anchor.diff:          };
       };
       var baz;
  -    var bar = undefined === bar ? 4 : bar;
  +    var bar = 'undefined' === typeof bar ? 4 : bar;
       return baz * bar;
   };")
   
  
positive.code:     alert(a);
      return alert(b);
  } finally {
      if (undefined === prevMv2) {
          delete arguments['callee']['mv'];
      } else {
          arguments['callee']['mv'] = prevMv2;
  
negative.code:     alert(a3);
      return alert(b);
  } finally {
      if ('undefined' === typeof prevMv2) {
          delete arguments['callee']['mv'];
      } else {
          arguments['callee']['mv'] = prevMv2;
  