As of the 4.1.3 sdk, with gradual type checkiing, I get:
ERROR: fenix5plus: /path/to/BulkDownloadRequestDelegate.mc:57: Invalid '$.Toybox.Lang.Method(code as $.Toybox.Lang.Number, data as Null or $.Toybox.WatchUi.BitmapResource) as Void' passed as parameter 4 of type '$.Toybox.Lang.Method(responseCode as $.Toybox.Lang.Number, data as Null or $.Toybox.Graphics.BitmapReference or $.Toybox.WatchUi.BitmapResource) as Void'.
Prior to 4.1.3 all the samples compiled with -l 1.
