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;
template <class> struct result_of; // not defined
template <class Fn, class... ArgTypes> struct result_of<Fn(ArgTypes...)>;
template <class T> using result_of_t = typename result_of<T>::type;
}Requires: For is_literal_type, remove_all_extents_t<T> shall be a complete type or cv void. For result_of<Fn(ArgTypes...)>, Fn and all types in the parameter pack ArgTypes shall be complete types, cv void, or arrays of unknown bound.
is_literal_type<T> is a UnaryTypeTrait ([meta.rqmts]) with a base characteristic of true_type if T is a literal type, and false_type otherwise. The partial specialization result_of<Fn(ArgTypes...)> is a TransformationTrait whose member typedef type is defined if and only if invoke_result<Fn, ArgTypes...>::type is defined. If type is defined, it names the same type as invoke_result_t<Fn, ArgTypes...>.