version bump: 1.0.0 -> (breaking) -> 2.0.0
error: breaking changes in `<std::vec::Vec<T> as old::Abc>`
 --> trait_impls/old.rs:9:1
  |
9 | impl<T> Abc for Vec<T> { }
  | ^^^^^^^^^^^^^^^^^^^^^^
  |
  = warning: trait impl specialized or removed (breaking)

error: breaking changes in `<old::Def as std::clone::Clone>`
  --> trait_impls/old.rs:11:1
   |
11 | impl Clone for Def {
   | ^^^^^^^^^^^^^^^^^^
   |
   = warning: trait impl specialized or removed (breaking)

warning: technically breaking changes in `<std::boxed::Box<T> as new::Abc>`
  --> trait_impls/new.rs:11:1
   |
11 | impl<T: Clone> Abc for Box<T> { }
   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |
   = note: trait impl generalized or newly added (technically breaking)

warning: technically breaking changes in `<std::boxed::Box<new::Def> as new::Abc>`
  --> trait_impls/new.rs:13:1
   |
13 | impl Abc for Box<Def> { }
   | ^^^^^^^^^^^^^^^^^^^^^
   |
   = note: trait impl generalized or newly added (technically breaking)

warning: technically breaking changes in `<() as new::Abc>`
  --> trait_impls/new.rs:15:1
   |
15 | impl Abc for () { }
   | ^^^^^^^^^^^^^^^
   |
   = note: trait impl generalized or newly added (technically breaking)

warning: technically breaking changes in `<std::cell::Cell<(bool, T)> as new::Abc>`
  --> trait_impls/new.rs:17:1
   |
17 | impl<T> Abc for Cell<(bool, T)> { }
   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |
   = note: trait impl generalized or newly added (technically breaking)

error: aborting due to 2 previous errors; 4 warnings emitted