Re: [boost] [variant] Heads-up!

Subject: Re: [boost] [variant] Heads-up!
From: Steven Watanabe (watanabesj_at_[hidden])
Date: 2019-04-29 19:47:22

AMDG

On 4/29/19 1:08 PM, Antony Polukhin wrote:
> <snip>
> This discussion was considered. Please see the two comments from
> Nikita Kniazev https://github.com/boostorg/variant/pull/59#issuecomment-459573177
> 

>From the PR:
> The nullified recursive_wrapper is in a valid but unspecified state

Strictly speaking this is true, but it is
backwards incompatible because the state
was not valid in previous versions.

> Users may misinterpret "Never-Empty" Guarantee that was designed for throwing copy, and existed before move semantics. This is a documentation issue and can be easily be fixed.

I don't understand this.  Never-Empty means Never-Empty.
The meaning of the guarantee is based solely on what
constitutes a valid state of a variant.  How we get into
the empty state has no bearing on the matter.

In Christ,
Steven Watanabe