Allocator-aware @safe reference counting is still not possible

[Paul Backus]

On Monday, 30 January 2023 at 17:51:52 UTC, Richard (Rikki) 
Andrew Cattermole wrote:
> Effectively @safe means as much code is machine checked, but we 
> want to isolate to library code the unsafe parts, where we 
> ensure those guarantees for what we can by auditing instead.

Yes; I assumed that this went without saying. Even with language 
features like an isolated qualifier to help us, it will still be 
necessary for the data structures and allocators to use @trusted 
code internally.

> So no I don't think we can have 1/2 without hiring some people, 
> but we can get close enough to it with what resources we do 
> have, just by telling people to not use something and push them 
> instead to use things that do offer it as long you don't do 
> something outright stupid (which lets face it, they probably 
> won't be using anything other than the default global 
> allocator).

I am afraid that this description is far too vague for me to 
understand what you have in mind here. Are you advocating for 
(1)+(3), (2)+(3), or maybe some hybrid of both? Like, if you use 
one of the Officially Blessed allocators, the container will be 
@safe, and if you use a 3rd-party custom allocator, it'll be 
@system?