{"ast_node_type":"variable","tokens":[{"end":89,"kind":"keyword","start":0,"text":"let"}]}
        let sig_len = caller_sig.instantiate_identity().skip_binder().inputs().len() + 1;
    if let Err(err) = check_constraints(tcx, def_id, sig_id) {
        let err_type = Ty::new_error(tcx, err);