src/test/ui/unknown-language-item.stderr

   1 error[E0522]: definition of an unknown language item: `foo`
   2   --> $DIR/unknown-language-item.rs:14:1
   3    |
   4 14 | #[lang = "foo"]
   5    | ^^^^^^^^^^^^^^^ definition of unknown language item `foo`
   6
   7 error: aborting due to previous error
   8