Add new tests, cf. #1060 (void generators)

Change-Id: I7a2bcc85731e426c6d0073d65c06878f917d6627
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/154681
Reviewed-by: Lasse R.H. Nielsen <lrn@google.com>
Commit-Queue: Erik Ernst <eernst@google.com>

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*`.
+}

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*`.
+}

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*`.
+}

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*`.
+}