Skip to content

specialization: default items completely drop candidates instead of ambiguity #105782

Closed
#130654
#121848
Closed
specialization: default items completely drop candidates instead of ambiguity#105782
#130654
#121848
Labels
A-coherenceArea: CoherenceA-specializationArea: Trait impl specializationA-trait-systemArea: Trait systemC-bugCategory: This is a bug.F-specialization`#![feature(specialization)]`I-unsoundIssue: A soundness hole (worst kind of bug), see: https://en.wikipedia.org/wiki/SoundnessS-bug-has-testStatus: This bug is tracked inside the repo by a `known-bug` test.T-compilerRelevant to the compiler team, which will review and decide on the PR/issue.T-typesRelevant to the types team, which will review and decide on the PR/issue.fixed-by-next-solverFixed by the next-generation trait solver, `-Znext-solver`.requires-nightlyThis issue requires a nightly compiler in some way. When possible, use a F-* label instead.

Description

@lcnr
lcnr
opened on Dec 16, 2022

which is unsound during coherence, as coherence requires completeness

#![feature(specialization)]

trait Default {
   type Id;
}

impl<T> Default for T {
   default type Id = T;
}

trait Overlap {
   type Assoc;
}

impl Overlap for u32 {
   type Assoc = usize;
}

impl Overlap for <u32 as Default>::Id {
   type Assoc = Box<usize>;
}

rust/compiler/rustc_trait_selection/src/traits/project.rs

Line 1526 in 03770f0

let eligible = match &impl_source {

Activity

  1. lcnr
    added
    A-trait-systemArea: Trait system
    I-unsoundIssue: A soundness hole (worst kind of bug), see: https://en.wikipedia.org/wiki/Soundness
    A-specializationArea: Trait impl specialization
    C-bugCategory: This is a bug.
    requires-nightlyThis issue requires a nightly compiler in some way. When possible, use a F-* label instead.
    F-specialization`#![feature(specialization)]`
    A-coherenceArea: Coherence
    on Dec 16, 2022
  2. Noratrieb
    added
    T-compilerRelevant to the compiler team, which will review and decide on the PR/issue.
    T-typesRelevant to the types team, which will review and decide on the PR/issue.
    on Apr 5, 2023
  3. matthiaskrgr
    added a commit that references this issue on Apr 27, 2023

    Rollup merge of rust-lang#110878 - whtahy:105107/known-bug-tests-for-…

    7e34afb
  4. jackh726
    added
    S-bug-has-testStatus: This bug is tracked inside the repo by a `known-bug` test.
    on Apr 27, 2023
  5. matthiaskrgr
    added a commit that references this issue on Apr 27, 2023

    Rollup merge of rust-lang#110878 - whtahy:105107/known-bug-tests-for-…

    1091a7a

  6. lcnr commented on Mar 5, 2024

    @lcnr
    lcnr
    on Mar 5, 2024
    ContributorAuthor

    when closing this issue, also add the test from #74299

  7. lcnr
    added
    fixed-by-next-solverFixed by the next-generation trait solver, `-Znext-solver`.
    on Mar 5, 2024
  8. bors
    added a commit that references this issue on Apr 23, 2024

    Auto merge of rust-lang#121848 - lcnr:stabilize-next-solver, r=<try>

    62bea82
  9. bors
    added a commit that references this issue on May 2, 2024

    Auto merge of rust-lang#121848 - lcnr:stabilize-next-solver, r=compil…

    26ba153
  10. bors
    added 3 commits that reference this issue on Aug 15, 2024

    Auto merge of rust-lang#121848 - lcnr:stabilize-next-solver, r=<try>

    3f9e86e

    Auto merge of rust-lang#121848 - lcnr:stabilize-next-solver, r=<try>

    a2cff3b

    Auto merge of rust-lang#121848 - lcnr:stabilize-next-solver, r=<try>

    cf34612
  11. bors
    added a commit that references this issue on Sep 6, 2024

    Auto merge of rust-lang#121848 - lcnr:stabilize-next-solver, r=compil…

    17b322f
  12. bors
    closed this as completedin 17b322fon Sep 6, 2024
  13. compiler-errors
    reopened this on Sep 11, 2024
  14. bors
    added a commit that references this issue on Sep 21, 2024

    Auto merge of rust-lang#130654 - lcnr:stabilize-coherence-again, r=<try>

    454f2fe
  15. bors
    added 3 commits that reference this issue on Oct 3, 2024

    Auto merge of rust-lang#130654 - lcnr:stabilize-coherence-again, r=<try>

    d017df7

    Auto merge of rust-lang#130654 - lcnr:stabilize-coherence-again, r=<try>

    86a8d60

    Auto merge of rust-lang#130654 - lcnr:stabilize-coherence-again, r=co…

    a0c2aba
  16. bors
    closed this as completedin a0c2abaon Oct 15, 2024
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-coherenceArea: CoherenceA-specializationArea: Trait impl specializationA-trait-systemArea: Trait systemC-bugCategory: This is a bug.F-specialization`#![feature(specialization)]`I-unsoundIssue: A soundness hole (worst kind of bug), see: https://en.wikipedia.org/wiki/SoundnessS-bug-has-testStatus: This bug is tracked inside the repo by a `known-bug` test.T-compilerRelevant to the compiler team, which will review and decide on the PR/issue.T-typesRelevant to the types team, which will review and decide on the PR/issue.fixed-by-next-solverFixed by the next-generation trait solver, `-Znext-solver`.requires-nightlyThis issue requires a nightly compiler in some way. When possible, use a F-* label instead.

    Type

    No type

    Projects

    No projects

      Milestone

      No milestone

      Relationships

      None yet

      Development

      No branches or pull requests

      Issue actions