20 = note: required for `IteratorOfWrapped<(), Map<IteratorOfWrapped<(), Map<IteratorOfWrapped<(), Map<IteratorOfWrapped<(), Map<IteratorOfWrapped<(), Map<IteratorOfWrapped<(), Map<IteratorOfWrapped<(), Map<IteratorOfWrapped<(), Map<IteratorOfWrapped<(), Map<IteratorOfWrapped<(), Map<IteratorOfWrapped<(), Map<IteratorOfWrapped<(), Map<IteratorOfWrapped<(), Map<IteratorOfWrapped<(), Map<IteratorOfWrapped<(), Map<IteratorOfWrapped<(), Map<IteratorOfWrapped<(), Map<IteratorOfWrapped<(), Map<IteratorOfWrapped<(), Map<IteratorOfWrapped<(), Map<IteratorOfWrapped<(), Map<IteratorOfWrapped<(), Map<IteratorOfWrapped<(), Map<IteratorOfWrapped<(), Map<IteratorOfWrapped<(), Map<IteratorOfWrapped<(), Map<IteratorOfWrapped<(), Map<IteratorOfWrapped<(), Map<IteratorOfWrapped<(), Map<IteratorOfWrapped<(), Map<IteratorOfWrapped<(), Map<IteratorOfWrapped<(), Map<IteratorOfWrapped<(), Map<IteratorOfWrapped<(), Map<IteratorOfWrapped<(), Map<IteratorOfWrapped<(), Map<IteratorOfWrapped<(), Map<IteratorOfWrapped<(), Map<IteratorOfWrapped<(), Map<IteratorOfWrapped<(), Map<IteratorOfWrapped<(), Map<IteratorOfWrapped<(), Map<IteratorOfWrapped<(), Map<IteratorOfWrapped<(), Map<IteratorOfWrapped<(), Map<IteratorOfWrapped<(), Map<IteratorOfWrapped<(), Map<IteratorOfWrapped<(), Map<IteratorOfWrapped<(), Map<IteratorOfWrapped<(), Map<IteratorOfWrapped<(), Map<IteratorOfWrapped<(), Map<IteratorOfWrapped<(), Map<IteratorOfWrapped<(), Map<IteratorOfWrapped<(), Map<IteratorOfWrapped<(), Map<IteratorOfWrapped<(), Map<IteratorOfWrapped<(), Map<IteratorOfWrapped<(), Map<IteratorOfWrapped<(), Map<IteratorOfWrapped<(), Map<IteratorOfWrapped<(), Map<IteratorOfWrapped<(), Map<IteratorOfWrapped<(), Map<IteratorOfWrapped<(), Map<IteratorOfWrapped<(), Map<IteratorOfWrapped<(), Map<IteratorOfWrapped<(), Map<IteratorOfWrapped<(), Map<IteratorOfWrapped<(), Map<IteratorOfWrapped<(), Map<IteratorOfWrapped<(), Map<IteratorOfWrapped<(), Map<IteratorOfWrapped<(), Map<IteratorOfWrapped<(), Map<IteratorOfWrapped<(), Map<IteratorOfWrapped<(), Map<IteratorOfWrapped<(), Map<IteratorOfWrapped<(), Map<IteratorOfWrapped<(), Map<IteratorOfWrapped<(), Map<IteratorOfWrapped<(), Map<IteratorOfWrapped<(), Map<IteratorOfWrapped<(), Map<IteratorOfWrapped<(), Map<IteratorOfWrapped<(), std::iter::Empty<()>>, [closure@$DIR/issue-91949-hangs-on-recursion.rs:26:45: 26:48]>>, [closure@$DIR/issue-91949-hangs-on-recursion.rs:26:45: 26:48]>>, [closure@$DIR/issue-91949-hangs-on-recursion.rs:26:45: 26:48]>>, [closure@$DIR/issue-91949-hangs-on-recursion.rs:26:45: 26:48]>>, [closure@$DIR/issue-91949-hangs-on-recursion.rs:26:45: 