I have to admit that I didn't test it before my first response. But now I did and can verify that it in deed "it does relay an error from deriving module to using [module/ghci]". So if I don't do any comparisons on Ego everything succeeds. If there is any comparision then ghc (6.6 in my case) returns the appropriate error.
Still a bit strange for me, but now atleast I know it. :-) Andreas ----- Original Message ----- From: "Isaac Dupree" <[EMAIL PROTECTED]> To: "Andreas Marth" <[EMAIL PROTECTED]> Cc: "Dougal Stanton" <[EMAIL PROTECTED]>; "haskell-cafe" <haskell-cafe@haskell.org> Sent: Thursday, August 09, 2007 8:06 PM Subject: Re: [Haskell-cafe] Derivation of Eq given Ord > Andreas Marth wrote: > > I would say that qualifies as a bug because it relays an error from compile > > time to run time. > > It doesn't relay anything to run time - ghci has to _compile_ the > expressions you give it too. If you _compile something_ successfully, > you will know that _it_ will not fail in the stated way (which is all > you need to know for a normal program with 'main'). > > However it does relay an error from deriving module to using > [module/ghci], which may not be right. HOWEVER, I can't reproduce it - > ghc (6.6.1) always tells me > No instance for (Eq Foo) > arising from the superclasses of an instance declaration > whether data or newtype, deriving Ord, no Eq instance, and no using > operations at all, and Hugs does too (in different words). > > Isaac _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
