Warn when skipping anonymous types – maybe with an option to generate them

[kevmoo]

Recently, with the chartjs library, I got this output.

@JS()
abstract class Chart {
  // ...
  external static dynamic /*{
        global: ChartSettings;
    }*/
      get defaults;
  external static set defaults(
      dynamic /*{
        global: ChartSettings;
    }*/
      v);
}

1. It'd be great if the tool warned when this type of thing was generated
2. I'd love to have a flag to auto-generate a class – even an ugly one – for these maps.

Call 'em $generated1 $generated2 etc etc – at least I could use tools to refactor and rename, if I want.