On Sun, Aug 11, 2013 at 10:00 PM, Richard Eisenberg <e...@cis.upenn.edu> wrote: > According to the Haskell 2010 report > (http://www.haskell.org/onlinereport/haskell2010/haskellch11.html#x18-18200011), > a datatype with no constructors cannot derive any instances.
You're quite right! I should have looked over the ticket first, where Adam pointed this out. > But, instead of creating a new extension for this feature, what about just > co-opting EmptyDataDecls? More concretely, I propose this: > > Under H98: EmptyDataDecls allows both the declaration of empty data decls and > deriving instances for them. > > Under H2010: EmptyDataDecls allows deriving instances for empty data decls. > > This proposal brings the annoyance that H2010 no longer implies > EmptyDataDecls. > > Thoughts? > > Richard > IMHO, I'd find this inconsistency in extension behavior much more annoying than just going against the standard on this note. But that's just my 0.02c. -- Regards, Austin - PGP: 4096R/0x91384671 _______________________________________________ ghc-devs mailing list ghc-devs@haskell.org http://www.haskell.org/mailman/listinfo/ghc-devs
