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

Andrzej Krzemienski wrote:

So, you mean -- unless I am using the special "valueless" type -- all assignments/emplacements/swaps are strong (possibly at the expense of double buffering in some cases)? That is, there is no "get C upon unsuccessful assignment of A to B"?

The only situation in which you get a C is when C is the special `valueless` type, yes. This does not mean that all assignments are strong. In variant v1, v2; v1 = v2; the assignment is basic, because that's the guarantee vector<string>::operator= gives.