[Haskell] functional dependencies not satisfactory?

[Wolfgang Jeltsch]

Am Dienstag, 4. September 2007 22:00 schrieben Sie:
> […]

> It should be emphasized that this program worked the very first time I
> typed it in.

Which version of GHC are you using?  I’m a bit confused since the latest 
successful nightly build for i386-unknown-linux seems to be from August 20.  
Are type families already implemented in this version?  Was there any change 
in type family support since then?

Best wishes,
Wolfgang