<!DOCTYPE html>
<title> postMessage(): cloning source port </title>
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<div id=log></div>
<script>
test(function() {
  var channel = new MessageChannel();
  channel.port1.start();
  assert_throws("DataCloneError", function() {
    channel.port1.postMessage("ports", [channel.port1]);
  });
});
</script>