24 Ranges library [ranges]

24.5 Range utilities [range.utility]

24.5.2 Helper concepts [range.utility.helpers]

Many of the types in subclause [range.utility] are specified in terms of the following exposition-only concepts: template<class R> concept simple-view = // exposition only view<R> && range<const R> && same_­as<iterator_t<R>, iterator_t<const R>> && same_­as<sentinel_t<R>, sentinel_t<const R>>; template<class I> concept has-arrow = // exposition only input_­iterator<I> && (is_pointer_v<I> || requires(I i) { i.operator->(); }); template<class T, class U> concept different-from = // exposition only !same_­as<remove_cvref_t<T>, remove_cvref_t<U>>;