Volunteers wanted

  • We are looking for someone with access to an arm/musl system to help troubleshoot #60297

Backport nominations

  • Update LLVM submodule #64317

    • Approved for beta backport
  • fix nounwind attribute logic #63909

    • No conclusion reached yet. We’ll revisit next week.
  • pprust: Do not print spaces before some tokens #63897

    • Approved for beta backport

Working group sync


  • After a long hiatus, this working group is being rebooted with a focus on expanding Polonius coverage to include initialization checking and region subtyping in addition to borrow checking.

  • Work is also proceceeding on a book which will document the rules for Polonius. The hope is this will both make it easier to understand Polonius and also help make it easier for new contributors to get involved.

  • @Albin Stjerna is also working on a master’s thesis which overlaps with the Polonius work.

  • @Aaron Weiss and @nikomatsakis realized that there maybe opportunities to make Polonius more precise. Related video chat

  • @lqd has been working on a rustc compare mode which will check Polonius against the current borrow checker.

@Matthew Jasper and @lqd have made a number of fixes and cleanups so nearly all of the rustc tests pass under the Polonius compare-mode.

  • Some general performance work has been done but there’s more to do especially around large constants.

  • Some vocabularly is also being decided on.

Link to full discussion


  • RFC 2229 changes closures so they don’t capture entire variables, but rather subpaths.

  • @blitzerr has been working on a refactoring related to how closure substitutions work. This is mostly done but it’s hit some issues related to diagnostics and needs also needs to be rebased.

  • Work is ongoing.

Link to full discussion