[Haskell-beginners] cabal install hakyll: global constraint requires installed instance + other conflicts

Daniel Trstenjak daniel.trstenjak at gmail.com
Thu Aug 25 12:43:17 UTC 2016


Hi Stanislaw,

> What is going on here? Why am I getting different errors with the new
> cabal version?

No idea. Perhaps remove the sandbox for the hakyll build and start a new
one.

> What is the relationship between system-wide packages and those in the
> sandbox? I thought sandbox is meant to be an isolated environment?!?

Some packages are fixed with the GHC version, like the base one.

> How do I get the list of all the packages currently installed in the
> sandbox? Is this:
> 
> $ ls ./lib/x86_64-linux-ghc-7.6.3/
> the way?

Yes.

> Why is 'base' not on the list, although the new cabal is not
> complaining about it anymore?

The last hakyll version supporting your ghc compiler 7.6.3 was 4.7.5.2.

I don't know why cabal gets stuck here, it should take this hakyll
version, but you might help cabal with its dependency resolution by
directly installing 4.7.5.2:

   cabal install hakyll-4.7.5.2

Greetings,
Daniel


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