error: The tag of 'Two' collides with the tag of 'One'.
  --> tests/derive-serial/fail-forward-collide-with-inferred.rs:11:29
   |
11 |     #[concordium(forward = [0, 6])]
   |                             ^

error: The tag of 'One' collides with the tag of 'Two'.
 --> tests/derive-serial/fail-forward-collide-with-inferred.rs:8:5
  |
8 |     One {
  |     ^^^