Hi Simon,

You should be giving a type signature to rewrap! That should fix it.

Thanks, all works fine now :-) Neil

| -----Original Message----- | From: glasgow-haskell-users-bounces@haskell.org [mailto:glasgow-haskell-users-bounces@haskell.org] On Behalf Of | Neil Mitchell | Sent: 17 December 2007 16:23 | To: glasgow-haskell-users@haskell.org | Subject: GADT pattern match in non-rigid context | | Hi, | | Upgrading from GHC 6.6 to 6.8 has caused some code to stop working: | | ---------------------------------------------------------------------- | {-# OPTIONS_GHC -fglasgow-exts #-} | | module Data2 where | | data CCompany | | data Paradise :: * -> * where | CC :: Paradise CCompany | | rewrapCC CC = [] | ---------------------------------------------------------------------- | | [1 of 1] Compiling Data2 ( Data2.hs, interpreted ) | | Data2.hs:12:9: | GADT pattern match in non-rigid context for `CC' | Tell GHC HQ if you'd like this to unify the context | In the pattern: CC | In the definition of `rewrapCC': rewrapCC CC = [] | | This code is from the Uniplate benchmarking code, which runs the | Paradise benchmark from SYB on Uniplate, Compos and SYB. The Compos | code uses GADT's, so the program first needs to convert from standard | data structures to GADT's before it can work, then back at the end. | It's the problem of converting from a GADT to a normal data structure | that is failing. | | So is there an easy workaround? Or should I be asking GHC HQ to unify things? | | Thanks | | Neil | _______________________________________________ | Glasgow-haskell-users mailing list | Glasgow-haskell-users@haskell.org | http://www.haskell.org/mailman/listinfo/glasgow-haskell-users

| >> You should be giving a type signature to rewrap! That should fix it. | > | > Thanks, all works fine now :-) | | it would be great if the error message suggested giving a type signature | as a solution (or maybe it already does, in the HEAD?) Good point: I'll do that. Simon | >> | -----Original Message----- | >> | From: glasgow-haskell-users-bounces@haskell.org [mailto:glasgow-haskell- | users-bounces@haskell.org] On Behalf Of | >> | Neil Mitchell | >> | Sent: 17 December 2007 16:23 | >> | To: glasgow-haskell-users@haskell.org | >> | Subject: GADT pattern match in non-rigid context | >> | | >> | Hi, | >> | | >> | Upgrading from GHC 6.6 to 6.8 has caused some code to stop working: | >> | | >> | ---------------------------------------------------------------------- | >> | {-# OPTIONS_GHC -fglasgow-exts #-} | >> | | >> | module Data2 where | >> | | >> | data CCompany | >> | | >> | data Paradise :: * -> * where | >> | CC :: Paradise CCompany | >> | | >> | rewrapCC CC = [] | >> | ---------------------------------------------------------------------- | >> | | >> | [1 of 1] Compiling Data2 ( Data2.hs, interpreted ) | >> | | >> | Data2.hs:12:9: | >> | GADT pattern match in non-rigid context for `CC' | >> | Tell GHC HQ if you'd like this to unify the context | >> | In the pattern: CC | >> | In the definition of `rewrapCC': rewrapCC CC = [] | >> | | >> | This code is from the Uniplate benchmarking code, which runs the | >> | Paradise benchmark from SYB on Uniplate, Compos and SYB. The Compos | >> | code uses GADT's, so the program first needs to convert from standard | >> | data structures to GADT's before it can work, then back at the end. | >> | It's the problem of converting from a GADT to a normal data structure | >> | that is failing. | >> | | >> | So is there an easy workaround? Or should I be asking GHC HQ to unify | things? | >> | | >> | Thanks | >> | | >> | Neil | >> | _______________________________________________ | >> | Glasgow-haskell-users mailing list | >> | Glasgow-haskell-users@haskell.org | >> | http://www.haskell.org/mailman/listinfo/glasgow-haskell-users | >> | > _______________________________________________ | > Glasgow-haskell-users mailing list | > Glasgow-haskell-users@haskell.org | > http://www.haskell.org/mailman/listinfo/glasgow-haskell-users | >