#include <di/meta/compare.h>

Concept definition

template<typename T, typename U, typename Category partial_ordering>
concept di::concepts::ThreeWayComparableWith = 
    (detail::ComparesAs<meta::Type<detail::DefinitelyThreeWayComparableWith<T, T>>, Category>) ||
    (ThreeWayComparable<T> && ThreeWayComparable<U> && detail::WeaklyEqualityComparableWith<T, U> &&
     detail::PartiallyOrderedWith<T, U> && detail::WeaklyThreeWayComparableWith<T, U, Category>)