error[E0271]: type mismatch resolving `for<'a> <<std::vec::Vec<T> as Iterable>::Iter<'a> as std::iter::Iterator>::Item == <std::vec::Vec<T> as Iterable>::Item<'a>`
  --> $DIR/iterable.rs:20:5
   |
LL | impl<T> Iterable for Vec<T> {
   | --------------------------- in this `impl` item
LL |     type Item<'a> where T: 'a = <std::slice::Iter<'a, T> as Iterator>::Item;
   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ expected reference, found associated type
   | 
  ::: $SRC_DIR/libcore/iter/traits/iterator.rs:LL:COL
   |
LL |     type Item;
   |          ---- associated type defined here
   |
   = note:    expected reference `&T`
           found associated type `<std::vec::Vec<T> as Iterable>::Item<'_>`
   = note: consider constraining the associated type `<std::vec::Vec<T> as Iterable>::Item<'_>` to `&_`
   = note: for more information, visit https://doc.rust-lang.org/book/ch19-03-advanced-traits.html

error[E0271]: type mismatch resolving `for<'a> <<[T] as Iterable>::Iter<'a> as std::iter::Iterator>::Item == <[T] as Iterable>::Item<'a>`
  --> $DIR/iterable.rs:32:5
   |
LL | impl<T> Iterable for [T] {
   | ------------------------ in this `impl` item
LL |     type Item<'a> where T: 'a = <std::slice::Iter<'a, T> as Iterator>::Item;
   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ expected reference, found associated type
   | 
  ::: $SRC_DIR/libcore/iter/traits/iterator.rs:LL:COL
   |
LL |     type Item;
   |          ---- associated type defined here
   |
   = note:    expected reference `&T`
           found associated type `<[T] as Iterable>::Item<'_>`
   = note: consider constraining the associated type `<[T] as Iterable>::Item<'_>` to `&_`
   = note: for more information, visit https://doc.rust-lang.org/book/ch19-03-advanced-traits.html

error[E0271]: type mismatch resolving `for<'a> <<std::vec::Vec<T> as Iterable>::Iter<'a> as std::iter::Iterator>::Item == <std::vec::Vec<T> as Iterable>::Item<'a>`
  --> $DIR/iterable.rs:24:30
   |
LL | trait Iterable {
   | -------------- required by `Iterable`
...
LL |     fn iter<'a>(&'a self) -> Self::Iter<'a> {
   |                              ^^^^^^^^^^^^^^ expected associated type, found reference
   |
   = note: expected associated type `<std::vec::Vec<T> as Iterable>::Item<'_>`
                    found reference `&T`
   = note: consider constraining the associated type `<std::vec::Vec<T> as Iterable>::Item<'_>` to `&_` or calling a method that returns `<std::vec::Vec<T> as Iterable>::Item<'_>`
   = note: for more information, visit https://doc.rust-lang.org/book/ch19-03-advanced-traits.html

error[E0271]: type mismatch resolving `for<'a> <<[T] as Iterable>::Iter<'a> as std::iter::Iterator>::Item == <[T] as Iterable>::Item<'a>`
  --> $DIR/iterable.rs:36:30
   |
LL | trait Iterable {
   | -------------- required by `Iterable`
...
LL |     fn iter<'a>(&'a self) -> Self::Iter<'a> {
   |                              ^^^^^^^^^^^^^^ expected associated type, found reference
   |
   = note: expected associated type `<[T] as Iterable>::Item<'_>`
                    found reference `&T`
   = note: consider constraining the associated type `<[T] as Iterable>::Item<'_>` to `&_` or calling a method that returns `<[T] as Iterable>::Item<'_>`
   = note: for more information, visit https://doc.rust-lang.org/book/ch19-03-advanced-traits.html

error: aborting due to 4 previous errors

For more information about this error, try `rustc --explain E0271`.