1 // { dg-do run { target c++17 } } 2 // { dg-options "-fconcepts" } 3 4 template<typename T> Class()5 concept bool Class () { return __is_class(T); } 6 7 struct Test { 8 void f(auto a) requires Class<decltype(a)>(); 9 } test; 10 11 struct S { }s; 12 main()13int main() { 14 test.f(s); 15 } 16 f(auto a)17void Test::f(auto a) requires Class<decltype(a)>() { } 18