<mp-units/framework/quantity_point.h>
template<
ReferenceOf<PO._quantity_spec_> auto R1,
typename Rep1,
std::derived_from<quantity_point> QP>
[[nodiscard]]
constexpr
QuantityPoint auto
operator+(
quantity<R1, Rep1> const& q,
QP const& qp)
requires requires { q + qp.quantity_ref_from(PO); };