Re: [boost] [variant2] documentation request

Subject: Re: [boost] [variant2] documentation request
From: Peter Dimov (lists_at_[hidden])
Date: 2019-03-03 03:17:38

> Andrzej Krzemienski wrote:
>
> > For instance, the variant's move assignment will sometimes use T's move 
> > assignment rather than move constructor when changing the variant's 
> > type, as in the following example:
> >
> > https://wandbox.org/permlink/GDRyS54bpdLP7GVa
>
> Interesting.
>
> Since the destructors and the move assignments are trivial, this variant 
> has a pseudo-trivial move constructor, that is, it does the equivalent of 
> memcpy.
>
> This however doesn't quite match the specification.
>
> I need to look into the latest changes to std::variant to see how it 
> handles triviality in this case.

Not surprisingly std::variant gets this correct and only trivially assigns 
when trivially constructible too. Should be fixed in 
https://github.com/pdimov/variant2/commit/fdfe9df167ea7a4356691c4c25dc14c1a92b15c7, 
thanks.