Am Mittwoch, 24. September 2008 15:11 schrieb Ian Lynagh:
On Wed, Sep 24, 2008 at 12:55:29PM +0200, Wolfgang Jeltsch wrote:
I thought, someone said that with the new typing machinery in GHC 6.10, more functional dependency programs are accepted because functional dependencies are handled similarly to type families (or something like that). Is this true? Since the type family version is okay, why shouldn’t the functional dependency version be okay?
In http://hackage.haskell.org/trac/ghc/ticket/345 Simon says: Ultimately, I think we can implement fundeps using type families, and then the fundep version will work too. Until then, it'll only work in type-family form.
Thanks Ian
And further:
So, since we now have a good workaround (well, actually, a better way to write the program rather than a workaround), I'll leave it open, but at low priority and with milestone bottom.
So for now the answer is: Use type families and thereby drop 6.6 compatibility? Best wishes, Wolfgang