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//@ run-pass
#![allow(non_camel_case_types)]
// 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());
}
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