On Mon, 20 Oct 2025 at 14:36, Timur Doumler <cpp_at_[hidden]> wrote:

> P3846 is wrong, if it suggests that there's only three ways to address
> the problem. That's missing a
>
> 4) provide an assertion that cannot change its meaning based on build flags.
>
>
> That is not really an option 4, but rather a completely different feature, precisely because it loses the ability to change the semantic at build time. So really your option 4 is the same as my option 3: not standardise a feature that lets you change the semantic at build time.

It doesn't lose the ability you speak of, and is nothing at all like
your option 3, because when supplied alongside P2900, it easily
attenuates if not completely alleviates the concerns about plain
P2900. It's beyond me how many papers suggesting "you can have
that thing you want, but please also provide alternative option
so-and-so in the same shipping package, and not at some unknown time
in the future which may be never" need to be written before that sinks in.