I have noticed the following circumstance that specifies rhs.error() be
copied instead of moved:

expected<T, E>& operator=(unexpected<G>&& e);

For the case !bool(*this), it says: "move assign unexpected(e.error()) to
unex"

I think it should be: "move assign unexpected(std::move(e.error())) to
unex", given the is_nothrow_move_constructible_v<E> constraint.

I'm guessing it's a copy-paste error, or am I missing something?

Reported here: https://github.com/viboes/std-make/issues/42

Cheers,
Emile Cormier