A range type could be very simple if it were just used for storage - you couldn’t do anything with it other than passing it around and converting it to somethin

A range type could be very simple if it were just used for storage - you couldn’t do anything with it other than passing it around and converting it to something else, and there would be a runtime check when creating it. But such a thing would be useful mostly for fields in data structures, and the runtime checks would add overhead. (Though, perhaps it would replace an array bounds check somewhere else?)