Re: [boost] Strong guarantee variant (Was: Outcome/expected/etc/etc/etc)

Subject: Re: [boost] Strong guarantee variant (Was: Outcome/expected/etc/etc/etc)
From: Peter Dimov (lists_at_[hidden])
Date: 2017-06-06 11:14:55

Niall Douglas wrote:
> > I wonder whether the people who insist on the strong guarantee on 
> > assignment realize that when the variant holds a vector, and you assign 
> > it a vector, assignment delegates to vector<>::operator= and as a result 
> > you get the basic guarantee because that's what all standard types 
> > provide.
>
> I'd expect nothing else. No state change means you always pass through to 
> operator=().

I don't understand of what value is a guarantee that is strong when you 
change type, but basic if you don't, but perhaps I'm missing something here.