diff --git a/pkgs/development/ocaml-modules/cstruct/default.nix b/pkgs/development/ocaml-modules/cstruct/default.nix
index 8fac97fde6c9..38bfe8236153 100644
--- a/pkgs/development/ocaml-modules/cstruct/default.nix
+++ b/pkgs/development/ocaml-modules/cstruct/default.nix
@@ -7,7 +7,7 @@
   crowbar,
 }:
 
-buildDunePackage rec {
+buildDunePackage (finalAttrs: {
   pname = "cstruct";
   version = "6.2.0";
 
@@ -15,7 +15,7 @@ buildDunePackage rec {
   duneVersion = "3";
 
   src = fetchurl {
-    url = "https://github.com/mirage/ocaml-cstruct/releases/download/v${version}/cstruct-${version}.tbz";
+    url = "https://github.com/mirage/ocaml-cstruct/releases/download/v${finalAttrs.version}/cstruct-${finalAttrs.version}.tbz";
     hash = "sha256-mngHM5JYDoNJFI+jq0sbLpidydMNB0AbBMlrfGDwPmI=";
   };
 
@@ -33,4 +33,4 @@ buildDunePackage rec {
     homepage = "https://github.com/mirage/ocaml-cstruct";
     maintainers = [ lib.maintainers.vbgl ];
   };
-}
+})