Tracking Issue for Rust 2024: Rescope temporary lifetimes with respect to `else`

traviscross commented 6 months ago

This is a tracking issue for shortening the scope of temporary lifetimes in if-let blocks to end before else. E.g.:

if let Some(x) = ref_cell.write().some_method_that_returns_option() {
} else {
    // question is whether the `ref_cell` is still write-locked here;
    // currently, it is, but it wouldn't be under this change
}

About tracking issues

Tracking issues are used to record the overall progress of implementation. They are also used as hubs connecting to other relevant issues, e.g., bugs or open design questions. A tracking issue is however not meant for large scale discussion, questions, or bug reports about a feature. Instead, open a dedicated issue for the specific matter and add the relevant feature gate label.

Steps

[x] Implement with a feature gate.
- https://github.com/rust-lang/rust/pull/107251
[x] Do a crater run to analyze impact.
- https://github.com/rust-lang/rust/pull/125151
- https://github.com/rust-lang/rust/pull/129466
  - https://github.com/rust-lang/cargo/pull/14447
[x] Decide to stabilize in Rust 2024.
- https://github.com/rust-lang/rust/issues/131154
[x] Stabilize in nightly Rust 2024.
- https://github.com/rust-lang/rust/pull/131984
[x] Implement migration lints.
N/A: Add documentation to the dev guide.
- See the instructions.
[ ] Add documentation to the reference.
- See the instructions.
[ ] Add documentation to the edition guide.
- https://github.com/rust-lang/edition-guide/pull/318
[ ] Ensure ready for Rust 2024 stabilization.

Unresolved Questions

TODO.

Implementation history

dingxiangfei2009 commented 6 months ago

@rustbot claim

dingxiangfei2009 commented 6 months ago

Update: #107251 has been repurposed for this edition change.

rust-lang / rust