--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gcc/testsuite/g++.dg/ext/char8_t-overload-2.C	Thu Feb 13 11:34:05 2020 +0900
@@ -0,0 +1,26 @@
+// Test overloading for UTF-8 literals when -fchar8_t is in effect.
+// { dg-do compile }
+// { dg-options "-std=c++17 -fchar8_t" }
+
+template<typename T1, typename T2>
+  struct is_same
+  { static const bool value = false; };
+
+template<typename T>
+  struct is_same<T, T>
+  { static const bool value = true; };
+
+int fc(char);
+long fc(char8_t);
+static_assert(is_same<decltype(fc('x')), int>::value, "Error");
+static_assert(is_same<decltype(fc(u8'x')), long>::value, "Error");
+
+int fs(const char*);
+long fs(const char8_t*);
+static_assert(is_same<decltype(fs("x")), int>::value, "Error");
+static_assert(is_same<decltype(fs(u8"x")), long>::value, "Error");
+
+int fr(const char(&)[2]);
+long fr(const char8_t(&)[2]);
+static_assert(is_same<decltype(fr("x")), int>::value, "Error");
+static_assert(is_same<decltype(fr(u8"x")), long>::value, "Error");