llvm · mizvekov · Apr 1, 2025 · Mar 28, 2025
diff --git a/clang-tools-extra/clangd/AST.cpp b/clang-tools-extra/clangd/AST.cpp
@@ -119,8 +119,7 @@ getQualification(ASTContext &Context, const DeclContext *DestContext,
       // There can't be any more tag parents after hitting a namespace.
       assert(!ReachedNS);
       (void)ReachedNS;
-      NNS = NestedNameSpecifier::Create(Context, nullptr, false,
-                                        TD->getTypeForDecl());
+      NNS = NestedNameSpecifier::Create(Context, nullptr, TD->getTypeForDecl());
     } else if (auto *NSD = llvm::dyn_cast<NamespaceDecl>(CurContext)) {
       ReachedNS = true;
       NNS = NestedNameSpecifier::Create(Context, nullptr, NSD);

diff --git a/clang-tools-extra/clangd/CodeComplete.cpp b/clang-tools-extra/clangd/CodeComplete.cpp
@@ -1467,7 +1467,6 @@ bool allowIndex(CodeCompletionContext &CC) {
     return true;
   case NestedNameSpecifier::Super:
   case NestedNameSpecifier::TypeSpec:
-  case NestedNameSpecifier::TypeSpecWithTemplate:
   // Unresolved inside a template.
   case NestedNameSpecifier::Identifier:
     return false;

diff --git a/clang-tools-extra/clangd/DumpAST.cpp b/clang-tools-extra/clangd/DumpAST.cpp
@@ -157,7 +157,6 @@ class DumpVisitor : public RecursiveASTVisitor<DumpVisitor> {
       NNS_KIND(Identifier);
       NNS_KIND(Namespace);
       NNS_KIND(TypeSpec);
-      NNS_KIND(TypeSpecWithTemplate);
       NNS_KIND(Global);
       NNS_KIND(Super);
       NNS_KIND(NamespaceAlias);

diff --git a/clang-tools-extra/clangd/FindTarget.cpp b/clang-tools-extra/clangd/FindTarget.cpp
@@ -500,7 +500,6 @@ struct TargetFinder {
       }
       return;
     case NestedNameSpecifier::TypeSpec:
-    case NestedNameSpecifier::TypeSpecWithTemplate:
       add(QualType(NNS->getAsType(), 0), Flags);
       return;
     case NestedNameSpecifier::Global:

diff --git a/clang-tools-extra/include-cleaner/lib/WalkAST.cpp b/clang-tools-extra/include-cleaner/lib/WalkAST.cpp
@@ -144,7 +144,6 @@ class ASTWalker : public RecursiveASTVisitor<ASTWalker> {
     case NestedNameSpecifier::Global:
       return true;
     case NestedNameSpecifier::TypeSpec:
-    case NestedNameSpecifier::TypeSpecWithTemplate:
     case NestedNameSpecifier::Super:
     case NestedNameSpecifier::Identifier:
       return false;

diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
@@ -275,6 +275,10 @@ Improvements to Clang's diagnostics
 - Diagnostics on chained comparisons (``a < b < c``) are now an error by default. This can be disabled with
   ``-Wno-error=parentheses``.
 - Clang now better preserves the sugared types of pointers to member.
+- Clang now better preserves the presence of the template keyword with dependent
+  prefixes.
+- When printing types for diagnostics, clang now doesn't suppress the scopes of
+  template arguments contained within nested names.
 - The ``-Wshift-bool`` warning has been added to warn about shifting a boolean. (#GH28334)
 - Fixed diagnostics adding a trailing ``::`` when printing some source code
   constructs, like base classes.

diff --git a/clang/include/clang/AST/ASTContext.h b/clang/include/clang/AST/ASTContext.h
@@ -1837,15 +1837,14 @@ class ASTContext : public RefCountedBase<ASTContext> {
                              TagDecl *OwnedTagDecl = nullptr) const;
   QualType getDependentNameType(ElaboratedTypeKeyword Keyword,
                                 NestedNameSpecifier *NNS,
-                                const IdentifierInfo *Name,
-                                QualType Canon = QualType()) const;
+                                const IdentifierInfo *Name) const;
 
   QualType getDependentTemplateSpecializationType(
-      ElaboratedTypeKeyword Keyword, NestedNameSpecifier *NNS,
-      const IdentifierInfo *Name, ArrayRef<TemplateArgumentLoc> Args) const;
+      ElaboratedTypeKeyword Keyword, const DependentTemplateStorage &Name,
+      ArrayRef<TemplateArgumentLoc> Args) const;
   QualType getDependentTemplateSpecializationType(
-      ElaboratedTypeKeyword Keyword, NestedNameSpecifier *NNS,
-      const IdentifierInfo *Name, ArrayRef<TemplateArgument> Args) const;
+      ElaboratedTypeKeyword Keyword, const DependentTemplateStorage &Name,
+      ArrayRef<TemplateArgument> Args, bool IsCanonical = false) const;
 
   TemplateArgument getInjectedTemplateArg(NamedDecl *ParamDecl) const;
 
