Adding adjusted `void` tests from CL 2699073003

tests/language_2/void_type_callbacks_test.dart

Index: tests/language_2/void_type_callbacks_test.dart
diff --git a/tests/language_2/void_type_callbacks_test.dart b/tests/language_2/void_type_callbacks_test.dart
new file mode 100644
index 0000000000000000000000000000000000000000..ea6fe9e2eba422d3d76a3bd37b4c2ccb85fb6958
--- /dev/null
+++ b/tests/language_2/void_type_callbacks_test.dart
@@ -0,0 +1,40 @@
+// Copyright (c) 2017, 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.
+
+// Dart test for type checks involving callbacks and the type void.
+
+import 'package:expect/expect.dart';
+
+class A<T> {
+  T x;
+
+  foo(T x) {
+  }
+
+  T bar(T f()) {
+    T tmp = f();
+    return tmp;
+  }
+
+  gee(T f()) {
+    x = bar(f);
+  }
+
+  Object xAsObject() => x;
+}
+
+void voidFun() => 499;
+int intFun() => 42;
+
+main() {
+  A<void> a = new A<void>();
+  a.foo(a.x);  //# 00: compile-time error
+  a.bar(voidFun);
+  Expect.equals(null, a.xAsObject());
+  a.x = a.bar(voidFun);  //# 01: compile-time error
+  a.gee(voidFun);
+  Expect.equals(499, a.xAsObject());
+  a.gee(intFun);
+  Expect.equals(42, a.xAsObject());
+}