rust-lang / rust-lang/rust-clippy
[lint request] lifetime_extending_transmute
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A-lint
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- Rust
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Description
Some people use "identity" transmutes to arbitrarily extend lifetimes, e.g.,
fn foo<'a>(x: &'a i32) -> &'static i32 {
unsafe { std::mem::transmute(x) }
}
We should warn on these. Sure, they aren't necessarily incorrect, but they are definitely suspicious.
Contributor guide
First steps
- Read the whole issue, then the project's contributing guide.
- Comment on the issue to say you are picking it up — it saves two people doing the same work.
- Fork the repository and make your change on a branch.
- Open a pull request that references the issue number.
Research direction
Start by locating Clippy's existing transmute-related lint entry points and tests, then inspect how the shown Rust example is represented by the type system. Done means the lifetime-extending identity transmute produces a warning as requested.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- rust
- Domain
- tooling
- Issue type
- Feature
- Difficulty
- 4/5
- Estimated time
- 3-5 days
- Activity status
- Stale
- Clarity
- Mostly clear
- Newbie friendliness
- 35/100