@@ -2393,11 +2392,9 @@ class ASTContext : public RefCountedBase<ASTContext> {
   TemplateName getQualifiedTemplateName(NestedNameSpecifier *NNS,
                                         bool TemplateKeyword,
                                         TemplateName Template) const;
+  TemplateName
+  getDependentTemplateName(const DependentTemplateStorage &Name) const;
 
-  TemplateName getDependentTemplateName(NestedNameSpecifier *NNS,
-                                        const IdentifierInfo *Name) const;
-  TemplateName getDependentTemplateName(NestedNameSpecifier *NNS,
-                                        OverloadedOperatorKind Operator) const;
   TemplateName
   getSubstTemplateTemplateParm(TemplateName replacement, Decl *AssociatedDecl,
                                unsigned Index,

diff --git a/clang/include/clang/AST/ASTImporter.h b/clang/include/clang/AST/ASTImporter.h
@@ -446,6 +446,14 @@ class TypeSourceInfo;
     /// returns nullptr only if the FromId was nullptr.
     IdentifierInfo *Import(const IdentifierInfo *FromId);
 
+    /// Import the given identifier or overloaded operator from the "from"
+    /// context into the "to" context.
+    ///
+    /// \returns The equivalent identifier or overloaded operator in the "to"
+    /// context.
+    IdentifierOrOverloadedOperator
+    Import(IdentifierOrOverloadedOperator FromIO);
+
     /// Import the given Objective-C selector from the "from"
     /// context into the "to" context.
     ///

diff --git a/clang/include/clang/AST/ASTNodeTraverser.h b/clang/include/clang/AST/ASTNodeTraverser.h
@@ -396,8 +396,7 @@ class ASTNodeTraverser
     // FIXME: Provide a NestedNameSpecifier visitor.
     NestedNameSpecifier *Qualifier = T->getQualifier();
     if (NestedNameSpecifier::SpecifierKind K = Qualifier->getKind();
-        K == NestedNameSpecifier::TypeSpec ||
-        K == NestedNameSpecifier::TypeSpecWithTemplate)
+        K == NestedNameSpecifier::TypeSpec)
       Visit(Qualifier->getAsType());
     if (T->isSugared())
       Visit(T->getMostRecentCXXRecordDecl()->getTypeForDecl());

diff --git a/clang/include/clang/AST/AbstractBasicReader.h b/clang/include/clang/AST/AbstractBasicReader.h
@@ -279,10 +279,8 @@ class DataStreamBasicReader : public BasicReaderBase<Impl> {
         continue;
 
       case NestedNameSpecifier::TypeSpec:
-      case NestedNameSpecifier::TypeSpecWithTemplate:
         cur = NestedNameSpecifier::Create(ctx, cur,
-                          kind == NestedNameSpecifier::TypeSpecWithTemplate,
-                          asImpl().readQualType().getTypePtr());
+                                          asImpl().readQualType().getTypePtr());
         continue;
 
       case NestedNameSpecifier::Global:

diff --git a/clang/include/clang/AST/AbstractBasicWriter.h b/clang/include/clang/AST/AbstractBasicWriter.h
@@ -260,7 +260,6 @@ class DataStreamBasicWriter : public BasicWriterBase<Impl> {
         continue;
 
       case NestedNameSpecifier::TypeSpec:
-      case NestedNameSpecifier::TypeSpecWithTemplate:
         asImpl().writeQualType(QualType(NNS->getAsType(), 0));
         continue;
 

diff --git a/clang/include/clang/AST/NestedNameSpecifier.h b/clang/include/clang/AST/NestedNameSpecifier.h
@@ -52,8 +52,7 @@ class NestedNameSpecifier : public llvm::FoldingSetNode {
   enum StoredSpecifierKind {
     StoredIdentifier = 0,
     StoredDecl = 1,
-    StoredTypeSpec = 2,
-    StoredTypeSpecWithTemplate = 3
+    StoredTypeSpec = 2
   };
 
   /// The nested name specifier that precedes this nested name
@@ -89,10 +88,6 @@ class NestedNameSpecifier : public llvm::FoldingSetNode {
     /// A type, stored as a Type*.
     TypeSpec,
 
-    /// A type that was preceded by the 'template' keyword,
-    /// stored as a Type*.
-    TypeSpecWithTemplate,
-
     /// The global specifier '::'. There is no stored value.
     Global,
 
@@ -137,9 +132,8 @@ class NestedNameSpecifier : public llvm::FoldingSetNode {
                                      const NamespaceAliasDecl *Alias);
 
   /// Builds a nested name specifier that names a type.
-  static NestedNameSpecifier *Create(const ASTContext &Context,
-                                     NestedNameSpecifier *Prefix,
-                                     bool Template, const Type *T);
+  static NestedNameSpecifier *
+  Create(const ASTContext &Context, NestedNameSpecifier *Prefix, const Type *T);
 
   /// Builds a specifier that consists of just an identifier.
   ///
@@ -194,8 +188,7 @@ class NestedNameSpecifier : public llvm::FoldingSetNode {
 
