std::experimental::ranges:: Semiregular

From cppreference.com
template < class T >
concept bool Semiregular = Copyable < T > && DefaultConstructible < T > ;
(ranges TS)

The Semiregular concept specifies that a type is both copyable and default constructible. It is satisfied by types that behave similarly to built-in types like int , except that they need not support comparison with == .