{"ast_node_type":"other","tokens":[{"end":36,"kind":"keyword","start":0,"text":"lca"}]}
        lca = shallowest_node(&lca);
            algo::least_common_ancestor(&fst_expanded.parent()?, &lst_expanded.parent()?)?;
        if lca.first_token() == Some(fst_expanded) && lca.last_token() == Some(lst_expanded) {