warning: missing documentation for the crate
  --> $DIR/check.rs:5:1
   |
LL | / #![feature(rustdoc_missing_doc_code_examples)]
LL | |
LL | |
LL | | #![warn(missing_docs)]
...  |
LL | | pub fn foo() {}
   | |_______________^
   |
note: the lint level is defined here
  --> $DIR/check.rs:8:9
   |
LL | #![warn(missing_docs)]
   |         ^^^^^^^^^^^^

warning: missing documentation for a function
  --> $DIR/check.rs:12:1
   |
LL | pub fn foo() {}
   | ^^^^^^^^^^^^

warning: no documentation found for this crate's top-level module
   |
   = help: The following guide may be of use:
           https://doc.rust-lang.org/$CHANNEL/rustdoc/how-to-write-documentation.html
note: the lint level is defined here
  --> $DIR/check.rs:10:9
   |
LL | #![warn(rustdoc::all)]
   |         ^^^^^^^^^^^^
   = note: `#[warn(rustdoc::missing_crate_level_docs)]` implied by `#[warn(rustdoc::all)]`

warning: missing code example in this documentation
  --> $DIR/check.rs:12:1
   |
LL | pub fn foo() {}
   | ^^^^^^^^^^^^^^^
   |
note: the lint level is defined here
  --> $DIR/check.rs:9:9
   |
LL | #![warn(rustdoc::missing_doc_code_examples)]
   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

warning: 4 warnings emitted