Re: DData modules

On Thu, Jan 13, 2005 at 02:13:08PM +0000, Malcolm Wallace wrote:

Ross Paterson writes:

...

Also, these modules import Data.Monoid, which contains the non-H98 instance Monoid (a -> a), making it (and these) non-portable.

In what sense is instance Monoid (a -> a) not Haskell'98? It looks perfectly OK to me. Is it because the two type variable arguments to (->) are the same?

Yes -- the Report even makes an example of instance C (a,a). But it seems that nhc98 implements this extension.