When we know that we are parsing a class-name, implicitly construct a
TypenameType if getTypeName is looking at a member of an unknown
specialization. This allows us to properly parse class templates that
derived from type that could only otherwise be described by a typename type, 
e.g.,

  template<class T> struct X {};
  template<typename T> struct Y : public X<T>::X { }; 

Fixes PR4381.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@80123 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Parse/ParseDeclCXX.cpp b/lib/Parse/ParseDeclCXX.cpp
index 3a82868..0a97825 100644
--- a/lib/Parse/ParseDeclCXX.cpp
+++ b/lib/Parse/ParseDeclCXX.cpp
@@ -457,7 +457,8 @@
 
   // We have an identifier; check whether it is actually a type.
   TypeTy *Type = Actions.getTypeName(*Tok.getIdentifierInfo(), 
-                                     Tok.getLocation(), CurScope, SS);
+                                     Tok.getLocation(), CurScope, SS,
+                                     true);
   if (!Type) {
     Diag(Tok, DestrExpected ? diag::err_destructor_class_name 
                             : diag::err_expected_class_name);