[NFC] Move DeclID from serialization/ASTBitCodes.h to AST/DeclID.h (#89873)

Previously, the DeclID is defined in serialization/ASTBitCodes.h under
clang::serialization namespace. However, actually the DeclID is not
purely used in serialization part. The DeclID is already widely used in
AST and all around the clang project via classes like `LazyPtrDecl` or
calling `ExternalASTSource::getExernalDecl()`. All such uses are via the
raw underlying type of `DeclID` as `uint32_t`. This is not pretty good.

This patch moves the DeclID class family to a new header `AST/DeclID.h`
so that the whole project can use the wrapped class `DeclID`,
`GlobalDeclID` and `LocalDeclID` instead of the raw underlying type.
This can improve the readability and the type safety.

17 files changed, 123 insertions, 137 deletions

diff --git a/clang/lib/AST/ASTContext.cpp b/clang/lib/AST/ASTContext.cpp
index 0f894c6..a7386f755 100644
--- a/clang/lib/AST/ASTContext.cpp
+++ b/clang/lib/AST/ASTContext.cpp
@@ -1083,8 +1083,7 @@ void ASTContext::addModuleInitializer(Module *M, Decl *D) {
   Inits->Initializers.push_back(D);
 }
 
-void ASTContext::addLazyModuleInitializers(Module *M,
-                                           ArrayRef<Decl::DeclID> IDs) {
+void ASTContext::addLazyModuleInitializers(Module *M, ArrayRef<DeclID> IDs) {
   auto *&Inits = ModuleInitializers[M];
   if (!Inits)
     Inits = new (*this) PerModuleInitializers;
diff --git a/clang/lib/AST/Decl.cpp b/clang/lib/AST/Decl.cpp
index 474e0cc..f452902 100644
--- a/clang/lib/AST/Decl.cpp
+++ b/clang/lib/AST/Decl.cpp
@@ -2151,7 +2151,7 @@ VarDecl *VarDecl::Create(ASTContext &C, DeclContext *DC, SourceLocation StartL,
   return new (C, DC) VarDecl(Var, C, DC, StartL, IdL, Id, T, TInfo, S);
 }
 
-VarDecl *VarDecl::CreateDeserialized(ASTContext &C, Decl::DeclID ID) {
+VarDecl *VarDecl::CreateDeserialized(ASTContext &C, DeclID ID) {
   return new (C, ID)
       VarDecl(Var, C, nullptr, SourceLocation(), SourceLocation(), nullptr,
               QualType(), nullptr, SC_None);
@@ -2929,7 +2929,7 @@ QualType ParmVarDecl::getOriginalType() const {
   return T;
 }
 
-ParmVarDecl *ParmVarDecl::CreateDeserialized(ASTContext &C, Decl::DeclID ID) {
+ParmVarDecl *ParmVarDecl::CreateDeserialized(ASTContext &C, DeclID ID) {
   return new (C, ID)
       ParmVarDecl(ParmVar, C, nullptr, SourceLocation(), SourceLocation(),
                   nullptr, QualType(), nullptr, SC_None, nullptr);
@@ -4553,7 +4553,7 @@ FieldDecl *FieldDecl::Create(const ASTContext &C, DeclContext *DC,
                                BW, Mutable, InitStyle);
 }
 
-FieldDecl *FieldDecl::CreateDeserialized(ASTContext &C, Decl::DeclID ID) {
+FieldDecl *FieldDecl::CreateDeserialized(ASTContext &C, DeclID ID) {
   return new (C, ID) FieldDecl(Field, nullptr, SourceLocation(),
                                SourceLocation(), nullptr, QualType(), nullptr,
                                nullptr, false, ICIS_NoInit);
@@ -4863,7 +4863,7 @@ EnumDecl *EnumDecl::Create(ASTContext &C, DeclContext *DC,
   return Enum;
 }
 
-EnumDecl *EnumDecl::CreateDeserialized(ASTContext &C, Decl::DeclID ID) {
+EnumDecl *EnumDecl::CreateDeserialized(ASTContext &C, DeclID ID) {
   EnumDecl *Enum =
       new (C, ID) EnumDecl(C, nullptr, SourceLocation(), SourceLocation(),
                            nullptr, nullptr, false, false, false);
@@ -5025,7 +5025,7 @@ RecordDecl *RecordDecl::Create(const ASTContext &C, TagKind TK, DeclContext *DC,
   return R;
 }
 
-RecordDecl *RecordDecl::CreateDeserialized(const ASTContext &C, Decl::DeclID ID) {
+RecordDecl *RecordDecl::CreateDeserialized(const ASTContext &C, DeclID ID) {
   RecordDecl *R = new (C, ID)
       RecordDecl(Record, TagTypeKind::Struct, C, nullptr, SourceLocation(),
                  SourceLocation(), nullptr, nullptr);
@@ -5297,7 +5297,7 @@ PragmaCommentDecl *PragmaCommentDecl::Create(const ASTContext &C,
 }
 
 PragmaCommentDecl *PragmaCommentDecl::CreateDeserialized(ASTContext &C,
-                                                         Decl::DeclID ID,
+                                                         DeclID ID,
                                                          unsigned ArgSize) {
   return new (C, ID, additionalSizeToAlloc<char>(ArgSize + 1))
       PragmaCommentDecl(nullptr, SourceLocation(), PCK_Unknown);
@@ -5322,7 +5322,7 @@ PragmaDetectMismatchDecl::Create(const ASTContext &C, TranslationUnitDecl *DC,
 }
 
 PragmaDetectMismatchDecl *
-PragmaDetectMismatchDecl::CreateDeserialized(ASTContext &C, Decl::DeclID ID,
+PragmaDetectMismatchDecl::CreateDeserialized(ASTContext &C, DeclID ID,
                                              unsigned NameValueSize) {
   return new (C, ID, additionalSizeToAlloc<char>(NameValueSize + 1))
       PragmaDetectMismatchDecl(nullptr, SourceLocation(), 0);
@@ -5349,7 +5349,7 @@ LabelDecl *LabelDecl::Create(ASTContext &C, DeclContext *DC,
   return new (C, DC) LabelDecl(DC, IdentL, II, nullptr, GnuLabelL);
 }
 
-LabelDecl *LabelDecl::CreateDeserialized(ASTContext &C, Decl::DeclID ID) {
+LabelDecl *LabelDecl::CreateDeserialized(ASTContext &C, DeclID ID) {
   return new (C, ID) LabelDecl(nullptr, SourceLocation(), nullptr, nullptr,
                                SourceLocation());
 }
@@ -5390,7 +5390,7 @@ ImplicitParamDecl *ImplicitParamDecl::Create(ASTContext &C, QualType Type,
 }
 
 ImplicitParamDecl *ImplicitParamDecl::CreateDeserialized(ASTContext &C,
-                                                         Decl::DeclID ID) {
+                                                         DeclID ID) {
   return new (C, ID) ImplicitParamDecl(C, QualType(), ImplicitParamKind::Other);
 }
 
@@ -5408,7 +5408,7 @@ FunctionDecl::Create(ASTContext &C, DeclContext *DC, SourceLocation StartLoc,
   return New;
 }
 
-FunctionDecl *FunctionDecl::CreateDeserialized(ASTContext &C, Decl::DeclID ID) {
+FunctionDecl *FunctionDecl::CreateDeserialized(ASTContext &C, DeclID ID) {
   return new (C, ID) FunctionDecl(
       Function, C, nullptr, SourceLocation(), DeclarationNameInfo(), QualType(),
       nullptr, SC_None, false, false, ConstexprSpecKind::Unspecified, nullptr);
@@ -5418,7 +5418,7 @@ BlockDecl *BlockDecl::Create(ASTContext &C, DeclContext *DC, SourceLocation L) {
   return new (C, DC) BlockDecl(DC, L);
 }
 
-BlockDecl *BlockDecl::CreateDeserialized(ASTContext &C, Decl::DeclID ID) {
+BlockDecl *BlockDecl::CreateDeserialized(ASTContext &C, DeclID ID) {
   return new (C, ID) BlockDecl(nullptr, SourceLocation());
 }
 
@@ -5432,7 +5432,7 @@ CapturedDecl *CapturedDecl::Create(ASTContext &C, DeclContext *DC,
       CapturedDecl(DC, NumParams);
 }
 
