Porting std.typecons to Phobos 3

[Adam Wilson]

On Saturday, 9 November 2024 at 05:32:38 UTC, Richard (Rikki) 
Andrew Cattermole wrote:
> I'm going to suggest that we avoid bringing over Tuple and 
> Nullable to PhobosV3.
>
> We don't need them currently, and they may have an 
> implementation in language by the time that we do.
>
> However, planning out how we might bring them over is a good 
> idea!

JMD needs them for Ranges, so we need them.

Furthermore, unless there is ongoing active programming work to 
get these into the language, frankly, we have absolutely no idea 
when they will land, it could be next year, it could be 10 years. 
If they land before Phobos 3 does we can re-evaluate, but until 
then we have to assume that we have to provide them as library 
types.