| // Test that we reliably check the value of the associated type. |
| |
| #![crate_type = "lib"] |
| #![no_implicit_prelude] |
| |
| use std::option::Option::{self, None, Some}; |
| use std::vec::Vec; |
| |
| trait Iterator { |
| type Item; |
| |
| fn next(&mut self) -> Option<Self::Item>; |
| } |
| |
| fn is_iterator_of<A, I: Iterator<Item=A>>(_: &I) {} |
| |
| struct Adapter<I> { |
| iter: I, |
| found_none: bool, |
| } |
| |
| impl<T, I> Iterator for Adapter<I> where I: Iterator<Item=Option<T>> { |
| type Item = T; |
| |
| fn next(&mut self) -> Option<T> { |
| loop {} |
| } |
| } |
| |
| fn test_adapter<T, I: Iterator<Item=Option<T>>>(it: I) { |
| is_iterator_of::<Option<T>, _>(&it); // Sanity check |
| let adapter = Adapter { iter: it, found_none: false }; |
| is_iterator_of::<T, _>(&adapter); // OK |
| is_iterator_of::<Option<T>, _>(&adapter); //~ ERROR type mismatch |
| } |