rust-lang/rust-clippy

Lint for unused empty function value

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#15,957 建立於 2025年10月26日

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 (10 留言) (0 反應) (1 負責人)Rust (10,406 star) (1,391 fork)batch import
C-bugI-false-negativegood first issue

描述

What it does

Suggests turning let _unused = returns_nothing(); to returns_nothing();

Advantage

Increases code hygiene

Drawbacks

None

Example

let _unused: () = returns_nothing();

Could be written as:

returns_nothing();

Comparison with existing lints

No similar lints were found

Additional Context

A quick Github search shows around 116 thousand instances of the aforementioned example

貢獻者指南

技術棧
rust
領域
developer experience
議題類型
feature
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
預計時間有經驗貢獻者完成調查、實作、測試並準備 pull request 的粗略時間範圍。
half day
活動狀態議題目前的可參與程度：新鮮、活躍、陳舊、阻塞或等待維護者輸入。
blocked
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
Rust programmingclippy internalsAST manipulation
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。
20
研究方向
To implement this lint, study existing lints in clippy lints/src/ for patterns, especially those related to unused variables or expressions. The example shows a let binding with type (), so you need to detect let statements where the initializer's type is unit and the binding is unused (e.g., name starts with underscore). Check the Clippy documentation for adding a new lint and look at similar lints like 'let unit value'. The issue also provides a GitHub search showing many instances, which can help test the lint.
Lint for unused empty function value · rust-lang/rust-clippy#15957 | Good First Issue