PR15633: Note that we are EnteringContext when parsing the nested name

specifier for an enumeration. Also fix a crash-on-invalid if a non-dependent
name specifier is used to declare an enum template.

llvm-svn: 178502

clang/include/clang/Basic/DiagnosticCommonKinds.td

@@ -77,6 +77,7 @@ def note_decl_hiding_tag_type : Note<
   "%1 %0 is hidden by a non-type declaration of %0 here">;
 def err_attribute_not_type_attr : Error<
   "%0 attribute cannot be applied to types">;
+def err_enum_template : Error<"enumeration cannot be a template">;
 
 // Sema && Lex
 def ext_c99_longlong : Extension<

clang/include/clang/Basic/DiagnosticParseKinds.td

@@ -556,7 +556,6 @@ def err_explicit_instantiation_with_definition : Error<
     "explicit template instantiation cannot have a definition; if this "
     "definition is meant to be an explicit specialization, add '<>' after the "
     "'template' keyword">;
-def err_enum_template : Error<"enumeration cannot be a template">;
 def err_explicit_instantiation_enum : Error<
     "enumerations cannot be explicitly instantiated">;
 def err_expected_template_parameter : Error<"expected template parameter">;

clang/lib/Parse/ParseDecl.cpp

@@ -3262,7 +3262,7 @@ void Parser::ParseEnumSpecifier(SourceLocation StartLoc, DeclSpec &DS,
     ColonProtectionRAIIObject X(*this, AllowFixedUnderlyingType);
 
     if (ParseOptionalCXXScopeSpecifier(SS, ParsedType(),
-                                       /*EnteringContext=*/false))
+                                       /*EnteringContext=*/true))
       return;
 
     if (SS.isSet() && Tok.isNot(tok::identifier)) {

clang/lib/Sema/SemaDecl.cpp

@@ -9387,6 +9387,11 @@ Decl *Sema::ActOnTag(Scope *S, unsigned TagSpec, TagUseKind TUK,
                                                     TUK == TUK_Friend,
                                                     isExplicitSpecialization,
                                                     Invalid)) {
+      if (Kind == TTK_Enum) {
+        Diag(KWLoc, diag::err_enum_template);
+        return 0;
+      }
+
       if (TemplateParams->size() > 0) {
         // This is a declaration or definition of a class template (which may
         // be a member of another template).

clang/test/SemaCXX/enum-scoped.cpp

@@ -252,3 +252,17 @@ namespace pr13128 {
     enum class E { C };
   };
 }
+
+namespace PR15633 {
+  template<typename T> struct A {
+    struct B {
+      enum class E : T;
+      enum class E2 : T;
+    };
+  };
+  template<typename T> enum class A<T>::B::E { e };
+  template class A<int>;
+
+  struct B { enum class E; };
+  template<typename T> enum class B::E { e }; // expected-error {{enumeration cannot be a template}}
+}