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  "path": "/t/pre-pre-rfc-ability-to-specify-a-trait-as-marker-trait/24159#post_2",
  "publishedAt": "2026-04-08T23:04:37.000Z",
  "site": "https://internals.rust-lang.org",
  "tags": [
    "github.com/rust-lang/rust",
    "Tracking issue for allowing overlapping implementations for marker trait",
    "nikomatsakis"
  ],
  "textContent": "RFC'd and accepted over a decade ago.\n\ngithub.com/rust-lang/rust\n\n####  Tracking issue for allowing overlapping implementations for marker trait\n\nopened 05:09PM - 16 Nov 15 UTC\n\n\n\n          nikomatsakis\n        \n\nA-trait-system  T-lang  B-unstable  B-RFC-implemented  C-tracking-issue  F-marker_trait_attr  S-tracking-needs-to-bake  T-types  S-tracking-blocked\n\nTracking issue for rust-lang/rfcs#1268. ## Status - [x] Initial implementa…tion: #41309 - [ ] Documentation - [ ] Move to stabilize - [ ] Stabilization PR ## Known bugs - [ ] [cross-crate support lacking?](https://github.com/rust-lang/rust/issues/29864#issuecomment-295907958) - [x] #102360 ## History - initial implementation #41309 - https://github.com/rust-lang/rust/pull/53693 ## Prior to stabilization 1. Is it ok that adding items to a previously empty trait is a breaking change? Should we make declaring something a marker trait more explicit somehow? --> resolved by adding explicit `#[marker]` annotation, see https://github.com/rust-lang/rust/pull/53693 ## Other notes In #96766 we decided NOT to disable the orphan check for marker traits as part of this work (just the overlap check), which was a proposed extension.",
  "title": "[Pre-Pre RFC] Ability to specify a trait as marker trait"
}