diff --git a/src/nix-eval-jobs.cc b/src/nix-eval-jobs.cc
index 51fb27e..2615f30 100644
--- a/src/nix-eval-jobs.cc
+++ b/src/nix-eval-jobs.cc
@@ -116,6 +116,18 @@ struct MyArgs : MixEvalArgs, MixCommonArgs
 
 static MyArgs myArgs;
 
+static Value* releaseExprTopLevelValue(EvalState & state, Bindings & autoArgs) {
+    Value vTop;
+
+    state.evalFile(lookupFileArg(state, myArgs.releaseExpr), vTop);
+
+    auto vRoot = state.allocValue();
+
+    state.autoCallFunction(autoArgs, vTop, *vRoot);
+
+    return vRoot;
+}
+
 static void worker(
     EvalState & state,
     Bindings & autoArgs,