I couldn't find again the example I saw many years ago, I could only find a GCC bug that has been fixed now. So you're likely right and I just didn't remember correctly. But we still can have the zeroing out of memory before deallocation that can get silently optimized away. Maybe also naive attempts at checking for signed integer overflow could be silently optimized away. My general point is that, if the compiler determines that the code has dead instructions/unneded checks, it is very likely that the programmer's mental model of the code is wrong. So, just like the case of using an integer as a pointer or vice versa, we should have a warning telling the programmers that some code is going to not be compiled. Also in the case of the null pointer check: this would make the programmer realize that the check is happening too late and should instead be performed earlier
