It's really a bug. I've fixed it in my tree, but I'm at 2.8 and don't have time to validate etc. So I'm doubtful that I'll be in time to get a fix into 6.12.1, alas.
Well, maybe I can build a patch and send it to Simon/Ian for testing. I'll try to do that if it's important to you.
it's bit of an exotic case because of the higher-kindedness so I don't think it'll bite too man people
There's a good workaround: use "standalone deriving".
You
| -----Original Message-----
| From: glasgow-haskell-users-bounces@haskell.org [mailto:glasgow-haskell-
| users-bounces@haskell.org] On Behalf Of Ron Alford
| Sent: 10 April 2010 22:33
| To: glasgow-haskell-users
| Subject: Re: Deriving regression or bad code?
|
| Just for fun, I tried it on 6.12.1.20100330 with the same result.
| Does anyone have a workaround? Otherwise I need to revert to 6.10.
|
| -Ron
|
| On Thu, Apr 8, 2010 at 10:35 AM, Ron Alford