error[E0405]: cannot find trait `OuterTrait` in this scope
  --> $DIR/issue-21221-3.rs:25:6
   |
25 | impl OuterTrait for Foo {}
   |      ^^^^^^^^^^ not found in this scope
   |
help: possible candidate is found in another module, you can import it into scope
   |
16 | use issue_21221_3::outer::OuterTrait;
   |

error: cannot continue compilation due to previous error