traits thing that doesn't work

gistfile1.txt

import dvec::dvec;


iface core_iter<A> {
    fn each2(blk: fn(A) -> bool);
}

impl core_iter<A> for option<A> {
    fn each2(f: fn(A) -> bool) {
        alt self {
          none { }
          some(a) { f(a); }
        }
    }
}

impl core_iter<A> for dvec<A> {
    fn each2(f: fn(A) -> bool) {
        import dvec::extensions;
        self.swap { |v| vec::each(v, f); v }
    }
}

impl extensions<A,IA:core_iter<A>> for IA {
    fn all2(blk: fn(A) -> bool) -> bool {
        for self.each2 {|a|
            if !blk(a) { ret false; }
        }
        ret true;
    }

    fn foldl2<B>(+b0: B, blk: fn(B, A) -> B) -> B {
        let mut b <- b0;
        for self.each2 {|a|
            b = blk(b, a);
        }
        ret b;
    }
}

fn main() {
    for some(5).each2() {|x|
        log(error, x);
    }
    //let z = some(5).foldl2(0, {|a, b| a + b});
    let z = some(5).all2() {|a| a == 5};
    log(error, z);
}