alt Hacker NewsI think it’s a really easy sell, actually: if you go past the end of the array far enough you end up accessing the stack which includes parts of the program like “where does this function return to” or “what is the index used to perform this access” or “there is no page mapped there”. None of these are arbitrary values.
The "anything can happen" means that the compiler can simply silently refuse to emit the code does the access.
Documenting that the instructions to access will always be eliminated makes it easier to predict what will happen.