Added test using void in new positions.

tests/language/generalized_void_syntax_test.dart

+// 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 the reserved word `void` is allowed to occur as a type.
+
+import 'package:expect/expect.dart';
+
+class A<T> {
+  T t;
+  const A(this.t);
+}
+
+const void x1 = null;
+const A<void> x2 = const A<void>(null);
+
+final void x3 = null;
+final A<void> x4 = new A<void>(null);
+
+void x5 = null, x6;
+A<void> x7 = new A<void>(null), x8;
+
+void get g1 => null;
+A<void> get g2 => new A<void>(null);
+void set s1(void x) => null;
+void set s2(A<void> x) => null;
+void m1(void x, [void y]) => null;
+void m2(void x, {void y}) => null;
+A<void> m3(A<void> x, [A<void> y]) => new A<void>(null);
+A<void> m4(A<void> x, {A<void> y}) => new A<void>(null);
+
+class B<S, T> {}
+
+class C extends A<void> with B<void, A<void>> implements A<void> {
+  static final void x1 = null;
+  static final A<void> x2 = new A<void>(null);
+
+  static const void x3 = null;
+  static const A<void> x4 = const A<void>(null);
+
+  final void x5 = null, x6;
+  final A<void> x7 = new A<void>(null), x8;
+
+  static void x9 = null, x10;
+  static A<void> x11 = new A<void>(null), x12;
+
+  covariant void x13 = null, x14;
+  covariant A<void> x15 = new A<void>(null), x16;
+  
+  static void get g1 => null;
+  static A<void> get g2 => new A<void>(null);
+  static void set s1(void x) => null;
+  static void set s2(A<void> x) => null;
+  static void m1(void x, [void y]) => null;
+  static void m2(void x, {void y}) => null;
+  static A<void> m3(A<void> x, [A<void> y]) => null;
+  static A<void> m4(A<void> x, {A<void> y}) => null;
+
+  void get g3 => null;
+  A<void> get g4 => new A<void>(null);
+  void set s3(void x) => null;
+  void set s4(A<void> x) => null;
+  void m5(void x, [void y]) => null;
+  void m6(void x, {void y}) => null;
+  A<void> m7(A<void> x, [A<void> y]) => null;
+  A<void> m8(A<void> x, {A<void> y}) => null;
+
+  // Ensure that all members are used, and use `void` in expressions.
+  void run() {
+    var ignore = [x1, x2, x3, x4, x5, x6, x7, x8, x9, x10, x11, x12, x13, x14,
+      x15, x16, g1, g2, g3, g4];
+    
+    s1 = null;
+    s2 = new A<void>(null);
+    s3 = null;
+    s4 = new A<void>(null);
+    m1(null, null);
+    m2(null, y: null);
+    m3(null, new A<void>(null));
+    m4(null, y: new A<void>(null));
+    m5(null, null);
+    m6(null, y: null);
+    m7(null, new A<void>(null));
+    m8(null, y: new A<void>(null));
+
+    void pretendToUse(dynamic x) => null;
+    pretendToUse(<void>[]);
+    pretendToUse(<void, void>{});
+    pretendToUse(<A<void>>[]);
+    pretendToUse(<A<void>, A<void>>{});
+  }
+}
+
+// Testing syntax, just enforce compilation.
+main() {
+  var ignore = [x1, x2, x3, x4, x5, x6, x7, x8, g1, g2];
+
+  s1 = null;
+  s2 = new A<void>(null);
+  m1(null, null);
+  m2(null, y: null);
+  m3(null, null);
+  m4(null, y: null);
+  new C().run();
+}