iOS Qt 5.5.0a QML engine nullifies values in array if used with push/shift resulting in assertion crashes

Qt 5.5 Alpha nullifies values in an array if objects returned from a JavaScript obejct get pushed and shifted in and out of an array.

I attached a simple example which adds up to 100 items into an array and subsequently prints out the current array status. After some iterations there is a log output like the following (truncated manually):

qml: [ ...

,

,

,null,null,null,null,null,null,null,null,null,null,null,

, ... ]

Note that if we push the objects into the array without calling the doNothing() function all values are stored as intended.

This is also related to QTBUG-45888 which crashes the app if you try to access such a null value (a sample is included in the attached example line 20).

This looks like a regression as the sample runs perfectly fine on Qt 5.4.1 (iOS).