13 Mar
2009
13 Mar
'09
4:49 a.m.
Hello,
On Thu, Mar 12, 2009 at 17:02, Bernd Brassel
Hi Bernd,
I guess this might be the same issue reported some time ago ( http://thread.gmane.org/gmane.comp.lang.haskell.generics/53/focus=54):
José Pedro Magalhães wrote: the
derived instances of Data do not define dataCast1. If you define your own instance of Data for MyMaybe and add the definition of dataCast1 you will get the expected behavior.
Your link pointed me in the right direction to fix the bug for my application. Many thanks! Did you submit a bug report?
Now I did: http://hackage.haskell.org/trac/ghc/ticket/3087 Thanks, Pedro