diff --git a/tests/language/async_star/void_async_star_test.dart b/tests/language/async_star/void_async_star_test.dart
new file mode 100644
index 000000000000..8e3c77d775b7
--- /dev/null
+++ b/tests/language/async_star/void_async_star_test.dart
@@ -0,0 +1,38 @@
+// Copyright (c) 2020, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+// It is an error for an `async*` function to have return type `void`.
+
+import 'dart:async';
+
+/*space*/ void f1() async* {
+  //      ^^^^
+  // [analyzer] unspecified
+  // [cfe] unspecified
+}
+
+class C {
+  static void f2() async* {
+    //   ^^^^
+    // [analyzer] unspecified
+    // [cfe] unspecified
+  }
+
+  /*space*/ void f3() async* {
+    //      ^^^^
+    // [analyzer] unspecified
+    // [cfe] unspecified
+  }
+}
+
+void main() {
+  /*space*/ void f4() async* {
+    //      ^^^^
+    // [analyzer] unspecified
+    // [cfe] unspecified
+  }
+
+  // No function literal: It is probably not possible to infer the
+  // return type `void` for a function literal marked `async*`.
+}
diff --git a/tests/language/sync_star/void_sync_star_test.dart b/tests/language/sync_star/void_sync_star_test.dart
new file mode 100644
index 000000000000..4c387f37896b
--- /dev/null
+++ b/tests/language/sync_star/void_sync_star_test.dart
@@ -0,0 +1,36 @@
+// Copyright (c) 2020, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+// It is an error for a `sync*` function to have return type `void`.
+
+/*space*/ void f1() sync* {
+  //      ^^^^
+  // [analyzer] unspecified
+  // [cfe] unspecified
+}
+
+class C {
+  static void f2() sync* {
+    //   ^^^^
+    // [analyzer] unspecified
+    // [cfe] unspecified
+  }
+
+  /*space*/ void f3() sync* {
+    //      ^^^^
+    // [analyzer] unspecified
+    // [cfe] unspecified
+  }
+}
+
+void main() {
+  /*space*/ void f4() sync* {
+    //      ^^^^
+    // [analyzer] unspecified
+    // [cfe] unspecified
+  }
+
+  // No function literal: It is probably not possible to infer the
+  // return type `void` for a function literal marked `sync*`.
+}
diff --git a/tests/language_2/async_star/void_async_star_test.dart b/tests/language_2/async_star/void_async_star_test.dart
new file mode 100644
index 000000000000..8e3c77d775b7
--- /dev/null
+++ b/tests/language_2/async_star/void_async_star_test.dart
@@ -0,0 +1,38 @@
+// Copyright (c) 2020, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+// It is an error for an `async*` function to have return type `void`.
+
+import 'dart:async';
+
+/*space*/ void f1() async* {
+  //      ^^^^
+  // [analyzer] unspecified
+  // [cfe] unspecified
+}
+
+class C {
+  static void f2() async* {
+    //   ^^^^
+    // [analyzer] unspecified
+    // [cfe] unspecified
+  }
+
+  /*space*/ void f3() async* {
+    //      ^^^^
+    // [analyzer] unspecified
+    // [cfe] unspecified
+  }
+}
+
+void main() {
+  /*space*/ void f4() async* {
+    //      ^^^^
+    // [analyzer] unspecified
+    // [cfe] unspecified
+  }
+
+  // No function literal: It is probably not possible to infer the
+  // return type `void` for a function literal marked `async*`.
+}
diff --git a/tests/language_2/sync_star/void_sync_star_test.dart b/tests/language_2/sync_star/void_sync_star_test.dart
new file mode 100644
index 000000000000..4c387f37896b
--- /dev/null
+++ b/tests/language_2/sync_star/void_sync_star_test.dart
@@ -0,0 +1,36 @@
+// Copyright (c) 2020, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+// It is an error for a `sync*` function to have return type `void`.
+
+/*space*/ void f1() sync* {
+  //      ^^^^
+  // [analyzer] unspecified
+  // [cfe] unspecified
+}
+
+class C {
+  static void f2() sync* {
+    //   ^^^^
+    // [analyzer] unspecified
+    // [cfe] unspecified
+  }
+
+  /*space*/ void f3() sync* {
+    //      ^^^^
+    // [analyzer] unspecified
+    // [cfe] unspecified
+  }
+}
+
+void main() {
+  /*space*/ void f4() sync* {
+    //      ^^^^
+    // [analyzer] unspecified
+    // [cfe] unspecified
+  }
+
+  // No function literal: It is probably not possible to infer the
+  // return type `void` for a function literal marked `sync*`.
+}