Re: [boost] variant2 never empty guarantees (was: Re: Outcome/expected/etc/etc/etc)

Andrzej Krzemienski wrote:

If you are not doing double buffering, how can you guarantee that `emplace` is strong? You move the original to the side?

I could do that, but I construct on the side instead and move it into place. This is another instance where people may disagree because emplace should as a principle always construct in-place. But realistically, construct on the side + move is never inferior to move original to the side, construct in-place, optionally move original back if constructor throws.