Have you tried proposing these API's on the internals.rust-lang.org forum or via posting a proposed RFC? It's not clear to me if they're sound in the general case, but if that's the case they can absolutely be added.
I should. I'm not too familiar with the process so far, but I'll find some time for it.
These functions are indeed generally sound (also for `Rc`), as any value that cares would be `!Unpin`, which would still bar access to `&mut T`.
`make_mut_pinned` also shouldn't cause too much confusion, as availability of `Clone` would have to be declared explicitly just about everywhere that's relevant.
They can be implemented as very thin wrappers around their non-pinning equivalents, with only a few `unsafe` operations to make the types fit.
> I should. I'm not too familiar with the process so far, but I'll find some time for it.
The internals forum is good for informal discussion, so start there. Posting a RFC proposal is of course the formal step for actually getting the feature included in Rust proper.
These functions are indeed generally sound (also for `Rc`), as any value that cares would be `!Unpin`, which would still bar access to `&mut T`. `make_mut_pinned` also shouldn't cause too much confusion, as availability of `Clone` would have to be declared explicitly just about everywhere that's relevant.
They can be implemented as very thin wrappers around their non-pinning equivalents, with only a few `unsafe` operations to make the types fit.