anchor.diff:  		if ( seenHashCodes.contains( value.hashCode.toString( ) ) )
   			return new ClassObjectData( )
   				..objectType = reflect( value ).type.reflectedType
  -				..hashcode = value.hashCode.toString( )
  +				..previousHashCode = value.hashCode.toString( )
   				..properties = {
   			};
   		seenHashCodes.add( value.hashCode.toString( ) );
  
positive.code: 	bool get isNativeType
  	=> false;
  
  	String hashcode;
  
  	Map<String, BaseObjectData> properties;
  }
  
negative.code: 
  			var result = new NoMirrorsMap( ).convert( json, new JsonConverter( ), new ClassConverter( ) ) as Person;
  
  			expect( result.id, 1 );
  			expect( result.children, isNotNull );
  			expect( result.parents, isNotNull );
  		} );
  
  		test( "Can deserialize objects with circular references", ( )
  