Perfect forwarding

[Petar]

On Monday, 27 July 2020 at 14:08:30 UTC, Andrei Alexandrescu 
wrote:
> On 7/26/20 8:19 AM, Andrej Mitrovic wrote:
>> On Sunday, 26 July 2020 at 11:56:16 UTC, Jacob Carlborg wrote:
>>> On 2020-07-26 04:10, Andrei Alexandrescu wrote:
>>>
>>>> That needs fixed. What primitives would you need for that?
>>>
>>> It has already been implemented but rejected [1]. Andrei, you 
>>> were part of the discussions and approved the changes.
>>>
>>> [1] https://github.com/dlang/dmd/pull/5201
>> 
>> Ah, this was in the back of my head when someone mentioned 
>> template parameters.
>> 
>> I haven't looked at that in a long time.
>
> Well... would you like to revive it?

One question that was brought up recently by an unrelated DMD PR 
[1] was whether new traits require a DIP. None of the traits we 
added in the past few years have gone through the DIP process as 
far as I remember. Of course, going through the DIP process can 
only improve the quality, but on the other hand, one could argue 
that it would make things unnecessary hard for easy additions 
like isDeprecated [2] and isDisabled [3].

How high should the bar be? Should we decide on a case-by-case 
basis?

[1]: 
https://github.com/dlang/dmd/pull/11442#issuecomment-661996482
[2]: https://github.com/dlang/dmd/pull/7178
[3]: https://github.com/dlang/dmd/pull/7569