anchor.diff:            outArgs[_variadicIndex]
                 = new Tuple.$withList(inArgs.sublist(initialLength, inArgs.length - 1), seq);
           }
  +
           return $dart$core.Function.apply(_function, outArgs, null);
         }
       }
  
positive.code: 
    dart$Callable([$dart$core.Function this._function, $dart$core.int this._variadicIndex = -1]);
  
    // for non-spread calls
    $dart$core.Function get f => _variadicIndex == -1 ? _function : this;
  
    // for spread calls, always use noSuchMethod.
    //$dart$core.Function get s => this;
  
    noSuchMethod($dart$core.Invocation invocation) {
      if (invocation.memberName == #call) {
  
negative.code: 
  abstract
  class Callable {
      $dart$core.Function get f;
      s();
  }
  
  //
  