hoge.hpp

    template < class... Units1, template <class> class Synonym1, auto Value1,
               class... Units2, template <class> class Synonym2, auto Value2,
               std::enable_if_t<
                   is_same_dimensional_v<
                       dimensional_t<Units1...>,
                       dimensional_t<Units2...>>,
               bool> = false >
    inline constexpr auto
    operator+ (static_quantity_t<Synonym1<dimensional_t<Units1...>>, Value1>, static_quantity_t<Synonym2<dimensional_t<Units2...>>, Value2>) noexcept
        -> static_quantity_t<mitamagic::scaled_dimension_t<dimensional_t<Units1...>, dimensional_t<Units2...>>,
                             make_scaled_value<dimensional_t<Units1...>,
                                               dimensional_t<Units2...>,
                                               std::common_type_t<decltype(Value1), decltype(Value2)>,
                                               Value1, Value2, Add>()>
        { return {}; }