The following crash has been observed:

TypeError Unable to get property getChildren of undefined or null
reference
at findListItemInfo (:28227:9)
at getImmediatelyContainingArgumentInfo (:28113:17)
at getContainingArgumentlnfo (:28120:21)
at getSignatureHelpltems (:28084:13)
at getSignatureHelpitems (:34611:13)
at Anonymous function (:35825:17)
at simpleForwardCall (:35672:9)
at forwardJSONCall (:35686:13)
at forwardJSONCall (:35717:13)
at getSignatureHelpItems (:35824:13)

There is no known repro for this, but @CyrusNajmabadi has reported it a few times. Cyrus, can you add a repro if you manage to capture one?