Why proc behavior depends if it defined after or before another proc?

[Hlaaftana]

Because the proc that uses `R.init(v)` uses what is called a "closed symbol 
choice" for init, meaning only the init definitions before it are possible 
symbol choices. To prevent this, use the [mixin 
statement](https://nim-lang.org/docs/manual.html#generics-mixin-statement) like 
so:
    
    
    func init*[R, A](_: type[seq[R]], list: seq[A]): seq[R] =
      mixin init
      for v in list:
        result.add R.init(v)
    
    
    Run