Skip to content

associated type_consts can have defaults without the associated_type_defaults feature gate #130288

New issue
New issue
Closed
Closed
associated type_consts can have defaults without the associated_type_defaults feature gate#130288
Assignees
LaneAsade
Labels
A-const-genericsArea: const generics (parameters and arguments)C-bugCategory: This is a bug.F-gca_min_const_items`#![feature(gca_min_const_items)]` (previously: `min_generic_const_args`)T-compilerRelevant to the compiler team, which will review and decide on the PR/issue.

Description

@BoxyUwU
BoxyUwU
opened on Sep 12, 2024

The following is valid rust code:

#![feature(min_generic_const_args)

trait Trait {
    #[type_const]`
    const ASSOC: usize = 10;
}

We don't allow this for types, e.g. type Assoc = u32;. I expect associated type consts to have equivalent problems to associated type defaults given they are functionally equivalent in the type system. We should feature gate this under associated_type_defaults

Activity

  1. BoxyUwU
    added
    T-compilerRelevant to the compiler team, which will review and decide on the PR/issue.
    A-const-genericsArea: const generics (parameters and arguments)
    F-gca_min_const_items`#![feature(gca_min_const_items)]` (previously: `min_generic_const_args`)
    on Sep 12, 2024
  2. rustbot
    added
    needs-triageThis issue may need triage. Remove when done. See docs forge.rust-lang.org/release/issue-triaging
    on Sep 12, 2024
  3. BoxyUwU
    removed
    needs-triageThis issue may need triage. Remove when done. See docs forge.rust-lang.org/release/issue-triaging
    on Sep 12, 2024
  4. workingjubilee
    added
    C-bugCategory: This is a bug.
    on Feb 14, 2025
  5. BoxyUwU
    changed the title [-]Trait associated constants can have defaults while types cant[/-] [+]associated type_consts can have defaults without the `associated_type_defaults` feature gate[/+] on Feb 3, 2026

  6. LaneAsade commented on Feb 7, 2026

    @LaneAsade
    LaneAsade
    on Feb 7, 2026
    Member

    @rustbot claim

  7. rustbot
    assigned
    LaneAsade
    on Feb 7, 2026
  8. JonathanBrouwer
    added 3 commits that reference this issue on Feb 22, 2026

    Rollup merge of rust-lang#152385 - LaneAsade:gate-type-const-defaults…

    1bff785

    Rollup merge of rust-lang#152385 - LaneAsade:gate-type-const-defaults…

    60caefc

    Rollup merge of rust-lang#152385 - LaneAsade:gate-type-const-defaults…

    3880323
  9. rust-timer
    added a commit that references this issue on Feb 22, 2026

    Unrolled build for #152385

    2af7441

  10. fmease commented on Apr 6, 2026

    @fmease
    fmease
    on Apr 6, 2026
    Member

    This was fixed in PR #152385.

  11. fmease
    closed this as completedon Apr 6, 2026
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment

Metadata

Metadata

Assignees

Labels

A-const-genericsArea: const generics (parameters and arguments)C-bugCategory: This is a bug.F-gca_min_const_items`#![feature(gca_min_const_items)]` (previously: `min_generic_const_args`)T-compilerRelevant to the compiler 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