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1.98 beta regressions involving ambiguous glob imports #159432

Closed as not planned
Closed as not planned
1.98 beta regressions involving ambiguous glob imports#159432
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A-resolveArea: Name/path resolution done by `rustc_resolve` specificallyC-bugCategory: This is a bug.I-lang-nominatedNominated for discussion during a lang team meeting.I-lang-radarItems that are on lang's radar and will need eventual work or consideration.P-lang-drag-0Lang team prioritization drag level 0.https://rust-lang.zulipchat.com/#narrow/channel/410516-t-lang.T-compilerRelevant to the compiler team, which will review and decide on the PR/issue.T-langRelevant to the language teamregression-from-stable-to-betaPerformance or correctness regression from stable to beta.

Description

@theemathas
theemathas
opened on Jul 17, 2026

This regression was found by the 1.98 crater run.

[INFO] [stdout] error[E0659]: `SequenceNumber` is ambiguous
[INFO] [stdout]    --> /opt/rustwide/cargo-home/git/checkouts/ros2-client-a2a0f36ac41415ea/3cab61b/src/service/mod.rs:347:51
[INFO] [stdout]     |
[INFO] [stdout] 347 |       sequence_number_gen: atomic::AtomicI64::new(SequenceNumber::default().into()),
[INFO] [stdout]     |                                                   ^^^^^^^^^^^^^^ ambiguous name
[INFO] [stdout]     |
[INFO] [stdout]     = note: ambiguous because of multiple glob imports of a name in the same module
[INFO] [stdout] note: `SequenceNumber` could refer to the struct imported here
[INFO] [stdout]    --> /opt/rustwide/cargo-home/git/checkouts/ros2-client-a2a0f36ac41415ea/3cab61b/src/service/mod.rs:10:3
[INFO] [stdout]     |
[INFO] [stdout]  10 |   *,
[INFO] [stdout]     |   ^
[INFO] [stdout]     = help: consider adding an explicit import of `SequenceNumber` to disambiguate
[INFO] [stdout] note: `SequenceNumber` could also refer to the struct imported here
[INFO] [stdout]    --> /opt/rustwide/cargo-home/git/checkouts/ros2-client-a2a0f36ac41415ea/3cab61b/src/service/mod.rs:18:9
[INFO] [stdout]     |
[INFO] [stdout]  18 | pub use request_id::*;
[INFO] [stdout]     |         ^^^^^^^^^^^^^
[INFO] [stdout]     = help: consider adding an explicit import of `SequenceNumber` to disambiguate

This error looks like it plausibly could be intentionally caused by #149195. cc @petrochenkov @mu001999

Errors similar to the above error affect 30 crates that were not previously found by the above PR's crater run:

Affected crates

Activity

  1. theemathas
    added
    A-resolveArea: Name/path resolution done by `rustc_resolve` specifically
    T-compilerRelevant to the compiler team, which will review and decide on the PR/issue.
    regression-from-stable-to-betaPerformance or correctness regression from stable to beta.
    C-bugCategory: This is a bug.
    E-needs-bisectionCall for participation: This issue needs bisection: https://github.com/rust-lang/cargo-bisect-rustc
    E-needs-mcveCall for participation: This issue has a repro, but needs a Minimal Complete and Verifiable Example
    on Jul 17, 2026
  2. rustbot
    added
    needs-triageThis issue may need triage. Remove when done. See docs forge.rust-lang.org/release/issue-triaging
    I-prioritizeIssue needs a team member to assess the impact. Will be replaced by P-{low,medium,high,critical}
    on Jul 17, 2026
  3. theemathas
    added a parent issue on Jul 17, 2026

  4. petrochenkov commented on Jul 17, 2026

    @petrochenkov
    petrochenkov
    on Jul 17, 2026
    Contributor

    From a cursory look, everything looks like legitimate examples of ambiguous glob imports.
    The lint was reported for several years, most affected crates fixed it, but there's a long tail of outdated versions of the crates stuck in lock files.

