Unnecssary parenthesis lint

[bilelmoussaoui]

What it does

Currently, if the code contains unnecessary parenthesis, clippy doesn't warn the user about it. It would be nice if there was some new lint to detect these cases and warn the user about them.

Lint Name

No response

Category

style

Advantage

• Remove unnecessary parenthesis in the code

Drawbacks

No response

Example

fn new_rect(x: f64, y: f64, width: f64, height: f64) {
    println!("I am a rectangle ({x},{y}) ({width}, {height})");
}

fn main() {
    let x = 0f32;
    let y = 0f32;
    let width = 100f32;
    let height = 100f32;

    new_rect((x) as f64, (y) as f64, (width) as f64, (height) as f64);
}

Could be written as:

fn new_rect(x: f64, y: f64, width: f64, height: f64) {
    println!("I am a rectangle ({x},{y}) ({width}, {height})");
}

fn main() {
    let x = 0f32;
    let y = 0f32;
    let width = 100f32;
    let height = 100f32;

    new_rect(x as f64, y as f64, width as f64, height as f64);
}

[asquared31415]

rustc has an unused_parens lint, this might be a shortcoming of that lint. notably some_fn((x)) and let _ = (x); do have a warning triggered, so it might be something to do with being part of the as cast there?

Edit: it is not always possible to remove the parens in an as cast, for example removing the parentheses in (1 + 2) as f32 makes it stop compiling, since 1 + 2 as f32 parses as 1 + (2 as f32), which is {integer} + f32 and so presumably rustc doesn't attempt to check unused parens in this case, to be on the safe side.

[KisaragiEffective]

@rustbot claim