error: `into_iter` call on an empty collection
  --> tests/ui/iter_on_empty_collections.rs:5:16
   |
LL |     assert_eq!([].into_iter().next(), Option::<i32>::None);
   |                ^^^^^^^^^^^^^^ help: try: `std::iter::empty()`
   |
   = note: `-D clippy::iter-on-empty-collections` implied by `-D warnings`
   = help: to override `-D warnings` add `#[allow(clippy::iter_on_empty_collections)]`

error: `iter_mut` call on an empty collection
  --> tests/ui/iter_on_empty_collections.rs:6:16
   |
LL |     assert_eq!([].iter_mut().next(), Option::<&mut i32>::None);
   |                ^^^^^^^^^^^^^ help: try: `std::iter::empty()`

error: `iter` call on an empty collection
  --> tests/ui/iter_on_empty_collections.rs:7:16
   |
LL |     assert_eq!([].iter().next(), Option::<&i32>::None);
   |                ^^^^^^^^^ help: try: `std::iter::empty()`

error: `into_iter` call on an empty collection
  --> tests/ui/iter_on_empty_collections.rs:8:16
   |
LL |     assert_eq!(None.into_iter().next(), Option::<i32>::None);
   |                ^^^^^^^^^^^^^^^^ help: try: `std::iter::empty()`

error: `iter_mut` call on an empty collection
  --> tests/ui/iter_on_empty_collections.rs:9:16
   |
LL |     assert_eq!(None.iter_mut().next(), Option::<&mut i32>::None);
   |                ^^^^^^^^^^^^^^^ help: try: `std::iter::empty()`

error: `iter` call on an empty collection
  --> tests/ui/iter_on_empty_collections.rs:10:16
   |
LL |     assert_eq!(None.iter().next(), Option::<&i32>::None);
   |                ^^^^^^^^^^^ help: try: `std::iter::empty()`

error: `iter` call on an empty collection
  --> tests/ui/iter_on_empty_collections.rs:28:66
   |
LL |     for i in smth.as_ref().map_or([].iter(), |s| s.iter()).chain([].iter()) {
   |                                                                  ^^^^^^^^^ help: try: `std::iter::empty()`

error: aborting due to 7 previous errors