José Miguel Vilaça <[EMAIL PROTECTED]> writes:
> I had used some code which worked fine on GHC 6.4 and now it dont compile
> on GHC 6.6.
I am unable to reproduce your problem. It is saddening that everyone
neglects to provide self-contained code for others to reproduce the
alleged problems.
I have cooked up a small resemblance to demonstrate the lack of
problems. It is accepted by GHC 6.6 just fine. It is self-contained,
so you can reproduce the same success too.
> instance InfoKind a b => InfoKind (Maybe a) b where
[...]
{-# OPTIONS_GHC -fglasgow-exts #-}
class InfoKind a b where
info :: a -> b -> Bool
instance InfoKind Int Double where
info x y = fromIntegral x == y
instance InfoKind a b => InfoKind (Maybe a) b where
info Nothing y = False
info (Just x) y = info x y
testInfoKind = [ info (45::Int) (45::Double),
info (Nothing::Maybe Int) (45::Double),
info (Just 45::Maybe Int) (45::Double)
]
> multiListViewGetTSelections :: MultiListView x () -> IO [x]
> multiListViewGetTSelections multiListView =
> do { Just ((model, _) :: (Var [x], x -> String)) <-
> unsafeObjectGetClientData multiListView
[...]
{-# OPTIONS_GHC -fglasgow-exts #-}
data Multi a = Multi (IO (Maybe ([a], a->String)))
deMulti (Multi x) = x
multiGetList :: Multi x -> IO [x]
multiGetList m =
do { Just ((list,_) :: ([x],x->String)) <- deMulti m
; return list
}
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