Nils Schweinsberg <m...@n-sch.de> writes: > On Sun, 4 Jul 2010 15:47:21 +0200, Ertugrul Soeylemez <e...@ertes.de> wrote: >> This requires a bunch of type system extensions, though, most notably >> the UndecidableInstances extension. But it's safe to use here. > > Probably a bit off topic, but whats wrong with UndecidableInstances? Where > is it safe to use, when would you avoid it and what can go wrong here?
I've been told that it's safe to use; enabling it just tells GHC that you're sure that the instance constraints are OK (as they might be too complicated for GHC's type checker; e.g. I have to use it when doing a whole bunch of associated type constraints as GHC doens't like having such a large set of constraints on the instance definition). -- Ivan Lazar Miljenovic ivan.miljeno...@gmail.com IvanMiljenovic.wordpress.com _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
