right, the error is when the itf *doesn't* have the member.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@53826 91177308-0d34-0410-b5e6-96231b3b80d8

include/clang/Basic/DiagnosticKinds.def

@@ -882,7 +882,7 @@ DIAG(err_typecheck_subscript_not_object, ERROR,
 DIAG(err_typecheck_member_reference_structUnion, ERROR,
      "member reference is not to a structure or union")
 DIAG(err_typecheck_member_reference_ivar, ERROR,
-     "'%0' has member named '%1'")
+     "'%0' does not have a member named '%1'")
 DIAG(err_typecheck_member_reference_arrow, ERROR,
      "member reference is not a pointer")
 DIAG(err_typecheck_incomplete_tag, ERROR,