rust-lang/rust-clippy

New lint: wildcard pattern in let

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#4,090 建立於 2019年5月13日

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 (9 留言) (0 反應) (0 負責人)Rust (10,406 star) (1,391 fork)batch import
A-lintL-restrictiongood first issue

描述

I think there should be a warning about the wildcard pattern in let. I can't imagine any situation where this makes sense, and there are cases where it's a mistake caused by taking _ for identifier though it's not.

Wrong:

{
    let _ = my scope guard or whatever
    // dropped right away

    do stuff
}

Correct:

{
    let _g = my scope guard or whatever

    do stuff

    // dropped at the end of the scope
}

貢獻者指南

技術棧
rust
領域
toolingdeveloper 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。
1-2 days
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stale
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 contribution basics
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。
60
研究方向
The issue requests a new lint to warn against using the wildcard pattern ` ` in a `let` statement, which causes immediate drop of the bound value. To implement, study existing lint implementations in the `clippy lints` crate, e.g., the `let underscore` lint. Create a new lint file following the pattern, register it in the lint list, and add tests. The lint should detect `let = expr` and suggest using a named binding. See comments in the issue for further discussion on edge cases.