--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gcc/testsuite/gcc.dg/Wcxx-compat-4.c	Fri Oct 27 22:46:09 2017 +0900
@@ -0,0 +1,49 @@
+/* { dg-do compile } */
+/* { dg-options "-Wc++-compat" } */
+enum E1 { A, B, C };
+enum E2 { D, E, F };
+
+enum E1 g1;
+enum E2 g2;
+
+void
+f1 ()
+{
+  int a;
+  int d;
+  enum E1 e1;
+  enum E2 e2;
+  a = A;
+  a = !B;
+  d = E;
+  e1 = A;
+  e1 = D;		/* { dg-warning "invalid in C\[+\]\[+\]" } */
+  e1 = 0;		/* { dg-warning "invalid in C\[+\]\[+\]" } */
+  e1 = (enum E1) 0;
+  e1 = (enum E2) 0;	/* { dg-warning "invalid in C\[+\]\[+\]" } */
+  e1 = e2;		/* { dg-warning "invalid in C\[+\]\[+\]" } */
+  e1 = g1;
+  e1 = g2;		/* { dg-warning "invalid in C\[+\]\[+\]" } */
+  e2 = A;		/* { dg-warning "invalid in C\[+\]\[+\]" } */
+  e2 = D;
+}
+
+struct s { enum E1 e1 : 3; };
+
+void
+f2 (struct s sv)
+{
+  sv.e1 = A;
+  sv.e1 = D;		/* { dg-warning "invalid in C\[+\]\[+\]" } */
+  g1 = sv.e1;
+  g2 = sv.e1;		/* { dg-warning "invalid in C\[+\]\[+\]" } */
+}
+
+void
+f3 (struct s *pv)
+{
+  pv->e1 = A;
+  pv->e1 = D;		/* { dg-warning "invalid in C\[+\]\[+\]" } */
+  g1 = pv->e1;
+  g2 = pv->e1;		/* { dg-warning "invalid in C\[+\]\[+\]" } */
+}