rust/src/test/compile-fail/borrowck-anon-fields-variant.rs

// Tests that we are able to distinguish when loans borrow different
// anonymous fields of an enum variant vs the same anonymous field.

enum Foo {
    X, Y(uint, uint)
}

fn distinct_variant() {
    let mut y = Y(1, 2);

    let a = match y {
      Y(ref mut a, _) => a,
      X => fail!()
    };

    let b = match y {
      Y(_, ref mut b) => b,
      X => fail!()
    };

    *a += 1;
    *b += 1;
}

fn same_variant() {
    let mut y = Y(1, 2);

    let a = match y {
      Y(ref mut a, _) => a,
      X => fail!()
    };

    let b = match y {
      Y(ref mut b, _) => b, //~ ERROR cannot borrow
      X => fail!()
    };

    *a += 1;
    *b += 1;
}

fn main() {
}