Tomasz I'm happy to say that this is fixed. Try the HEAD. I've immortalised your example as tests gadt21 and gadt22
Simon | -----Original Message----- | From: Tomasz Zielonka [mailto:[EMAIL PROTECTED] | Sent: 14 November 2006 07:31 | To: Simon Peyton-Jones | Subject: Re: Major type-class overhaul | | On Mon, Nov 13, 2006 at 03:33:25PM +0000, Simon Peyton-Jones wrote: | > | If you want, I can create a small example. | > | > yes please. I can't help at all without ! | | It seems that it was my error, at least to some degree. Example | code giving this strange error: | | {-# OPTIONS -fglasgow-exts -Wall #-} | | module Expr where | | import Data.Set (Set) | | data Type a where | TypeInt :: Type Int | TypeSet :: {- Ord a => -} Type a -> Type (Set a) | TypeFun :: Type a -> Type b -> Type (a -> b) | | data Expr :: * -> * where | Const :: Type a -> a -> Expr a | | data DynExpr = forall a. DynExpr (Expr a) | | withOrdDynExpr :: DynExpr -> (forall a. Ord a => Expr a -> b) -> | Maybe b | withOrdDynExpr (DynExpr e@(Const (TypeSet _) _)) f = Just (f e) | withOrdDynExpr (DynExpr e@(Const TypeInt _)) f = Just (f e) | withOrdDynExpr _ _ = Nothing | | It compiles when you uncomment the (Ord a) context. | When there is no context, I get the "Overlapping instances" | error. | | Best regards | Tomasz _______________________________________________ Cvs-ghc mailing list [EMAIL PROTECTED] http://www.haskell.org/mailman/listinfo/cvs-ghc
