Tracking Issue for RFC 3086: macro metavariable expressions

This is a tracking issue for the RFC "3086" (rust-lang/rfcs#3086). The feature gate for the issue is `#![feature(macro_metavar_expr)]`. ### About tracking issues Tracking issues are used to record the overall progress of implementation. They are also used as hubs connecting to other relevant issues, e.g., bugs or open design questions. A tracking issue is however *not* meant for large scale discussion, questions, or bug reports about a feature. Instead, open a dedicated issue for the specific matter and add the relevant feature gate label. ### Steps - [x] Implement the RFC (cc @markbt -- has there been work done here already?) - [ ] Adjust documentation ([see instructions on rustc-dev-guide][doc-guide]) - [ ] Stabilization PR ([see instructions on rustc-dev-guide][stabilization-guide]) [stabilization-guide]: https://rustc-dev-guide.rust-lang.org/stabilization_guide.html#stabilization-pr [doc-guide]: https://rustc-dev-guide.rust-lang.org/stabilization_guide.html#documentation-prs ### Unresolved questions and bugs - [ ] [Figure out problems around hygiene](https://github.com/rust-lang/rust/issues/83527#issuecomment-1073506711) ### Implementation history * 2022-02-25, [[1/2] Implement macro meta-variable expressions](https://github.com/rust-lang/rust/pull/94368) * 2022-03-11, [[2/2] Implement macro meta-variable expressions](https://github.com/rust-lang/rust/pull/94833) * 2022-03-12, [Fix remaining meta-variable expression TODOs](https://github.com/rust-lang/rust/pull/9

Posted by nikomatsakis on Mar 26, 2021, 7:50 PM

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• github (Software)

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