The argument should be made mutable instead of rebinding it to mutable.
貢獻者指南
技術棧
rust
領域
toolingdeveloper experience
議題類型
feature
難度面向新貢獻者的預計實作難度，1 表示很小改動，5 表示專家級工作。
3
預計時間有經驗貢獻者完成調查、實作、測試並準備 pull request 的粗略時間範圍。
1-2 days
活動狀態議題目前的可參與程度：新鮮、活躍、陳舊、阻塞或等待維護者輸入。
stale
清晰度議題是否清楚說明預期改動、驗收標準和下一步。
mostly clear
前置要求
basic Rustclippy lint structure
新手友善度1-100 的估計分數，表示該議題對首次貢獻者的友善程度。
40
研究方向
The issue proposes a new lint to detect `let mut x = x;` where `x` is a function parameter. The goal is to suggest making the parameter mutable directly in the function signature. To implement, study existing clippy lints like `mut mut` or similar patterns in the clippy source code. Look at the clippy documentation for adding a new lint, and consider potential false positives, e.g., when the function argument is used elsewhere or the rebinding is intentional. The implementation should check for function parameter bindings followed by an immediate `let mut` rebinding with the same name.
Lint `let mut x = x;` where `x` is a function argument · rust-lang/rust-clippy#1657 | Good First Issue
