Moving out of a function both owned and borrowed entities properly?

[alice]

@SkiFire13

@alice

Unsound means that it violates one of Rust's safety rules. An equivalent way to say it is that any program that is unsound has "undefined behavior".

I don't think unsound directly means that something has undefined behaviour. I generally use it to indicate that a set of API could lead to undefined behaviour if misused by safe code, but it doesn't always do.

Thanks. That's a good way to see it.

[alice]

The fact that you can't do that is why my previous post said that you should hide the context behind methods on the struct that use it in only safe ways.

[Wandalen]

I see. Makes sense, but I am trying to internalize that.

[alice]

You can think of it this way: To make the struct self-referential, you construct a value that the borrow-checker can't check, and which you have to be careful with. If you expose that unchecked value to the user, then you are in trouble because the user might not be careful with it.