Remove redundant CXXScopeSpec from TemplateIdAnnotation.

A TemplateIdAnnotation represents only a template-id, not a
nested-name-specifier plus a template-id. Don't make a redundant copy of
the CXXScopeSpec and store it on the template-id annotation.

This slightly improves error recovery by more properly handling the case
where we would form an invalid CXXScopeSpec while parsing a typename
specifier, instead of accidentally putting the token stream into a
broken "annot_template_id with a scope specifier, but with no preceding
annot_cxxscope token" state.

(cherry picked from commit a42fd84cff265b7e9faa3fe42885ee171393e4db)

2 files changed, 7 insertions, 9 deletions

diff --git a/clang/lib/Sema/SemaExprCXX.cpp b/clang/lib/Sema/SemaExprCXX.cpp
index a73e6906fce..938420d85c6 100644
--- a/clang/lib/Sema/SemaExprCXX.cpp
+++ b/clang/lib/Sema/SemaExprCXX.cpp
@@ -7317,7 +7317,7 @@ ExprResult Sema::ActOnPseudoDestructorExpr(Scope *S, Expr *Base,
     ASTTemplateArgsPtr TemplateArgsPtr(TemplateId->getTemplateArgs(),
                                        TemplateId->NumArgs);
     TypeResult T = ActOnTemplateIdType(S,
-                                       TemplateId->SS,
+                                       SS,
                                        TemplateId->TemplateKWLoc,
                                        TemplateId->Template,
                                        TemplateId->Name,
@@ -7370,7 +7370,7 @@ ExprResult Sema::ActOnPseudoDestructorExpr(Scope *S, Expr *Base,
       ASTTemplateArgsPtr TemplateArgsPtr(TemplateId->getTemplateArgs(),
                                          TemplateId->NumArgs);
       TypeResult T = ActOnTemplateIdType(S,
-                                         TemplateId->SS,
+                                         SS,
                                          TemplateId->TemplateKWLoc,
                                          TemplateId->Template,
                                          TemplateId->Name,
diff --git a/clang/lib/Sema/SemaTemplate.cpp b/clang/lib/Sema/SemaTemplate.cpp
index 1184446796e..8a50a9e1538 100755
--- a/clang/lib/Sema/SemaTemplate.cpp
+++ b/clang/lib/Sema/SemaTemplate.cpp
@@ -1050,7 +1050,8 @@ makeTemplateArgumentListInfo(Sema &S, TemplateIdAnnotation &TemplateId) {
   return TemplateArgs;
 }
 
-bool Sema::ActOnTypeConstraint(TemplateIdAnnotation *TypeConstr,
+bool Sema::ActOnTypeConstraint(const CXXScopeSpec &SS,
+                               TemplateIdAnnotation *TypeConstr,
                                TemplateTypeParmDecl *ConstrainedParameter,
                                SourceLocation EllipsisLoc) {
   ConceptDecl *CD =
@@ -1080,8 +1081,7 @@ bool Sema::ActOnTypeConstraint(TemplateIdAnnotation *TypeConstr,
         makeTemplateArgumentListInfo(*this, *TypeConstr);
   }
   return AttachTypeConstraint(
-      TypeConstr->SS.isSet() ? TypeConstr->SS.getWithLocInContext(Context) :
-      NestedNameSpecifierLoc(),
+      SS.isSet() ? SS.getWithLocInContext(Context) : NestedNameSpecifierLoc(),
       DeclarationNameInfo(DeclarationName(TypeConstr->Name),
                           TypeConstr->TemplateNameLoc), CD,
       TypeConstr->LAngleLoc.isValid() ? &TemplateArgs : nullptr,
@@ -7872,13 +7872,11 @@ bool Sema::CheckTemplatePartialSpecializationArgs(
 
 DeclResult Sema::ActOnClassTemplateSpecialization(
     Scope *S, unsigned TagSpec, TagUseKind TUK, SourceLocation KWLoc,
-    SourceLocation ModulePrivateLoc, TemplateIdAnnotation &TemplateId,
-    const ParsedAttributesView &Attr,
+    SourceLocation ModulePrivateLoc, CXXScopeSpec &SS,
+    TemplateIdAnnotation &TemplateId, const ParsedAttributesView &Attr,
     MultiTemplateParamsArg TemplateParameterLists, SkipBodyInfo *SkipBody) {
   assert(TUK != TUK_Reference && "References are not specializations");
 
-  CXXScopeSpec &SS = TemplateId.SS;
-
   // NOTE: KWLoc is the location of the tag keyword. This will instead
   // store the location of the outermost template keyword in the declaration.
   SourceLocation TemplateKWLoc = TemplateParameterLists.size() > 0