-CapturedDecl *CapturedDecl::CreateDeserialized(ASTContext &C, Decl::DeclID ID,
+CapturedDecl *CapturedDecl::CreateDeserialized(ASTContext &C, DeclID ID,
                                                unsigned NumParams) {
   return new (C, ID, additionalSizeToAlloc<ImplicitParamDecl *>(NumParams))
       CapturedDecl(nullptr, NumParams);
@@ -5458,8 +5458,8 @@ EnumConstantDecl *EnumConstantDecl::Create(ASTContext &C, EnumDecl *CD,
   return new (C, CD) EnumConstantDecl(C, CD, L, Id, T, E, V);
 }
 
-EnumConstantDecl *
-EnumConstantDecl::CreateDeserialized(ASTContext &C, Decl::DeclID ID) {
+EnumConstantDecl *EnumConstantDecl::CreateDeserialized(ASTContext &C,
+                                                       DeclID ID) {
   return new (C, ID) EnumConstantDecl(C, nullptr, SourceLocation(), nullptr,
                                       QualType(), nullptr, llvm::APSInt());
 }
@@ -5486,7 +5486,7 @@ IndirectFieldDecl::Create(ASTContext &C, DeclContext *DC, SourceLocation L,
 }
 
 IndirectFieldDecl *IndirectFieldDecl::CreateDeserialized(ASTContext &C,
-                                                         Decl::DeclID ID) {
+                                                         DeclID ID) {
   return new (C, ID)
       IndirectFieldDecl(C, nullptr, SourceLocation(), DeclarationName(),
                         QualType(), std::nullopt);
@@ -5547,7 +5547,7 @@ bool TypedefNameDecl::isTransparentTagSlow() const {
   return isTransparent;
 }
 
-TypedefDecl *TypedefDecl::CreateDeserialized(ASTContext &C, Decl::DeclID ID) {
+TypedefDecl *TypedefDecl::CreateDeserialized(ASTContext &C, DeclID ID) {
   return new (C, ID) TypedefDecl(C, nullptr, SourceLocation(), SourceLocation(),
                                  nullptr, nullptr);
 }
@@ -5560,7 +5560,7 @@ TypeAliasDecl *TypeAliasDecl::Create(ASTContext &C, DeclContext *DC,
   return new (C, DC) TypeAliasDecl(C, DC, StartLoc, IdLoc, Id, TInfo);
 }
 
-TypeAliasDecl *TypeAliasDecl::CreateDeserialized(ASTContext &C, Decl::DeclID ID) {
+TypeAliasDecl *TypeAliasDecl::CreateDeserialized(ASTContext &C, DeclID ID) {
   return new (C, ID) TypeAliasDecl(C, nullptr, SourceLocation(),
                                    SourceLocation(), nullptr, nullptr);
 }
@@ -5591,7 +5591,7 @@ FileScopeAsmDecl *FileScopeAsmDecl::Create(ASTContext &C, DeclContext *DC,
 }
 
 FileScopeAsmDecl *FileScopeAsmDecl::CreateDeserialized(ASTContext &C,
-                                                       Decl::DeclID ID) {
+                                                       DeclID ID) {
   return new (C, ID) FileScopeAsmDecl(nullptr, nullptr, SourceLocation(),
                                       SourceLocation());
 }
@@ -5609,7 +5609,7 @@ TopLevelStmtDecl *TopLevelStmtDecl::Create(ASTContext &C, Stmt *Statement) {
 }
 
 TopLevelStmtDecl *TopLevelStmtDecl::CreateDeserialized(ASTContext &C,
-                                                       Decl::DeclID ID) {
+                                                       DeclID ID) {
   return new (C, ID)
       TopLevelStmtDecl(/*DC=*/nullptr, SourceLocation(), /*S=*/nullptr);
 }
@@ -5630,7 +5630,7 @@ EmptyDecl *EmptyDecl::Create(ASTContext &C, DeclContext *DC, SourceLocation L) {
   return new (C, DC) EmptyDecl(DC, L);
 }
 
-EmptyDecl *EmptyDecl::CreateDeserialized(ASTContext &C, Decl::DeclID ID) {
+EmptyDecl *EmptyDecl::CreateDeserialized(ASTContext &C, DeclID ID) {
   return new (C, ID) EmptyDecl(nullptr, SourceLocation());
 }
 
@@ -5663,7 +5663,7 @@ HLSLBufferDecl *HLSLBufferDecl::Create(ASTContext &C,
   return Result;
 }
 
-HLSLBufferDecl *HLSLBufferDecl::CreateDeserialized(ASTContext &C, Decl::DeclID ID) {
+HLSLBufferDecl *HLSLBufferDecl::CreateDeserialized(ASTContext &C, DeclID ID) {
   return new (C, ID) HLSLBufferDecl(nullptr, false, SourceLocation(), nullptr,
                                     SourceLocation(), SourceLocation());
 }
@@ -5719,7 +5719,7 @@ ImportDecl *ImportDecl::CreateImplicit(ASTContext &C, DeclContext *DC,
   return Import;
 }
 
-ImportDecl *ImportDecl::CreateDeserialized(ASTContext &C, Decl::DeclID ID,
+ImportDecl *ImportDecl::CreateDeserialized(ASTContext &C, DeclID ID,
                                            unsigned NumLocations) {
   return new (C, ID, additionalSizeToAlloc<SourceLocation>(NumLocations))
       ImportDecl(EmptyShell());
@@ -5752,6 +5752,6 @@ ExportDecl *ExportDecl::Create(ASTContext &C, DeclContext *DC,
   return new (C, DC) ExportDecl(DC, ExportLoc);
 }
 
-ExportDecl *ExportDecl::CreateDeserialized(ASTContext &C, Decl::DeclID ID) {
+ExportDecl *ExportDecl::CreateDeserialized(ASTContext &C, DeclID ID) {
   return new (C, ID) ExportDecl(nullptr, SourceLocation());
 }
diff --git a/clang/lib/AST/DeclBase.cpp b/clang/lib/AST/DeclBase.cpp
index 7cb6b31..a2d88cf 100644
--- a/clang/lib/AST/DeclBase.cpp
+++ b/clang/lib/AST/DeclBase.cpp
@@ -70,8 +70,8 @@ void Decl::updateOutOfDate(IdentifierInfo &II) const {
 #define ABSTRACT_DECL(DECL)
 #include "clang/AST/DeclNodes.inc"
 
-void *Decl::operator new(std::size_t Size, const ASTContext &Context,
-                         Decl::DeclID ID, std::size_t Extra) {
+void *Decl::operator new(std::size_t Size, const ASTContext &Context, DeclID ID,
+                         std::size_t Extra) {
   // Allocate an extra 8 bytes worth of storage, which ensures that the
   // resulting pointer will still be 8-byte aligned.
   static_assert(sizeof(unsigned) * 2 >= alignof(Decl),
diff --git a/clang/lib/AST/DeclCXX.cpp b/clang/lib/AST/DeclCXX.cpp
index 426c526..c525c33 100644
--- a/clang/lib/AST/DeclCXX.cpp
+++ b/clang/lib/AST/DeclCXX.cpp
@@ -57,7 +57,7 @@ using namespace clang;
 
 void AccessSpecDecl::anchor() {}
 
-AccessSpecDecl *AccessSpecDecl::CreateDeserialized(ASTContext &C, Decl::DeclID ID) {
+AccessSpecDecl *AccessSpecDecl::CreateDeserialized(ASTContext &C, DeclID ID) {
   return new (C, ID) AccessSpecDecl(EmptyShell());
 }
 
@@ -160,8 +160,8 @@ CXXRecordDecl::CreateLambda(const ASTContext &C, DeclContext *DC,
   return R;
 }
 
-CXXRecordDecl *
-CXXRecordDecl::CreateDeserialized(const ASTContext &C, Decl::DeclID ID) {
+CXXRecordDecl *CXXRecordDecl::CreateDeserialized(const ASTContext &C,
+                                                 DeclID ID) {
   auto *R = new (C, ID)
       CXXRecordDecl(CXXRecord, TagTypeKind::Struct, C, nullptr,
                     SourceLocation(), SourceLocation(), nullptr, nullptr);
@@ -2163,7 +2163,7 @@ CXXDeductionGuideDecl *CXXDeductionGuideDecl::Create(
 }
 
