[Haskell-cafe] Can't make a derived instance of `Typeable (A B)': `A' has arguments of kind other than `*'

[Christopher Done]

Suppose I have a data type:

data A f = A { a :: f Integer }

why can't I derive a Typeable instance like so?

deriving instance Typeable (A Maybe)

I get:

    Can't make a derived instance of `Typeable (A Maybe)':
      `A' has arguments of kind other than `*'
    In the stand-alone deriving instance for `Typeable (A Maybe)'

I would have expected that the arguments are instantiated by the Maybe
type constructor and thus the type of A would be:

Maybe Integer -> A

What am I missing?
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