Rust array corruption?

gistfile1.rs

struct Element {
    vals: &[float];
}

impl Element {
    fn test() {
        // Prints a random value close to, but not exactly equal to, 0.
        // e.g. 9.52676e-317, 1.43533e-316          
        // Optimization flags make it exactly 0.
        log(info, self.vals[0]);

        assert(self.vals[0] == 1.0); // Fails
        assert(self.vals[1] == 1.0);
        assert(self.vals[2] == 1.0);
        assert(self.vals[3] == 1.0);
    }
}

fn Element() -> Element {
    return Element {
        vals: &[1.0, 1.0, 1.0, 1.0]
    };
}

fn main() {
    let sprite = Element();
    sprite.test();
}