Now I know rust has entered a stable phase, I might give it a look!
For more on how this works:
https://blog.rust-lang.org/2014/10/30/Stability.html
https://github.com/rust-lang/rfcs/blob/master/text/1122-lang...
https://github.com/rust-lang/rfcs/blob/master/text/1105-api-...
These are the RFCs and policies we came up with when cutting 1.0. I haven't read them in a while, but there haven't been any changes. Some of the text and/or examples might be reflective of the time they're written.
Oh, and one more thing: we have a tool, "crater", that we run every so often against every open source package in the ecosystem to make sure things don't break. Some of the most popular packages are built on every commit, as well.