diff --git a/pkgs/development/ocaml-modules/brr/default.nix b/pkgs/development/ocaml-modules/brr/default.nix
index 12a8a1635fd9..d16508db6303 100644
--- a/pkgs/development/ocaml-modules/brr/default.nix
+++ b/pkgs/development/ocaml-modules/brr/default.nix
@@ -10,11 +10,11 @@
   js_of_ocaml-toplevel,
 }:
 
-stdenv.mkDerivation rec {
+stdenv.mkDerivation (finalAttrs: {
   pname = "ocaml${ocaml.version}-brr";
   version = "0.0.8";
   src = fetchurl {
-    url = "https://erratique.ch/software/brr/releases/brr-${version}.tbz";
+    url = "https://erratique.ch/software/brr/releases/brr-${finalAttrs.version}.tbz";
     hash = "sha256-g4ROHy9rHlaEFi5+euyRuEKK5HwKJWPmFkdvFhdIYgg=";
   };
   buildInputs = [
@@ -36,4 +36,4 @@ stdenv.mkDerivation rec {
     maintainers = [ lib.maintainers.vbgl ];
     inherit (ocaml.meta) platforms;
   };
-}
+})