22 General utilities library [utilities]

22.8 Expected objects [expected]

22.8.3 Class template unexpected [expected.unexpected]

22.8.3.5 Equality operator [expected.un.eq]

template<class E2> friend constexpr bool operator==(const unexpected& x, const unexpected<E2>& y);
Mandates: The expression x.error() == y.error() is well-formed and its result is convertible to bool.
Returns: x.error() == y.error().