rust-lang/rust-clippy

Lint for .clone().into_boxed_str()

Open

#15,951 建立於 2025年10月25日

在 GitHub 查看
 (4 留言) (0 反應) (1 負責人)Rust (10,406 star) (1,391 fork)batch import
A-lintgood first issue

描述

What it does

Suggest turning s.clone().into_boxed_str() into Box::from(s.as_str()).

Possibly could be grouped together with other inefficient string conversions.

Advantage

Removes a call to __rust_realloc

Drawbacks

No response

Example

fn foo(s: &String) -> Box<str> {
    s.clone().into_boxed_str()
}

Could be written as:

fn foo(s: &String) -> Box<str> {
    Box::from(s.as_str())
}

Comparison with existing lints

redundant_clone generally doesn't consider the semantics of the

Additional Context

A GitHub search shows this unoptimal pattern is actually used fairly often.

貢獻者指南

技術棧
rust
領域
toolingperformance
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。
blocked
清晰度議題是否清楚說明預期改動、驗收標準和下一步。
clear
前置要求
Basic RustClippy lint developmentRust AST inspection
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。
50
研究方向
Examine existing lints like `redundant clone` in the clippy source at `clippy lints/src/` to understand the pattern. Look at how similar conversions are handled. The issue provides a clear pattern to detect: `x.clone().into boxed str()`. Check if there is an active assignee (the issue shows one assignee) and coordinate accordingly. The implementation should add a new lint or extend an existing one, with proper tests and documentation.