T4528.hs:9:1:
    Can't make a derived instance of ‛Enum (Foo a)’:
      ‛Foo’ must be an enumeration type
      (an enumeration consists of one or more nullary, non-GADT constructors)
    In the stand-alone deriving instance for ‛Enum (Foo a)’

T4528.hs:10:1:
    Can't make a derived instance of ‛Bounded (Foo a)’:
      ‛Foo’ must be an enumeration type
      (an enumeration consists of one or more nullary, non-GADT constructors)
        or
      ‛Foo’ must have precisely one constructor
    In the stand-alone deriving instance for ‛Bounded (Foo a)’