mp_units::operator+

[[nodiscard]]
constexpr
basic_fixed_string<CharT, 1 + N>
operator+(
    CharT const lhs,
    basic_fixed_string const& rhs) noexcept;

[[nodiscard]]
constexpr
basic_fixed_string<CharT, N + 1>
operator+(
    basic_fixed_string const& lhs,
    CharT rhs) noexcept;

template<std::size_t N2>
[[nodiscard]]
constexpr
basic_fixed_string<CharT, N + N2>
operator+(
    basic_fixed_string const& lhs,
    basic_fixed_string<CharT, N2> const& rhs) noexcept;

template<std::size_t N2>
[[nodiscard]]
consteval
basic_fixed_string<CharT, N + N2 ‐ 1>
operator+(
    basic_fixed_string const& lhs,
    CharT const(& rhs)[]) noexcept;

template<std::size_t N1>
[[nodiscard]]
consteval
basic_fixed_string<CharT, N1 + N ‐ 1>
operator+(
    CharT const(& lhs)[],
    basic_fixed_string const& rhs) noexcept;

template<
    std::derived_from<quantity> Q,
    RepresentationOf<quantity_spec> Value>
requires detail::DimensionlessOne<Q::reference> &&
             detail::InvokeResultOf<quantity_spec, std::plus<>, Rep, const Value&>
[[nodiscard]]
constexpr
Quantity auto
operator+(
    Q const& lhs,
    Value const& rhs);

template<
    std::derived_from<quantity> Q,
    RepresentationOf<quantity_spec> Value>
requires detail::DimensionlessOne<Q::reference> &&
             detail::InvokeResultOf<quantity_spec, std::plus<>, Rep, const Value&>
[[nodiscard]]
constexpr
Quantity auto
operator+(
    Value const& lhs,
    Q const& rhs);

template<
    std::size_t N2,
    std::size_t M2>
[[nodiscard]]
constexpr
symbol_text<N + N2, M + M2>
operator+(
    symbol_text const& lhs,
    symbol_text<N2, M2> const& rhs);

template<
    std::derived_from<quantity> Q,
    auto R2,
    typename Rep2>
requires detail::CommonlyInvocableQuantities<std::plus<>, quantity, quantity<R2, Rep2>>
[[nodiscard]]
constexpr
Quantity auto
operator+(
    Q const& lhs,
    quantity<R2, Rep2> const& rhs);

template<
    std::derived_from<quantity_point> QP,
    ReferenceOf<PO._quantity_spec_> auto R2,
    typename Rep2>
[[nodiscard]]
constexpr
QuantityPoint auto
operator+(
    QP const& qp,
    quantity<R2, Rep2> const& q)
requires requires { qp.quantity_ref_from(PO) + q; };

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); };