--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gcc/testsuite/g++.dg/concepts/equiv.C	Fri Oct 27 22:46:09 2017 +0900
@@ -0,0 +1,34 @@
+// { dg-options "-std=c++17 -fconcepts" }
+
+// Check equivalence of short- and longhand declarations.
+
+template<typename T>
+  concept bool C() { return __is_class(T); }
+
+template<typename T>
+  concept bool D() { return __is_empty(T); }
+
+struct X { } x;
+
+void f1(C x);
+template<C T> void f2(T x);
+void f3(C x);
+template<C T> void f4(T x) requires D<T>();
+template<C T> void f5(T x) requires D<T>();
+template<C T> void f6(T x) requires D<T>();
+
+int main() {
+  f1(x);
+  f2(x);
+  f3(x);
+  f4(x);
+  f5(x);
+  f6(x);
+}
+
+template<typename T> requires C<T>() void f1(T x) { }
+template<typename T> requires C<T>() void f2(T x) { }
+template<C T> void f3(T x) { }
+template<typename T> requires C<T>() void f4(T x) requires D<T>() { }
+template<typename T> requires C<T>() and D<T>() void f5(T x) { }
+template<typename T> void f6(T x) requires C<T>() and D<T>() { }