diff --git a/lib/src/record_replay/manifest.dart b/lib/src/record_replay/manifest.dart
index 45c1177..635f37e 100644
--- a/lib/src/record_replay/manifest.dart
+++ b/lib/src/record_replay/manifest.dart
@@ -10,8 +10,7 @@
 import 'run_manifest_entry.dart';
 
 /// Tests if two lists contain pairwise equal elements.
-bool _areListsEqual/*<T>*/(
-    List<dynamic/*=T*/ > list1, List<dynamic/*=T*/ > list2) {
+bool _areListsEqual<T>(List<T> list1, List<T> list2) {
   int i = 0;
   return list1 != null &&
       list2 != null &&
diff --git a/pubspec.yaml b/pubspec.yaml
index 0c14a37..b739081 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -17,4 +17,4 @@
   test: ^0.12.10
 
 environment:
-  sdk: '>=1.19.0 <2.0.0-dev.infinity'
+  sdk: '>=1.21.0 <2.0.0-dev.infinity'