Error in cabal-installing hspec

Question

I'm trying to install hspec, but I'm getting this:

$ cabal install hspec
Resolving dependencies...                                                                                                                                               
cabal: dependencies conflict: ghc-7.2.2 requires containers ==0.4.2.0 however                                                                                           
containers-0.4.2.0 was excluded because ghc-7.2.2 requires containers                                                                                                   
==0.4.1.0                                                  

What does this even mean?

Also, using ghc 7.2.2, cabal 10.2.

Answer 1

It sounds like you somehow broke your GHC install. GHC 7.2.2 comes with containers-0.4.1.0 (the version of which is the same as for GHC 7.2.1). It might be possible to fix it, but if the global package setup is broken then it would probably be easiest to re-install GHC.

What does ghc-pkg list containers say?

If containers-0.4.2.2 is found only in the per-user install (i.e. the /home/clark/.ghc/${arch}-${os}-7.2.2/package.conf.d output), then rm'ing /home/clark/.ghc/ and re-installing all the packages you installed with cabal install will fix it.