Tracking issue for RFC 2229, "Closures Capture Disjoint Fields"

[Centril]

This is a tracking issue for the RFC "Closures Capture Disjoint Fields" (rust-lang/rfcs#2229).

Status

This is under active development by the wg-rfc-2229 compiler-team working group. You can track their progress on the project-rfc-2229 repository.

Implementation plan and status

See the RFC 2229 project board and milestones.

Links, see also

• RFC 2229 implementation plan compiler-team#292, a Major Change Proposal outlining an initial plan

Unresolved questions:

• How to optimize pointers. Can borrows that all reference parts of the same object be stored as a single pointer? How should this optimization be implemented (e.g. a special repr, refinement typing)?
• How to signal that a function is pure. Is this even needed/wanted? Any other places where the language could benefit?
• Should Box be special?
• Drop order can change as a result of this RFC, is this a real stability problem? How should this be resolved?

This issue has been assigned to @arora-aman via this comment.

[eddyb]

IIRC, this needs to wait for the new MIR (NLL) borrow-checker to replace the old one.
cc @rust-lang/wg-compiler-nll

[samsartor]

I would love to follow this through and give the code a shot, but it's probably too big of a first contribution to the compiler. Maybe I'll take a swing at some starter issues and then come back if no one else has gotten it done.

@eddyb Yes, this definitely should be built on NLL.