Lint for useless tuple binding.

[cedws]

fn main() {
    let a = 1;
    
    match (a, 2) {
        (a, 2) => {},
        _ => {},
    }
}

The match (a, 2) can be reduced to just match 2, and the (a, 2) => {} can be reduced to 2 => {}.

[mati865]

The match (a, 2) can be reduced to just match 2

You meant match a?

[cedws]

Nope. Since we already have the variable a declared above, it's useless to define a binding for it in the match statement.

[cedws]

Some examples.

fn main() {
    let a = 1;
    
    match (a, 2) {
        (a, 2) => {},
        _ => {},
    }
}

should be reduced to

fn main() {
    let a = 1;
    
    match 2 {
        2 => {},
        _ => {},
    }
}

fn main() {
    let a = 1;
    
    match (a, 2) {
        (1, 2) => println!("{}", 1),
        // Useless tuple binding `a`, it's already been declared above. Can be replaced with `_`.
        (a, 2) => println!("{}", a),
    }
}

[camsteffen]

Related to if not the same as #7122