{"ast_node_type":"variable","tokens":[{"end":97,"kind":"keyword","start":0,"text":"while"}]}
        while let Some(bb) = self.visit_stack.last_mut().and_then(|(_, iter)| iter.next_back()) {
        // two iterations yield `B` and finally `A` for a final traversal of [E, D, C, B, A]
            self.visit(bb);