--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/clang/test/Modules/hidden-names.cpp	Thu Feb 13 15:10:13 2020 +0900
@@ -0,0 +1,13 @@
+// RUN: rm -rf %t
+// RUN: %clang_cc1 -fmodules-cache-path=%t -fmodules -fimplicit-module-maps -I %S/Inputs/hidden-names %s -verify
+// expected-no-diagnostics
+
+#include "visible.h"
+
+using namespace NS;
+
+namespace {
+  struct X { void f(); };
+}
+
+void X::f() {}