Deriving regression or bad code?

[Simon Peyton-Jones]

The standalone deriving decl you need is the one for (Data (a :+: b)), not for Expr

Simon

| -----Original Message-----
| From: glasgow-haskell-users-bounces at haskell.org [mailto:glasgow-haskell-
| users-bounces at haskell.org] On Behalf Of Ron Alford
| Sent: 12 April 2010 11:09
| To: Simon Peyton-Jones
| Cc: glasgow-haskell-users
| Subject: Re: Deriving regression or bad code?
| 
| I was getting a similar error with standalone deriving (already
| attached to that bug), but I didn't try it through-out.  I'll let you
| know how it goes.
| 
| -Ron
| 
| 
| On Mon, Apr 12, 2010 at 6:01 AM, Simon Peyton-Jones
| <simonpj at microsoft.com> wrote:
| > 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 at haskell.org [mailto:glasgow-haskell-
| > | users-bounces at 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 <ronwalf at volus.net> wrote:
| > | > At Igloo's suggestion, it's now a ticket:
| > | > http://hackage.haskell.org/trac/ghc/ticket/3965
| > | >
| > | > -Ron
| > | >
| > | > On Thu, Apr 8, 2010 at 1:39 AM, Ron Alford <ronwalf at volus.net> wrote:
| > | >> I've attached the simplest example of my code that used to compile in
| > | >> GHC 6.10 now gives the error in GHC 6.12.1:
| > | > ...
| > | >
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| >
| >
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