gistfile1.txt

impl y for option<int> {
    fn hi() { io::print("int"); }
}

impl x for option<uint> {
    fn hi() { io::print("uint"); }
}

fn to_uint(x: option<uint>) {}

fn main() {
    let x = none;
    x.hi();     // unifies x with <int>...
    to_uint(x); // ...thus failing here.
}