[fauigerzigerk]

Yes it's safe but undesirable, like Java's NullPointerException.

A more interesting question is why it was not possible to use compile time borrow checking in this particular case. It shows how valuable the borrow checker is when you can use it.

[GoblinSlayer]

Well, yeah it's a bug just like the NullPointerException. You see how a buggy program behaves.