anchor.diff:    int hashCode() => argumentCount + 1000 * namedArguments.length;
     int get namedArgumentCount() => namedArguments.length;
     int get positionalArgumentCount() => argumentCount - namedArgumentCount;
  +  Type get receiverType() => null;
   
     static final Selector GETTER =
         const Selector.constant(SelectorKind.GETTER, 0);
  
positive.code:   }
  
    bool operator ==(other) {
      if (other is !Selector || other is TypedSelector) return false;
      return argumentCount == other.argumentCount
             && namedArguments.length == other.namedArguments.length
             && sameNames(namedArguments, other.namedArguments);
  
negative.code: 
      return false;
    }
  }
  