IMO it is good to call this a crash in the sense of fail-fast. Then you do not get into the "but my program doesn't run anymore after that, what do you mean tha

IMO it is good to call this a crash in the sense of fail-fast. Then you do not get into the "but my program doesn't run anymore after that, what do you mean that's not a crash" discussion. But it is not undefined behavior. It crashes _all the time_ in that situation, which makes life so much easier than UB.