mrdocs::swap

constexpr
void
swap(
    Error& lhs,
    Error& rhs) noexcept;

constexpr
void
swap(
    Expected& a,
    Expected& b) noexcept(noexcept(a.swap(b)))
requires requires { a.swap(b); };

constexpr
void
swap(
    Expected& x,
    Expected& y) noexcept(noexcept(x.swap(y)))
requires requires {x.swap(y);};

constexpr
void
swap(
    Polymorphic& lhs,
    Polymorphic& rhs) noexcept;

constexpr
void
swap(
    Unexpected& x,
    Unexpected& y) noexcept(noexcept(x.swap(y)))
requires std::is_swappable_v<E>;

template<class T>
constexpr
void
swap(
    Optional<T&>& a,
    Optional<T&>& b) noexcept;