=====
>>> main.whiley
type u8 is (int n) where 0 <= n && n <= 255
                                                  
u8[] xs = [0]

method m():
   skip

public export method test():
   m()
   assert |xs| > 0
---
E722 main.whiley 10,10:17
=====
>>> main.whiley 2:4
type u8s is (u8[] xs) where |xs| > 0
u8s xs = [0]
---