68 lines
1.8 KiB
C++
68 lines
1.8 KiB
C++
|
// RUN: %clang_cc1 -std=c++2a -x c++ %s -verify
|
||
|
|
|
||
|
|
using A = int;
|
||
|
|
|
||
|
|
template<typename T, typename U>
|
||
|
|
constexpr bool is_same_v = false;
|
||
|
|
|
||
|
|
template<typename T>
|
||
|
|
constexpr bool is_same_v<T, T> = true;
|
||
|
|
|
||
|
|
template<typename T, typename U>
|
||
|
|
concept same_as = is_same_v<T, U>;
|
||
|
|
|
||
|
|
static_assert(requires { requires true; 0; typename A;
|
||
|
|
{ 0 } -> same_as<int>; });
|
||
|
|
static_assert(is_same_v<bool, decltype(requires { requires false; })>);
|
||
|
|
|
||
|
|
// Check that requires expr is an unevaluated context.
|
||
|
|
struct Y {
|
||
|
|
int i;
|
||
|
|
static constexpr bool r = requires { i; };
|
||
|
|
};
|
||
|
|
|
||
|
|
template<typename T> requires requires (T t) {
|
||
|
|
requires false; // expected-note{{because 'false' evaluated to false}}
|
||
|
|
requires false;
|
||
|
|
requires requires {
|
||
|
|
requires false;
|
||
|
|
};
|
||
|
|
}
|
||
|
|
struct r1 { };
|
||
|
|
|
||
|
|
using r1i = r1<int>;
|
||
|
|
// expected-error@-1 {{constraints not satisfied for class template 'r1' [with T = int]}}
|
||
|
|
|
||
|
|
template<typename T> requires requires (T t) {
|
||
|
|
requires requires {
|
||
|
|
requires false; // expected-note{{because 'false' evaluated to false}}
|
||
|
|
};
|
||
|
|
}
|
||
|
|
struct r2 { };
|
||
|
|
|
||
|
|
using r2i = r2<int>;
|
||
|
|
// expected-error@-1 {{constraints not satisfied for class template 'r2' [with T = int]}}
|
||
|
|
|
||
|
|
template<typename T> requires requires (T t) {
|
||
|
|
requires requires {
|
||
|
|
requires true;
|
||
|
|
};
|
||
|
|
requires true;
|
||
|
|
requires requires {
|
||
|
|
requires false; // expected-note{{because 'false' evaluated to false}}
|
||
|
|
};
|
||
|
|
}
|
||
|
|
struct r3 { };
|
||
|
|
|
||
|
|
using r3i = r3<int>;
|
||
|
|
// expected-error@-1 {{constraints not satisfied for class template 'r3' [with T = int]}}
|
||
|
|
|
||
|
|
template<typename T>
|
||
|
|
struct S { static const int s = T::value; };
|
||
|
|
|
||
|
|
template<typename T> requires requires { T::value; S<T>::s; }
|
||
|
|
// expected-note@-1 {{because 'T::value' would be invalid: type 'int' cannot be used prior to '::' because it has no members}}
|
||
|
|
struct r4 { };
|
||
|
|
|
||
|
|
using r4i = r4<int>;
|
||
|
|
// expected-error@-1 {{constraints not satisfied for class template 'r4' [with T = int]}}
|