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Tracking Issue for pattern types (pattern_types) #123646

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1 of 2 issues completed
Open
Tracking Issue for pattern types (pattern_types)#123646
1 of 2 issues completed
Labels
B-experimentalBlocker: In-tree experiment; RFC pending, not yet approved or unneeded (requires FCP to stabilize).C-tracking-issueCategory: An issue tracking the progress of sth. like the implementation of an RFCF-pattern_types`#![feature(pattern_types)]`S-tracking-perma-unstableStatus: The feature will stay unstable indefinitely.T-langRelevant to the language teamT-typesRelevant to the types team, which will review and decide on the PR/issue.

Description

@oli-obk
oli-obk
opened on Apr 8, 2024

This is a tracking issue for the feature gate #![feature(pattern_types).

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. You can also start a thread on zulip in the pattern type stream

Steps

Unresolved Questions

  • Pattern type ranges cause monomorphization time errors on wraparound ranges (u8 is 10..5)
    • Same problems as having N + 2 in an array length for u8 is N..5 or even u8 is A..B
  • should we forbid full-range patterns like u8 is 0..?
  • Are pattern types always ABI compatible with their base type? Miri currently accepts them as ABI-compatible, we should either stably document that or remove this allowance from Miri.

Implementation history

Activity

  1. oli-obk
    added
    C-tracking-issueCategory: An issue tracking the progress of sth. like the implementation of an RFC
    on Apr 8, 2024
  2. fmease
    added
    T-typesRelevant to the types team, which will review and decide on the PR/issue.
    S-tracking-perma-unstableStatus: The feature will stay unstable indefinitely.
    F-pattern_types`#![feature(pattern_types)]`
    on Apr 8, 2024
  3. rust-lang
    locked as off topic and limited conversation to collaborators on Apr 10, 2024

  4. oli-obk commented on Apr 10, 2024

    @oli-obk
    oli-obk
    on Apr 10, 2024
    ContributorAuthor

    Tracking issues have a tendency to become unmanageable. Please open a dedicated new issue and label it with F-pattern_types for absolutely any topics you want to discuss or have questions about. See rust-lang/compiler-team#739 for details and discussions on this prospective policy.

  5. rust-lang
    unlocked this conversation on Apr 15, 2024
  6. oli-obk
    added this to pattern typeson May 25, 2024
  7. oli-obk
    moved this to Todo in pattern typeson May 25, 2024
  8. tgross35
    added a commit that references this issue on Aug 8, 2024

    Rollup merge of rust-lang#128800 - clarfonthey:core-pattern-type, r=c…

    36b9aee
  9. rust-timer
    added a commit that references this issue on Aug 8, 2024

    Unrolled build for rust-lang#128800

    0f72cba
  10. oli-obk
    added a sub-issue on Jan 24, 2025
  11. oli-obk
    added a sub-issue on Feb 5, 2025
  12. jieyouxu
    added
    T-langRelevant to the language team
    B-experimentalBlocker: In-tree experiment; RFC pending, not yet approved or unneeded (requires FCP to stabilize).
    on Feb 5, 2025

  13. 3 remaining items

  14. nikomatsakis
    moved this from Needs champion to Exploration in Lang team featureson Mar 5, 2025
  15. Zalathar
    added a commit that references this issue on Apr 15, 2025

    Rollup merge of rust-lang#138393 - oli-obk:pattern-type-in-pattern, r…

    a295c7e
  16. jieyouxu
    added a commit that references this issue on Apr 15, 2025

    Rollup merge of rust-lang#138393 - oli-obk:pattern-type-in-pattern, r…

    5a5bda9
  17. Zalathar
    added a commit that references this issue on Apr 15, 2025

    Rollup merge of rust-lang#138393 - oli-obk:pattern-type-in-pattern, r…

    aa9a80c
  18. rust-timer
    added a commit that references this issue on Apr 15, 2025

    Unrolled build for rust-lang#138393

    26b6b0a
  19. tgross35
    added a commit that references this issue on Apr 29, 2025

    Rollup merge of rust-lang#139909 - oli-obk:or-patterns, r=BoxyUwU

    a20fe8f
  20. rust-timer
    added a commit that references this issue on Apr 29, 2025

    Unrolled build for rust-lang#139909

    527f766
  21. flip1995
    added a commit that references this issue on May 1, 2025

    Rollup merge of #139909 - oli-obk:or-patterns, r=BoxyUwU

    6d58910

  22. cosmicexplorer commented on Jan 9, 2026

    @cosmicexplorer
    cosmicexplorer
    on Jan 9, 2026 · Hidden as resolved

  23. clarfonthey commented on Jan 9, 2026

    @clarfonthey
    clarfonthey
    on Jan 9, 2026 · Hidden as resolved

  24. yhx-12243 commented on May 30, 2026

    @yhx-12243
    yhx-12243
    on May 30, 2026 · Hidden as off-topic

  25. oli-obk commented on May 31, 2026

    @oli-obk
    oli-obk
    on May 31, 2026 · Hidden as off-topic
    Author
  26. RalfJung
    changed the title [-]Tracking Issue for pattern types[/-] [+]Tracking Issue for pattern types (`pattern_types`)[/+] on Aug 8, 2026
  27. JonathanBrouwer
    added a commit that references this issue on Aug 11, 2026

    Rollup merge of rust-lang#160775 - RalfJung:pattern-unsafe-transparen…

    fca480b
  28. rust-timer
    added a commit that references this issue on Aug 11, 2026

    Unrolled build for #160775

    b9301c5
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    B-experimentalBlocker: In-tree experiment; RFC pending, not yet approved or unneeded (requires FCP to stabilize).C-tracking-issueCategory: An issue tracking the progress of sth. like the implementation of an RFCF-pattern_types`#![feature(pattern_types)]`S-tracking-perma-unstableStatus: The feature will stay unstable indefinitely.T-langRelevant to the language teamT-typesRelevant to the types team, which will review and decide on the PR/issue.

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