diff --git a/sdk/lib/_internal/vm/lib/async_patch.dart b/sdk/lib/_internal/vm/lib/async_patch.dart
index b3b414e73bd..0192bfe424f 100644
--- a/sdk/lib/_internal/vm/lib/async_patch.dart
+++ b/sdk/lib/_internal/vm/lib/async_patch.dart
@@ -43,7 +43,7 @@ class _AsyncAwaitCompleter<T> implements Completer<T> {
     }
   }
 
-  void start(void Function() f) {
+  void start(f) {
     f();
     isSync = true;
   }
diff --git a/sdk_nnbd/lib/_internal/vm/lib/async_patch.dart b/sdk_nnbd/lib/_internal/vm/lib/async_patch.dart
index 675a8b50d23..b2b57d778ae 100644
--- a/sdk_nnbd/lib/_internal/vm/lib/async_patch.dart
+++ b/sdk_nnbd/lib/_internal/vm/lib/async_patch.dart
@@ -41,7 +41,7 @@ class _AsyncAwaitCompleter<T> implements Completer<T> {
     }
   }
 
-  void start(void Function() f) {
+  void start(f) {
     f();
     isSync = true;
   }