 CXXDeductionGuideDecl *CXXDeductionGuideDecl::CreateDeserialized(ASTContext &C,
-                                                                 Decl::DeclID ID) {
+                                                                 DeclID ID) {
   return new (C, ID) CXXDeductionGuideDecl(
       C, nullptr, SourceLocation(), ExplicitSpecifier(), DeclarationNameInfo(),
       QualType(), nullptr, SourceLocation(), nullptr,
@@ -2176,7 +2176,7 @@ RequiresExprBodyDecl *RequiresExprBodyDecl::Create(
 }
 
 RequiresExprBodyDecl *RequiresExprBodyDecl::CreateDeserialized(ASTContext &C,
-                                                               Decl::DeclID ID) {
+                                                               DeclID ID) {
   return new (C, ID) RequiresExprBodyDecl(C, nullptr, SourceLocation());
 }
 
@@ -2281,7 +2281,7 @@ CXXMethodDecl::Create(ASTContext &C, CXXRecordDecl *RD, SourceLocation StartLoc,
       isInline, ConstexprKind, EndLocation, TrailingRequiresClause);
 }
 
-CXXMethodDecl *CXXMethodDecl::CreateDeserialized(ASTContext &C, Decl::DeclID ID) {
+CXXMethodDecl *CXXMethodDecl::CreateDeserialized(ASTContext &C, DeclID ID) {
   return new (C, ID) CXXMethodDecl(
       CXXMethod, C, nullptr, SourceLocation(), DeclarationNameInfo(),
       QualType(), nullptr, SC_None, false, false,
@@ -2699,7 +2699,7 @@ CXXConstructorDecl::CXXConstructorDecl(
 void CXXConstructorDecl::anchor() {}
 
 CXXConstructorDecl *CXXConstructorDecl::CreateDeserialized(ASTContext &C,
-                                                           Decl::DeclID ID,
+                                                           DeclID ID,
                                                            uint64_t AllocKind) {
   bool hasTrailingExplicit = static_cast<bool>(AllocKind & TAKHasTailExplicit);
   bool isInheritingConstructor =
@@ -2845,8 +2845,8 @@ bool CXXConstructorDecl::isSpecializationCopyingObject() const {
 
 void CXXDestructorDecl::anchor() {}
 
-CXXDestructorDecl *
-CXXDestructorDecl::CreateDeserialized(ASTContext &C, Decl::DeclID ID) {
+CXXDestructorDecl *CXXDestructorDecl::CreateDeserialized(ASTContext &C,
+                                                         DeclID ID) {
   return new (C, ID) CXXDestructorDecl(
       C, nullptr, SourceLocation(), DeclarationNameInfo(), QualType(), nullptr,
       false, false, false, ConstexprSpecKind::Unspecified, nullptr);
@@ -2877,8 +2877,8 @@ void CXXDestructorDecl::setOperatorDelete(FunctionDecl *OD, Expr *ThisArg) {
 
 void CXXConversionDecl::anchor() {}
 
-CXXConversionDecl *
-CXXConversionDecl::CreateDeserialized(ASTContext &C, Decl::DeclID ID) {
+CXXConversionDecl *CXXConversionDecl::CreateDeserialized(ASTContext &C,
+                                                         DeclID ID) {
   return new (C, ID) CXXConversionDecl(
       C, nullptr, SourceLocation(), DeclarationNameInfo(), QualType(), nullptr,
       false, false, ExplicitSpecifier(), ConstexprSpecKind::Unspecified,
@@ -2923,8 +2923,7 @@ LinkageSpecDecl *LinkageSpecDecl::Create(ASTContext &C, DeclContext *DC,
   return new (C, DC) LinkageSpecDecl(DC, ExternLoc, LangLoc, Lang, HasBraces);
 }
 
-LinkageSpecDecl *LinkageSpecDecl::CreateDeserialized(ASTContext &C,
-                                                     Decl::DeclID ID) {
+LinkageSpecDecl *LinkageSpecDecl::CreateDeserialized(ASTContext &C, DeclID ID) {
   return new (C, ID)
       LinkageSpecDecl(nullptr, SourceLocation(), SourceLocation(),
                       LinkageSpecLanguageIDs::C, false);
@@ -2946,7 +2945,7 @@ UsingDirectiveDecl *UsingDirectiveDecl::Create(ASTContext &C, DeclContext *DC,
 }
 
 UsingDirectiveDecl *UsingDirectiveDecl::CreateDeserialized(ASTContext &C,
-                                                           Decl::DeclID ID) {
+                                                           DeclID ID) {
   return new (C, ID) UsingDirectiveDecl(nullptr, SourceLocation(),
                                         SourceLocation(),
                                         NestedNameSpecifierLoc(),
@@ -2985,7 +2984,7 @@ NamespaceDecl *NamespaceDecl::Create(ASTContext &C, DeclContext *DC,
       NamespaceDecl(C, DC, Inline, StartLoc, IdLoc, Id, PrevDecl, Nested);
 }
 
-NamespaceDecl *NamespaceDecl::CreateDeserialized(ASTContext &C, Decl::DeclID ID) {
+NamespaceDecl *NamespaceDecl::CreateDeserialized(ASTContext &C, DeclID ID) {
   return new (C, ID) NamespaceDecl(C, nullptr, false, SourceLocation(),
                                    SourceLocation(), nullptr, nullptr, false);
 }
@@ -3046,8 +3045,8 @@ NamespaceAliasDecl *NamespaceAliasDecl::Create(ASTContext &C, DeclContext *DC,
                                         QualifierLoc, IdentLoc, Namespace);
 }
 
-NamespaceAliasDecl *
-NamespaceAliasDecl::CreateDeserialized(ASTContext &C, Decl::DeclID ID) {
+NamespaceAliasDecl *NamespaceAliasDecl::CreateDeserialized(ASTContext &C,
+                                                           DeclID ID) {
   return new (C, ID) NamespaceAliasDecl(C, nullptr, SourceLocation(),
                                         SourceLocation(), nullptr,
                                         NestedNameSpecifierLoc(),
@@ -3102,8 +3101,7 @@ UsingShadowDecl::UsingShadowDecl(Kind K, ASTContext &C, EmptyShell Empty)
     : NamedDecl(K, nullptr, SourceLocation(), DeclarationName()),
       redeclarable_base(C) {}
 
-UsingShadowDecl *
-UsingShadowDecl::CreateDeserialized(ASTContext &C, Decl::DeclID ID) {
+UsingShadowDecl *UsingShadowDecl::CreateDeserialized(ASTContext &C, DeclID ID) {
   return new (C, ID) UsingShadowDecl(UsingShadow, C, EmptyShell());
 }
 
@@ -3126,7 +3124,7 @@ ConstructorUsingShadowDecl::Create(ASTContext &C, DeclContext *DC,
 }
 
 ConstructorUsingShadowDecl *
-ConstructorUsingShadowDecl::CreateDeserialized(ASTContext &C, Decl::DeclID ID) {
+ConstructorUsingShadowDecl::CreateDeserialized(ASTContext &C, DeclID ID) {
   return new (C, ID) ConstructorUsingShadowDecl(C, EmptyShell());
 }
 
@@ -3174,7 +3172,7 @@ UsingDecl *UsingDecl::Create(ASTContext &C, DeclContext *DC, SourceLocation UL,
   return new (C, DC) UsingDecl(DC, UL, QualifierLoc, NameInfo, HasTypename);
 }
 
-UsingDecl *UsingDecl::CreateDeserialized(ASTContext &C, Decl::DeclID ID) {
+UsingDecl *UsingDecl::CreateDeserialized(ASTContext &C, DeclID ID) {
   return new (C, ID) UsingDecl(nullptr, SourceLocation(),
                                NestedNameSpecifierLoc(), DeclarationNameInfo(),
                                false);
@@ -3198,7 +3196,7 @@ UsingEnumDecl *UsingEnumDecl::Create(ASTContext &C, DeclContext *DC,
       UsingEnumDecl(DC, EnumType->getType()->getAsTagDecl()->getDeclName(), UL, EL, NL, EnumType);
 }
 
-UsingEnumDecl *UsingEnumDecl::CreateDeserialized(ASTContext &C, Decl::DeclID ID) {
+UsingEnumDecl *UsingEnumDecl::CreateDeserialized(ASTContext &C, DeclID ID) {
   return new (C, ID)
       UsingEnumDecl(nullptr, DeclarationName(), SourceLocation(),
                     SourceLocation(), SourceLocation(), nullptr);
@@ -3217,7 +3215,7 @@ UsingPackDecl *UsingPackDecl::Create(ASTContext &C, DeclContext *DC,
   return new (C, DC, Extra) UsingPackDecl(DC, InstantiatedFrom, UsingDecls);
 }
 
