mp_units::value_cast

template<
    typename ToRep,
    Unit auto ToU,
    typename FwdQP,
    QuantityPoint QP = std::remove_cvref_t<FwdQP>>
requires (MP_UNITS_WEAK_UNIT_OF(MP_UNITS_REMOVE_CONST(decltype(ToU)), QP::quantity_spec)) &&
          RepresentationOf<ToRep, QP::quantity_spec> && std::constructible_from<ToRep, typename QP::rep> &&
          detail::SaneScaling<QP::unit, ToU, ToRep>
[[nodiscard]]
constexpr
QuantityPoint auto
value_cast(FwdQP&& qp);