"Panic" is a fancy name for unchecked exception. It can arise from any code, for example, by out-of-index accesses or arithmetic overflows. In the other words,

"Panic" is a fancy name for unchecked exception. It can arise from any code, for example, by out-of-index accesses or arithmetic overflows. In the other words, if you want to allow, say, `arr[0]` without any checking, you should accept that it can abruptly terminate the current thread. (Pony is a rare example of the contrapositive.) I too agree that "Result + panic" is better for the very same reason, but it doesn't mean exceptions are gone.