The header <type_traits> has the following addition:
namespace std { template <class T> struct is_literal_type; template <class T> constexpr bool is_literal_type_v = is_literal_type<T>::value; }
Requires: remove_all_extents_t<T> shall be a complete type or (possibly cv-qualified) void.
Effects: is_literal_type has a base-characteristic of true_type if T is a literal type ([basic.types]), and a base-characteristic of false_type otherwise.