When using a selector including a pseudo-selector that requires Sizzle with the siblings method, unexpected elements are returned.

Given the following markup:

<div id="d1"></div>
<div>
    <span></span>
</div>

And the following jQuery:

$("#d1").siblings("div span:last");

You would expect that an empty set be returned, as there are no span siblings of #d1. However, the div containing the span is returned.

JSFiddle example. Reproduced in Chrome 14, Firefox 7 and IE9.

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