That's where I have problem with this design, the API authors have little control on the type of argument it can support. You can't force Clamp(to: 0...3) since the callers will just provide a separate Clamp with different parameter.
This proposal does not support additional arguments in wrapper attributes on parameters for this exact reason. I mentioned up-thread that there are a few ideas for how to support this in the future in a way that ensures that callers can't change those arguments, for example: