1*a0f50d73SSaar Raz // RUN: %clang_cc1 -std=c++2a -fconcepts-ts -x c++ %s -verify 2*a0f50d73SSaar Raz 3*a0f50d73SSaar Raz using A = int; 4*a0f50d73SSaar Raz 5*a0f50d73SSaar Raz template<typename T, typename U> 6*a0f50d73SSaar Raz constexpr bool is_same_v = false; 7*a0f50d73SSaar Raz 8*a0f50d73SSaar Raz template<typename T> 9*a0f50d73SSaar Raz constexpr bool is_same_v<T, T> = true; 10*a0f50d73SSaar Raz 11*a0f50d73SSaar Raz template<typename T, typename U> 12*a0f50d73SSaar Raz concept same_as = is_same_v<T, U>; 13*a0f50d73SSaar Raz 14*a0f50d73SSaar Raz static_assert(requires { requires true; 0; typename A; 15*a0f50d73SSaar Raz { 0 } -> same_as<int>; }); 16*a0f50d73SSaar Raz static_assert(is_same_v<bool, decltype(requires { requires false; })>); 17*a0f50d73SSaar Raz 18*a0f50d73SSaar Raz // Check that requires expr is an unevaluated context. 19*a0f50d73SSaar Raz struct Y { 20*a0f50d73SSaar Raz int i; 21*a0f50d73SSaar Raz static constexpr bool r = requires { i; }; 22*a0f50d73SSaar Raz }; 23*a0f50d73SSaar Raz 24*a0f50d73SSaar Raz template<typename T> requires requires (T t) { 25*a0f50d73SSaar Raz requires false; // expected-note{{because 'false' evaluated to false}} 26*a0f50d73SSaar Raz requires false; 27*a0f50d73SSaar Raz requires requires { 28*a0f50d73SSaar Raz requires false; 29*a0f50d73SSaar Raz }; 30*a0f50d73SSaar Raz } 31*a0f50d73SSaar Raz struct r1 { }; 32*a0f50d73SSaar Raz 33*a0f50d73SSaar Raz using r1i = r1<int>; 34*a0f50d73SSaar Raz // expected-error@-1 {{constraints not satisfied for class template 'r1' [with T = int]}} 35*a0f50d73SSaar Raz 36*a0f50d73SSaar Raz template<typename T> requires requires (T t) { 37*a0f50d73SSaar Raz requires requires { 38*a0f50d73SSaar Raz requires false; // expected-note{{because 'false' evaluated to false}} 39*a0f50d73SSaar Raz }; 40*a0f50d73SSaar Raz } 41*a0f50d73SSaar Raz struct r2 { }; 42*a0f50d73SSaar Raz 43*a0f50d73SSaar Raz using r2i = r2<int>; 44*a0f50d73SSaar Raz // expected-error@-1 {{constraints not satisfied for class template 'r2' [with T = int]}} 45*a0f50d73SSaar Raz 46*a0f50d73SSaar Raz template<typename T> requires requires (T t) { 47*a0f50d73SSaar Raz requires requires { 48*a0f50d73SSaar Raz requires true; 49*a0f50d73SSaar Raz }; 50*a0f50d73SSaar Raz requires true; 51*a0f50d73SSaar Raz requires requires { 52*a0f50d73SSaar Raz requires false; // expected-note{{because 'false' evaluated to false}} 53*a0f50d73SSaar Raz }; 54*a0f50d73SSaar Raz } 55*a0f50d73SSaar Raz struct r3 { }; 56*a0f50d73SSaar Raz 57*a0f50d73SSaar Raz using r3i = r3<int>; 58*a0f50d73SSaar Raz // expected-error@-1 {{constraints not satisfied for class template 'r3' [with T = int]}} 59*a0f50d73SSaar Raz 60*a0f50d73SSaar Raz template<typename T> 61*a0f50d73SSaar Raz struct S { static const int s = T::value; }; 62*a0f50d73SSaar Raz 63*a0f50d73SSaar Raz template<typename T> requires requires { T::value; S<T>::s; } 64*a0f50d73SSaar Raz // expected-note@-1 {{because 'T::value' would be invalid: type 'int' cannot be used prior to '::' because it has no members}} 65*a0f50d73SSaar Raz struct r4 { }; 66*a0f50d73SSaar Raz 67*a0f50d73SSaar Raz using r4i = r4<int>; 68*a0f50d73SSaar Raz // expected-error@-1 {{constraints not satisfied for class template 'r4' [with T = int]}}