error[E0405]: cannot find trait `T` in this scope
  --> $DIR/issue-21221-2.rs:28:6
   |
28 | impl T for Foo { }
   |      ^ not found in this scope
   |
   = help: possible candidate is found in another module, you can import it into scope:
             `use foo::bar::T;`

error: main function not found

error: cannot continue compilation due to previous error