tests/ui/issues/issue-21245.rs

   1 // check-pass
   2 #![allow(dead_code)]
   3 // Regression test for issue #21245. Check that we are able to infer
   4 // the types in these examples correctly. It used to be that
   5 // insufficient type propagation caused the type of the iterator to be
   6 // incorrectly unified with the `*const` type to which it is coerced.
   7
   8 // pretty-expanded FIXME #23616
   9
  10 use std::ptr;
  11
  12 trait IntoIterator {
  13     type Iter: Iterator;
  14
  15     fn into_iter2(self) -> Self::Iter;
  16 }
  17
  18 impl<I> IntoIterator for I where I: Iterator {
  19     type Iter = I;
  20
  21     fn into_iter2(self) -> I {
  22         self
  23     }
  24 }
  25
  26 fn desugared_for_loop_bad<T>(v: Vec<T>) {
  27     match IntoIterator::into_iter2(v.iter()) {
  28         mut iter => {
  29             loop {
  30                 match ::std::iter::Iterator::next(&mut iter) {
  31                     ::std::option::Option::Some(x) => {
  32                         unsafe { ptr::read(x); }
  33                     },
  34                     ::std::option::Option::None => break
  35                 }
  36             }
  37         }
  38     }
  39 }
  40
  41 fn desugared_for_loop_good<T>(v: Vec<T>) {
  42     match v.iter().into_iter() {
  43         mut iter => {
  44             loop {
  45                 match ::std::iter::Iterator::next(&mut iter) {
  46                     ::std::option::Option::Some(x) => {
  47                         unsafe { ptr::read(x); }
  48                     },
  49                     ::std::option::Option::None => break
  50                 }
  51             }
  52         }
  53     }
  54 }
  55
  56 fn main() {}