-UsingPackDecl *UsingPackDecl::CreateDeserialized(ASTContext &C, Decl::DeclID ID,
+UsingPackDecl *UsingPackDecl::CreateDeserialized(ASTContext &C, DeclID ID,
                                                  unsigned NumExpansions) {
   size_t Extra = additionalSizeToAlloc<NamedDecl *>(NumExpansions);
   auto *Result =
@@ -3243,7 +3241,7 @@ UnresolvedUsingValueDecl::Create(ASTContext &C, DeclContext *DC,
 }
 
 UnresolvedUsingValueDecl *
-UnresolvedUsingValueDecl::CreateDeserialized(ASTContext &C, Decl::DeclID ID) {
+UnresolvedUsingValueDecl::CreateDeserialized(ASTContext &C, DeclID ID) {
   return new (C, ID) UnresolvedUsingValueDecl(nullptr, QualType(),
                                               SourceLocation(),
                                               NestedNameSpecifierLoc(),
@@ -3273,7 +3271,7 @@ UnresolvedUsingTypenameDecl::Create(ASTContext &C, DeclContext *DC,
 }
 
 UnresolvedUsingTypenameDecl *
-UnresolvedUsingTypenameDecl::CreateDeserialized(ASTContext &C, Decl::DeclID ID) {
+UnresolvedUsingTypenameDecl::CreateDeserialized(ASTContext &C, DeclID ID) {
   return new (C, ID) UnresolvedUsingTypenameDecl(
       nullptr, SourceLocation(), SourceLocation(), NestedNameSpecifierLoc(),
       SourceLocation(), nullptr, SourceLocation());
@@ -3286,7 +3284,7 @@ UnresolvedUsingIfExistsDecl::Create(ASTContext &Ctx, DeclContext *DC,
 }
 
 UnresolvedUsingIfExistsDecl *
-UnresolvedUsingIfExistsDecl::CreateDeserialized(ASTContext &Ctx, Decl::DeclID ID) {
+UnresolvedUsingIfExistsDecl::CreateDeserialized(ASTContext &Ctx, DeclID ID) {
   return new (Ctx, ID)
       UnresolvedUsingIfExistsDecl(nullptr, SourceLocation(), DeclarationName());
 }
@@ -3310,7 +3308,7 @@ StaticAssertDecl *StaticAssertDecl::Create(ASTContext &C, DeclContext *DC,
 }
 
 StaticAssertDecl *StaticAssertDecl::CreateDeserialized(ASTContext &C,
-                                                       Decl::DeclID ID) {
+                                                       DeclID ID) {
   return new (C, ID) StaticAssertDecl(nullptr, SourceLocation(), nullptr,
                                       nullptr, SourceLocation(), false);
 }
@@ -3332,7 +3330,7 @@ BindingDecl *BindingDecl::Create(ASTContext &C, DeclContext *DC,
   return new (C, DC) BindingDecl(DC, IdLoc, Id);
 }
 
-BindingDecl *BindingDecl::CreateDeserialized(ASTContext &C, Decl::DeclID ID) {
+BindingDecl *BindingDecl::CreateDeserialized(ASTContext &C, DeclID ID) {
   return new (C, ID) BindingDecl(nullptr, SourceLocation(), nullptr);
 }
 
@@ -3363,7 +3361,7 @@ DecompositionDecl *DecompositionDecl::Create(ASTContext &C, DeclContext *DC,
 }
 
 DecompositionDecl *DecompositionDecl::CreateDeserialized(ASTContext &C,
-                                                         Decl::DeclID ID,
+                                                         DeclID ID,
                                                          unsigned NumBindings) {
   size_t Extra = additionalSizeToAlloc<BindingDecl *>(NumBindings);
   auto *Result = new (C, ID, Extra)
@@ -3401,8 +3399,7 @@ MSPropertyDecl *MSPropertyDecl::Create(ASTContext &C, DeclContext *DC,
   return new (C, DC) MSPropertyDecl(DC, L, N, T, TInfo, StartL, Getter, Setter);
 }
 
-MSPropertyDecl *MSPropertyDecl::CreateDeserialized(ASTContext &C,
-                                                   Decl::DeclID ID) {
+MSPropertyDecl *MSPropertyDecl::CreateDeserialized(ASTContext &C, DeclID ID) {
   return new (C, ID) MSPropertyDecl(nullptr, SourceLocation(),
                                     DeclarationName(), QualType(), nullptr,
                                     SourceLocation(), nullptr, nullptr);
@@ -3419,7 +3416,7 @@ MSGuidDecl *MSGuidDecl::Create(const ASTContext &C, QualType T, Parts P) {
   return new (C, DC) MSGuidDecl(DC, T, P);
 }
 
-MSGuidDecl *MSGuidDecl::CreateDeserialized(ASTContext &C, Decl::DeclID ID) {
+MSGuidDecl *MSGuidDecl::CreateDeserialized(ASTContext &C, DeclID ID) {
   return new (C, ID) MSGuidDecl(nullptr, QualType(), Parts());
 }
 
@@ -3529,7 +3526,7 @@ UnnamedGlobalConstantDecl::Create(const ASTContext &C, QualType T,
 }
 
 UnnamedGlobalConstantDecl *
-UnnamedGlobalConstantDecl::CreateDeserialized(ASTContext &C, Decl::DeclID ID) {
+UnnamedGlobalConstantDecl::CreateDeserialized(ASTContext &C, DeclID ID) {
   return new (C, ID)
       UnnamedGlobalConstantDecl(C, nullptr, QualType(), APValue());
 }
diff --git a/clang/lib/AST/DeclFriend.cpp b/clang/lib/AST/DeclFriend.cpp
index 1fabf8a..f6d11e5 100644
--- a/clang/lib/AST/DeclFriend.cpp
+++ b/clang/lib/AST/DeclFriend.cpp
@@ -62,7 +62,7 @@ FriendDecl *FriendDecl::Create(ASTContext &C, DeclContext *DC,
   return FD;
 }
 
-FriendDecl *FriendDecl::CreateDeserialized(ASTContext &C, Decl::DeclID ID,
+FriendDecl *FriendDecl::CreateDeserialized(ASTContext &C, DeclID ID,
                                            unsigned FriendTypeNumTPLists) {
   std::size_t Extra =
       additionalSizeToAlloc<TemplateParameterList *>(FriendTypeNumTPLists);
diff --git a/clang/lib/AST/DeclObjC.cpp b/clang/lib/AST/DeclObjC.cpp
index d4275ee..f98ec67 100644
--- a/clang/lib/AST/DeclObjC.cpp
+++ b/clang/lib/AST/DeclObjC.cpp
@@ -862,7 +862,7 @@ ObjCMethodDecl *ObjCMethodDecl::Create(
       isImplicitlyDeclared, isDefined, impControl, HasRelatedResultType);
 }
 
-ObjCMethodDecl *ObjCMethodDecl::CreateDeserialized(ASTContext &C, Decl::DeclID ID) {
+ObjCMethodDecl *ObjCMethodDecl::CreateDeserialized(ASTContext &C, DeclID ID) {
   return new (C, ID) ObjCMethodDecl(SourceLocation(), SourceLocation(),
                                     Selector(), QualType(), nullptr, nullptr);
 }
@@ -1486,7 +1486,7 @@ ObjCTypeParamDecl *ObjCTypeParamDecl::Create(ASTContext &ctx, DeclContext *dc,
 }
 
 ObjCTypeParamDecl *ObjCTypeParamDecl::CreateDeserialized(ASTContext &ctx,
-                                                         Decl::DeclID ID) {
+                                                         DeclID ID) {
   return new (ctx, ID) ObjCTypeParamDecl(ctx, nullptr,
                                          ObjCTypeParamVariance::Invariant,
                                          SourceLocation(), 0, SourceLocation(),
@@ -1551,7 +1551,7 @@ ObjCInterfaceDecl *ObjCInterfaceDecl::Create(
 }
 
