version bump: 1.0.0 -> (breaking) -> 2.0.0
error: breaking changes in `abc`
 --> infer_regress/new.rs:1:1
  |
1 | pub fn abc<A>(_: A) { }
  | ^^^^^^^^^^^^^^^^^^^
  |
  = note: variance loosened (non-breaking)
  = warning: type error: expected type parameter `A`, found `()` (breaking)

error: breaking changes in `Abc`
 --> infer_regress/new.rs:3:1
  |
3 | pub struct Abc<A>(pub A, pub ());
  | ^^^^^^^^^^^^^^^^^
  |
  = warning: type error: expected type parameter `A`, found `()` (breaking)

error: aborting due to 2 previous errors