warning: extern crate `barbar` is unused in crate `unused_aliases`
  --> $DIR/unused-aliases.rs:8:1
   |
LL | #![warn(unused_crate_dependencies)]
   | ^
   |
   = help: remove the dependency or add `use barbar as _;` to the crate root
note: the lint level is defined here
  --> $DIR/unused-aliases.rs:8:9
   |
LL | #![warn(unused_crate_dependencies)]
   |         ^^^^^^^^^^^^^^^^^^^^^^^^^

warning: 1 warning emitted