GADTs and functional dependencies

Wolfgang Jeltsch g9ks157k at
Wed Sep 24 11:09:15 EDT 2008

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
> 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 

Best wishes,

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