  5. theemathas commented on Jul 17, 2026

    @theemathas
    theemathas
    on Jul 17, 2026
    ContributorAuthor

    Some more instances of this from the rustdoc crater run:

    Affected crates
  6. theemathas
    removed
    E-needs-bisectionCall for participation: This issue needs bisection: https://github.com/rust-lang/cargo-bisect-rustc
    E-needs-mcveCall for participation: This issue has a repro, but needs a Minimal Complete and Verifiable Example
    needs-triageThis issue may need triage. Remove when done. See docs forge.rust-lang.org/release/issue-triaging
    on Jul 17, 2026

  7. theemathas commented on Jul 25, 2026

    @theemathas
    theemathas
    on Jul 25, 2026
    ContributorAuthor

    My understanding of the state of this is: This is intended breakage. However, I find it a bit worrying that there are many instances of this that were not detected by the previous crater run (used to inform making that breakage) missed a lot of affected crates.

    Should this issue be closed, or should we get FCP from T-lang to affirm the intended breakage first?

  8. theemathas
    added
    T-langRelevant to the language team
    on Jul 25, 2026
  9. apiraino
    added
    I-compiler-nominatedNominated for discussion during a compiler team meeting.
    on Jul 27, 2026

  10. apiraino commented on Jul 30, 2026

    @apiraino
    apiraino
    on Jul 30, 2026
    Contributor

    Discussed during T-compiler triage.

    We are ok with these additional crates accepted as breakage but we want to be sure that also t-lang approves this result, since they were unexpected (see previous comment). Or at least why the rustdoc ones (see Guillaume's comment).

    One discriminating factor is whether this breaking change was behind a FCW for enough time. If this is the case, we're fine with this result. By reading this comment in #149195 it seems that it is (or should be the case, IIUC). @mejrs is trying to find out in #159901

    @rustbot label -I-compiler-nominated +I-lang-nominated

  11. rustbot
    added
    I-lang-nominatedNominated for discussion during a lang team meeting.
    and removed
    I-compiler-nominatedNominated for discussion during a compiler team meeting.
    on Jul 30, 2026

  12. mejrs commented on Jul 30, 2026

    @mejrs
    mejrs
    on Jul 30, 2026
    Member

    @mejrs is trying to find out in #159901

    I don't think it is related actually (but someone with more expertise should determine that), the pattern in #159901 has worked and still works unchanged.

    My comment in the triage meeting was more about the fact that this code exists in the compiler

    use rustc_span::Ident;

pub fn foo() {
    use rustc_ast::token::*; // Exports (private) `rustc_span::Ident;` and `rustc_ast::TokenKind::Ident`
    // use Ident
}

    yet a FCW was not issued in the local crate. So I'm wondering if we are missing more cases where a FCW should be issued.

  13. traviscross
    added
    I-lang-radarItems that are on lang's radar and will need eventual work or consideration.
    P-lang-drag-1Lang team prioritization drag level 1. https://rust-lang.zulipchat.com/#narrow/channel/410516-t-lang
    P-lang-drag-0Lang team prioritization drag level 0.https://rust-lang.zulipchat.com/#narrow/channel/410516-t-lang.
    and removed
    P-lang-drag-1Lang team prioritization drag level 1. https://rust-lang.zulipchat.com/#narrow/channel/410516-t-lang
    on Aug 5, 2026

  14. traviscross commented on Aug 5, 2026

    @traviscross
    traviscross
    on Aug 5, 2026
    Contributor

    We talked about this in the lang meeting with all members present. We're going to accept this breakage.

  15. theemathas
    closed this as not plannedon Aug 5, 2026
  16. apiraino
    removed
    I-prioritizeIssue needs a team member to assess the impact. Will be replaced by P-{low,medium,high,critical}
    on Aug 6, 2026
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    A-resolveArea: Name/path resolution done by `rustc_resolve` specificallyC-bugCategory: This is a bug.I-lang-nominatedNominated for discussion during a lang team meeting.I-lang-radarItems that are on lang's radar and will need eventual work or consideration.P-lang-drag-0Lang team prioritization drag level 0.https://rust-lang.zulipchat.com/#narrow/channel/410516-t-lang.T-compilerRelevant to the compiler team, which will review and decide on the PR/issue.T-langRelevant to the language teamregression-from-stable-to-betaPerformance or correctness regression from stable to beta.

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