 ObjCInterfaceDecl *ObjCInterfaceDecl::CreateDeserialized(const ASTContext &C,
-                                                         Decl::DeclID ID) {
+                                                         DeclID ID) {
   auto *Result = new (C, ID)
       ObjCInterfaceDecl(C, nullptr, SourceLocation(), nullptr, nullptr,
                         SourceLocation(), nullptr, false);
@@ -1865,7 +1865,7 @@ ObjCIvarDecl *ObjCIvarDecl::Create(ASTContext &C, ObjCContainerDecl *DC,
                                   synthesized);
 }
 
-ObjCIvarDecl *ObjCIvarDecl::CreateDeserialized(ASTContext &C, Decl::DeclID ID) {
+ObjCIvarDecl *ObjCIvarDecl::CreateDeserialized(ASTContext &C, DeclID ID) {
   return new (C, ID) ObjCIvarDecl(nullptr, SourceLocation(), SourceLocation(),
                                   nullptr, QualType(), nullptr,
                                   ObjCIvarDecl::None, nullptr, false);
@@ -1914,7 +1914,7 @@ ObjCAtDefsFieldDecl
 }
 
 ObjCAtDefsFieldDecl *ObjCAtDefsFieldDecl::CreateDeserialized(ASTContext &C,
-                                                             Decl::DeclID ID) {
+                                                             DeclID ID) {
   return new (C, ID) ObjCAtDefsFieldDecl(nullptr, SourceLocation(),
                                          SourceLocation(), nullptr, QualType(),
                                          nullptr);
@@ -1949,7 +1949,7 @@ ObjCProtocolDecl *ObjCProtocolDecl::Create(ASTContext &C, DeclContext *DC,
 }
 
 ObjCProtocolDecl *ObjCProtocolDecl::CreateDeserialized(ASTContext &C,
-                                                       Decl::DeclID ID) {
+                                                       DeclID ID) {
   ObjCProtocolDecl *Result =
       new (C, ID) ObjCProtocolDecl(C, nullptr, nullptr, SourceLocation(),
                                    SourceLocation(), nullptr);
@@ -2148,7 +2148,7 @@ ObjCCategoryDecl *ObjCCategoryDecl::Create(
 }
 
 ObjCCategoryDecl *ObjCCategoryDecl::CreateDeserialized(ASTContext &C,
-                                                       Decl::DeclID ID) {
+                                                       DeclID ID) {
   return new (C, ID) ObjCCategoryDecl(nullptr, SourceLocation(),
                                       SourceLocation(), SourceLocation(),
                                       nullptr, nullptr, nullptr);
@@ -2189,7 +2189,7 @@ ObjCCategoryImplDecl *ObjCCategoryImplDecl::Create(
 }
 
 ObjCCategoryImplDecl *ObjCCategoryImplDecl::CreateDeserialized(ASTContext &C,
-                                                               Decl::DeclID ID) {
+                                                               DeclID ID) {
   return new (C, ID) ObjCCategoryImplDecl(nullptr, nullptr, nullptr,
                                           SourceLocation(), SourceLocation(),
                                           SourceLocation());
@@ -2296,7 +2296,7 @@ ObjCImplementationDecl::Create(ASTContext &C, DeclContext *DC,
 }
 
 ObjCImplementationDecl *
-ObjCImplementationDecl::CreateDeserialized(ASTContext &C, Decl::DeclID ID) {
+ObjCImplementationDecl::CreateDeserialized(ASTContext &C, DeclID ID) {
   return new (C, ID) ObjCImplementationDecl(nullptr, nullptr, nullptr,
                                             SourceLocation(), SourceLocation());
 }
@@ -2339,7 +2339,7 @@ ObjCCompatibleAliasDecl::Create(ASTContext &C, DeclContext *DC,
 }
 
 ObjCCompatibleAliasDecl *
-ObjCCompatibleAliasDecl::CreateDeserialized(ASTContext &C, Decl::DeclID ID) {
+ObjCCompatibleAliasDecl::CreateDeserialized(ASTContext &C, DeclID ID) {
   return new (C, ID) ObjCCompatibleAliasDecl(nullptr, SourceLocation(),
                                              nullptr, nullptr);
 }
@@ -2360,7 +2360,7 @@ ObjCPropertyDecl::Create(ASTContext &C, DeclContext *DC, SourceLocation L,
 }
 
 ObjCPropertyDecl *ObjCPropertyDecl::CreateDeserialized(ASTContext &C,
-                                                       Decl::DeclID ID) {
+                                                       DeclID ID) {
   return new (C, ID) ObjCPropertyDecl(nullptr, SourceLocation(), nullptr,
                                       SourceLocation(), SourceLocation(),
                                       QualType(), nullptr, None);
@@ -2393,7 +2393,7 @@ ObjCPropertyImplDecl *ObjCPropertyImplDecl::Create(ASTContext &C,
 }
 
 ObjCPropertyImplDecl *ObjCPropertyImplDecl::CreateDeserialized(ASTContext &C,
-                                                               Decl::DeclID ID) {
+                                                               DeclID ID) {
   return new (C, ID) ObjCPropertyImplDecl(nullptr, SourceLocation(),
                                           SourceLocation(), nullptr, Dynamic,
                                           nullptr, SourceLocation());
diff --git a/clang/lib/AST/DeclOpenMP.cpp b/clang/lib/AST/DeclOpenMP.cpp
index b178a15..9f1d2bd 100644
--- a/clang/lib/AST/DeclOpenMP.cpp
+++ b/clang/lib/AST/DeclOpenMP.cpp
@@ -35,9 +35,8 @@ OMPThreadPrivateDecl *OMPThreadPrivateDecl::Create(ASTContext &C,
   return D;
 }
 
-OMPThreadPrivateDecl *OMPThreadPrivateDecl::CreateDeserialized(ASTContext &C,
-                                                               Decl::DeclID ID,
-                                                               unsigned N) {
+OMPThreadPrivateDecl *
+OMPThreadPrivateDecl::CreateDeserialized(ASTContext &C, DeclID ID, unsigned N) {
   return OMPDeclarativeDirective::createEmptyDirective<OMPThreadPrivateDecl>(
       C, ID, 0, N);
 }
@@ -63,7 +62,7 @@ OMPAllocateDecl *OMPAllocateDecl::Create(ASTContext &C, DeclContext *DC,
   return D;
 }
 
-OMPAllocateDecl *OMPAllocateDecl::CreateDeserialized(ASTContext &C, Decl::DeclID ID,
+OMPAllocateDecl *OMPAllocateDecl::CreateDeserialized(ASTContext &C, DeclID ID,
                                                      unsigned NVars,
                                                      unsigned NClauses) {
   return OMPDeclarativeDirective::createEmptyDirective<OMPAllocateDecl>(
@@ -89,7 +88,7 @@ OMPRequiresDecl *OMPRequiresDecl::Create(ASTContext &C, DeclContext *DC,
                                                                    L);
 }
 
-OMPRequiresDecl *OMPRequiresDecl::CreateDeserialized(ASTContext &C, Decl::DeclID ID,
+OMPRequiresDecl *OMPRequiresDecl::CreateDeserialized(ASTContext &C, DeclID ID,
                                                      unsigned N) {
   return OMPDeclarativeDirective::createEmptyDirective<OMPRequiresDecl>(
       C, ID, N, 0, SourceLocation());
@@ -117,7 +116,7 @@ OMPDeclareReductionDecl *OMPDeclareReductionDecl::Create(
 }
 
 OMPDeclareReductionDecl *
-OMPDeclareReductionDecl::CreateDeserialized(ASTContext &C, Decl::DeclID ID) {
+OMPDeclareReductionDecl::CreateDeserialized(ASTContext &C, DeclID ID) {
   return new (C, ID) OMPDeclareReductionDecl(
       OMPDeclareReduction, /*DC=*/nullptr, SourceLocation(), DeclarationName(),
       QualType(), /*PrevDeclInScope=*/nullptr);
@@ -147,9 +146,8 @@ OMPDeclareMapperDecl *OMPDeclareMapperDecl::Create(
       C, DC, Clauses, 1, L, Name, T, VarName, PrevDeclInScope);
 }
 
