rust-lang/rust-clippy

Lint `static mut FOO: T` where `T` has a safe counterpart

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#4070 opened on May 8, 2019

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 (5 comments) (0 reactions) (0 assignees)Rust (10,406 stars) (1,391 forks)batch import
A-lintL-correctnessgood first issue

Description

There is no reason to ever write static mut FOO: u32. Instead one should use static FOO: AtomicU32 which does the same thing, is just as efficient and requires no unsafe code.

We should lint this for at least

  • u8, u16, u32, u64
  • i8, i16, i32, i64
  • isize, usize
  • bool
  • *mut T

Contributor guide

Tech stack
rust
Domain
tooling
Issue type
feature
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.
1-2 days
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
stale
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
clear
Prerequisites
Rust knowledgeClippy development setup
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
70
Research direction
Implement a new lint in clippy that detects `static mut` with types that have safe atomic counterparts, specifically integer types, bool, and raw pointers. Look at existing lint implementations in the clippy source (e.g., `clippy lints/src/`) for patterns and register the new lint. Add tests to ensure correctness. The lint should suggest using `AtomicXxx` or `Cell` as appropriate.