error[E0624]: method `private_method` is private
  --> $DIR/multiple-files.rs:7:35
   |
LL |     other_file::WithPrivateMethod.private_method();
   |                                   ^^^^^^^^^^^^^^ private method
   |
  ::: $DIR/auxiliary/other_file.rs:5:5
   |
LL |     fn private_method(&self) {}
   |     ^^^^^^^^^^^^^^^^^^^^^^^^ private method defined here
   |