--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gcc/testsuite/g++.dg/lookup/missing-std-include-7.C	Thu Oct 25 07:37:49 2018 +0900
@@ -0,0 +1,100 @@
+/* PR c++/85021: Verify that we suggest missing headers for common names in std::
+   if there's a "using namespace std;" active.  */
+
+/* No using-directive.  */
+
+void test_1 ()
+{
+  cout << "test"; // { dg-error "'cout' was not declared in this scope" }
+  // { dg-bogus "'<iostream>'" "" { target *-*-* } .-1 }
+}
+
+/* Local using-directive.  */
+
+void test_2 ()
+{
+  using namespace std;
+  cout << "test"; // { dg-error "'cout' was not declared in this scope" }
+  // { dg-message "'std::cout' is defined in header '<iostream>'" "" { target *-*-* } .-1 }
+}
+
+/* Local using-directive, but not of "std".  */
+
+namespace not_std {}
+void test_3 ()
+{
+  using namespace not_std;
+  cout << "test"; // { dg-error "'cout' was not declared in this scope" }
+  // { dg-bogus "'<iostream>'" "" { target *-*-* } .-1 }
+}
+
+/* Local using-directive in wrong block.  */
+
+void test_4 ()
+{
+  {
+    using namespace std;
+  }
+  cout << "test"; // { dg-error "'cout' was not declared in this scope" }
+  // { dg-bogus "'<iostream>'" "" { target *-*-* } .-1 }
+}
+
+/* Local using-directive used from nested block.  */
+
+void test_5 ()
+{
+  using namespace std;
+
+  for (int i = 0; i < 10; i++)
+    {
+      cout << "test"; // { dg-error "'cout' was not declared in this scope" }
+      // { dg-message "'std::cout' is defined in header '<iostream>'" "" { target *-*-* } .-1 }
+    }
+}
+
+namespace ns_1 {
+
+namespace ns_2 {
+
+using namespace std;
+
+/* using-directive within the same namespace.  */
+
+void test_6 ()
+{
+  cout << "test"; // { dg-error "'cout' was not declared in this scope" }
+  // { dg-message "'std::cout' is defined in header '<iostream>'" "" { target *-*-* } .-1 }
+}
+
+namespace ns_3 {
+
+/* Locate the using-directive within ns_2, the parent namespace.  */
+
+void test_7 ()
+{
+  cout << "test"; // { dg-error "'cout' was not declared in this scope" }
+  // { dg-message "'std::cout' is defined in header '<iostream>'" "" { target *-*-* } .-1 }
+}
+
+} // namespace ns_3
+} // namespace ns_2
+
+/* Back in ns_1, should not locate the using-directive.  */
+
+void test_8 ()
+{
+  cout << "test"; // { dg-error "'cout' was not declared in this scope" }
+  // { dg-bogus "'<iostream>'" "" { target *-*-* } .-1 }
+}
+
+} // namespace ns_1
+
+/* using-directive in global namespace.  */
+using namespace std;
+
+void test_9 ()
+{
+  cout << "test"; // { dg-error "'cout' was not declared in this scope" }
+  // { dg-message "'std::cout' is defined in header '<iostream>'" "" { target *-*-* } .-1 }
+}
+