Index: include/clang/Basic/DiagnosticParseKinds.td
===================================================================
--- include/clang/Basic/DiagnosticParseKinds.td	(revision 140148)
+++ include/clang/Basic/DiagnosticParseKinds.td	(working copy)
@@ -225,6 +225,9 @@
   "type name does not allow storage class to be specified">;
 def err_typename_invalid_functionspec : Error<
   "type name does not allow function specifier to be specified">;
+def err_typename_identifiers_only : Error<
+  "type name is allowed for identifiers only">;
+  
 def err_invalid_decl_spec_combination : Error<
   "cannot combine with previous '%0' declaration specifier">;
 def err_invalid_vector_decl_spec_combination : Error<
Index: lib/Parse/ParseDeclCXX.cpp
===================================================================
--- lib/Parse/ParseDeclCXX.cpp	(revision 140148)
+++ lib/Parse/ParseDeclCXX.cpp	(working copy)
@@ -468,6 +468,14 @@
     return 0;
   }
 
+  // "typename" keyword is allowed for identifiers only,
+  // because it may be a type definition.
+  if (IsTypeName && Name.getKind() != UnqualifiedId::IK_Identifier) {
+    Diag(Name.getSourceRange().getBegin(), diag::err_typename_identifiers_only);
+    // Proceed parsing, but reset the IsTypeName flag.
+    IsTypeName = false;
+  }
+
   ParsedAttributes attrs(AttrFactory);
 
   // Maybe this is an alias-declaration.