ihaskell_emacs_error:

      # ihaskell package installation:
      (lib.lowPrio
      (let ihaskell = pkgs.fetchFromGitHub {
        owner = "gibiansky";
        repo = "IHaskell";
        rev = "a442c0b6d4cf1fb17eaa3bf2827f04b21ad334bf";
        sha256 = "0fprbj4g02wn8600siwy4wizz8qx4imsvlvkr36p2ndmrpsynbbl";
      };
       in import "${ihaskell}/release.nix" {
                                             compiler = "ghc865";
                                             nixpkgs = pkgs;
                                             packages = self: with self; [];
					                                 }))