[hamandcheese]

If you're the type of moron who will write:

  chargeCustomer(amountDollars: valueInCents)

I have little faith that types would help you. You could simply do:

  chargeCustomer(amount: Dollars.from_int(valueInCents))

And create the same bug.

Positional arguments is just as big an evil as non-typed units, IMO.