use cmp::{Eq, Ord}; use num::from_int; pub trait NumExt: Eq, Ord, Num {} pub impl f32: NumExt {} fn num_eq_one(n: T) { io::println(fmt!("%?", n == from_int(1))) } fn main() { num_eq_one(1f32); // you need to actually use the function to trigger the ICE }