I believe this is because of aeson depending on *any* version of deepseq. This was very recently fixed in the development version:
https://github.com/mailrank/aeson/pull/25 2011/9/20 Rune Harder Bak <[email protected]>: > Sometimes when one of our developers (using Arch-linux) tries to cabal > install packages he gets > a "no instance for" error. > Code that compiles fine on my computer, and other computers I try it > on. Even some packages on hackage > (trying to install aeson-native for instance gives Data/Aeson/Types.hs:196:22: > No instance for (NFData Object) > arising from a use of `rnf' > Possible fix: add an instance declaration for (NFData Object) > In the expression: rnf o > In an equation for `rnf': rnf (Object o) = rnf o > In the instance declaration for `NFData Value') > I tried removing the .ghc and .cabal folder, even reinstalled ghc-7.04 > and cabal-install (most recent), but the problem persisted (might not > have been a clean install though, I'm no Arch expert) > I know this is kind of vauge, and not in she shape of filling a bug > report, heck I can't even reproduce the error on my computer. > But perhaps somebody else has run in to this strange behavior before? > > Best, > Rune > > _______________________________________________ > Haskell-Cafe mailing list > [email protected] > http://www.haskell.org/mailman/listinfo/haskell-cafe > _______________________________________________ Haskell-Cafe mailing list [email protected] http://www.haskell.org/mailman/listinfo/haskell-cafe
