Description
((possibly a minor item - or maybe exactly not...))
That example likely firmly is UB (fully intentionally, of course, in this casting example).
Thus, wording
"Surprised? I’m just glad I didn’t crash the program."
possibly is exactly what one would NOT want to see written in such guidelines docs.
If an application is entering UB, then it possibly better should firmly/cleanly crash (full stop! Fail-Fast), in order to not proceed beyond (continue with!) now-tainted (corrupted) application state (within an application that might be up to life-or-death handling reliability severity level, yet now keeps spewing/furthering CORRUPTION, possibly even to persistence layers).
Related: E.26: If you can’t throw exceptions, consider failing fast
While desired behaviour (termination, continuation) may vary according to application reliability requirements, such a blanket statement better should not be mentioned.
So, "glad I didn't crash" probably insinuates a wrong/dangerous kind of thinking here, and if so should be usefully reworded or eliminated.
Thanks!