New lint: Prefer mem::take over Vec::split_off(0) · rust-lang/rust-clippy#4953

2019-12-25T04:28:07.000Z

```rust let mut vec = vec![1,2,3]; let vec2 = vec.split_off(0); ``` Should be written as ```rust let vec2 = std::mem::take(&mut vec); ```

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A-lintS-needs-discussiongood first issue

Description

let mut vec = vec![1,2,3];
let vec2 = vec.split_off(0);

Should be written as

let vec2  = std::mem::take(&mut vec);

Tech stack: rust
Domain: toolingdeveloper experience
Issue type: feature
Difficulty: 3
Estimated time: 1-3 hours
Activity status: blocked
Clarity: clear
Prerequisites: Rust syntaxclippy lint structure
Newbie friendliness: 30
Research direction: The issue requests a new lint to suggest using `std::mem::take` instead of `Vec::split off(0)`. The assignee is `andre digiexam` (see triagebot assignment). To implement, study existing lints in the `clippy lints` directory, particularly those that match method calls (e.g., `methods` module). Add a new lint pass, register it, and create test cases in `tests/ui`. The explanation and code examples in the issue provide clear before/after patterns.