Make an error message more clear.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@74481 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Sema/SemaType.cpp b/lib/Sema/SemaType.cpp
index c0b4e9f..7fa6d70 100644
--- a/lib/Sema/SemaType.cpp
+++ b/lib/Sema/SemaType.cpp
@@ -697,7 +697,7 @@
   // C++ 8.3.3p3: A pointer to member shall not pointer to ... a member
   //   with reference type, or "cv void."
   if (T->isReferenceType()) {
-    Diag(Loc, diag::err_illegal_decl_pointer_to_reference)
+    Diag(Loc, diag::err_illegal_decl_mempointer_to_reference)
       << (Entity? Entity.getAsString() : "type name");
     return QualType();
   }