-OMPDeclareMapperDecl *OMPDeclareMapperDecl::CreateDeserialized(ASTContext &C,
-                                                               Decl::DeclID ID,
-                                                               unsigned N) {
+OMPDeclareMapperDecl *
+OMPDeclareMapperDecl::CreateDeserialized(ASTContext &C, DeclID ID, unsigned N) {
   return OMPDeclarativeDirective::createEmptyDirective<OMPDeclareMapperDecl>(
       C, ID, N, 1, SourceLocation(), DeclarationName(), QualType(),
       DeclarationName(), /*PrevDeclInScope=*/nullptr);
@@ -179,7 +177,7 @@ OMPCapturedExprDecl *OMPCapturedExprDecl::Create(ASTContext &C, DeclContext *DC,
 }
 
 OMPCapturedExprDecl *OMPCapturedExprDecl::CreateDeserialized(ASTContext &C,
-                                                             Decl::DeclID ID) {
+                                                             DeclID ID) {
   return new (C, ID) OMPCapturedExprDecl(C, nullptr, nullptr, QualType(),
                                          /*TInfo=*/nullptr, SourceLocation());
 }
diff --git a/clang/lib/AST/DeclTemplate.cpp b/clang/lib/AST/DeclTemplate.cpp
index 67bb9e4..ca998b5 100644
--- a/clang/lib/AST/DeclTemplate.cpp
+++ b/clang/lib/AST/DeclTemplate.cpp
@@ -337,7 +337,7 @@ void RedeclarableTemplateDecl::loadLazySpecializationsImpl() const {
   CommonBase *CommonBasePtr = getMostRecentDecl()->getCommonPtr();
   if (CommonBasePtr->LazySpecializations) {
     ASTContext &Context = getASTContext();
-    Decl::DeclID *Specs = CommonBasePtr->LazySpecializations;
+    DeclID *Specs = CommonBasePtr->LazySpecializations;
     CommonBasePtr->LazySpecializations = nullptr;
     for (uint32_t I = 0, N = *Specs++; I != N; ++I)
       (void)Context.getExternalSource()->GetExternalDecl(Specs[I]);
@@ -418,7 +418,7 @@ FunctionTemplateDecl::Create(ASTContext &C, DeclContext *DC, SourceLocation L,
 }
 
 FunctionTemplateDecl *FunctionTemplateDecl::CreateDeserialized(ASTContext &C,
-                                                               Decl::DeclID ID) {
+                                                               DeclID ID) {
   return new (C, ID) FunctionTemplateDecl(C, nullptr, SourceLocation(),
                                           DeclarationName(), nullptr, nullptr);
 }
@@ -503,7 +503,7 @@ ClassTemplateDecl *ClassTemplateDecl::Create(ASTContext &C, DeclContext *DC,
 }
 
 ClassTemplateDecl *ClassTemplateDecl::CreateDeserialized(ASTContext &C,
-                                                         Decl::DeclID ID) {
+                                                         DeclID ID) {
   return new (C, ID) ClassTemplateDecl(C, nullptr, SourceLocation(),
                                        DeclarationName(), nullptr, nullptr);
 }
@@ -652,14 +652,14 @@ TemplateTypeParmDecl *TemplateTypeParmDecl::Create(
 }
 
 TemplateTypeParmDecl *
-TemplateTypeParmDecl::CreateDeserialized(const ASTContext &C, Decl::DeclID ID) {
+TemplateTypeParmDecl::CreateDeserialized(const ASTContext &C, DeclID ID) {
   return new (C, ID)
       TemplateTypeParmDecl(nullptr, SourceLocation(), SourceLocation(), nullptr,
                            false, false, std::nullopt);
 }
 
 TemplateTypeParmDecl *
-TemplateTypeParmDecl::CreateDeserialized(const ASTContext &C, Decl::DeclID ID,
+TemplateTypeParmDecl::CreateDeserialized(const ASTContext &C, DeclID ID,
                                          bool HasTypeConstraint) {
   return new (C, ID,
               additionalSizeToAlloc<TypeConstraint>(HasTypeConstraint ? 1 : 0))
@@ -759,7 +759,7 @@ NonTypeTemplateParmDecl *NonTypeTemplateParmDecl::Create(
 }
 
 NonTypeTemplateParmDecl *
-NonTypeTemplateParmDecl::CreateDeserialized(ASTContext &C, Decl::DeclID ID,
+NonTypeTemplateParmDecl::CreateDeserialized(ASTContext &C, DeclID ID,
                                             bool HasTypeConstraint) {
   return new (C, ID, additionalSizeToAlloc<std::pair<QualType,
                                                      TypeSourceInfo *>,
@@ -770,7 +770,7 @@ NonTypeTemplateParmDecl::CreateDeserialized(ASTContext &C, Decl::DeclID ID,
 }
 
 NonTypeTemplateParmDecl *
-NonTypeTemplateParmDecl::CreateDeserialized(ASTContext &C, Decl::DeclID ID,
+NonTypeTemplateParmDecl::CreateDeserialized(ASTContext &C, DeclID ID,
                                             unsigned NumExpandedTypes,
                                             bool HasTypeConstraint) {
   auto *NTTP =
@@ -836,13 +836,13 @@ TemplateTemplateParmDecl::Create(const ASTContext &C, DeclContext *DC,
 }
 
 TemplateTemplateParmDecl *
-TemplateTemplateParmDecl::CreateDeserialized(ASTContext &C, Decl::DeclID ID) {
+TemplateTemplateParmDecl::CreateDeserialized(ASTContext &C, DeclID ID) {
   return new (C, ID) TemplateTemplateParmDecl(nullptr, SourceLocation(), 0, 0,
                                               false, nullptr, false, nullptr);
 }
 
 TemplateTemplateParmDecl *
-TemplateTemplateParmDecl::CreateDeserialized(ASTContext &C, Decl::DeclID ID,
+TemplateTemplateParmDecl::CreateDeserialized(ASTContext &C, DeclID ID,
                                              unsigned NumExpansions) {
   auto *TTP =
       new (C, ID, additionalSizeToAlloc<TemplateParameterList *>(NumExpansions))
@@ -948,8 +948,7 @@ ClassTemplateSpecializationDecl::Create(ASTContext &Context, TagKind TK,
 }
 
 ClassTemplateSpecializationDecl *
-ClassTemplateSpecializationDecl::CreateDeserialized(ASTContext &C,
-                                                    Decl::DeclID ID) {
+ClassTemplateSpecializationDecl::CreateDeserialized(ASTContext &C, DeclID ID) {
   auto *Result =
     new (C, ID) ClassTemplateSpecializationDecl(C, ClassTemplateSpecialization);
   Result->setMayHaveOutOfDateDef(false);
@@ -1035,8 +1034,7 @@ ConceptDecl *ConceptDecl::Create(ASTContext &C, DeclContext *DC,
   return TD;
 }
 
-ConceptDecl *ConceptDecl::CreateDeserialized(ASTContext &C,
-                                             Decl::DeclID ID) {
+ConceptDecl *ConceptDecl::CreateDeserialized(ASTContext &C, DeclID ID) {
   ConceptDecl *Result = new (C, ID) ConceptDecl(nullptr, SourceLocation(),
                                                 DeclarationName(),
                                                 nullptr, nullptr);
@@ -1070,7 +1068,7 @@ ImplicitConceptSpecializationDecl *ImplicitConceptSpecializationDecl::Create(
 
 ImplicitConceptSpecializationDecl *
 ImplicitConceptSpecializationDecl::CreateDeserialized(
-    const ASTContext &C, Decl::DeclID ID, unsigned NumTemplateArgs) {
+    const ASTContext &C, DeclID ID, unsigned NumTemplateArgs) {
   return new (C, ID, additionalSizeToAlloc<TemplateArgument>(NumTemplateArgs))
       ImplicitConceptSpecializationDecl(EmptyShell{}, NumTemplateArgs);
 }
@@ -1133,7 +1131,7 @@ Create(ASTContext &Context, TagKind TK,DeclContext *DC,
 
 ClassTemplatePartialSpecializationDecl *
 ClassTemplatePartialSpecializationDecl::CreateDeserialized(ASTContext &C,
-                                                           Decl::DeclID ID) {
+                                                           DeclID ID) {
   auto *Result = new (C, ID) ClassTemplatePartialSpecializationDecl(C);
   Result->setMayHaveOutOfDateDef(false);
   return Result;
@@ -1160,7 +1158,7 @@ FriendTemplateDecl::Create(ASTContext &Context, DeclContext *DC,
 }
 
 FriendTemplateDecl *FriendTemplateDecl::CreateDeserialized(ASTContext &C,
-                                                           Decl::DeclID ID) {
+                                                           DeclID ID) {
   return new (C, ID) FriendTemplateDecl(EmptyShell());
 }
 
