> Something that would be neat to see from Rust here would be a way to measure the impact of these sorts of compiler and dependency bumps in order to reduce the blast radius of this sort of thing. Ideally being able to say "this change requires X devs to do process which cost Y minutes, so it's worth investing Z minutes to avoid / document it". I often want to make public API changes to a library I maintain, but the best tool I have for understanding who those changes will affect is often a GitHub search for code.
They have such a tool, its called crater. It was used used in making the decision to delay merging the new trait impl until the new version of time was published and in wide use.