--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gcc/testsuite/gcc.dg/c99-tag-2.c	Fri Oct 27 22:46:09 2017 +0900
@@ -0,0 +1,16 @@
+/* Test for handling of tags.  A struct defined in an inner scope does
+   not match one declared in an outer scope.  */
+/* Origin: Joseph Myers <jsm@polyomino.org.uk> */
+/* { dg-do compile } */
+/* { dg-options "-std=iso9899:1999 -pedantic-errors" } */
+
+struct s;
+struct t { struct s *p; } x;
+
+void
+f (void)
+{
+  /* This is a different struct s from the outer one.  */
+  struct s { int a; } y;
+  x.p = &y; /* { dg-error "incompatible" } */
+}