version bump: 1.0.0 -> (breaking) -> 2.0.0
error: breaking changes in `Def`
 --> addition_use/new.rs:5:1
  |
5 | pub struct Def<'a> {
  | ^^^^^^^^^^^^^^^^^^
  |
  = warning: type error: expected `()`, found struct `new::Abc` (breaking)
  = warning: type error: expected `()`, found trait object `dyn new::Bcd` (breaking)

error: aborting due to previous error