nl_tokens: When errorNode is undefined it means we should not report any errors .
pl_tokens: <mask> checkElementTypeOfIterable ( iterable , errorNode ) { var elementType = getElementTypeOfIterable ( iterable , errorNode ) ; // Now even though we have extracted the iteratedType, we will have to validate that the type // passed in is actually an Iterable. if ( errorNode && elementType ) { checkTypeAssignableTo ( iterable , createIterableType ( elementType ) , errorNode ) ; } return elementType || anyType ; }