18 Concepts library [concepts]

18.4 Language-related concepts [concepts.lang]

18.4.2 Concept same_­as [concept.same]

template<class T, class U> concept same-as-impl = is_same_v<T, U>; // exposition only template<class T, class U> concept same_­as = same-as-impl<T, U> && same-as-impl<U, T>;
[Note:
same_­as<T, U> subsumes same_­as<U, T> and vice versa.
— end note]