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Why does aeson-based installation not work?

I have two Arch (64) machines on which I am trying to install Yesod. Firstly, the simplest installation of "cabal install yesod" goes great. In the second case, I get the following error when building an aesod-dependent dependency:

Configuring aeson-native-0.3.3 ...
Preprocessing the aeson-native-0.3.3 library ...
Building aeson-native-0.3.3 ...
[1 of 6] Compiling Data.Aeson.Functions (Data / Aeson / Functions.hs, dist / build / Data / Aeson / Functions.o)
[2 of 6] Compilation of data. Aeson.Types (data / Aeson / Types.hs, dist / build / Data / Aeson / Types.o)

Data / eson / Types.hs: 196: 22:
There is no instance for the object (NFData object)
arising from the use of rnf'<br> Possible fix: add an instance declaration for (NFData Object)<br> In the expression: rnf o<br> In an equation for rnf': rnf (Object o) = rnf o
In the instance declaration for the NFData Value parameter
cabal: Error: some packages could not be installed:
aeson-native-0.3.3 failed at the construction stage. The exception was:
ExitFailure 1

After the failure above, I performed a new installation of ghc and deleted the ghc-pkg and .cabal directories. Again, the same error. There seems to be nothing wrong with aeson-native, as it works great elsewhere, so my environment should blame something. On a failed machine, I experimented in the past using pacman to manage hacker libraries (mainly for xmonad). Not sure if that matters, but I was never sure how / if the bondage and pacman have no idea what each other is doing.

GHC - 7.0.3. I made an update to cache all installations. Any ideas what might be wrong in this environment?

Thanks / o

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2 answers

You are not alone. This should be fixed:

 > cabal install deepseq-1.1.0.2 > ghc-pkg unregister deepseq-1.2.0.1 --force

And then you can install any aeson package. Make sure that this is really deepseq-1.2.0.1 that you installed by typing ghc-pkg list deepseq

I had this error too a few days ago, but for aeson not aeson-native . I pulled out the fix request on github, and then on the hack, but, unfortunately, only for aeson not aeson-native . May I suggest you try fulfilling the patch request in the aeson-native package. I am really pleased to return something to the community, try it! :)

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Object is simply a synonym for the Data.Map type, and it seems that the NFData instance for Data.Map has recently been moved from deepseq to containers .

However, this new version of containers apparently not yet been released in Hackage, so since you are using the latest version of deepseq , no instance was found in any packages.

I expect it to get better soon. Meanwhile, you should be able to downgrade deepseq to version 1.1.0.2 , which is the latest version before the instance was moved.

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