{"ast_node_type":"variable","tokens":[{"end":59,"kind":"keyword","start":0,"text":"let"}]}
        let b_principal_def_id = b_data.principal_def_id();
        // trait upcasting. We're just removing auto traits (or shortening the lifetime).
        if a_data.principal_def_id() == b_principal_def_id || b_principal_def_id.is_none() {