Why would memory get corrupted in this example? To put it differently: if the code didn't have the `if index < array.len()` check, clearly things would be diffe

Why would memory get corrupted in this example? To put it differently: if the code didn't have the `if index < array.len()` check, clearly things would be different. How would you describe this distinction, other than "memory safety"? (Asking because it's not clear whether you're using an unusual definition of memory safety, or just didn't notice the bounds check in the example.)