nixpkgs/pkgs/misc/bleeding-edge-fetch-info/haskell_src_exts.nix

 args: with args; fetchurl { 
  url = http://mawercer.de/~nix/repos/haskell_src_exts.tar.gz;
  sha256 = "6cb2214ee3a62083325c907e47979b5fdf6809ce0ef2cd400fba0219b3f42090";}