src/test/ui/proc-macro/macros-in-extern-derive.stderr

   1 error[E0774]: `derive` may only be applied to `struct`s, `enum`s and `union`s
   2   --> $DIR/macros-in-extern-derive.rs:2:5
   3    |
   4 LL |     #[derive(Copy)]
   5    |     ^^^^^^^^^^^^^^^ not applicable here
   6 LL |     fn f();
   7    |     ------- not a `struct`, `enum` or `union`
   8
   9 error: aborting due to previous error
  10
  11 For more information about this error, try `rustc --explain E0774`.