error: you are iterating over `Iterator::next()` which is an Option; this will compile but is probably not what you want
  --> $DIR/for_loop_unfixable.rs:20:15
   |
LL |     for _v in vec.iter().next() {}
   |               ^^^^^^^^^^^^^^^^^
   |
   = note: `-D clippy::iter-next-loop` implied by `-D warnings`

error: aborting due to previous error