   /// Retrieve the type stored in this nested name specifier.
   const Type *getAsType() const {
-    if (Prefix.getInt() == StoredTypeSpec ||
-        Prefix.getInt() == StoredTypeSpecWithTemplate)
+    if (Prefix.getInt() == StoredTypeSpec)
       return (const Type *)Specifier;
 
     return nullptr;
@@ -401,13 +394,10 @@ class NestedNameSpecifierLocBuilder {
   /// \param Context The AST context in which this nested-name-specifier
   /// resides.
   ///
-  /// \param TemplateKWLoc The location of the 'template' keyword, if present.
-  ///
   /// \param TL The TypeLoc that describes the type preceding the '::'.
   ///
   /// \param ColonColonLoc The location of the trailing '::'.
-  void Extend(ASTContext &Context, SourceLocation TemplateKWLoc, TypeLoc TL,
-              SourceLocation ColonColonLoc);
+  void Extend(ASTContext &Context, TypeLoc TL, SourceLocation ColonColonLoc);
 
   /// Extend the current nested-name-specifier by another
   /// nested-name-specifier component of the form 'identifier::'.

diff --git a/clang/include/clang/AST/ODRHash.h b/clang/include/clang/AST/ODRHash.h
@@ -94,6 +94,7 @@ class ODRHash {
   void AddStmt(const Stmt *S);
   void AddIdentifierInfo(const IdentifierInfo *II);
   void AddNestedNameSpecifier(const NestedNameSpecifier *NNS);
+  void AddDependentTemplateName(const DependentTemplateStorage &Name);
   void AddTemplateName(TemplateName Name);
   void AddDeclarationName(DeclarationName Name, bool TreatAsDecl = false);
   void AddTemplateArgument(TemplateArgument TA);

diff --git a/clang/include/clang/AST/PropertiesBase.td b/clang/include/clang/AST/PropertiesBase.td
@@ -692,25 +692,26 @@ let Class = PropertyTypeCase<TemplateName, "QualifiedTemplate"> in {
 let Class = PropertyTypeCase<TemplateName, "DependentTemplate"> in {
   def : ReadHelper<[{
     auto dtn = node.getAsDependentTemplateName();
+    auto name = dtn->getName();
   }]>;
   def : Property<"qualifier", NestedNameSpecifier> {
     let Read = [{ dtn->getQualifier() }];
   }
   def : Property<"identifier", Optional<Identifier>> {
-    let Read = [{ makeOptionalFromPointer(
-                    dtn->isIdentifier()
-                      ? dtn->getIdentifier()
-                      : nullptr) }];
+    let Read = [{ makeOptionalFromPointer(name.getIdentifier()) }];
   }
   def : Property<"operatorKind", OverloadedOperatorKind> {
     let Conditional = [{ !identifier }];
-    let Read = [{ dtn->getOperator() }];
+    let Read = [{ name.getOperator() }];
+  }
+  def : Property<"HasTemplateKeyword", Bool> {
+    let Read = [{ dtn->hasTemplateKeyword() }];
   }
   def : Creator<[{
     if (identifier) {
-      return ctx.getDependentTemplateName(qualifier, *identifier);
+      return ctx.getDependentTemplateName({qualifier, *identifier, HasTemplateKeyword});
     } else {
-      return ctx.getDependentTemplateName(qualifier, *operatorKind);
+      return ctx.getDependentTemplateName({qualifier, *operatorKind, HasTemplateKeyword});
     }
   }]>;
 }

diff --git a/clang/include/clang/AST/RecursiveASTVisitor.h b/clang/include/clang/AST/RecursiveASTVisitor.h
@@ -795,7 +795,6 @@ bool RecursiveASTVisitor<Derived>::TraverseNestedNameSpecifier(
     return true;
 
   case NestedNameSpecifier::TypeSpec:
-  case NestedNameSpecifier::TypeSpecWithTemplate:
     TRY_TO(TraverseType(QualType(NNS->getAsType(), 0)));
   }
 
@@ -820,7 +819,6 @@ bool RecursiveASTVisitor<Derived>::TraverseNestedNameSpecifierLoc(
     return true;
 
   case NestedNameSpecifier::TypeSpec:
-  case NestedNameSpecifier::TypeSpecWithTemplate:
     TRY_TO(TraverseTypeLoc(NNS.getTypeLoc()));
     break;
   }
@@ -1172,7 +1170,8 @@ DEF_TRAVERSE_TYPE(DependentNameType,
                   { TRY_TO(TraverseNestedNameSpecifier(T->getQualifier())); })
 
 DEF_TRAVERSE_TYPE(DependentTemplateSpecializationType, {
-  TRY_TO(TraverseNestedNameSpecifier(T->getQualifier()));
+  const DependentTemplateStorage &S = T->getDependentTemplateName();
+  TRY_TO(TraverseNestedNameSpecifier(S.getQualifier()));
   TRY_TO(TraverseTemplateArguments(T->template_arguments()));
 })