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

error: aborting due to previous error