[Nix-dev] package dependency problem: ghc-mod: cannot satisfy -package-id mtl-2.1.3.1

[Peter Simons]

Hi Paul,

 > I have a problem keeping ghc-mod happy. After trying a number of other
 > approaches I have opted to install all haskell packages to my profile
 > via the 'hsEnv' approach. 

what exactly is an hsEnv approach?

Best regards,
Peter