Allowing `e` of any type in `void f(...) => e` in the analyzer.

tests/language/void_arrow_return_test.dart

Index: tests/language/void_arrow_return_test.dart
diff --git a/tests/language/void_arrow_return_test.dart b/tests/language/void_arrow_return_test.dart
new file mode 100644
index 0000000000000000000000000000000000000000..0bbcdadc93b3e71fce96edfb4fc2e77c9480dd18
--- /dev/null
+++ b/tests/language/void_arrow_return_test.dart
@@ -0,0 +1,11 @@
+// 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.
+
+// Testing that a void arrow function is allowed to return any type of value.
+
+void foo() => 42;
+
+main() {
+  foo();
+}