src/tools/clippy/tests/ui/match_single_binding.rs

#![warn(clippy::match_single_binding)]
#![allow(clippy::no_effect, clippy::toplevel_ref_arg)]
#![expect(clippy::let_unit_value, clippy::useless_vec)]

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) {
        //~^ match_single_binding
        (x, y, z) => {
            println!("{x} {y} {z}");
        },
    }
    // Lint
    match (a, b, c) {
        //~^ match_single_binding
        (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 {
        //~^ match_single_binding
        _ => println!("whatever"),
    }
    // Lint
    match a {
        //~^ match_single_binding
        _ => {
            let x = 29;
            println!("x has a value of {x}");
        },
    }
    // Lint
    match a {
        //~^ match_single_binding
        _ => {
            let e = 5 * a;
            if e >= 5 {
                println!("e is superior to 5");
            }
        },
    }
    // Lint
    let p = Point { x: 0, y: 7 };
    match p {
        //~^ match_single_binding
        Point { x, y } => println!("Coords: ({x}, {y})"),
    }
    // Lint
    match p {
        //~^ match_single_binding
        Point { x: x1, y: y1 } => println!("Coords: ({x1}, {y1})"),
    }
    // Lint
    let x = 5;
    match x {
        //~^ match_single_binding
        ref r => println!("Got a reference to {r}"),
    }
    // Lint
    let mut x = 5;
    match x {
        //~^ match_single_binding
        ref mut mr => println!("Got a mutable reference to {mr}"),
    }
    // Lint
    let product = match coords() {
        //~^ match_single_binding
        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() {
            //~^ match_single_binding
            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"),
    }

    // Lint
    let x = 1;
    match x {
        //~^ match_single_binding
        // =>
        _ => println!("Not an array index start"),
    }
}

fn issue_8723() {
    let (mut val, idx) = ("a b", 1);

    val = match val.split_at(idx) {
        //~^ match_single_binding
        (pre, suf) => {
            println!("{pre}");
            suf
        },
    };

    let _ = val;
}

fn side_effects() {}

fn issue_9575() {
    let _ = || match side_effects() {
        //~^ match_single_binding
        _ => println!("Needs curlies"),
    };
}

fn issue_9725(r: Option<u32>) {
    match r {
        //~^ match_single_binding
        x => match x {
            Some(_) => {
                println!("Some");
            },
            None => {
                println!("None");
            },
        },
    };
}

fn issue_10447() -> usize {
    match 1 {
        //~^ match_single_binding
        _ => (),
    }

    let a = match 1 {
        //~^ match_single_binding
        _ => (),
    };

    match 1 {
        //~^ match_single_binding
        _ => side_effects(),
    }

    let b = match 1 {
        //~^ match_single_binding
        _ => side_effects(),
    };

    match 1 {
        //~^ match_single_binding
        _ => println!("1"),
    }

    let c = match 1 {
        //~^ match_single_binding
        _ => println!("1"),
    };

    let in_expr = [
        match 1 {
            //~^ match_single_binding
            _ => (),
        },
        match 1 {
            //~^ match_single_binding
            _ => side_effects(),
        },
        match 1 {
            //~^ match_single_binding
            _ => println!("1"),
        },
    ];

    2
}

fn issue14634() {
    macro_rules! id {
        ($i:ident) => {
            $i
        };
    }
    match dbg!(3) {
        _ => println!("here"),
    }
    //~^^^ match_single_binding
    match dbg!(3) {
        id!(a) => println!("found {a}"),
    }
    //~^^^ match_single_binding
    let id!(_a) = match dbg!(3) {
        id!(b) => dbg!(b + 1),
    };
    //~^^^ match_single_binding
}

mod issue14991 {
    struct AnnoConstWOBlock {
        inner: [(); match 1 {
            //~^ match_single_binding
            _n => 42,
        }],
    }

    struct AnnoConstWBlock {
        inner: [(); {
            match 1 {
                //~^ match_single_binding
                _n => 42,
            }
        }],
    }
}

mod issue15018 {
    fn used_later(a: i32, b: i32, c: i32) {
        let x = 1;
        match (a, b, c) {
            //~^ match_single_binding
            (x, y, z) => println!("{x} {y} {z}"),
        }
        println!("x = {x}");
    }

    fn not_used_later(a: i32, b: i32, c: i32) {
        match (a, b, c) {
            //~^ match_single_binding
            (x, y, z) => println!("{x} {y} {z}"),
        }
    }

    #[allow(irrefutable_let_patterns)]
    fn not_used_later_but_shadowed(a: i32, b: i32, c: i32) {
        match (a, b, c) {
            //~^ match_single_binding
            (x, y, z) => println!("{x} {y} {z}"),
        }
        let x = 1;
        println!("x = {x}");
    }

    #[allow(irrefutable_let_patterns)]
    fn not_used_later_but_shadowed_nested(a: i32, b: i32, c: i32) {
        match (a, b, c) {
            //~^ match_single_binding
            (x, y, z) => println!("{x} {x} {y}"),
        }
        if let (x, y, z) = (a, b, c) {
            println!("{x} {y} {z}")
        }

        {
            let x: i32 = 1;
            match (a, b, c) {
                //~^ match_single_binding
                (x, y, z) => println!("{x} {y} {z}"),
            }
            if let (x, y, z) = (a, x, c) {
                println!("{x} {y} {z}")
            }
        }

        {
            match (a, b, c) {
                //~^ match_single_binding
                (x, y, z) => println!("{x} {y} {z}"),
            }
            let fn_ = |y| {
                println!("{a} {b} {y}");
            };
            fn_(c);
        }
    }
}

#[allow(clippy::short_circuit_statement)]
fn issue15269(a: usize, b: usize, c: usize) -> bool {
    a < b
        && match b {
            //~^ match_single_binding
            b => b < c,
        };

    a < b
        && match (a, b) {
            //~^ match_single_binding
            (a, b) => b < c,
        }
}

#[allow(
    irrefutable_let_patterns,
    clippy::blocks_in_conditions,
    clippy::unused_unit,
    clippy::let_unit_value,
    clippy::unit_arg,
    clippy::unnecessary_operation
)]
fn issue15537(a: i32) -> ((), (), ()) {
    let y = (
        { todo!() },
        match { a } {
            //~^ match_single_binding
            _ => (),
        },
        (),
    );

    let y = [
        { todo!() },
        match { a } {
            //~^ match_single_binding
            _ => (),
        },
        (),
    ];

    fn call(x: (), y: (), z: ()) {}
    let y = call(
        { todo!() },
        match { a } {
            //~^ match_single_binding
            _ => (),
        },
        (),
    );

    struct Foo;
    impl Foo {
        fn method(&self, x: (), y: (), z: ()) {}
    }
    let x = Foo;
    x.method(
        { todo!() },
        match { a } {
            //~^ match_single_binding
            _ => (),
        },
        (),
    );

    -match { a } {
        //~^ match_single_binding
        _ => 1,
    };

    _ = match { a } {
        //~^ match_single_binding
        _ => 1,
    };

    if let x = match { a } {
        //~^ match_single_binding
        _ => 1,
    } {}

    if match { a } {
        //~^ match_single_binding
        _ => true,
    } {
        todo!()
    }

    [1, 2, 3][match { a } {
        //~^ match_single_binding
        _ => 1usize,
    }];

    todo!()
}