How about generating this instead:

```
ol.layer.TileLayerExport = function(options) {
  /** @type {ol.layer.TileLayerOptions} */
  var arg = /** @type {ol.layer.TileLayerOptions} */ (options);
  if ((goog.isDefAndNotNull(options)) {
    arg.brightness = options.brightness;
    arg.contrast = options.contrast;
    ...
  }
  goog.base(this, arg);
};
```


?