What does malloc have to do with anything? Returning a pointer to the stack is just as likely to break everything if done improperly. Moving or copying a struct

What does malloc have to do with anything? Returning a pointer to the stack is just as likely to break everything if done improperly. Moving or copying a struct that points at itself is also going to break. In fact, "how to to either of these things" is such a common question for new rust programmers trying to solve their borrow checker complaints that it constitutes pretty good evidence people are doing these things all the time with little understanding of why they are problematic. And even if you _do_ know better, circumventing the borrow checker is fairly trivial.