error: extern crate `bar` is unused in crate `deny_attr`
  --> $DIR/deny-attr.rs:6:1
   |
LL | #![deny(unused_crate_dependencies)]
   | ^
   |
   = help: remove the dependency or add `use bar as _;` to the crate root
note: the lint level is defined here
  --> $DIR/deny-attr.rs:6:9
   |
LL | #![deny(unused_crate_dependencies)]
   |         ^^^^^^^^^^^^^^^^^^^^^^^^^

error: aborting due to 1 previous error