{"ast_node_type":"variable","tokens":[{"end":89,"kind":"keyword","start":0,"text":"let"}]}
        let (&first_span, first_alias_spans) = regular_traits[0].1.split_last().unwrap();
        // and all other preceding spans are trait alias expansions.
        let (&second_span, second_alias_spans) = regular_traits[1].1.split_last().unwrap();