Iterating over Traits causes segfault on Linux! (rust 0.6)

bark.rs

extern mod std;

struct Dog {
	name : ~str
}

trait Barks {
        fn bark(&self) -> ~str;
}

impl Barks for Dog {
  fn bark(&self) -> ~str {
        let mut out = ~"woof! (I'm ";
        out = str::append(out, self.name);
        out = str::append(out, ~")");
        return out;
  }
}


fn main() {
        let snoopy = ~Dog{name: ~"snoopy"};
        let bubbles = ~Dog{name: ~"bubbles"};
        let barker = [snoopy as ~Barks, bubbles as ~Barks];

	for barker.each |pup| {
                println(fmt!("%s", pup.bark()));
	}
}

// Expected Output: "woof! (I'm snoopy)"
// > "woof! (I'm bubbles)"

// Actual Ouptut:
// "woof! (I'm snoopy)"
// SEGMENTATION FAULT