Don't allow statement-nodes in expression contexts.

tests/language/side_effect_throw_test.dart

Index: tests/language/side_effect_throw_test.dart
diff --git a/tests/language/side_effect_throw_test.dart b/tests/language/side_effect_throw_test.dart
new file mode 100644
index 0000000000000000000000000000000000000000..d987638c33214f2a7e947b5ac5b3a347d0eed7ed
--- /dev/null
+++ b/tests/language/side_effect_throw_test.dart
@@ -0,0 +1,26 @@
+// Copyright (c) 2012, 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.
+
+class B {
+  static var x;
+  operator <<(other) {
+    x = other;
+    return 33;
+  }
+}
+
+class A {
+  get _m() => new B();
+  opshl(int n) {
+    // 'n' must be a number, but we are not allowed throw throw before we have
+    // evaluated _m << 499.
+    return (_m << 499) | (2 - n);
+  }
+}
+
+main() {
+  var a = new A();
+  Expect.throws(() => a.opshl("string"));
+  Expect.equals(499, B.x);
+}