[jcmoyer]

Breaking changes still happen, but commits to the rust repo are tagged with [breaking-change] so you can easily do a `git log --grep breaking-change` and (hopefully) get a good idea of how to fix your code. For more gradual breaking changes, the developers have been good at adding lints to rustc so you're told how to fix your code via compile-time warnings. Vec migration and crate attribute syntax are two recent examples of this.

[steveklabnik]

It's worth mentioning that this policy is only a few weeks old, so it's more of a 'will be in the future' thing than it is 'all the changes so far' thing.