That would make it impossible to have a failed pattern match become an automatic 'fail' with a MonadFail constraint, right? I think that's a pretty nice feature, actually. But perhaps I misunderstand your idea. Erik On Wed, Jun 10, 2015 at 3:00 PM, Johan Tibell <johan.tibell@gmail.com> wrote:
An idea. Could the new desugaring be the same as for normal functions with a missing case? Code that uses fail would have to add the constraint still, but code that really didn't want to use fail would 1) get a warning about an incomplete pattern match and 2) get a runtime error for the failed pattern match produced by GHC. Is there anything I'm not thinking of here why this wouldn't work?
_______________________________________________ Libraries mailing list Libraries@haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/libraries