--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gcc/testsuite/g++.dg/overload/builtin5.C	Mon May 25 07:50:57 2020 +0900
@@ -0,0 +1,21 @@
+// { dg-do compile { target c++17 } }
+// Don't add built-in operator for ++ on bool.
+
+template<typename T>
+struct S { operator T&(); };
+
+template<int> void
+foo (S<bool>& s)
+{
+  --s; // { dg-error "no match for" }
+  ++s; // { dg-error "no match for" }
+  s++; // { dg-error "declared for postfix" }
+  s--; // { dg-error "declared for postfix" }
+}
+
+void
+bar ()
+{
+  S<bool> s;
+  foo<0> (s);
+}