error: type parameter `T` is part of concrete type but not used in parameter list for the `impl Trait` type alias
  --> $DIR/issue-58887.rs:16:41
   |
LL |       fn unwrap_items(self) -> Self::Iter {
   |  _________________________________________^
LL | |
LL | |
LL | |         self.map(|x| x.unwrap())
LL | |     }
   | |_____^

error: type parameter `E` is part of concrete type but not used in parameter list for the `impl Trait` type alias
  --> $DIR/issue-58887.rs:16:41
   |
LL |       fn unwrap_items(self) -> Self::Iter {
   |  _________________________________________^
LL | |
LL | |
LL | |         self.map(|x| x.unwrap())
LL | |     }
   | |_____^

error: could not find defining uses
  --> $DIR/issue-58887.rs:13:5
   |
LL |     type Iter = impl Iterator<Item = T>;
   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

error: aborting due to 3 previous errors