diff --git a/pkgs/development/libraries/msgpack-c/default.nix b/pkgs/development/libraries/msgpack-c/default.nix
index ded03015f39f..fed8cee33231 100644
--- a/pkgs/development/libraries/msgpack-c/default.nix
+++ b/pkgs/development/libraries/msgpack-c/default.nix
@@ -6,14 +6,14 @@
 , zlib
 }:
 
-stdenv.mkDerivation rec {
+stdenv.mkDerivation (finalAttrs: {
   pname = "msgpack-c";
   version = "6.0.0";
 
   src = fetchFromGitHub {
     owner = "msgpack";
     repo = "msgpack-c";
-    rev = "refs/tags/c-${version}";
+    rev = "refs/tags/c-${finalAttrs.version}";
     hash = "sha256-TfC37QKwqvHxsLPgsEqJYkb7mpRQekbntbBPV4v4FO8=";
   };
 
@@ -25,7 +25,7 @@ stdenv.mkDerivation rec {
 
   cmakeFlags = [
     "-DMSGPACK_BUILD_EXAMPLES=OFF" # examples are not installed even if built
-  ] ++ lib.optional (!doCheck) "-DMSGPACK_BUILD_TESTS=OFF";
+  ] ++ lib.optional (!finalAttrs.doCheck) "-DMSGPACK_BUILD_TESTS=OFF";
 
   checkInputs = [
     gtest
@@ -37,8 +37,8 @@ stdenv.mkDerivation rec {
   meta = with lib; {
     description = "MessagePack implementation for C";
     homepage = "https://github.com/msgpack/msgpack-c";
-    changelog = "https://github.com/msgpack/msgpack-c/blob/${src.rev}/CHANGELOG.md";
+    changelog = "https://github.com/msgpack/msgpack-c/blob/${finalAttrs.src.rev}/CHANGELOG.md";
     license = licenses.boost;
     maintainers = with maintainers; [ nickcao ];
   };
-}
+})