diff --git a/packages/flutter/test/material/time_picker_theme_test.dart b/packages/flutter/test/material/time_picker_theme_test.dart
index 0b9947815d..ceeb9be37d 100644
--- a/packages/flutter/test/material/time_picker_theme_test.dart
+++ b/packages/flutter/test/material/time_picker_theme_test.dart
@@ -2,6 +2,8 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+// @dart = 2.8
+
 import 'package:flutter/material.dart';
 import 'package:flutter/painting.dart';
 import 'package:flutter/rendering.dart';