{"ast_node_type":"variable","tokens":[{"end":97,"kind":"keyword","start":0,"text":"let"}]}
                            let span = if let (Some((_, first_span)), Some((_, second_span))) = (
                            let (_, second_expected_ty) = formal_and_expected_inputs[second_idx];
                                provided_arg_tys.get(first_idx.to_provided_idx()),