Viewing file:  concepts3.C (1010 B) -rw-r--r--
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// { dg-do compile { target c++20 } }
template <class T, class U> concept same_as = __is_same_as(T,U);
template<typename T>
concept C1 = requires (T& t) { // { dg-message "in requirements" }
t.~T();
};
template<typename T>
concept C2 = requires (T& t) { // { dg-message "in requirements" }
{ t.~T() } -> same_as<void>;
};
template<typename T>
concept C3 = requires { // { dg-message "in requirements" }
typename T::type;
};
class S1
{
~S1() { }
using type = int;
};
void driver() {
static_assert(C1<S1>, ""); // { dg-error "static assertion failed" }
static_assert(C2<S1>, ""); // { dg-error "static assertion failed" }
static_assert(C3<S1>, ""); // { dg-error "static assertion failed" }
}
template<typename T>
requires C1<T>
void f1() { }
template<typename T>
requires C2<T>
void f2() { }
template<typename T>
requires C3<T>
void f3() { }
void driver2() {
f1<S1>(); // { dg-error "no match" }
f2<S1>(); // { dg-error "no match" }
f3<S1>(); // { dg-error "no match" }
}
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