rust-lang/rust-clippy

unused_lifetime false positive

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#2,678 opened on Apr 17, 2018

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 (12 comments) (0 reactions) (1 assignee)Rust (1,391 forks)batch import
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Description

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

Contributor guide

Research direction
Inspect the unused lifetime lint implementation in clippy lints/src/lifetimes.rs. Trace how it checks if a lifetime is used. Note that in unsafe functions, lifetimes may be used via raw pointers. Modify the logic to consider such usage.
Tech stack
rust
Domain
developer experience
Issue type
Bug
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
Half day
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
Active
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
Clear
Prerequisites
Rust
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
60