fn main() {
    let x: u32 = 4;

    let equal_to_x = move |z: u32| z == x;

    println!("x: {x}");

    let y = 4;

    assert!(equal_to_x(y));
}

#[cfg(test)]
mod tests {
    #[test]
    #[ignore]
    fn closures_move_test() {
        let mut x = vec![1, 2, 3];

        // 所有权转移到闭包内了
        // let equal_to_x = move |z: Vec<i32>| z == x;

        let mut res: bool = false;
        let equal_to_x = |z: Vec<i32>| -> Vec<i32> {
            x.pop();
            res = z == x;
            x
        };

        let y = vec![1, 2, 3];

        x = equal_to_x(y);
        println!("can't use x here {:?}", x);

        assert!(res);
    }

    #[test]
    fn closures_mut_test() {
        let mut x = vec![1, 2, 3];

        let mut res: bool = false;
        let mut equal_to_x = |z: Vec<i32>| {
            x.pop();
            res = z == x;
        };

        let y = vec![1, 2, 3];
        equal_to_x(y);
        println!("can't use x here {:?}", x);

        assert!(false);
    }
}