rust-lang / rust-lang/rust-clippy

Lint `let mut x = x;` where `x` is a function argument

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A-lint good first issue L-unnecessary T-middle
Dominant language
Rust
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Avg merge
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Description

The argument should be made mutable instead of rebinding it to mutable.

Contributor guide

Open the contributing guide

First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Locate the Clippy lint implementation and its tests for let mut x = x; when x is a function argument. First inspect nearby lints for redundant rebinding, then add coverage showing that the argument should be declared mutable; done means the pattern is reported without affecting other rebinding cases.

Written by the indexing model from the issue text.

Assessment

Tech stack
rust
Domain
tooling
Issue type
Feature
Difficulty
3/5
Estimated time
1-2 days
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
35/100

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