22 General utilities library [utilities]

22.8 Expected objects [expected]

22.8.7 Partial specialization of expected for void types [expected.void]

22.8.7.8 Equality operators [expected.void.eq]

template<class T2, class E2> requires is_void_v<T2> friend constexpr bool operator==(const expected& x, const expected<T2, E2>& y);
Mandates: The expression x.error() == y.error() is well-formed and its result is convertible to bool.
Returns: If x.has_value() does not equal y.has_value(), false; otherwise x.has_value() || static_cast<bool>(x.error() == y.error()).
template<class E2> friend constexpr bool operator==(const expected& x, const unexpected<E2>& e);
Mandates: The expression x.error() == e.error() is well-formed and its result is convertible to bool.
Returns: !x.has_value() && static_cast<bool>(x.error() == e.error()).