static modulation for nim

static_modulo.nim

import std/random

func mods[T: static Natural](a: int, b: type T): range[0 .. T-1] =
  cast[type result](a mod b.int)

let  n = rand 0 .. 100
case n.mods 4
of 3,2,1: echo "huh"
of 0    : echo "got you"

the compiler does not nag and say:

not all cases are covered for the expression n.mods 4