On Thu, 24 Apr 2025 at 17:48, Andrey Semashev via Std-Proposals
<std-proposals_at_[hidden]> wrote:

> The value of the proposal would be standardizing the protocol for
> creating moved-from objects. This would be useful for generic
> programming, where the user would be able to create moved-from objects
> from any library that supports the protocol (whether it is the standard
> library or not).

How generic is that? If a type doesn't opt in, what happens? Is the
result ill-formed, or a well-formed break in the attempted generality
where you just won't get the benefits you thought you get?