On 24 Apr 2025 17:21, Jonathan Wakely via Std-Proposals wrote:
> On Thu, 24 Apr 2025 at 14:57, Breno Guimarães via Std-Proposals
> <std-proposals_at_[hidden]> wrote:
>>
>> If the author of the class needs to implement the specialization for moved_from<T>, they might very well implement a constructor that takes a tag indicating it's a type for overwrite.
>> I don't get why this facility would help in any way
>
> Exactly. If you are able to modify the class to support a possible
> change to the language which might happen one day, you could modify
> the class today to not require such a change to the language. If you
> can't add such a constructor, you wouldn't be able to take advantage
> of a hypothetical language change either.

The value of the proposal would be standardizing the protocol for
creating moved-from objects. This would be useful for generic
programming, where the user would be able to create moved-from objects
from any library that supports the protocol (whether it is the standard
library or not).