diff --git a/pkgs/development/ocaml-modules/macaddr/default.nix b/pkgs/development/ocaml-modules/macaddr/default.nix
index 7de7d60b912c..aab3c3a79568 100644
--- a/pkgs/development/ocaml-modules/macaddr/default.nix
+++ b/pkgs/development/ocaml-modules/macaddr/default.nix
@@ -7,14 +7,14 @@
   ounit2,
 }:
 
-buildDunePackage rec {
+buildDunePackage (finalAttrs: {
   pname = "macaddr";
   version = "5.6.2";
 
   minimalOCamlVersion = "4.04";
 
   src = fetchurl {
-    url = "https://github.com/mirage/ocaml-ipaddr/releases/download/v${version}/ipaddr-${version}.tbz";
+    url = "https://github.com/mirage/ocaml-ipaddr/releases/download/v${finalAttrs.version}/ipaddr-${finalAttrs.version}.tbz";
     hash = "sha256-CKP6bmQRSQtmYeWxAinqnsa4w3OOn2slWFmxPxRb4TY=";
   };
 
@@ -30,4 +30,4 @@ buildDunePackage rec {
     license = lib.licenses.isc;
     maintainers = [ ];
   };
-}
+})