rust-lang/rust-clippy

unused_lifetime false positive

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#2,678 创建于 2018年4月17日

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 (12 评论) (0 反应) (1 负责人)Rust (10,406 star) (1,391 fork)batch import
C-enhancementgood first issue

描述

I'm using this type of stuff in a -sys-crate:

unsafe extern "C" fn callback<'a>(data: *mut c_void) {
    let _s = Box::from_raw(data as *mut S<'a>);
}

and this triggers unused_lifetime.

Playground with more context (also shows the #2677 issue): https://play.rust-lang.org/?gist=21a412537258ede9cbda42350501b90a&version=nightly

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rust
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developer experience
议题类型
bug
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前置要求
Rust programming language basicsUnderstanding of Rust lifetimes
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20
研究方向
The issue is a false positive for the `unused lifetime` lint in Clippy when a lifetime is used inside an `unsafe extern "C"` function via `Box::from raw`. Investigate the lint's logic in `clippy lints/src/unused lifetime.rs` (or similar path) to see why it incorrectly marks the lifetime as unused. Check existing tests and comments, especially referencing issue #2677. Consider whether the lint should account for lifetimes used in unsafe code that are not directly visible in the function signature. The playground link provides a minimal reproduction.
unused_lifetime false positive · rust-lang/rust-clippy#2678 | Good First Issue