mut-in-ident-patterns.rs

//@ run-pass
#![allow(dead_code)]
#![allow(unused_assignments)]
#![allow(non_camel_case_types)]
#![allow(non_shorthand_field_patterns)]

trait Foo {
    fn foo(&self, mut x: isize) -> isize {
        let val = x;
        x = 37 * x;
        val + x
    }
}

struct X;
impl Foo for X {}

pub fn main() {
    let (a, mut b) = (23, 4);
    assert_eq!(a, 23);
    assert_eq!(b, 4);
    b = a + b;
    assert_eq!(b, 27);


    assert_eq!(X.foo(2), 76);

    enum Bar {
       Foo(isize),
       Baz(f32, u8)
    }

    let (x, mut y) = (32, Bar::Foo(21));

    match x {
        mut z @ 32 => {
            assert_eq!(z, 32);
            z = 34;
            assert_eq!(z, 34);
        }
        _ => {}
    }

    check_bar(&y);
    y = Bar::Baz(10.0, 3);
    check_bar(&y);

    fn check_bar(y: &Bar) {
        match y {
            &Bar::Foo(a) => {
                assert_eq!(a, 21);
            }
            &Bar::Baz(a, b) => {
                assert_eq!(a, 10.0);
                assert_eq!(b, 3);
            }
        }
    }

    fn foo1((x, mut y): (f64, isize), mut z: isize) -> isize {
        y = 2 * 6;
        z = y + (x as isize);
        y - z
    }

    struct A {
        x: isize
    }
    let A { x: mut x } = A { x: 10 };
    assert_eq!(x, 10);
    x = 30;
    assert_eq!(x, 30);

    (|A { x: mut t }: A| { t = t+1; t })(A { x: 34 });

}