| #![allow(incomplete_features)] |
| #![feature(generic_associated_types)] |
| |
| // run-pass |
| |
| trait Iterable { |
| type Item<'a> where Self: 'a; |
| type Iter<'a>: Iterator<Item = Self::Item<'a>> where Self: 'a; |
| |
| fn iter<'a>(&'a self) -> Self::Iter<'a>; |
| } |
| |
| // Impl for struct type |
| impl<T> Iterable for Vec<T> { |
| type Item<'a> where T: 'a = <std::slice::Iter<'a, T> as Iterator>::Item; |
| type Iter<'a> where T: 'a = std::slice::Iter<'a, T>; |
| |
| fn iter<'a>(&'a self) -> Self::Iter<'a> { |
| self[..].iter() |
| } |
| } |
| |
| // Impl for a primitive type |
| impl<T> Iterable for [T] { |
| type Item<'a> where T: 'a = <std::slice::Iter<'a, T> as Iterator>::Item; |
| type Iter<'a> where T: 'a = std::slice::Iter<'a, T>; |
| |
| fn iter<'a>(&'a self) -> Self::Iter<'a> { |
| self.iter() |
| } |
| } |
| |
| fn make_iter<'a, I: Iterable + ?Sized>(it: &'a I) -> I::Iter<'a> { |
| it.iter() |
| } |
| |
| fn get_first<'a, I: Iterable + ?Sized>(it: &'a I) -> Option<I::Item<'a>> { |
| it.iter().next() |
| } |
| |
| fn main() { |
| let v = vec![1, 2, 3]; |
| assert_eq!(v, make_iter(&v).copied().collect::<Vec<_>>()); |
| assert_eq!(v, make_iter(&*v).copied().collect::<Vec<_>>()); |
| assert_eq!(Some(&1), get_first(&v)); |
| assert_eq!(Some(&1), get_first(&*v)); |
| } |