Basic support for declarative attribute/derive macros#21121
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ChayimFriedman2 merged 2 commits intorust-lang:masterfrom Nov 24, 2025
Merged
Basic support for declarative attribute/derive macros#21121ChayimFriedman2 merged 2 commits intorust-lang:masterfrom
ChayimFriedman2 merged 2 commits intorust-lang:masterfrom
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Zalathar
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Nov 24, 2025
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| let res = match loc.def.kind { | ||
| MacroDefKind::Declarative(id, _) => db |
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For some reason rustfmt took this extra , _ as a reason to re-indent the entire match. 🤷♂️
ChayimFriedman2
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Nov 24, 2025
| }; | ||
| } | ||
| }; | ||
| pub(crate) fn macro_styles_from_id(db: &dyn DefDatabase, macro_id: MacroId) -> MacroCallStyles { |
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Since this can only return one style, a bit better to return MacroCallStyle.
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The second part of the function (after the early return for proc macros) can return multiple styles in the MacroExpander::Declarative case.
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This PR adds basic support for parsing and applying declarative attribute macros and declarative derive macros, which are supported by rustc behind the
#![feature(macro_attr)]and#![feature(macro_derive)]feature gates.This affects both
macro_rules!macros andmacro(macros 2.0) macros.One notable omission is that this PR does not properly support declarative attributes with attribute arguments, as that would require some additional plumbing that I haven't investigated yet, and my main priority is to get derives working. For now, argument-less attribute macros are basically a “free” bonus feature bundled with derive support.
This PR focuses on being able to expand declarative attribute/derive macros internally, so that any items produced by the expansion can be seen by IDE features (e.g. making derived items/impls visible to autocomplete). There might be other relevant IDE features that haven't been fully hooked up or fleshed out.
Fixes #21043 (mostly).
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