anchor.diff:  }
   
   class LinkedHashMapKeyIterator<E> implements Iterator<E> {
  -  final _map;
  +  final dynamic/*=JsLinkedHashMap<E, dynamic>*/ _map;
     final int _modifications;
  -  LinkedHashMapCell _cell;
  +  LinkedHashMapCell/*<E, dynamic>*/ _cell;
     E _current;
   
     LinkedHashMapKeyIterator(this._map, this._modifications) {
  
positive.code: }
  
  class Es6LinkedHashMap<K, V> extends JsLinkedHashMap<K, V> {
  
    @override
    _getTableEntry(var table, var key) {
      return JS('var', '#.get(#)', table, key);
    }
  
  
negative.code:   }
  
    bool _containsTableEntry(var table, var key) {
      LinkedHashMapCell/*<K, V>*/ cell = _getTableCell(table, key);
      return cell != null;
    }
  
  