[Nix-dev] ghc-mod + nix-shell?

[Mateusz Kowalczyk]

Hi,

ghc-mod-5.x just came out so I thought I'll give it a try again – I had
bad experience with it when on Gentoo as it really hates mixing GHC
versions.

What I did was package 5.x and then add it to buildTools of my project
through shell.nix

After updating the cabal file and running cabal configure so it would
stop complaining, ‘ghc-mod’ command itself works:

[nix-shell:~/programming/tsuntsun]$ ghc-mod check src/Main.hs
src/Main.hs:62:1:The type signature for ‘unlessM’ lacks an accompanying
binding


but ghc-modi which is what is actually used does not:

[nix-shell:~/programming/tsuntsun]$ ghc-modi
NG BUG: <command line>: cannot satisfy -package-id
text-1.1.1.3-19b1d34e1f78946a216fb2a95da8973b\n    (use -v for more
information)

If I run ghc-pkg check then it tells me the package is broken

[nix-shell:~/programming/tsuntsun]$ TERM=xterm ghc-pkg check
There are problems in package ghc-mod-5.0.1:
  dependency "djinn-ghc-0.0.2.2-c9b696804551566f24c6318e5fc83a11"
doesn't exist
  dependency "ghc-paths-0.1.0.9-7d0e6178c3518b928e3a89e76cbed29c"
doesn't exist
  dependency "ghc-syb-utils-0.2.1.2-981aa43f46526d20b8f2800284ea5c4a"
doesn't exist
  dependency
"haskell-src-exts-1.15.0.1-2a731a74bc57b134a58a272454970c29" doesn't exist
  dependency "hlint-1.9.3-5855c5e6c81c6eee0e4e737b366a37d4" doesn't exist
  dependency "io-choice-0.0.5-77f5291ed82ac6c645917df71b2b8442" doesn't
exist
  dependency "monad-control-0.3.3.0-77020b8cc5cc6089930c75c98b452cd1"
doesn't exist
  dependency "monad-journal-0.2.3.0-aaa5a7e6af8534c7d3dbc5368ac0884a"
doesn't exist
  dependency "split-0.2.2-7c6e2bd13c1e04b85cc7ee759efb1a08" doesn't exist
  dependency "syb-0.4.2-3b61f5272a0cd76f5fc4924f04a86453" doesn't exist
  dependency "transformers-base-0.4.2-6e58862b37a26c65c3a96fa2518f39c3"
doesn't exist

The following packages are broken, either because they have a problem
listed above, or because they depend on a broken package.
ghc-mod-5.0.1


Does someone know what the proper way to use ghc-mod + nix-shell is? The
only thing I can find online is ghcWithPackages inside systemPackages
but I don't like that ‘solution’ and I suspect it would not work anyway:
it would not be able to see the packages inside my nix-shell.


-- 
Mateusz K.