On Sun, Jul 18, 2010 at 5:59 PM, Emil Melnikov <emilm...@gmail.com> wrote: > On 2010, July 18, 23:27 > Ivan Lazar Miljenovic <ivan.miljeno...@gmail.com> wrote: > >> When discussing a similar issue with Manuel Chakravarty, he convinced me >> that cunning newtype deriving is actually rather bad in practice and >> shouldn't be used as there's a lack of proofs or some such (I can't >> remember the arguments, but I remember being convinced by them :p). > > Hmm... I can't imagine how it is possible, since new and > original types are isomorphic. > > Can you give me some pointers to this discussion (links or > keywords)? >
They are isomorphic, but distinct. This trac ticket is relevant: http://hackage.haskell.org/trac/ghc/ticket/1496 _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
