diff --git a/pkgs/applications/science/logic/redprl/default.nix b/pkgs/applications/science/logic/redprl/default.nix
index 05a7b63f5568..eece691bfd78 100644
--- a/pkgs/applications/science/logic/redprl/default.nix
+++ b/pkgs/applications/science/logic/redprl/default.nix
@@ -1,25 +1,32 @@
-{ lib, stdenv, fetchgit, mlton }:
+{ lib, stdenv, fetchFromGitHub, mlton }:
+
 stdenv.mkDerivation {
   pname = "redprl";
   version = "unstable-2017-03-28";
 
-  src = fetchgit {
-    url = "https://github.com/RedPRL/sml-redprl.git";
+  src = fetchFromGitHub {
+    owner = "RedPRL";
+    repo = "sml-redprl";
     rev = "bdf027de732e4a8d10f9f954389dfff0c822f18b";
-    sha256 = "0cihwnd78d3ksxp6mppifm7xpi3fsii5mixvicajy87ggw8z305c";
     fetchSubmodules = true;
+    sha256 = "0cihwnd78d3ksxp6mppifm7xpi3fsii5mixvicajy87ggw8z305c";
   };
+
   buildInputs = [ mlton ];
-  patchPhase = ''
+
+  postPatch = ''
     patchShebangs ./script/
   '';
+
   buildPhase = ''
     ./script/mlton.sh
   '';
+
   installPhase = ''
     mkdir -p $out/bin
     mv ./bin/redprl $out/bin
   '';
+
   meta = with lib; {
     description = "A proof assistant for Nominal Computational Type Theory";
     homepage = "http://www.redprl.org/";