Fix hole in our enforcement of rule requiring 'typename' prior to a dependent

name. If the dependent name happened to end in a template-id (X<T>::Y<U>), we
would fail to notice that the 'typename' keyword is missing when resolving it
to a type.

It turns out that GCC has a similar bug. If this shows up in much real code, we
can easily downgrade this to an ExtWarn.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@293815 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 15 insertions, 8 deletions

diff --git a/lib/Parse/ParseDeclCXX.cpp b/lib/Parse/ParseDeclCXX.cpp
index 0775de33da..6403caa27b 100644
--- a/lib/Parse/ParseDeclCXX.cpp
+++ b/lib/Parse/ParseDeclCXX.cpp
@@ -1076,7 +1076,7 @@ TypeResult Parser::ParseBaseTypeSpecifier(SourceLocation &BaseLoc,
     TemplateIdAnnotation *TemplateId = takeTemplateIdAnnotation(Tok);
     if (TemplateId->Kind == TNK_Type_template ||
         TemplateId->Kind == TNK_Dependent_template_name) {
-      AnnotateTemplateIdTokenAsType();
+      AnnotateTemplateIdTokenAsType(/*IsClassName*/true);
 
       assert(Tok.is(tok::annot_typename) && "template-id -> type failed");
       ParsedType Type = getTypeAnnotation(Tok);
@@ -1124,10 +1124,10 @@ TypeResult Parser::ParseBaseTypeSpecifier(SourceLocation &BaseLoc,
 
     // Parse the full template-id, then turn it into a type.
     if (AnnotateTemplateIdToken(Template, TNK, SS, SourceLocation(),
-                                TemplateName, true))
+                                TemplateName))
       return true;
-    if (TNK == TNK_Dependent_template_name)
-      AnnotateTemplateIdTokenAsType();
+    if (TNK == TNK_Type_template || TNK == TNK_Dependent_template_name)
+      AnnotateTemplateIdTokenAsType(/*IsClassName*/true);
 
     // If we didn't end up with a typename token, there's nothing more we
     // can do.
@@ -1145,7 +1145,7 @@ TypeResult Parser::ParseBaseTypeSpecifier(SourceLocation &BaseLoc,
   // We have an identifier; check whether it is actually a type.
   IdentifierInfo *CorrectedII = nullptr;
   ParsedType Type = Actions.getTypeName(
-      *Id, IdLoc, getCurScope(), &SS, true, false, nullptr,
+      *Id, IdLoc, getCurScope(), &SS, /*IsClassName=*/true, false, nullptr,
       /*IsCtorOrDtorName=*/false,
       /*NonTrivialTypeSourceInfo=*/true,
       /*IsClassTemplateDeductionContext*/ false, &CorrectedII);
@@ -3377,7 +3377,7 @@ MemInitResult Parser::ParseMemInitializer(Decl *ConstructorDecl) {
     TemplateIdAnnotation *TemplateId = takeTemplateIdAnnotation(Tok);
     if (TemplateId->Kind == TNK_Type_template ||
         TemplateId->Kind == TNK_Dependent_template_name) {
-      AnnotateTemplateIdTokenAsType();
+      AnnotateTemplateIdTokenAsType(/*IsClassName*/true);
       assert(Tok.is(tok::annot_typename) && "template-id -> type failed");
       TemplateTypeTy = getTypeAnnotation(Tok);
     }
diff --git a/lib/Parse/ParseTemplate.cpp b/lib/Parse/ParseTemplate.cpp
index 6bc35e3df5..f12e3f55e5 100644
--- a/lib/Parse/ParseTemplate.cpp
+++ b/lib/Parse/ParseTemplate.cpp
@@ -1064,7 +1064,12 @@ bool Parser::AnnotateTemplateIdToken(TemplateTy Template, TemplateNameKind TNK,
 /// If there was a failure when forming the type from the template-id,
 /// a type annotation token will still be created, but will have a
 /// NULL type pointer to signify an error.
-void Parser::AnnotateTemplateIdTokenAsType() {
+///
+/// \param IsClassName Is this template-id appearing in a context where we
+/// know it names a class, such as in an elaborated-type-specifier or
+/// base-specifier? ('typename' and 'template' are unneeded and disallowed
+/// in those contexts.)
+void Parser::AnnotateTemplateIdTokenAsType(bool IsClassName) {
   assert(Tok.is(tok::annot_template_id) && "Requires template-id tokens");
 
   TemplateIdAnnotation *TemplateId = takeTemplateIdAnnotation(Tok);
@@ -1083,7 +1088,9 @@ void Parser::AnnotateTemplateIdTokenAsType() {
                                   TemplateId->TemplateNameLoc,
                                   TemplateId->LAngleLoc,
                                   TemplateArgsPtr,
-                                  TemplateId->RAngleLoc);
+                                  TemplateId->RAngleLoc,
+                                  /*IsCtorOrDtorName*/false,
+                                  IsClassName);
   // Create the new "type" annotation token.
   Tok.setKind(tok::annot_typename);
   setTypeAnnotation(Tok, Type.isInvalid() ? nullptr : Type.get());