> GHC (5.03.20020410) wrongly accepts the following: > > :::::::::::::: > C.lhs > :::::::::::::: > > module C > > where > > > class A a where > > a :: a -> Int > :::::::::::::: > X.lhs > :::::::::::::: > > module X > > where > > import qualified C > > > instance C.A Int where > > C.a = id
This has been fixed, and GHC 5.04 will behave correctly. > Incidentally, I also noticed that GHC and Hugs behave differently > for the following variant of X.lhs. > > :::::::::::::: > X.lhs > :::::::::::::: > > module X > > where > > import qualified C > > > instance C.A Int where > > a = const X.a > > > a = 4 > > GHC happily accepts the file while Hugs complains that > > ERROR "X.lhs":6 - Type error in instance member binding > *** Term : a > *** Type : a -> Integer > *** Does not match : Int -> Int > > There seems to be a difference in defaulting. [Don't ask me > which is the correct behaviour.] The problem disappears if I > supply an explicit type signature for `a'. Hugs's defaulting behaviour differs from Haskell 98 (and always has done). See for example this discussion on the Haskell mailing list: http://www.haskell.org/pipermail/haskell/2002-May/009616.html (plus other messages with the same subject). Could someone from the Hugs camp please document this? Cheers, Simon _______________________________________________ Glasgow-haskell-bugs mailing list [EMAIL PROTECTED] http://www.haskell.org/mailman/listinfo/glasgow-haskell-bugs
