Re: [Haskell-cafe] Bad interface problem.

-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Hi, On 11/07/12 05:51, Magicloud Magiclouds wrote:

I cleaned out everything, no luck....

On Fri, Jul 6, 2012 at 2:14 AM, Albert Y. C. Lai wrote:

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On 12-07-03 04:19 AM, Magicloud Magiclouds wrote:

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template-haskell-2.6.0.0:Language.Haskell.TH differs from name found in the interface file template-haskell:Language.Haskell.TH

You installed a bad template-haskell version. You can only use a version corresponding to your ghc version. I had a similar problem recently. My solution process was as follows: 1. check which template-haskell version came with my ghc: $ ghc -V The Glorious Glasgow Haskell Compilation System, version 7.4.2 $ ghc-pkg list template-haskell /home/claude/opt/lib/ghc-7.4.2/package.conf.d template-haskell-2.7.0.0 /home/claude/.ghc/x86_64-linux-7.4.2/package.conf.d $ 2. make sure to forbid every other version of template-haskell (because it will break horribly, as you found): $ cabal install --constraint='template-haskell==2.7.0.0' foo 3. if foo fails to install because it thinks it needs a different version of template-haskell, try adjusting dependencies in foo.cabal 4. if foo installs and works with the adjusted dependencies, let the maintainer know

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I think things are so messed up that it is time to clean out everything. See my http://www.vex.net/~trebla/haskell/sicp.xhtml#remove

In fact, time to read the whole article and avoid unsafe re-installs and "upgrades".

It's a good read for sure! Perhaps it could be updated to add a problem I ran into recently: "cabal install --solver=modular --avoid-reinstalls" sounds perfect, if sicp.xhtml scared you properly. But excessively avoiding reinstalls is bad, as cabal-install seems to install a different allowable version instead. The result for me was horrible diamond dependency problems - half my packages were built with one version of mtl/transformers, and the other half with a different version of mtl/transformers. When I then tried to ghci using some modules from both halves of my installed packages, I got very very confusing type errors complaining about almost-identical-looking types not being identical. Claude -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.12 (GNU/Linux) iQEcBAEBAgAGBQJP/RBbAAoJEHZDo4jueIiW164IALlHcaauJX2AjBZTDExU0mKC wlH+dIbaKkl8H1IMIXQnWSX0GxFGMsbPTdBXf/BC2CMXTcSJr8YMiyKewMAs734g DijNU/x/nQlcVruOk1c8EAijIKs938vT3dF0j863+afMAA+cRWlyLWfV50Y7AIG6 4hF0Fr5Q73GwonFzTXuX+iWLxBL1i2jXgPjKJvNTJZr+iGn5txCj+6ZpJyfIXaaw PZtQrnX/37vQ/ctbKsnDqRQI27/ENJyW3zm76Gax47EIpMvL8fHzEg8IpyR9/eR8 8ZfGKYNA1EsARHT3KS6pBPsVQdhn/qYInVZ5NYQ1r/kd9D6nqoy5pETdz3z/23Y= =Rzob -----END PGP SIGNATURE-----