The argument should be made mutable instead of rebinding it to mutable.
贡献者指南
技术栈
rust
领域
toolingdeveloper experience
议题类型
feature
难度面向新贡献者的预计实现难度，1 表示很小改动，5 表示专家级工作。
3
预计时间有经验贡献者完成调查、实现、测试并准备 pull request 的粗略时间范围。
1-2 days
活动状态议题当前的可参与程度：新鲜、活跃、陈旧、阻塞或等待维护者输入。
stale
清晰度议题是否清楚说明期望改动、验收标准和下一步。
mostly clear
前置要求
basic Rustclippy lint structure
新手友好度1-100 的估计分数，表示该议题对首次贡献者的友好程度。
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.
