{"ast_node_type":"variable","tokens":[{"end":58,"kind":"keyword","start":0,"text":"let"}]}
        let replace_expr = builder.make_mut(replace_expr);
        let (replace_expr, ref_data) = determine_ref_and_parens(ctx, &index.field_expr);
        EditTupleUsage::ReplaceExpr(replace_expr, ref_data.wrap_expr(field_name))