Is [distinct](https://nim-lang.org/docs/manual.html#types-distinct-type) not what you need?
You can define the needed operations from its base type using `borrow` pragma so you don't have to cast/coerce every time you use it Also, I did what @cdome suggested, defining `converter` s and it works like charm. I have several subtype and using converters to convert back and forth between the base type and its subtype.
