Add a lint for Option::take on a temporary

[scottmcm]

What it does

(Inspired by Take() vs as_ref().take() on URLO.)

Lint when calling Option::take on a temporary, as when you have an owned temporary there's no need to take it -- you already have ownership, and you won't be able to see the None left behind, so the take can just be omitted.

Lint Name

option_take_on_temporary

Category

suspicious, complexity

Advantage

• Shorter code
• Less confusing to to reader

Drawbacks

None, so long as the temporary detection is accurate.

Example

fn main() {
    let x = Some(2);
    let y = x.as_ref().take();
}

Could be written as:

fn main() {
    let x = Some(2);
    let y = x.as_ref();
}

[b-ncMN]

@rustbot claim