generic problem with static parameter

[hamidb80]

Nim Version

Nim Compiler Version 2.2.4 [Linux: amd64]
Compiled at 2025-04-22
Copyright (c) 2006-2025 by Andreas Rumpf

git hash: f7145dd
active boot switches: -d:release

Description

the code works in play.nim-lang.org with the latest version and also older versions, but not on my machine

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"

Current Output

play.nim(7, 7) template/generic instantiation of `mods` from here
play.nim(3, 11) Error: cannot instantiate: 'T'

Expected Output

compiles successfully

Known Workarounds

No response

Additional Information

No response

[metagn]

This would be how you normally write it:

func mods(a: int, b: static Natural): range[0 .. b-1]

I think there is no official way to attach a static generic parameter to a parameter after the fact, such that the generic parameter can be inferred from the static value of the normal parameter. In any case type is not the way to do it, normally it means that the parameter is a typedesc parameter, and interpreted as typeof it would just resolve to Natural.