template<class T, class U, class C = common_reference_t<const T&, const U&>> concept comparison-common-type-with-impl = // exposition only same_as<common_reference_t<const T&, const U&>, common_reference_t<const U&, const T&>> && requires { requires convertible_to<const T&, const C&> || convertible_to<T, const C&>; requires convertible_to<const U&, const C&> || convertible_to<U, const C&>; }; template<class T, class U> concept comparison-common-type-with = // exposition only comparison-common-type-with-impl<remove_cvref_t<T>, remove_cvref_t<U>>;

Let C be common_reference_t<const T&, const U&>.

Let t1 and t2 be equality-preserving expressions that are lvalues of type remove_cvref_t<T>, and let u1 and u2 be equality-preserving expressions that are lvalues of type remove_cvref_t<U>.