On Wed, Sep 22, 2021 at 4:20 AM Corentin via SG21 <sg21_at_[hidden]> wrote:
> On Wed, Sep 22, 2021 at 8:00 AM Jens Maurer via Liaison <liaison_at_[hidden]> wrote:
>>
>> On 21/09/2021 23.15, Uecker, Martin wrote:
>> > Am Dienstag, den 21.09.2021, 23:02 +0200 schrieb Jens Maurer:
>> >> On 21/09/2021 20.54, Uecker, Martin via Liaison wrote:
>> >>> Am Dienstag, den 21.09.2021, 10:06 -0700 schrieb Ryan McDougall:
>> >>>> It should *not* be ignorable in my opinion, because ignoring runs counter
>> >>>> to the purpose of the feature
>> >>>
>> >>> You mean that a compiler should not be allowed to ignore it
>> >>> when in "enforcing" mode and that a compiler that does not
>> >>> support this feature should fail during compilation? Correct?
>> >>
>> >> I think this "ignorable" discussion is misguided.
>> >>
>> >> As far as I understand, it is explicitly desired that all
>> >> conforming implementations diagnose syntactically ill-formed
>> >> precondition / postcondition expressions.
>> >
>> > But this is completely independent of
>> > the choice of the syntax.
>>
>> Yes.
>>
>> > Only for old compilers (i.e. then non-conforming to
>> > a new standard) it matters:
>>
>> Every new feature that comes with syntax changes is
>> likely unparsable for older compilers.
>> C99 VLAs, for example, are just errors in C89.
>>
>> I don't understand why we'd want to make a special
>> effort to accommodate older compilers for contracts
>> in particular, a major new language feature.
>
>
> +1.
> Please explain to me why we care in this specific context.
> Never have we promised that C++N code would do something sensible when compiled as C++(N-1)

WG21 does this routinely, as that is the expected outcome every time
we move something at plenary as a Defect Report.

~Aaron

>>
>>
>> Jens
>> _______________________________________________
>> Liaison mailing list
>> Liaison_at_[hidden]
>> Subscription: https://lists.isocpp.org/mailman/listinfo.cgi/liaison
>> Link to this post: http://lists.isocpp.org/liaison/2021/09/0756.php
>
> _______________________________________________
> SG21 mailing list
> SG21_at_[hidden]
> Subscription: https://lists.isocpp.org/mailman/listinfo.cgi/sg21
> Link to this post: http://lists.isocpp.org/sg21/2021/09/1207.php