[Haskell-cafe] Non-derivable Typeable

Roman Cheplyaka roma at ro-che.info
Tue Jan 22 15:34:54 CET 2013

I just found mkTyCon3 which generates the fingerprint automatically.
(I was looking at Data.Typeable.Internal.mkTyCon before.)
That answers my question.

(Of course, a way to derive the instance would be even better...)


* Roman Cheplyaka <roma at ro-che.info> [2013-01-22 15:28:55+0200]
> I need to declare a Typeable instance for a type which has an argument
> of kind * -> *. GHC refuses to derive it.
> What is a recommended way to go about it?
> In particular, if I write the instance by hand, how important is the
> fingerprint, and how could I generate it?
> Roman

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