The name crend denotes a customization point object ([customization.point.object]). The expression ranges::crend(E) for some subexpression E of type T is expression-equivalent to ranges::rend(static_cast<const T&>(E)).
Use of ranges::crend(E) with rvalue E is deprecated. [ Note: This deprecated usage exists so that ranges::crend(E) behaves similarly to std::crend(E) as defined in ISO/IEC 14882 when E is an rvalue. — end note ]
[ Note: Whenever ranges::crend(E) is a valid expression, the types of ranges::crend(E) and ranges::crbegin(E) satisfy Sentinel. — end note ]