarTemplatePartialSpecializationDecl>(this);
+  if (const ASTTemplateArgumentListInfo *ArgsAsWritten =
+          PS ? PS->getTemplateArgsAsWritten() : nullptr) {
+    printTemplateArgumentList(OS, ArgsAsWritten->arguments(), Policy);
+  } else {
+    const TemplateArgumentList &TemplateArgs = getTemplateArgs();
+    printTemplateArgumentList(OS, TemplateArgs.asArray(), Policy);
+  }
+}
+
+VarTemplateDecl *VarTemplateSpecializationDecl::getSpecializedTemplate() const {
+  if (const auto *PartialSpec =
+          SpecializedTemplate.dyn_cast<SpecializedPartialSpecialization *>())
+    return PartialSpec->PartialSpecialization->getSpecializedTemplate();
+  return SpecializedTemplate.get<VarTemplateDecl *>();
+}
+
+void VarTemplateSpecializationDecl::setTemplateArgsInfo(
+    const TemplateArgumentListInfo &ArgsInfo) {
+  TemplateArgsInfo.setLAngleLoc(ArgsInfo.getLAngleLoc());
+  TemplateArgsInfo.setRAngleLoc(ArgsInfo.getRAngleLoc());
+  for (const TemplateArgumentLoc &Loc : ArgsInfo.arguments())
+    TemplateArgsInfo.addArgument(Loc);
+}
+
+//===----------------------------------------------------------------------===//
+// VarTemplatePartialSpecializationDecl Implementation
+//===----------------------------------------------------------------------===//
+
+void VarTemplatePartialSpecializationDecl::anchor() {}
+
+VarTemplatePartialSpecializationDecl::VarTemplatePartialSpecializationDecl(
+    ASTContext &Context, DeclContext *DC, SourceLocation StartLoc,
+    SourceLocation IdLoc, TemplateParameterList *Params,
+    VarTemplateDecl *SpecializedTemplate, QualType T, TypeSourceInfo *TInfo,
+    StorageClass S, ArrayRef<TemplateArgument> Args,
+    const ASTTemplateArgumentListInfo *ArgInfos)
+    : VarTemplateSpecializationDecl(VarTemplatePartialSpecialization, Context,
+                                    DC, StartLoc, IdLoc, SpecializedTemplate, T,
+                                    TInfo, S, Args),
+      TemplateParams(Params), ArgsAsWritten(ArgInfos),
+      InstantiatedFromMember(nullptr, false) {
+  // TODO: The template parameters should be in DC by now. Verify.
+  // AdoptTemplateParameterList(Params, DC);
+}
+
+VarTemplatePartialSpecializationDecl *
+VarTemplatePartialSpecializationDecl::Create(
+    ASTContext &Context, DeclContext *DC, SourceLocation StartLoc,
+    SourceLocation IdLoc, TemplateParameterList *Params,
+    VarTemplateDecl *SpecializedTemplate, QualType T, TypeSourceInfo *TInfo,
+    StorageClass S, ArrayRef<TemplateArgument> Args,
+    const TemplateArgumentListInfo &ArgInfos) {
+  const ASTTemplateArgumentListInfo *ASTArgInfos
+    = ASTTemplateArgumentListInfo::Create(Context, ArgInfos);
+
+  auto *Result =
+      new (Context, DC) VarTemplatePartialSpecializationDecl(
+          Context, DC, StartLoc, IdLoc, Params, SpecializedTemplate, T, TInfo,
+          S, Args, ASTArgInfos);
+  Result->setSpecializationKind(TSK_ExplicitSpecialization);
+  return Result;
+}
+
+VarTemplatePartialSpecializationDecl *
+VarTemplatePartialSpecializationDecl::CreateDeserialized(ASTContext &C,
+                                                         unsigned ID) {
+  return new (C, ID) VarTemplatePartialSpecializationDecl(C);
+}
+
+static TemplateParameterList *
+createMakeIntegerSeqParameterList(const ASTContext &C, DeclContext *DC) {
+  // typename T
+  auto *T = TemplateTypeParmDecl::Create(
+      C, DC, SourceLocation(), SourceLocation(), /*Depth=*/1, /*Position=*/0,
+      /*Id=*/nullptr, /*Typename=*/true, /*ParameterPack=*/false,
+      /*HasTypeConstraint=*/false);
+  T->setImplicit(true);
+
+  // T ...Ints
+  TypeSourceInfo *TI =
+      C.getTrivialTypeSourceInfo(QualType(T->getTypeForDecl(), 0));
+  auto *N = NonTypeTemplateParmDecl::Create(
+      C, DC, SourceLocation(), SourceLocation(), /*Depth=*/0, /*Position=*/1,
