::static_assert<
    ::equal<
        ::difference<'C', 'A'>,
        ::sum<::difference<'B', 'A'>, ::difference<'B', 'A'>>
    >::value
>::commit;

::static_assert<::is_same<::remove_cv_t<::byte>, ::byte>::value>::commit;
::emit<::decltype(::difference<'B', 'A'>)>::commit;