@@ -1180,7 +1178,7 @@ TypeAliasTemplateDecl::Create(ASTContext &C, DeclContext *DC, SourceLocation L,
 }
 
 TypeAliasTemplateDecl *TypeAliasTemplateDecl::CreateDeserialized(ASTContext &C,
-                                                                 Decl::DeclID ID) {
+                                                                 DeclID ID) {
   return new (C, ID) TypeAliasTemplateDecl(C, nullptr, SourceLocation(),
                                            DeclarationName(), nullptr, nullptr);
 }
@@ -1217,8 +1215,7 @@ VarTemplateDecl *VarTemplateDecl::Create(ASTContext &C, DeclContext *DC,
   return TD;
 }
 
-VarTemplateDecl *VarTemplateDecl::CreateDeserialized(ASTContext &C,
-                                                     Decl::DeclID ID) {
+VarTemplateDecl *VarTemplateDecl::CreateDeserialized(ASTContext &C, DeclID ID) {
   return new (C, ID) VarTemplateDecl(C, nullptr, SourceLocation(),
                                      DeclarationName(), nullptr, nullptr);
 }
@@ -1340,7 +1337,7 @@ VarTemplateSpecializationDecl *VarTemplateSpecializationDecl::Create(
 }
 
 VarTemplateSpecializationDecl *
-VarTemplateSpecializationDecl::CreateDeserialized(ASTContext &C, Decl::DeclID ID) {
+VarTemplateSpecializationDecl::CreateDeserialized(ASTContext &C, DeclID ID) {
   return new (C, ID)
       VarTemplateSpecializationDecl(VarTemplateSpecialization, C);
 }
@@ -1432,7 +1429,7 @@ VarTemplatePartialSpecializationDecl::Create(
 
 VarTemplatePartialSpecializationDecl *
 VarTemplatePartialSpecializationDecl::CreateDeserialized(ASTContext &C,
-                                                         Decl::DeclID ID) {
+                                                         DeclID ID) {
   return new (C, ID) VarTemplatePartialSpecializationDecl(C);
 }
 
@@ -1546,7 +1543,7 @@ TemplateParamObjectDecl *TemplateParamObjectDecl::Create(const ASTContext &C,
 }
 
 TemplateParamObjectDecl *
-TemplateParamObjectDecl::CreateDeserialized(ASTContext &C, Decl::DeclID ID) {
+TemplateParamObjectDecl::CreateDeserialized(ASTContext &C, DeclID ID) {
   auto *TPOD = new (C, ID) TemplateParamObjectDecl(nullptr, QualType(), APValue());
   C.addDestruction(&TPOD->Value);
   return TPOD;
diff --git a/clang/lib/AST/ExternalASTSource.cpp b/clang/lib/AST/ExternalASTSource.cpp
index 2e54d9f..26ded22 100644
--- a/clang/lib/AST/ExternalASTSource.cpp
+++ b/clang/lib/AST/ExternalASTSource.cpp
@@ -68,7 +68,7 @@ bool ExternalASTSource::layoutRecordType(
   return false;
 }
 
-Decl *ExternalASTSource::GetExternalDecl(Decl::DeclID ID) { return nullptr; }
+Decl *ExternalASTSource::GetExternalDecl(DeclID ID) { return nullptr; }
 
 Selector ExternalASTSource::GetExternalSelector(uint32_t ID) {
   return Selector();
diff --git a/clang/lib/Frontend/ASTUnit.cpp b/clang/lib/Frontend/ASTUnit.cpp
index 3610a08..361331d 100644
--- a/clang/lib/Frontend/ASTUnit.cpp
+++ b/clang/lib/Frontend/ASTUnit.cpp
@@ -1067,7 +1067,7 @@ public:
 
   std::vector<Decl *> takeTopLevelDecls() { return std::move(TopLevelDecls); }
 
-  std::vector<serialization::DeclID> takeTopLevelDeclIDs() {
+  std::vector<DeclID> takeTopLevelDeclIDs() {
     return std::move(TopLevelDeclIDs);
   }
 
@@ -1101,7 +1101,7 @@ public:
 private:
   unsigned Hash = 0;
   std::vector<Decl *> TopLevelDecls;
-  std::vector<serialization::DeclID> TopLevelDeclIDs;
+  std::vector<DeclID> TopLevelDeclIDs;
   llvm::SmallVector<ASTUnit::StandaloneDiagnostic, 4> PreambleDiags;
 };
 
diff --git a/clang/lib/Frontend/FrontendAction.cpp b/clang/lib/Frontend/FrontendAction.cpp
index b7c9967..91ce16e 100644
--- a/clang/lib/Frontend/FrontendAction.cpp
+++ b/clang/lib/Frontend/FrontendAction.cpp
@@ -80,7 +80,7 @@ public:
     if (Previous)
       Previous->TypeRead(Idx, T);
   }
-  void DeclRead(serialization::DeclID ID, const Decl *D) override {
+  void DeclRead(DeclID ID, const Decl *D) override {
     if (Previous)
       Previous->DeclRead(ID, D);
   }
@@ -102,7 +102,7 @@ public:
                                    bool DeletePrevious)
       : DelegatingDeserializationListener(Previous, DeletePrevious) {}
 
-  void DeclRead(serialization::DeclID ID, const Decl *D) override {
+  void DeclRead(DeclID ID, const Decl *D) override {
     llvm::outs() << "PCH DECL: " << D->getDeclKindName();
     if (const NamedDecl *ND = dyn_cast<NamedDecl>(D)) {
       llvm::outs() << " - ";
@@ -128,7 +128,7 @@ public:
       : DelegatingDeserializationListener(Previous, DeletePrevious), Ctx(Ctx),
         NamesToCheck(NamesToCheck) {}
 
-  void DeclRead(serialization::DeclID ID, const Decl *D) override {
+  void DeclRead(DeclID ID, const Decl *D) override {
     if (const NamedDecl *ND = dyn_cast<NamedDecl>(D))
       if (NamesToCheck.find(ND->getNameAsString()) != NamesToCheck.end()) {
         unsigned DiagID
diff --git a/clang/lib/Frontend/MultiplexConsumer.cpp b/clang/lib/Frontend/MultiplexConsumer.cpp
index 744ea70..9e885c8 100644
--- a/clang/lib/Frontend/MultiplexConsumer.cpp
+++ b/clang/lib/Frontend/MultiplexConsumer.cpp
@@ -52,8 +52,7 @@ void MultiplexASTDeserializationListener::TypeRead(
     Listeners[i]->TypeRead(Idx, T);
 }
 
-void MultiplexASTDeserializationListener::DeclRead(
-    serialization::DeclID ID, const Decl *D) {
+void MultiplexASTDeserializationListener::DeclRead(DeclID ID, const Decl *D) {
   for (size_t i = 0, e = Listeners.size(); i != e; ++i)
     Listeners[i]->DeclRead(ID, D);
 }
diff --git a/clang/lib/Sema/MultiplexExternalSemaSource.cpp b/clang/lib/Sema/MultiplexExternalSemaSource.cpp
index 6a5f9f6..e48c724 100644
--- a/clang/lib/Sema/MultiplexExternalSemaSource.cpp
+++ b/clang/lib/Sema/MultiplexExternalSemaSource.cpp
@@ -46,7 +46,7 @@ void MultiplexExternalSemaSource::AddSource(ExternalSemaSource *Source) {
 // ExternalASTSource.
 //===----------------------------------------------------------------------===//
 
-Decl *MultiplexExternalSemaSource::GetExternalDecl(Decl::DeclID ID) {
+Decl *MultiplexExternalSemaSource::GetExternalDecl(DeclID ID) {
   for(size_t i = 0; i < Sources.size(); ++i)
     if (Decl *Result = Sources[i]->GetExternalDecl(ID))
       return Result;
diff --git a/clang/lib/Serialization/ASTReader.cpp b/clang/lib/Serialization/ASTReader.cpp
index 43b6904..df9984d 100644
--- a/clang/lib/Serialization/ASTReader.cpp
+++ b/clang/lib/Serialization/ASTReader.cpp
@@ -7668,8 +7668,7 @@ GlobalDeclID ASTReader::getGlobalDeclID(ModuleFile &F,
   return GlobalDeclID(ID + I->second);
 }
 
