About concern 10 (aka ES-047), please note that saying we discussed this
before does not solve the problem.

We have a problem. It is a problem for language teachability. It leads to
UB. Mitigations are just workarounds. There is no solution to that problem
at this point.

That might be acceptable for a white-paper or a Technical Specification.

In my humble opinion, this is not acceptable for an International Standard.

On Fri, Oct 17, 2025 at 1:07 PM Timur Doumler via SG21 <
sg21_at_[hidden]> wrote:

>
>
> On 17 Oct 2025, at 13:26, Daniela Engert via SG15 <sg15_at_[hidden]>
> wrote:
>
> It is. Otherwise you'd get UB with 'observe' contract evaluation semantics.
>
>
> See P3846R0 <https://wg21.link/p3846r0>, Concern 10 "Observing
> consecutive contract assertions is dangerous".
>
> With regards to why we allow pre and post to be evaluated multiple times,
> this is explained in quite some detail in P2899R1
> <https://wg21.link/p2899r1> Section 3.5.7. Also, Ville wrote a great
> motivation paper for this design decision a while ago that I recommend you
> check out: P3264R1 <https://wg21.link/p3264r1>.
>
>
> Hope this helps.
>
> Cheers,
> Timur
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