--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gcc/testsuite/g++.dg/lookup/name-clash6.C	Fri Oct 27 22:46:09 2017 +0900
@@ -0,0 +1,13 @@
+// Copyright (C) 2007 Free Software Foundation
+// Contributed by Ollie Wild <aaw@google.com>
+// { dg-do compile }
+
+// C++ Standard, 3.3, clause 4:
+// "[Note: a namespace name or a class template name must be unique in its
+// declarative region (7.3.2, clause 14). ]"
+
+class N; // { dg-message "previous declaration" }
+
+namespace N // { dg-error "redeclared" }
+{
+}