Add a test to check stack overflow in "fist-drop" section

[tamuhey]

I think it is great to add a test to this section to cause stack overflow before implementing our own Drop.

[kolulu23]

You can try this in the playground. refering to this post

[zenyusy]

tried a bit: playground-2 versions of drop

found that without impl Drop the prog would go stack overflow; with either version of drop it can run successfully.

can i say that both versions of drop are correct ?

while let Some(mut b) = self.head.take() { self.head = b.next.take(); }

while let Some(b) = self.head.take() { self.head = b.next; }

[GuilhermoReadonly]

Hey @zenyusy !

I know it has been 2 years since your comment but I decided to follow and try this excellent book recently and was wondering the same question as you !!!

In my opinion this is equivalent and I found the second impl more elegant because shorter and without making "b" mutable but i also would like the opinion of a more seasoned Rust developer :)

Cheers and kudos to the authors of this book !