Reference functions in an impl

refer.rs

struct MyThing {
    val: int
}

impl MyThing {
    fn remove_first(s: &str) -> ~str {
        s.slice_from(1).to_owned()
    }

    fn remove_last(&self, s: &str) -> ~str {
        s.slice_to(s.len() - 1).to_owned()
    }
}


fn main() {
    let mt = MyThing{val: 42};
    let s1 = "abc";
    let r1 = mt.remove_last(s1);
    println(r1);
    
    let s2 = "123";
    let r2 = MyThing::remove_last("123");  error: first-class methods are not supported
    println(r2);
}