rust-clippy/tests/ui/match_single_binding.rs

// run-rustfix

#![warn(clippy::match_single_binding)]
#![allow(unused_variables, clippy::toplevel_ref_arg)]

struct Point {
    x: i32,
    y: i32,
}

fn coords() -> Point {
    Point { x: 1, y: 2 }
}

macro_rules! foo {
    ($param:expr) => {
        match $param {
            _ => println!("whatever"),
        }
    };
}

fn main() {
    let a = 1;
    let b = 2;
    let c = 3;
    // Lint
    match (a, b, c) {
        (x, y, z) => {
            println!("{} {} {}", x, y, z);
        },
    }
    // Lint
    match (a, b, c) {
        (x, y, z) => println!("{} {} {}", x, y, z),
    }
    // Ok
    foo!(a);
    // Ok
    match a {
        2 => println!("2"),
        _ => println!("Not 2"),
    }
    // Ok
    let d = Some(5);
    match d {
        Some(d) => println!("{}", d),
        _ => println!("None"),
    }
    // Lint
    match a {
        _ => println!("whatever"),
    }
    // Lint
    match a {
        _ => {
            let x = 29;
            println!("x has a value of {}", x);
        },
    }
    // Lint
    match a {
        _ => {
            let e = 5 * a;
            if e >= 5 {
                println!("e is superior to 5");
            }
        },
    }
    // Lint
    let p = Point { x: 0, y: 7 };
    match p {
        Point { x, y } => println!("Coords: ({}, {})", x, y),
    }
    // Lint
    match p {
        Point { x: x1, y: y1 } => println!("Coords: ({}, {})", x1, y1),
    }
    // Lint
    let x = 5;
    match x {
        ref r => println!("Got a reference to {}", r),
    }
    // Lint
    let mut x = 5;
    match x {
        ref mut mr => println!("Got a mutable reference to {}", mr),
    }
    // Lint
    let product = match coords() {
        Point { x, y } => x * y,
    };
    // Lint
    let v = vec![Some(1), Some(2), Some(3), Some(4)];
    #[allow(clippy::let_and_return)]
    let _ = v
        .iter()
        .map(|i| match i.unwrap() {
            unwrapped => unwrapped,
        })
        .collect::<Vec<u8>>();
    // Ok
    let x = 1;
    match x {
        #[cfg(disabled_feature)]
        0 => println!("Disabled branch"),
        _ => println!("Enabled branch"),
    }

    // Ok
    let x = 1;
    let y = 1;
    match match y {
        0 => 1,
        _ => 2,
    } {
        #[cfg(disabled_feature)]
        0 => println!("Array index start"),
        _ => println!("Not an array index start"),
    }
    // False negative
    let x = 1;
    match x {
        // =>
        _ => println!("Not an array index start"),
    }
}