| // Copyright 2012 The Rust Project Developers. See the COPYRIGHT |
| // file at the top-level directory of this distribution and at |
| // http://rust-lang.org/COPYRIGHT. |
| // |
| // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or |
| // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license |
| // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your |
| // option. This file may not be copied, modified, or distributed |
| // except according to those terms. |
| |
| pub trait NumCast: Sized { |
| fn from(i: i32) -> Option<Self>; |
| } |
| |
| pub trait NumExt: PartialEq + PartialOrd + NumCast {} |
| |
| impl NumExt for f32 {} |
| impl NumCast for f32 { |
| fn from(i: i32) -> Option<f32> { Some(i as f32) } |
| } |
| |
| fn num_eq_one<T: NumExt>(n: T) { |
| println!("{}", n == NumCast::from(1).unwrap()) |
| } |
| |
| pub fn main() { |
| num_eq_one(1f32); // you need to actually use the function to trigger the ICE |
| } |
