Method f_up

datafusion/common/src/tree_node.rs:1911–1914

(&mut self, node: &'n Self::Node)

        }

        fn f_up(&mut self, node: &'n Self::Node) -> Result<TreeNodeRecursion> {
            self.visits.push(format!("f_up({})", node.data));
            (*self.f_up)(node)
        }
    }

    fn visit_continue<T>(_: &TestTreeNode<T>) -> Result<TreeNodeRecursion> {