error[E0271]: type mismatch resolving `<TakeWhile<&mut std::vec::IntoIter<u8>, [closure@$DIR/issue-31173.rs:6:39: 6:43]> as Iterator>::Item == &_`
  --> $DIR/issue-31173.rs:10:10
   |
LL |         .cloned()
   |          ^^^^^^ expected reference, found `u8`
   |
   = note: expected reference `&_`
                   found type `u8`
note: required by a bound in `cloned`
  --> $SRC_DIR/core/src/iter/traits/iterator.rs:LL:COL
   |
LL |         Self: Sized + Iterator<Item = &'a T>,
   |                                ^^^^^^^^^^^^ required by this bound in `cloned`

error[E0599]: the method `collect` exists for struct `Cloned<TakeWhile<&mut std::vec::IntoIter<u8>, [closure@$DIR/issue-31173.rs:6:39: 6:43]>>`, but its trait bounds were not satisfied
  --> $DIR/issue-31173.rs:12:10
   |
LL |         .collect();
   |          ^^^^^^^ method cannot be called on `Cloned<TakeWhile<&mut std::vec::IntoIter<u8>, [closure@$DIR/issue-31173.rs:6:39: 6:43]>>` due to unsatisfied trait bounds
   |
  ::: $SRC_DIR/core/src/iter/adapters/cloned.rs:LL:COL
   |
LL | pub struct Cloned<I> {
   | -------------------- doesn't satisfy `_: Iterator`
   |
  ::: $SRC_DIR/core/src/iter/adapters/take_while.rs:LL:COL
   |
LL | pub struct TakeWhile<I, P> {
   | -------------------------- doesn't satisfy `<_ as Iterator>::Item = &_`
   |
   = note: the following trait bounds were not satisfied:
           `<TakeWhile<&mut std::vec::IntoIter<u8>, [closure@$DIR/issue-31173.rs:6:39: 6:43]> as Iterator>::Item = &_`
           which is required by `Cloned<TakeWhile<&mut std::vec::IntoIter<u8>, [closure@$DIR/issue-31173.rs:6:39: 6:43]>>: Iterator`
           `Cloned<TakeWhile<&mut std::vec::IntoIter<u8>, [closure@$DIR/issue-31173.rs:6:39: 6:43]>>: Iterator`
           which is required by `&mut Cloned<TakeWhile<&mut std::vec::IntoIter<u8>, [closure@$DIR/issue-31173.rs:6:39: 6:43]>>: Iterator`

error: aborting due to 2 previous errors

Some errors have detailed explanations: E0271, E0599.
For more information about an error, try `rustc --explain E0271`.