error[E0432]: unresolved import `issue_36881_aux`
  --> $DIR/issue-36881.rs:5:9
   |
LL |     use issue_36881_aux::Foo;
   |         ^^^^^^^^^^^^^^^ maybe a missing crate `issue_36881_aux`?
   |
   = help: consider adding `extern crate issue_36881_aux` to use the `issue_36881_aux` crate

error: aborting due to previous error

For more information about this error, try `rustc --explain E0432`.