Robustify callers that rebuild typename type nodes again NULL return

types. Fixes PR6463.

llvm-svn: 97924

Author: DougGregor

clang/lib/Sema/SemaDeclCXX.cpp

@@ -1083,6 +1083,9 @@ Sema::ActOnMemInitializer(DeclPtrTy ConstructorD,
           // specialization, we take it as a type name.
           BaseType = CheckTypenameType((NestedNameSpecifier *)SS.getScopeRep(),
                                        *MemberOrBase, SS.getRange());
+          if (BaseType.isNull())
+            return true;
+
           R.clear();
         }
       }

clang/lib/Sema/SemaTemplate.cpp

@@ -4992,6 +4992,9 @@ CurrentInstantiationRebuilder::TransformTypenameType(TypeLocBuilder &TLB,
     Result = getDerived().RebuildTypenameType(NNS, T->getIdentifier(),
                                               SourceRange(TL.getNameLoc()));
 
+  if (Result.isNull())
+    return QualType();
+
   TypenameTypeLoc NewTL = TLB.push<TypenameTypeLoc>(Result);
   NewTL.setNameLoc(TL.getNameLoc());
   return Result;

clang/test/SemaTemplate/typename-specifier-4.cpp

@@ -99,3 +99,20 @@ namespace PR6268 {
     return Inner<U>();
   }
 }
+
+namespace PR6463 {
+  struct B { typedef int type; }; // expected-note 2{{member found by ambiguous name lookup}}
+  struct C { typedef int type; }; // expected-note 2{{member found by ambiguous name lookup}}
+
+  template<typename T>
+  struct A : B, C { 
+    type& a(); // expected-error{{found in multiple base classes}}
+    int x; 
+  };
+
+  // FIXME: Improve source ___location info here.
+  template<typename T>
+  typename A<T>::type& A<T>::a() { // expected-error{{found in multiple base classes}}
+    return x;  // expected-error{{undeclared identifier}}
+  }
+}