--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gcc/testsuite/g++.dg/cpp0x/defaulted57.C	Thu Oct 25 07:37:49 2018 +0900
@@ -0,0 +1,25 @@
+// Core Issue #1331 (const mismatch with defaulted copy constructor)
+// { dg-do compile { target c++11 } }
+
+// If T2 (what would be the implicit declaration) has a parameter of
+// type const C&, the corresponding parameter of T1 may be of type C&.
+
+struct S
+{
+  S& operator=(S &) = default;
+};
+
+struct T
+{
+  T& operator=(volatile T &) = default; // { dg-error "defaulted" }
+};
+
+struct U
+{
+  U& operator=(const volatile U &) = default; // { dg-error "defaulted" }
+};
+
+struct V
+{
+  V& operator=(const V &) = default;
+};