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Tracking issue for way to express intraprocedural finite state machines #132306
Description
This is a tracking issue for some form of:
The feature gate for the issue is #![feature(loop_match)].
From #138777:
This feature is based on rust-lang/rfcs#3720, though it does not exactly implement it. Rather, this is a language experiment to figure out how to impove that RFC. So, the RFC will eventually match the implementation we end up with, rather than the other way around.
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
- Approve as lang experiment.
- Accept an RFC.
- Implement in nightly.
- Add documentation to the dev guide.
- See the instructions.
- Add documentation to the reference.
- See the instructions.
- Add formatting for new syntax to the style guide.
- See the nightly style procedure.
- Stabilize.
- See the instructions.
Unresolved Questions
TODO.
Related
TODO.
cc @bjorn3 @folkertdev @rust-lang/lang
Activity
scottmcm commentedon Oct 29, 2024
I object under the phrasing as labelled matches. See rust-lang/rfcs#3720 (comment)
(I'm puzzled why an RFC open for less than a day got a tracking issue and label, TBH.)
traviscross commentedon Oct 29, 2024
Some form of this seemed particularly likely to me to yield a request for an experiment, especially as they already have implementation work, so the tracking issue was for a place to hang that.
[-]Tracking issue for labeled matches[/-][+]Tracking issue for way to express intraprocedural state machine[/+][-]Tracking issue for way to express intraprocedural state machine[/-][+]Tracking issue for way to express intraprocedural state machines[/+][-]Tracking issue for way to express intraprocedural state machines[/-][+]Tracking issue for way to express intraprocedural finite state machines[/+]#[loop_match]#138777 as a duplicate of this issueRollup merge of rust-lang#138780 - trifectatechfoundation:loop_match_…
Rollup merge of rust-lang#138780 - trifectatechfoundation:loop_match_…
Rollup merge of rust-lang#138780 - trifectatechfoundation:loop_match_…
Unrolled build for #138780
folkertdev commentedon Jul 1, 2025
@rustbot label +F-loop_match
19 remaining items
Auto merge of #144783 - folkertdev:loop-match-diverging-loop, r=Sparr…
Auto merge of #144783 - folkertdev:loop-match-diverging-loop, r=Sparr…
NobodyXu commentedon Sep 24, 2025
async-compression also has use of pattern of loop-match, would he interesting to see if this feature would improve its performance
https://github.com/Nullus157/async-compression/blob/main/crates/async-compression/src/tokio/write/generic/decoder.rs
Auto merge of #144783 - folkertdev:loop-match-diverging-loop, r=Sparr…
Auto merge of #144783 - folkertdev:loop-match-diverging-loop, r=Sparr…
Auto merge of #144783 - folkertdev:loop-match-diverging-loop, r=Sparr…
Auto merge of rust-lang#144783 - folkertdev:loop-match-diverging-loop…
Auto merge of rust-lang#144783 - folkertdev:loop-match-diverging-loop…
Auto merge of #144783 - folkertdev:loop-match-diverging-loop, r=Sparr…
Rollup merge of #143583 - folkertdev:loop-match-no-terminator-on-bloc…
Auto merge of #144783 - folkertdev:loop-match-diverging-loop, r=Sparr…
Auto merge of #144783 - folkertdev:loop-match-diverging-loop, r=Sparr…
Auto merge of #144783 - folkertdev:loop-match-diverging-loop, r=Sparr…
Evaluate `extern "tail"` and `#[loop_match]` against this design
Evaluate `extern "tail"` and `#[loop_match]` against this design