rust-lang/rustfmt

rustfmt eats attributes while formatting functions with variadic parameters

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#6,561 建立於 2025年5月11日

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 (3 留言) (0 反應) (0 負責人)Rust (4,893 star) (760 fork)batch import
C-buggood first issue

描述

If you format...

#[allow()]
unsafe extern "C" {
    #[allow()]
    pub fn foo(#[allow()] arg: *mut u8, #[allow()]...);
}

Then it will format into

#[allow()]
unsafe extern "C" {
    #[allow()]
    pub fn foo(#[allow()] arg: *mut u8, ...);
}

(The choice of attribute seems irrelevant, I've used allow because it compiles in any position).

Note that this position is explicitly documented at https://doc.rust-lang.org/nightly/reference/attributes.html#r-attributes.allowed-position

貢獻者指南

技術棧
rust
領域
toolingdeveloper experience
議題類型
bug
難度面向新貢獻者的預計實作難度，1 表示很小改動，5 表示專家級工作。
3
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half day
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fresh
清晰度議題是否清楚說明預期改動、驗收標準和下一步。
clear
前置要求
Basic Rust knowledgeUnderstanding of rustfmt internals
新手友善度1-100 的估計分數，表示該議題對首次貢獻者的友善程度。
35
研究方向
Investigate the formatting logic for variadic parameters in rustfmt, likely in the file `src/formatting/items.rs` or similar, where attributes are parsed and attached. The issue shows that attributes on the variadic parameter (`...`) are dropped. Check the code that handles function parameter attributes, particularly in the context of variadic arguments. The documentation at https://doc.rust lang.org/nightly/reference/attributes.html#r attributes.allowed position confirms that attributes are allowed on variadic parameters. Look for tests in the `tests/` directory that cover variadic functions to understand the expected behavior.
rustfmt eats attributes while formatting functions with variadic parameters · rust-lang/rustfmt#6561 | Good First Issue