Deepseq proposed patch

[Henning Thielemann]

On Thu, 10 Jun 2010, Julian Blake Kongslie wrote:

> Control.DeepSeq has a large number of instances for its class NFData,
> I'd like to propose a new one:
>
> import Data.Data
>
> dataDeepSeq :: (Data a) => a -> a
> dataDeepSeq a = gmapQr ($) a (seq . dataDeepSeq) a
>
> instance (Data a) => NFData a where
>  rnf a = dataDeepSeq a `seq` ()

Is this an instance at all? It is not of the form NFData Type or NFData 
(TypeCon a) or so.