I don't think there's anything you "can't" implement that the language reserves for itself anymore. There may be some edge case or something but in general it's

I don't think there's anything you "can't" implement that the language reserves for itself anymore. There may be some edge case or something but in general it's no longer an issue. The language reserves syntax for itself; you can't overload a[b] to mean anything other than either array/slice indexing or indexing into a map. You have to write methods like ".Get" or something, there's no __getattr__ or anything.