
Jason Dagit
On Fri, Nov 21, 2008 at 8:57 AM, Simon Peyton-Jones
You need a type signature for the case expression. As Daniel says, this is worth a readhttp://haskell.org/haskellwiki/Upgrading_packages%23Changes_to_GADT_matching...
Thanks Simon. I had read that several times in the past and I've pointed it out to others. It's still relevant but, my question was about whether or not examples like the one posted are really in error or if GHC is just being overly strict now.
In my case, we had rigid type signatures all over the place. The wiki document says that the type must be rigid at the point of the match. I guess
microsoft.com> wrote: that's what we were violating. If the code I posted isn't supposed to type check then I would like to report, as user feedback, that GADTs have become unwieldy. This is really worrying. I have spent some considerable time using GADTs to structure a library. I haven't tried 6.10 yet because it's not available in a packaged form for my flavour of linux. I will put some work into doing this today and report back. Dominic.