--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gcc/testsuite/g++.dg/warn/Wclass-conversion1.C	Thu Oct 25 07:37:49 2018 +0900
@@ -0,0 +1,19 @@
+// PR c++/87357
+// { dg-do compile }
+
+struct B { };
+
+struct X : public B {
+  operator X(); // { dg-warning "3:converting .X. to the same type will never use a type conversion operator" }
+  operator X&(); // { dg-warning "3:converting .X. to a reference to the same type will never use a type conversion operator" }
+  operator X() const; // { dg-warning "3:converting .X. to the same type will never use a type conversion operator" }
+  operator const X(); // { dg-warning "3:converting .X. to the same type will never use a type conversion operator" }
+
+  operator B(); // { dg-warning "3:converting .X. to a base class .B. will never use a type conversion operator" }
+  operator B&(); // { dg-warning "3:converting .X. to a reference to a base class .B. will never use a type conversion operator" }
+  operator B() const; // { dg-warning "3:converting .X. to a base class .B. will never use a type conversion operator" }
+  operator const B(); // { dg-warning "3:converting .X. to a base class .const B. will never use a type conversion operator" }
+
+  operator void(); // { dg-warning "3:converting .X. to .void. will never use a type conversion operator" }
+  operator void() const; // { dg-warning "3:converting .X. to .void. will never use a type conversion operator" }
+};