--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gcc/testsuite/gcc.dg/pr18596-1.c	Fri Oct 27 22:46:09 2017 +0900
@@ -0,0 +1,39 @@
+/* { dg-do compile } */
+/* { dg-options "-fno-unit-at-a-time -std=gnu89" } */
+
+int f(int i)
+{
+  static int g(); /* { dg-error "invalid storage class" } */
+  static int g() { return i; } /* { dg-error "invalid storage class" } */
+  return g();
+}
+
+int k (int i)
+{
+  static int g (); /* { dg-error "invalid storage class" } */
+  int g () {
+	return i;
+  }
+
+  return g ();
+}
+
+int l (int i)
+{
+  auto int g ();
+  static int g () { /* { dg-error "invalid storage class" } */
+    return i;
+  }
+
+  static int h () { /* { dg-error "invalid storage class" } */
+    return 3;
+  }
+  return g () + h ();
+}
+
+int m (int i)
+{
+  static g ();  /* { dg-error "invalid storage class" } */
+  static g () { return i; } /* { dg-error "invalid storage class" } */
+  return g ();
+}