rust-lang/rust-clippy

New lint: wildcard pattern in let

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#4,090 创建于 2019年5月13日

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 (9 评论) (0 反应) (0 负责人)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
}

贡献者指南

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rust
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toolingdeveloper experience
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feature
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Rust programmingClippy contribution basics
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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.