default.nix: rm data-fix override

Author: Anton-Latukha

default.nix

@@ -223,20 +223,6 @@ let
     root = packageRoot;
 
     overrides = self: super: {
-      # 2020-07-23 hnix uses multiple functions that are unavailable in
-      # data-fix < 0.3.
-      data-fix = haskellPackages.callPackage
-       ({ mkDerivation, base, deepseq, hashable, stdenv }:
-        mkDerivation {
-          pname = "data-fix";
-          version = "0.3.0";
-          sha256 = "9e59b3ed694b5139316093b3767842e60ad4821858459e7cd763e5773dfa99a0";
-          libraryHaskellDepends = [ base deepseq hashable ];
-          homepage = "https://github.com/spell-music/data-fix";
-          description = "Fixpoint data types";
-          license = stdenv.lib.licenses.bsd3;
-        }) {};
-
       # 2020-08-04 hnix uses custom LayoutOptions and therefore is
       # likely to be affected by the change in the ribbon width
       # calculation in prettyprinter-1.7.0.