[Nix-dev] Using several versions of GHC at once

[Peter Simons]

Hi Nikita,

 > I've also tried 'nix-env -p ~/ghc-6.10.4 -i cabal-install-1.16.0.2', but
 > 'binary' still fails with the same error:
 >
 > Warning: binary.cabal: This package requires Cabal version: >=1.8

I am not sure what is causing this error. The operation

  nix-env -i cabal-install-1.16.0.2

should install cabal-install built by the current default GHC version --
which is 7.6.3. That version comes with Cabal 1.16.x, so this error
should not occur.

I have committed a patch recently that fix building of cabal-install
with older GHC versions. Maybe that changes makes a difference. If you
have the chance, please try installing that package again with a recent
version of Nixpkgs.

Take care,
Peter