That's patently untrue -- trying to change direction now is actually
wasting EWG time.

If you only care about Language Safety you should be ignoring P2900.

On Mon, Oct 20, 2025 at 1:28 PM JOSE DANIEL GARCIA SANCHEZ <
josedaniel.garcia_at_[hidden]> wrote:

> It is a matter of priorities.
>
>
>
> On Mon, Oct 20, 2025 at 10:23 PM Ryan McDougall <mcdougall.ryan_at_[hidden]>
> wrote:
>
>> It’s not an either or thing.
>>
>> That’s like saying “we haven’t decided if the goal of WG21 is object
>> oriented programming or structured programming”.
>>
>> On Mon, Oct 20, 2025 at 1:21 PM JOSE DANIEL GARCIA SANCHEZ <
>> josedaniel.garcia_at_[hidden]> wrote:
>>
>>> We have never (to the best of my knowledge) decided if the goal of WG21
>>> is functional safety or language safety.
>>>
>>> Let's keep in mind that there are external pressures to pursue language
>>> safety.In particular (but not only) memory safety.
>>>
>>>
>>> On Mon, Oct 20, 2025 at 10:08 PM Ryan McDougall via SG21 <
>>> sg21_at_[hidden]> wrote:
>>>
>>>> They are comparable because they both address the needs of Functional
>>>> Safety as per p3578 <http://wg21.link/p3578>. SG23 took a poll on
>>>> whether they're better than macros see P3297 <http://wg21.link/P3297>.
>>>>
>>>> I think it's not a leap of logic that EWG has strong consensus to pass
>>>> P2900 precisely because they feel it's strictly better than macros.
>>>>
>>>> Cheers,
>>>>
>>>> On Mon, Oct 20, 2025 at 12:58 PM John Spicer <jhs_at_[hidden]> wrote:
>>>>
>>>>> We have never taken a poll of whether P2900 is better then macro
>>>>> solutions.
>>>>>
>>>>> Could you explain why you think contracts and macro-based solutions
>>>>> are comperable?
>>>>>
>>>>> John.
>>>>>
>>>>> On Oct 20, 2025, at 3:09 PM, Ryan McDougall <mcdougall.ryan_at_[hidden]>
>>>>> wrote:
>>>>>
>>>>> I’m saying we have decades of experience with macro based systems,
>>>>> which defines the floor of features/expectations. The consensus is P2900 is
>>>>> better taken as a whole. There are things i think should be different with
>>>>> p2900, but p2900 represents consensus. There has been no evidence put
>>>>> forward that there is a more correct course. Based on those decades of
>>>>> experience here are no outstanding questions that having a TS would answer.
>>>>>
>>>>> If i am wrong, please list precise questions that a TS would answer.
>>>>> “We don’t have enough experience” is a statement.
>>>>>
>>>>> Cheers,
>>>>>
>>>>> On Mon, Oct 20, 2025 at 11:54 AM John Spicer <jhs_at_[hidden]> wrote:
>>>>>
>>>>>> You keep saying things like we have “decades of experience with
>>>>>> macro-based systems”.
>>>>>>
>>>>>> If contracts were remotely similar to macro-based systems, we would
>>>>>> not be having this discussion.
>>>>>>
>>>>>> The problem is that contracts are *vastly* different.
>>>>>>
>>>>>> If you put P2900 and macro-based systems in the same set, that means
>>>>>> you don’t understand one or the other.
>>>>>>
>>>>>> John.
>>>>>>
>>>>>> On Oct 20, 2025, at 2:22 PM, Ryan McDougall via SG21 <
>>>>>> sg21_at_[hidden]> wrote:
>>>>>>
>>>>>> The "course corrections" do not actually suggest a future course
>>>>>> (beyond asserting without evidence"we need more experience" and kicking the
>>>>>> can down the road to a TS) -- we've had years for alternative proposals to
>>>>>> be put forward, and none have surpassed P2900.
>>>>>>
>>>>>> We *do* have decades of experience with macro-based systems, we *do*
>>>>>> have decades of experience building software at scale (see Software
>>>>>> Engineering at Google <https://abseil.io/resources/swe-book>), and
>>>>>> we *do* know who our users are (see P1995 and P3297) -- and while there are
>>>>>> many variations on contracts, P2900 represents our best consensus
>>>>>> interpretation of those decades of experience. Not all of these decisions
>>>>>> were everyone's first choice, but P2900 is the consensus. There is no
>>>>>> evidence that any other option would improve that.
>>>>>>
>>>>>> Multiple papers, like P2900 and P3578 <http://wg21.link/p3578> explain
>>>>>> exactly who the feature is for, and how and why each of these design
>>>>>> choices were made. There is no reason to believe the current course is
>>>>>> incorrect, or that another course would be more correct.
>>>>>>
>>>>>> On Mon, Oct 20, 2025 at 4:58 AM Ville Voutilainen via SG21 <
>>>>>> sg21_at_[hidden]> wrote:
>>>>>>
>>>>>>> On Mon, 20 Oct 2025 at 14:34, Timur Doumler via SG15
>>>>>>> <sg15_at_[hidden]> wrote:
>>>>>>> > Given the above, it seems to me like opposing C++26 contract
>>>>>>> assertions because you want that checks are always on / always enforced is
>>>>>>> kinda like this:
>>>>>>> >
>>>>>>> > – Alice: "I want safer roads for pedestrians." (reasonable and
>>>>>>> good request)
>>>>>>> > – Bob: "Here's a proposal to fund bike lanes in the city."
>>>>>>> (reasonable and good proposal roughly in the same area but with a different
>>>>>>> goal)
>>>>>>> > – Alice: "But bike lanes don't add more crosswalks or reduce speed
>>>>>>> limits. So they don't make roads safer for pedestrians. Therefore, we
>>>>>>> should not build bike lanes."
>>>>>>> >
>>>>>>> > Here, Alice is committing a logical fallacy. Just because bike
>>>>>>> lanes are not useful for Alice, it doesn't mean that they're not useful for
>>>>>>> Bob, and taking away bike lanes from Bob does nothing to give Alice what
>>>>>>> she wants.
>>>>>>>
>>>>>>> The colorful analogy doesn't include considerations where providing
>>>>>>> bike lanes for Bob and doing nothing else is not entirely harmless
>>>>>>> for
>>>>>>> the pedestrians Alice is focused on.
>>>>>>>
>>>>>>> It's also incorrect in its suggestion that bike lanes are not useful
>>>>>>> for Alice. Nobody has said that P2900 isn't useful. That's why it's
>>>>>>> included
>>>>>>> in *every* *single* *one* of the currently active proposals
>>>>>>> suggesting
>>>>>>> course corrections.
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>>>>>>>
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>>>>>>
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