The HappS version on Hackage does not yet support ghc 6.10, since GADT pattern matching and the Exception API have changed.
GADT pattern match with non-rigid result type `t1'
Solution: add a type signature
...
Adding a type signature via an auxiliary function instead of a case expression, the problem goes away.
readElementRigidity :: (Monad m,Xml t) => Rigidity m -> m ([Element],t) -> Maybe t
readElementRigidity Rigid m = ...
readElementRigidity Flexible m = ...
Is there a plan to update the version on Hackage to support ghc 6.10.1?
I don't know either if it may break backwards compatibility.
Cheers,
hugo
--
www.di.uminho.pt/~hpacheco