diff --git a/pkgs/development/ocaml-modules/hpack/default.nix b/pkgs/development/ocaml-modules/hpack/default.nix
index 8a865415e338..ed0863275241 100644
--- a/pkgs/development/ocaml-modules/hpack/default.nix
+++ b/pkgs/development/ocaml-modules/hpack/default.nix
@@ -6,12 +6,12 @@
   faraday,
 }:
 
-buildDunePackage rec {
+buildDunePackage (finalAttrs: {
   pname = "hpack";
   version = "0.13.0";
 
   src = fetchurl {
-    url = "https://github.com/anmonteiro/ocaml-h2/releases/download/${version}/h2-${version}.tbz";
+    url = "https://github.com/anmonteiro/ocaml-h2/releases/download/${finalAttrs.version}/h2-${finalAttrs.version}.tbz";
     hash = "sha256-DYm28XgXUpTnogciO+gdW4P8Mbl1Sb7DTwQyo7KoBw8=";
   };
 
@@ -34,4 +34,4 @@ buildDunePackage rec {
       anmonteiro
     ];
   };
-}
+})