[1mMain.hs:7.19:[1;31m error:[0m[1m
   • Cannot unify `m` with `I a` because the quantified variable `a` would
     escape its scope.
   • Relevant bindings:
       i :: I a
       unI :: SomeI -> m
   • In equation `unI (Main.MkSomeI i)  = i`
   • In function `Main.unI`
   • In recursive group:
         Main.unI
  [1;34m|[0m
[1;34m7[0m [1;34m| [0munI (MkSomeI i) = [1;31mi[0m
  [1;34m|[0m                   [1;31m^[0m

