change to deriving in 6.7 ??

[Conal Elliott]

by the way, i don't think i'm on the cvs-ghc list.  so please cc me in any
replies. thanks, - conal

On 8/15/07, Conal Elliott <conal at conal.net> wrote:
>
> I'm running ghc-6.7.20070802 and getting a new error message that didn't
> show up with ghc-6.6.  Code:
>
>     -- | Pairing for unary type constructors.
>     newtype Pair1 f g a = Pair1 {unPair1 :: (f a, g a)}
>       deriving (Eq, Ord, Show)
>
> Error message:
>
>     src/Data/Tupler.hs:26:0:
>     No instances for (Show (g a), Show (f a))
>       arising from the 'deriving' clause of a data type declaration
>                at src/Data/Tupler.hs:(26,0)-(27,25)
>     Possible fix:
>       add an instance declaration for (Show (g a), Show (f a))
>     When deriving the instance for (Show (Pair1 f g a))
>
> Has there been a change to "deriving"?  Is there a workaround?
>
> Thanks,  - Conal
>
>
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