rustfmt eats attributes while formatting functions with variadic parameters

描述

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

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

贡献者指南

技术栈

rust

领域

toolingdeveloper experience

议题类型

bug

难度面向新贡献者的预计实现难度，1 表示很小改动，5 表示专家级工作。

3

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half day

活动状态议题当前的可参与程度：新鲜、活跃、陈旧、阻塞或等待维护者输入。

fresh

清晰度议题是否清楚说明期望改动、验收标准和下一步。

clear

前置要求

Basic Rust knowledgeUnderstanding of rustfmt internals

新手友好度1-100 的估计分数，表示该议题对首次贡献者的友好程度。

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.