anchor.diff:    }
   
     String toString() => "Tuple: Item1: $Item1, Item2: $Item2";
  +
  +  int hashCode() => Util.getHashCode([Item1, Item2]);
   }
   
  -class Tuple3<T1, T2, T3> extends Tuple<T1, T2> {
  +class Tuple3<T1 extends Hashable, T2 extends Hashable, T3 extends Hashable>
  +  extends Tuple<T1, T2> implements Hashable {
     final T3 Item3;
   
     const Tuple3(T1 param1, T2 param2, this.Item3) :
  
positive.code: class Tuple<T1, T2> {
    final T1 Item1;
    final T2 Item2;
  
  
negative.code:   }
  
    String toString() => "Tuple3: Item1: $Item1, Item2: $Item2, Item3: $Item3";
  
    int hashCode() => Util.getHashCode([Item1, Item2, Item3]);
  }
  