Proof of concept for v2 - NO duplication, NO `static if` hell, NO difficulty with interoperability

[Dukc]

On Wednesday, 3 November 2021 at 17:46:15 UTC, Andrei 
Alexandrescu wrote:
> There's no splitting. You get to use std or std2. New code 
> should use std2. Old code can migrate to std2. There's gotta be 
> two by the pigeonhole principle. I don't see how this can be 
> done otherwise.

It could be done by figuring out a way to use two Phobos versions 
side-by-side, for example 2.092 and 2.096. But your scheme has 
advantages over that so I'm still all in for `std2`.