error: this loop could be written as a `for` loop
  --> $DIR/issue_2356.rs:15:29
   |
15 |         while let Some(e) = it.next() {
   |                             ^^^^^^^^^ help: try: `for e in it { .. }`
   |
note: lint level defined here
  --> $DIR/issue_2356.rs:1:9
   |
1  | #![deny(while_let_on_iterator)]
   |         ^^^^^^^^^^^^^^^^^^^^^

error: aborting due to previous error