[FOLD] don't ignore invalid nested name specifiers

Author: sdkrystian

clang/lib/Sema/SemaExprMember.cpp

@@ -767,7 +767,7 @@ ExprResult Sema::BuildMemberReferenceExpr(
   LookupResult R(*this, NameInfo, LookupMemberName);
 
   if (SS.isInvalid())
-    SS.clear();
+    return ExprError();
 
   // Implicit member accesses.
   if (!Base) {

clang/test/CXX/temp/temp.res/temp.local/p3.cpp

@@ -16,8 +16,7 @@ template <class T> struct Derived: Base<int>, Base<char> {
   void g(X0 *t) {
     t->Derived::Base<T>::f();
     t->Base<T>::f();
-    t->Base::f(); // expected-error{{member 'Base' found in multiple base classes of different types}} \
-    // expected-error{{no member named 'f' in 'X0'}}
+    t->Base::f(); // expected-error{{member 'Base' found in multiple base classes of different types}}
   }
 };