| // Copyright 2012-4 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. |
| |
| // Tests that type assignability is used to search for instances when |
| // making method calls, but only if there aren't any matches without |
| // it. |
| |
| trait iterable<A> { |
| fn iterate<F>(&self, blk: F) -> bool where F: FnMut(&A) -> bool; |
| } |
| |
| impl<'a,A> iterable<A> for &'a [A] { |
| fn iterate<F>(&self, f: F) -> bool where F: FnMut(&A) -> bool { |
| self.iter().all(f) |
| } |
| } |
| |
| impl<A> iterable<A> for Vec<A> { |
| fn iterate<F>(&self, f: F) -> bool where F: FnMut(&A) -> bool { |
| self.iter().all(f) |
| } |
| } |
| |
| fn length<A, T: iterable<A>>(x: T) -> usize { |
| let mut len = 0; |
| x.iterate(|_y| { |
| len += 1; |
| true |
| }); |
| return len; |
| } |
| |
| pub fn main() { |
| let x: Vec<isize> = vec!(0,1,2,3); |
| // Call a method |
| x.iterate(|y| { assert_eq!(x[*y as usize], *y); true }); |
| // Call a parameterized function |
| assert_eq!(length(x.clone()), x.len()); |
| // Call a parameterized function, with type arguments that require |
| // a borrow |
| assert_eq!(length::<isize, &[isize]>(&*x), x.len()); |
| |
| // Now try it with a type that *needs* to be borrowed |
| let z = [0,1,2,3]; |
| // Call a parameterized function |
| assert_eq!(length::<isize, &[isize]>(&z), z.len()); |
| } |