--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gcc/testsuite/gcc.dg/redecl-7.c	Fri Oct 27 22:46:09 2017 +0900
@@ -0,0 +1,23 @@
+/* Test for multiple declarations and composite types.  Diagnosis of
+   completion incompatible with implicit initializer.  */
+
+/* Origin: Joseph Myers <jsm@polyomino.org.uk> */
+/* { dg-do compile } */
+/* { dg-options "-g" } */
+
+int x[];
+
+void
+f (void)
+{
+  extern int x[2]; /* { dg-error "completed incompatibly" } */
+}
+
+/* The following is OK.  */
+
+int y[];
+void
+g (void)
+{
+  extern int y[1];
+}