brittany.nix

{ pkgs ? import <nixpkgs> { } }:

let
  brittany = pkgs.fetchFromGitHub {
    owner = "lspitzner";
    repo = "brittany";
    rev = "7b5c0dc4e398576dcc138741c8ca51f705a10ed1"; # add missing sha?
    sha256 = "1na2v15db2jf16vrmlzy7hblr63w6l6p72hr40i7c6dgxmg7vv52";
  };
  compiler = "ghc865";
  brittanyPkgs = import (builtins.fetchGit (import "${brittany}/pkgs.nix")) { haskell.packages.ghc865 = pkgs.haskell.packages.${compiler}; } ;
  # fix = f : let result = f result; in result;
  # with865 = brittanyPkgs (with865 // )
  # oldPkgsWith865 = brittanyPkgs.extend { haskell.packages.ghc865 = pkgs.callPackage pkgs.haskell.packages.${compiler} {}; };
in import "${brittany}/release.nix" { compiler = compiler ; 
                                    pkgs = brittanyPkgs;
                                  }

err.txt

error: anonymous function at /nix/store/sf383fa036yjih65d417rm2jzvysimwv-source/pkgs/top-level/default.nix:20:1 called with unexpected argument 'haskell', at /nix/store/sf383fa036yjih65d417rm2jzvysimwv-source/pkgs/top-level/impure.nix:82:1
(use '--show-trace' to show detailed location information)