On Sat, May 24, 2008 at 1:11 AM, Thomas Hartman <[EMAIL PROTECTED]> wrote: > World.hs:42:0: > No instances for (Eq (a (M.Map String Player)), > Eq (a (M.Map ItemId Item)), > Eq (a (M.Map PlayerId Player)), > Eq (a (M.Map RoomId Room)), > Eq (a RoomId)) > arising from the 'deriving' clause of a data type declaration > at World.hs:(42,0)-(50,14) > Possible fix: > add an instance declaration for > (Eq (a (M.Map String Player)), > Eq (a (M.Map ItemId Item)), > Eq (a (M.Map PlayerId Player)), > Eq (a (M.Map RoomId Room)), > Eq (a RoomId)) > When deriving the instance for (Eq (World a))
This error looks suspicious: notice that "a" in a type-constructor position. My guess is that you're accidentally using World's type parameter in a strange way. Perhaps you should double-check that your types and constructor definitions are using parentheses appropriately. Stuart _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
