error: needless `fn main` in doctest
  --> $DIR/needless_doc_main.rs:7:4
   |
LL | /// fn main() {
   |    ^^^^^^^^^^^^
   |
   = note: `-D clippy::needless-doctest-main` implied by `-D warnings`

error: needless `fn main` in doctest
  --> $DIR/needless_doc_main.rs:14:4
   |
LL | /// fn main() -> () {
   |    ^^^^^^^^^^^^^^^^^^

error: needless `fn main` in doctest
  --> $DIR/needless_doc_main.rs:21:4
   |
LL | /// fn main() {
   |    ^^^^^^^^^^^^

error: needless `fn main` in doctest
  --> $DIR/needless_doc_main.rs:28:4
   |
LL | /// fn main() {
   |    ^^^^^^^^^^^^

error: aborting due to 4 previous errors