According the HTML5 communication spec (http://www.w3.org/TR/html5/comms.html#dom-window-postmessage-2), window.postMessage() "Throws an INVALID_STATE_ERR if the ports array is not null and it contains either null entries or duplicate ports." but we currently throw a TypeError in this case. According to the structured clone spec (http://www.w3.org/TR/html5/common-dom-interfaces.html#structured-clone), we are supposed to throw a DATA_CLONE_ERR exception and abort the overall structured clone algorithm if the input is an unsupported native object type (e.g. Error, Function) or a host object (e.g. a DOM node). We currently throw a TypeError in this case as well. The V8 implementation behaves according to specification. This is already tested by: fast/dom/Window/window-postmessage-clone-really-deep-array.html fast/events/message-port-multi.html
Dependencies have landed. Closing this bug.