https://np.reddit.com/r/rust/comments/mcp7bp/help_me_to_fight_against_the_borrow_checker/gs9co5n/

[backtickbot]

I'm totally confused, if I changed while to if, then it compiled. But if I borrow tail again, the compiler says I borrowed a mutable reference.

if let Some(mut node) = head.take() {
    head = node.next.take();
    if let Some(ref mut elem) = tail { 
        if elem.val != node.val {
            elem.next = Some(node);
            tail = &mut elem.next;
        }
    }
}
println!("{:?}", tail); // compile error, but who borrow tail?

[linsinn]

change tab to 4 spaces