T1133A.hs:6:28:
    Can't make a derived instance of ‛Enum X’:
      ‛X’ must be an enumeration type
      (an enumeration consists of one or more nullary, non-GADT constructors)
      Try GeneralizedNewtypeDeriving for GHC's newtype-deriving extension
    In the newtype declaration for ‛X’