[1mMain.hs:8.15:[1;31m error:[0m[1m
   • Data family instance 'F Int' is not surely apart from previous instance
     'F (G a)'
  [1;34m|[0m
[1;34m8[0m [1;34m| [0mdata instance [1;31mF[0m Int = FI
  [1;34m|[0m               [1;31m^[0m

