config.nix

{
  packageOverrides = super: let self = super.pkgs; in
  {
    haskellPackages = super.haskellPackages.override {
      overrides = self: super: {
        project-m36-typed  = self.callPackage ~/test/project-m36-typed {};
        generic-lens       = self.callPackage ~/example/generic-lens {};
#        QuickCheck         = self.haskell.lib.doJailBreak super.QuickCheck {};
      };
    };
  };
}