Skip to content

Tracking Issue for casefold #157000

Open
Open

Description

@Jules-Bertholet

Feature gate: #![feature(casefold)]

This is a tracking issue for Unicode-aware case folding APIs in the standard library. These APIs do not perform NFC/NFKC normalization.

Public API

// `core`

impl char {
    pub fn to_casefold_unnormalized(self) -> ToCasefold;
}

mod char {
    #[derive(Debug, Clone)]
    pub struct ToCasefold { … };
    impl Iterator for ToCasefold {
        type Item = char;
        …
    }
    impl DoubleEndedIterator for ToCasefold { … }
    impl FusedIterator for ToCasefold {}
    impl ExactSizeIterator for ToCasefold {}
    impl fmt::Display for ToCasefold { … }
}

impl str {
    pub fn eq_ignore_case_unnormalized(&self, other: &str) -> bool;
}
// `alloc`

impl str {
    pub fn to_casefold_unnormalized(&self) -> String;
}

Steps / History

(Remember to update the S-tracking-* label when checking boxes.)

Unresolved Questions

@rustbot label A-Unicode

Footnotes

  1. https://std-dev-guide.rust-lang.org/feature-lifecycle/stabilization.html ↩

Activity

  1. added
    T-libs-api[DEPRECATED; DO NOT USE]
    C-tracking-issueCategory: An issue tracking the progress of sth. like the implementation of an RFC
    on May 27, 2026
  2. added
    S-tracking-needs-to-bakeStatus: The implementation is "complete" but it needs time to bake.
    and removed on Jun 14, 2026
  3. added a commit that references this issue on Jul 28, 2026
  4. added a commit that references this issue on Jul 28, 2026
  5. added
    T-libsRelevant to the library team, which will review and decide on the PR/issue.
    and removed
    T-libs-api[DEPRECATED; DO NOT USE]
    on Aug 12, 2026
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment

Metadata

Metadata

Assignees

No one assigned

    Labels

    A-UnicodeArea: UnicodeC-tracking-issueCategory: An issue tracking the progress of sth. like the implementation of an RFCS-tracking-needs-to-bakeStatus: The implementation is "complete" but it needs time to bake.T-libsRelevant to the library team, which will review and decide on the PR/issue.

    Type

    No type

    Projects

    No projects

      Milestone

      No milestone

      Relationships

      None yet

      Development

      No branches or pull requests

      Issue actions