rust-lang / rust-lang/rust-clippy
Add lint: restriction `local_variable_unused_in_branch`
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A-lint
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- Rust
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Description
What it does
Extremely strict variables unused
Advantage
No response
Drawbacks
No response
Example
#[deny(clippy::local_variable_unused_in_branch)]
fn foo(id: u32) {
if id == 0 {
// used in condition
on_zero();
} else {
// unused in control flow branches, lint this
on_other();
}
}
Could written as:
#[deny(clippy::local_variable_unused_in_branch)]
fn foo(id: u32) {
if id == 0 {
// used in condition
on_zero();
} else {
// unused in control flow branches, lint this
let _ = id;
on_other();
}
}
Comparison with existing lints
No response
Additional Context
No response
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
The issue names the proposed local_variable_unused_in_branch lint but no source file or test. Start by locating existing Clippy lints for unused variables and control-flow branches, then compare their behavior with the Rust example. Done means the lint reports the shown branch case while accepting the explicit let _ = id; form.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- rust
- Domain
- devtools
- Issue type
- Feature
- Difficulty
- 5/5
- Estimated time
- Over a week
- Activity status
- Stale
- Clarity
- Mostly clear
- Newbie friendliness
- 25/100