DIP1000: The return of 'Extend Return Scope Semantics'

[Dukc]

On Saturday, 29 May 2021 at 11:32:50 UTC, Dennis wrote:
> On Tuesday, 25 May 2021 at 11:24:59 UTC, Dennis wrote:
>> We want to express:
>> ```D
>> //                       ┌─────────>─────────┐
>> void move(T)(return T source, ref scope T target)
>> ```
>
> Here's a simple extension idea: 
> https://github.com/dlang/dmd/pull/12601
>
> Simply skip over `return` parameters when looking for the 
> 'first' parameter, since making a `return` parameter its own 
> destination has no use. It's still constraining the parameter 
> order, but may be good enough to move forward with `move`.

This is the way to go IMO.

The potential problem is that if we later on decide we need a 
more complex solution, it's going to be more complicated than if 
we do it now. So we kind of have to choose right away unless we 
want `move2`.

Still, ignoring return ref when choosing the output argument 
sounds the best compromise for me.