--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gcc/testsuite/g++.dg/cpp2a/concepts-friend3.C	Thu Feb 13 11:34:05 2020 +0900
@@ -0,0 +1,23 @@
+// { dg-do compile { target concepts } }
+
+template <class T> concept True = true;
+
+template <True U> struct B { int i = ++U::x; };
+template <True U> void f() { ++U::x; }
+template <class U> void g() requires True<U> { ++U::x; }
+
+template <class V> class C
+{
+  static int x;
+
+  template <True U> friend struct B;
+  template <True U> friend void f();
+  template <class U> friend void g() requires True<U>;
+};
+
+int main()
+{
+  f<C<int>>();
+  g<C<int>>();
+  B<C<int>>();
+}