+      /*Id=*/nullptr, TI->getType(), /*ParameterPack=*/true, TI);
+  N->setImplicit(true);
+
+  // <typename T, T ...Ints>
+  NamedDecl *P[2] = {T, N};
+  auto *TPL = TemplateParameterList::Create(
+      C, SourceLocation(), SourceLocation(), P, SourceLocation(), nullptr);
+
+  // template <typename T, ...Ints> class IntSeq
+  auto *TemplateTemplateParm = TemplateTemplateParmDecl::Create(
+      C, DC, SourceLocation(), /*Depth=*/0, /*Position=*/0,
+      /*ParameterPack=*/false, /*Id=*/nullptr, TPL);
+  TemplateTemplateParm->setImplicit(true);
+
+  // typename T
+  auto *TemplateTypeParm = TemplateTypeParmDecl::Create(
+      C, DC, SourceLocation(), SourceLocation(), /*Depth=*/0, /*Position=*/1,
+      /*Id=*/nullptr, /*Typename=*/true, /*ParameterPack=*/false,
+      /*HasTypeConstraint=*/false);
+  TemplateTypeParm->setImplicit(true);
+
+  // T N
+  TypeSourceInfo *TInfo = C.getTrivialTypeSourceInfo(
+      QualType(TemplateTypeParm->getTypeForDecl(), 0));
+  auto *NonTypeTemplateParm = NonTypeTemplateParmDecl::Create(
+      C, DC, SourceLocation(), SourceLocation(), /*Depth=*/0, /*Position=*/2,
+      /*Id=*/nullptr, TInfo->getType(), /*ParameterPack=*/false, TInfo);
+  NamedDecl *Params[] = {TemplateTemplateParm, TemplateTypeParm,
+                         NonTypeTemplateParm};
+
+  // template <template <typename T, T ...Ints> class IntSeq, typename T, T N>
+  return TemplateParameterList::Create(C, SourceLocation(), SourceLocation(),
+                                       Params, SourceLocation(), nullptr);
+}
+
+static TemplateParameterList *
+createTypePackElementParameterList(const ASTContext &C, DeclContext *DC) {
+  // std::size_t Index
+  TypeSourceInfo *TInfo = C.getTrivialTypeSourceInfo(C.getSizeType());
+  auto *Index = NonTypeTemplateParmDecl::Create(
+      C, DC, SourceLocation(), SourceLocation(), /*Depth=*/0, /*Position=*/0,
+      /*Id=*/nullptr, TInfo->getType(), /*ParameterPack=*/false, TInfo);
+
+  // typename ...T
+  auto *Ts = TemplateTypeParmDecl::Create(
+      C, DC, SourceLocation(), SourceLocation(), /*Depth=*/0, /*Position=*/1,
+      /*Id=*/nullptr, /*Typename=*/true, /*ParameterPack=*/true,
+      /*HasTypeConstraint=*/false);
+  Ts->setImplicit(true);
+
+  // template <std::size_t Index, typename ...T>
+  NamedDecl *Params[] = {Index, Ts};
+  return TemplateParameterList::Create(C, SourceLocation(), SourceLocation(),
+                                       llvm::makeArrayRef(Params),
+                                       SourceLocation(), nullptr);
+}
+
+static TemplateParameterList *createBuiltinTemplateParameterList(
+    const ASTContext &C, DeclContext *DC, BuiltinTemplateKind BTK) {
+  switch (BTK) {
+  case BTK__make_integer_seq:
+    return createMakeIntegerSeqParameterList(C, DC);
+  case BTK__type_pack_element:
+    return createTypePackElementParameterList(C, DC);
+  }
+
+  llvm_unreachable("unhandled BuiltinTemplateKind!");
+}
+
+void BuiltinTemplateDecl::anchor() {}
+
+BuiltinTemplateDecl::BuiltinTemplateDecl(const ASTContext &C, DeclContext *DC,
+                                         DeclarationName Name,
+                                         BuiltinTemplateKind BTK)
+    : TemplateDecl(BuiltinTemplate, DC, SourceLocation(), Name,
+                   createBuiltinTemplateParameterList(C, DC, BTK)),
+      BTK(BTK) {}
+
+void TypeConstraint::print(llvm::raw_ostream &OS, PrintingPolicy Policy) const {
+  if (NestedNameSpec)
+    NestedNameSpec.getNestedNameSpecifier()->print(OS, Policy);
+  ConceptName.printName(OS, Policy);
+  if (hasExplicitTemplateArgs()) {
+    OS << "<";
+    for (auto &ArgLoc : ArgsAsWritten->arguments())
+      ArgLoc.getArgument().print(Policy, OS);
+    OS << ">";
+  }
+}
\ No newline at end of file