Hello,
I have this code:
class C a b c | a b -> c where
f :: a -> b -> c
instance C a b c => C a (x,y,b) c where
f a (_,_,b) = f a b
instance C a (a,c,b) c where
f _ (_,c,_) = c
ghci -fglasgow-exts -fallow-overlapping-instances compiles it without
complaint but hugs -98 +o says:
ERROR "ClassProblem.hs":7 - Instances are not consistent with dependencies
*** This instance : C a (a,b,c) b
*** Conflicts with : C a (b,c,d) e
*** For class : C a b c
*** Under dependency : a b -> c
Can anyone tell me what the reason for this is and, maybe, how to avoid these
problems with Hugs?
Wolfgang
_______________________________________________
Haskell mailing list
[EMAIL PROTECTED]
http://www.haskell.org/mailman/listinfo/haskell
