A proposal paper to change the standard here would require two things at
minimum:
1. Strong motivation and compelling use-cases where this would be useful,
as well as considering alternatives
2. Discussion of implementations and impact of this change on possible
implementations

2 is relatively straightforward, 1 is lacking in the discussion so far.

Jeremy

On Mon, Dec 8, 2025 at 13:56 Nikl Kelbon via Std-Proposals <
std-proposals_at_[hidden]> wrote:

> Thats what standard exists for. Standard decides what is ub and what is
> not ub. How its even may be argument "its ub" in discussion about changing
> standard?
>
> пн, 8 дек. 2025 г. в 23:53, Jonathan Wakely <cxx_at_[hidden]>:
>
>>
>>
>> On Mon, 8 Dec 2025 at 18:42, Nikl Kelbon via Std-Proposals <
>> std-proposals_at_[hidden]> wrote:
>>
>>> About this:
>>>
>>> > There is no other container where getting an end iterator and
>>> inserting an element into the end of the container would *ever* leave
>>> that end iterator to be pointing to something valid. Not `list`, not
>>> `deque`
>>>
>>> https://godbolt.org/z/ndePjE9c6
>>>
>>> It works for deque. Its possible
>>>
>>
>> It's UB for deque as well though:
>> https://godbolt.org/z/6a7zo5Y5E
>>
>> --
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