26:48]>>, [closure@$DIR/issue-91949-hangs-on-recursion.rs:26:45: 26:48]>>, [closure@$DIR/issue-91949-hangs-on-recursion.rs:26:45: 26:48]>>, [closure@$DIR/issue-91949-hangs-on-recursion.rs:26:45: 26:48]>>, [closure@$DIR/issue-91949-hangs-on-recursion.rs:26:45: 26:48]>>, [closure@$DIR/issue-91949-hangs-on-recursion.rs:26:45: 26:48]>>, [closure@$DIR/issue-91949-hangs-on-recursion.rs:26:45: 26:48]>>, [closure@$DIR/issue-91949-hangs-on-recursion.rs:26:45: 26:48]>>, [closure@$DIR/issue-91949-hangs-on-recursion.rs:26:45: 26:48]>>, [closure@$DIR/issue-91949-hangs-on-recursion.rs:26:45: 26:48]>>, [closure@$DIR/issue-91949-hangs-on-recursion.rs:26:45: 26:48]>>, [closure@$DIR/issue-91949-hangs-on-recursion.rs:26:45: 26:48]>>, [closure@$DIR/issue-91949-hangs-on-recursion.rs:26:45: 26:48]>>, [closure@$DIR/issue-91949-hangs-on-recursion.rs:26:45: 26:48]>>, [closure@$DIR/issue-91949-hangs-on-recursion.rs:26:45: 26:48]>>, [closure@$DIR/issue-91949-hangs-on-recursion.rs:26:45: 26:48]>>, [closure@$DIR/issue-91949-hangs-on-recursion.rs:26:45: 26:48]>>, [closure@$DIR/issue-91949-hangs-on-recursion.rs:26:45: 26:48]>>, [closure@$DIR/issue-91949-hangs-on-recursion.rs:26:45: 26:48]>>, [closure@$DIR/issue-91949-hangs-on-recursion.rs:26:45: 26:48]>>, [closure@$DIR/issue-91949-hangs-on-recursion.rs:26:45: 26:48]>>, [closure@$DIR/issue-91949-hangs-on-recursion.rs:26:45: 26:48]>>, [closure@$DIR/issue-91949-hangs-on-recursion.rs:26:45: 26:48]>>, [closure@$DIR/issue-91949-hangs-on-recursion.rs:26:45: 26:48]>>, [closure@$DIR/issue-91949-hangs-on-recursion.rs:26:45: 26:48]>>, [closure@$DIR/issue-91949-hangs-on-recursion.rs:26:45: 26:48]>>, [closure@$DIR/issue-91949-hangs-on-recursion.rs:26:45: 26:48]>>, [closure@$DIR/issue-91949-hangs-on-recursion.rs:26:45: 26:48]>>, [closure@$DIR/issue-91949-hangs-on-recursion.rs:26:45: 26:48]>>, [closure@$DIR/issue-91949-hangs-on-recursion.rs:26:45: 26:48]>>, [closure@$DIR/issue-91949-hangs-on-recursion.rs:26:45: 26:48]>>, [closure@$DIR/issue-91949-hangs-on-recursion.rs:26:45: 26:48]>>, [closure@$DIR/issue-91949-hangs-on-recursion.rs:26:45: 26:48]>>, [closure@$DIR/issue-91949-hangs-on-recursion.rs:26:45: 26:48]>>, [closure@$DIR/issue-91949-hangs-on-recursion.rs:26:45: 26:48]>>, [closure@$DIR/issue-91949-hangs-on-recursion.rs:26:45: 26:48]>>, [closure@$DIR/issue-91949-hangs-on-recursion.rs:26:45: 26:48]>>, [closure@$DIR/issue-91949-hangs-on-recursion.rs:26:45: 26:48]>>, [closure@$DIR/issue-91949-hangs-on-recursion.rs:26:45: 26:48]>>, [closure@$DIR/issue-91949-hangs-on-recursion.rs:26:45: 26:48]>>, [closure@$DIR/issue-91949-hangs-on-recursion.rs:26:45: 