--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gcc/testsuite/g++.dg/concepts/template-parm7.C	Fri Oct 27 22:46:09 2017 +0900
@@ -0,0 +1,44 @@
+// { dg-options "-std=c++17 -fconcepts" }
+
+template<typename... Ts> struct are_same;
+
+template<>
+  struct are_same<> {
+    static constexpr bool value = true;
+  };
+
+template<typename T>
+  struct are_same<T> {
+    static constexpr bool value = true;
+  };
+
+template<typename T, typename U, typename... Ts>
+  struct are_same<T, U, Ts...> {
+    static constexpr bool value =
+      __is_same_as(T, U) && are_same<U, Ts...>::value;
+  };
+
+constexpr bool all_of() { return true; }
+constexpr bool all_of(bool b) { return b; }
+
+template<typename... Ts>
+  constexpr bool all_of(bool a, bool b, Ts... args) {
+    return (a && b) && all_of(b, args...);
+  }
+
+
+template<typename... Ts>
+  concept bool C1 = are_same<Ts...>::value;
+
+template<bool... Bs>
+  concept bool C2 = all_of(Bs...);
+
+template<C1... Ts> struct S1 { }; // OK
+S1<int, int, char> s1; // { dg-error "constraint failure|invalid type" }
+template<C1 Ts> struct S2 { }; // { dg-error "variadic constraint"  }
+
+template<C2... Bs> struct S3 { }; // OK
+S3<true, true, false> s3; // { dg-error "constraint failure|invalid type" }
+template<C2 Bs> struct S4 { }; // { dg-error "variadic constraint" }
+
+int main() { }