1 // { dg-options "-std=c++17 -fconcepts" }
3 template <class T> concept bool Copyable = requires (T t) { T(t); };
4 template <class T> concept bool Constructable = requires { T(); };
5 template <class T> concept bool Both = Copyable<T> && Constructable<T>;
7 template <Copyable... Ts>
8 constexpr int f(Ts...) { return 0; } // #1
11 constexpr int f(Ts...) { return 1; } // #2
15 static_assert(f(42) == 1);