Actionscript编译器问题:错误#1068:数组和*无法协调

Main Thread (Suspended: 
         VerifyError: Error #1068: Array and * cannot be reconciled.)

private var testArray:Array = [{},{},{}]

private function run():void {
  this.failure({});
}

private function failure(o:Object):void {
  for each(var el:Object in testArray) {
    o.ids = (o.ids||[]).concat(getArray());
  } 
}

private function getArray():Array {  return [Math.random()]; } 

> verify monkeyTest/failure()
>                         stack:
>                         scope: [global Object$ flash.events::EventDispatcher$
> flash.display::DisplayObject$
> flash.display::InteractiveObject$
> flash.display::DisplayObjectContainer$
> flash.display::Sprite$
> mx.core::FlexSprite$
> mx.core::UIComponent$
> mx.core::Container$
> mx.core::LayoutContainer$
> mx.core::Application$ monkeyTest$] 
>                          locals: monkeyTest Object? * * *   

编辑:

private function failure(o:Object):void {
      for each(var el:Object in testArray) {
        o.ids = o.ids || [];
        o.ids = o.ids.concat(getArray());
      } 
}