If you really don’t care about compiler warnings, what’s the actual point of using Rust?
Second case is the same. The other team needs to definitely know, that their assumptions expressed in their current code are broken and need to be adjusted.
We just need to stop to take whatever shit Google is doing as the one bar to measure all others, and need to understand that they may be different requirements than a typical business. We are not Google.
I don't want to update every place someone matches on my enum, when it's something not even in my project, just to get my PR to merge. Three teams use it? Fine. Ten? More? Not fine. You are adding cases into someone else's code just to unblock your own work.
The second case is actually not the same at all. Realistically, they will just pin your dependency to an older version. Now they can't benefit from new features and security fixes without going in and adding in a new case. Massive waste of time for them.
And of course I'm not just taking whatever Google says at face value. I read their justification, and it makes total sense for anyone that works on a non-trivial project. It follows how any stable public API is supposed to be designed.
Then don't upgrade your dependency onto the other crate.
Anything more than a hobbyist will have properly pinned versions, and not just sling around version ranges loosely. At the very least will not update lock file just like that, without considering, that there may be consequences.