18 Concepts library [concepts]

18.4 Language-related concepts [concepts.lang]

18.4.2 Concept Same [concept.same]

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