-bool ASTReader::isDeclIDFromModule(serialization::GlobalDeclID ID,
-                                   ModuleFile &M) const {
+bool ASTReader::isDeclIDFromModule(GlobalDeclID ID, ModuleFile &M) const {
   // Predefined decls aren't from any module.
   if (ID.get() < NUM_PREDEF_DECL_IDS)
     return false;
@@ -7821,8 +7820,8 @@ DeclID ASTReader::mapGlobalIDToModuleFileGlobalID(ModuleFile &M,
   assert(I != GlobalDeclMap.end() && "Corrupted global declaration map");
   ModuleFile *Owner = I->second;
 
-  llvm::DenseMap<ModuleFile *, serialization::DeclID>::iterator Pos
-    = M.GlobalToLocalDeclIDs.find(Owner);
+  llvm::DenseMap<ModuleFile *, DeclID>::iterator Pos =
+      M.GlobalToLocalDeclIDs.find(Owner);
   if (Pos == M.GlobalToLocalDeclIDs.end())
     return 0;
 
@@ -7872,7 +7871,7 @@ void ASTReader::FindExternalLexicalDecls(
       if (!IsKindWeWant(K))
         continue;
 
-      auto ID = (serialization::DeclID)+LexicalDecls[I + 1];
+      auto ID = (DeclID) + LexicalDecls[I + 1];
 
       // Don't add predefined declarations to the lexical context more
       // than once.
@@ -7954,7 +7953,7 @@ void ASTReader::FindFileRegionDecls(FileID File,
   SourceLocation EndLoc = BeginLoc.getLocWithOffset(Length);
 
   DeclIDComp DIDComp(*this, *DInfo.Mod);
-  ArrayRef<serialization::LocalDeclID>::iterator BeginIt =
+  ArrayRef<LocalDeclID>::iterator BeginIt =
       llvm::lower_bound(DInfo.Decls, BeginLoc, DIDComp);
   if (BeginIt != DInfo.Decls.begin())
     --BeginIt;
@@ -7967,13 +7966,12 @@ void ASTReader::FindFileRegionDecls(FileID File,
              ->isTopLevelDeclInObjCContainer())
     --BeginIt;
 
-  ArrayRef<serialization::LocalDeclID>::iterator EndIt =
+  ArrayRef<LocalDeclID>::iterator EndIt =
       llvm::upper_bound(DInfo.Decls, EndLoc, DIDComp);
   if (EndIt != DInfo.Decls.end())
     ++EndIt;
 
-  for (ArrayRef<serialization::LocalDeclID>::iterator
-         DIt = BeginIt; DIt != EndIt; ++DIt)
+  for (ArrayRef<LocalDeclID>::iterator DIt = BeginIt; DIt != EndIt; ++DIt)
     Decls.push_back(GetDecl(getGlobalDeclID(*DInfo.Mod, *DIt)));
 }
 
diff --git a/clang/lib/Serialization/ASTReaderDecl.cpp b/clang/lib/Serialization/ASTReaderDecl.cpp
index bb82173..9707eed 100644
--- a/clang/lib/Serialization/ASTReaderDecl.cpp
+++ b/clang/lib/Serialization/ASTReaderDecl.cpp
@@ -279,7 +279,7 @@ namespace clang {
         IDs.erase(std::unique(IDs.begin(), IDs.end()), IDs.end());
       }
 
-      auto *Result = new (C) serialization::DeclID[1 + IDs.size()];
+      auto *Result = new (C) DeclID[1 + IDs.size()];
       *Result = IDs.size();
 
       std::copy(DeclIDIterator(IDs.begin()), DeclIDIterator(IDs.end()),
@@ -4215,7 +4215,7 @@ void ASTReader::loadDeclUpdateRecords(PendingUpdateRecord &Record) {
   // The declaration may have been modified by files later in the chain.
   // If this is the case, read the record containing the updates from each file
   // and pass it to ASTDeclReader to make the modifications.
-  serialization::GlobalDeclID ID = Record.ID;
+  GlobalDeclID ID = Record.ID;
   Decl *D = Record.D;
   ProcessingUpdatesRAIIObj ProcessingUpdates(*this);
   DeclUpdateOffsetsMap::iterator UpdI = DeclUpdateOffsets.find(ID);
@@ -4357,7 +4357,7 @@ namespace {
     llvm::SmallPtrSetImpl<ObjCCategoryDecl *> &Deserialized;
     ObjCCategoryDecl *Tail = nullptr;
     llvm::DenseMap<DeclarationName, ObjCCategoryDecl *> NameCategoryMap;
-    serialization::GlobalDeclID InterfaceID;
+    GlobalDeclID InterfaceID;
     unsigned PreviousGeneration;
 
     void add(ObjCCategoryDecl *Cat) {
@@ -4399,11 +4399,10 @@ namespace {
     }
 
   public:
-    ObjCCategoriesVisitor(ASTReader &Reader,
-                          ObjCInterfaceDecl *Interface,
-                          llvm::SmallPtrSetImpl<ObjCCategoryDecl *> &Deserialized,
-                          serialization::GlobalDeclID InterfaceID,
-                          unsigned PreviousGeneration)
+    ObjCCategoriesVisitor(
+        ASTReader &Reader, ObjCInterfaceDecl *Interface,
+        llvm::SmallPtrSetImpl<ObjCCategoryDecl *> &Deserialized,
+        GlobalDeclID InterfaceID, unsigned PreviousGeneration)
         : Reader(Reader), Interface(Interface), Deserialized(Deserialized),
           InterfaceID(InterfaceID), PreviousGeneration(PreviousGeneration) {
       // Populate the name -> category map with the set of known categories.
@@ -4457,8 +4456,7 @@ namespace {
 
 } // namespace
 
-void ASTReader::loadObjCCategories(serialization::GlobalDeclID ID,
-                                   ObjCInterfaceDecl *D,
+void ASTReader::loadObjCCategories(GlobalDeclID ID, ObjCInterfaceDecl *D,
                                    unsigned PreviousGeneration) {
   ObjCCategoriesVisitor Visitor(*this, D, CategoriesDeserialized, ID,
                                 PreviousGeneration);
diff --git a/clang/lib/Serialization/ASTWriter.cpp b/clang/lib/Serialization/ASTWriter.cpp
index 3019586..842ea58 100644
--- a/clang/lib/Serialization/ASTWriter.cpp
+++ b/clang/lib/Serialization/ASTWriter.cpp
@@ -5100,7 +5100,7 @@ void ASTWriter::WriteSpecialDeclRecords(Sema &SemaRef) {
     Stream.EmitRecord(SEMA_DECL_REFS, SemaDeclRefs);
 
   // Write the record containing decls to be checked for deferred diags.
-  SmallVector<serialization::DeclID, 64> DeclsToCheckForDeferredDiags;
+  SmallVector<DeclID, 64> DeclsToCheckForDeferredDiags;
   for (auto *D : SemaRef.DeclsToCheckForDeferredDiags)
     if (wasDeclEmitted(D))
       DeclsToCheckForDeferredDiags.push_back(getDeclID(D));
@@ -6079,7 +6079,7 @@ void ASTWriter::associateDeclWithFile(const Decl *D, DeclID ID) {
   if (!Info)
     Info = std::make_unique<DeclIDInFileInfo>();
 
-  std::pair<unsigned, serialization::DeclID> LocDecl(Offset, ID);
+  std::pair<unsigned, DeclID> LocDecl(Offset, ID);
   LocDeclIDsTy &Decls = Info->DeclIDs;
   Decls.push_back(LocDecl);
 }
diff --git a/clang/lib/Serialization/ASTWriterDecl.cpp b/clang/lib/Serialization/ASTWriterDecl.cpp
index c6db107..fe86719 100644
--- a/clang/lib/Serialization/ASTWriterDecl.cpp
+++ b/clang/lib/Serialization/ASTWriterDecl.cpp
@@ -2786,9 +2786,9 @@ void ASTWriter::WriteDecl(ASTContext &Context, Decl *D) {
                                       "serializing");
 
   // Determine the ID for this declaration.
-  serialization::DeclID ID;
+  DeclID ID;
   assert(!D->isFromASTFile() && "should not be emitting imported decl");
-  serialization::DeclID &IDR = DeclIDs[D];
+  DeclID &IDR = DeclIDs[D];
   if (IDR == 0)
     IDR = NextDeclID++;