26:48]>>, [closure@$DIR/issue-91949-hangs-on-recursion.rs:26:45: 26:48]>>, [closure@$DIR/issue-91949-hangs-on-recursion.rs:26:45: 26:48]>>, [closure@$DIR/issue-91949-hangs-on-recursion.rs:26:45: 26:48]>>, [closure@$DIR/issue-91949-hangs-on-recursion.rs:26:45: 26:48]>>, [closure@$DIR/issue-91949-hangs-on-recursion.rs:26:45: 26:48]>>, [closure@$DIR/issue-91949-hangs-on-recursion.rs:26:45: 26:48]>>, [closure@$DIR/issue-91949-hangs-on-recursion.rs:26:45: 26:48]>>, [closure@$DIR/issue-91949-hangs-on-recursion.rs:26:45: 26:48]>>, [closure@$DIR/issue-91949-hangs-on-recursion.rs:26:45: 26:48]>>, [closure@$DIR/issue-91949-hangs-on-recursion.rs:26:45: 26:48]>>, [closure@$DIR/issue-91949-hangs-on-recursion.rs:26:45: 26:48]>>, [closure@$DIR/issue-91949-hangs-on-recursion.rs:26:45: 26:48]>>, [closure@$DIR/issue-91949-hangs-on-recursion.rs:26:45: 26:48]>>, [closure@$DIR/issue-91949-hangs-on-recursion.rs:26:45: 26:48]>>, [closure@$DIR/issue-91949-hangs-on-recursion.rs:26:45: 26:48]>>, [closure@$DIR/issue-91949-hangs-on-recursion.rs:26:45: 26:48]>>, [closure@$DIR/issue-91949-hangs-on-recursion.rs:26:45: 26:48]>>, [closure@$DIR/issue-91949-hangs-on-recursion.rs:26:45: 26:48]>>, [closure@$DIR/issue-91949-hangs-on-recursion.rs:26:45: 26:48]>>, [closure@$DIR/issue-91949-hangs-on-recursion.rs:26:45: 26:48]>>, [closure@$DIR/issue-91949-hangs-on-recursion.rs:26:45: 26:48]>>, [closure@$DIR/issue-91949-hangs-on-recursion.rs:26:45: 26:48]>>, [closure@$DIR/issue-91949-hangs-on-recursion.rs:26:45: 26:48]>>, [closure@$DIR/issue-91949-hangs-on-recursion.rs:26:45: 26:48]>>, [closure@$DIR/issue-91949-hangs-on-recursion.rs:26:45: 26:48]>>, [closure@$DIR/issue-91949-hangs-on-recursion.rs:26:45: 26:48]>>, [closure@$DIR/issue-91949-hangs-on-recursion.rs:26:45: 26:48]>>, [closure@$DIR/issue-91949-hangs-on-recursion.rs:26:45: 26:48]>>, [closure@$DIR/issue-91949-hangs-on-recursion.rs:26:45: 26:48]>>, [closure@$DIR/issue-91949-hangs-on-recursion.rs:26:45: 26:48]>>, [closure@$DIR/issue-91949-hangs-on-recursion.rs:26:45: 26:48]>>, [closure@$DIR/issue-91949-hangs-on-recursion.rs:26:45: 26:48]>>, [closure@$DIR/issue-91949-hangs-on-recursion.rs:26:45: 26:48]>>, [closure@$DIR/issue-91949-hangs-on-recursion.rs:26:45: 26:48]>>, [closure@$DIR/issue-91949-hangs-on-recursion.rs:26:45: 26:48]>>, [closure@$DIR/issue-91949-hangs-on-recursion.rs:26:45: 26:48]>>, [closure@$DIR/issue-91949-hangs-on-recursion.rs:26:45: 26:48]>>, [closure@$DIR/issue-91949-hangs-on-recursion.rs:26:45: 26:48]>>, [closure@$DIR/issue-91949-hangs-on-recursion.rs:26:45: 26:48]>>, [closure@$DIR/issue-91949-hangs-on-recursion.rs:26:45: 26:48]>>` to implement `Iterator`