Ability to detach references or move semantics? about reference-types

[RossTate]

Cool. Will try to remember to follow up later. In the meanwhile, this probably is not an issue for the reference types proposal. The GC or Design proposals might be better fits.

[rossberg]

That would indeed be cool. I'm not aware of any prior discussion about it in the context of Wasm. However, as you guessed correctly, it would require a much more sophisticated type system, and such type systems are prone to be super-hard to combine with a variety of other features (cf. Rust and the decade-long quest to iron out the details of its semantics). It might also be difficult to target by compilers. Altogether very much a research problem -- which I'd be very curious to see somebody tackling.

[RossTate]

@lukewagner and I were chatting about something like this in the context of Interface Types. But rather than guarantee safety through static types (because, as @rossberg said, that requires fairly sophisticated types), we would guarantee it through dynamic means in a way that would interact well with memory management. Anyways, we were halfway through the conversation when I got distracted by deadlines outside of wasm, but maybe we'll have something to get your thoughts on later.

[lachlansneff]

@RossTate My initial thought was being able to convert an regular ref into an owning ref when there's just a single reference to the value, but I wasn't sure that's viable with a tracing garbage collector.

Agreeing with @rossberg here, a type system is a no go. But, that being said, I'd love to see discussion about dynamically enforcing this.

[rossberg]

I am closing this, since it is outside the scope of the current proposal. If there is enough interest, somebody should start a follow-up proposal.