diff --git a/pkgs/top-level/guile-2-test.nix b/pkgs/top-level/guile-2-test.nix
index bb2b7daa83fb..ffa216e8ef61 100644
--- a/pkgs/top-level/guile-2-test.nix
+++ b/pkgs/top-level/guile-2-test.nix
@@ -8,7 +8,7 @@ let
 
   pkgs = allPackages {
     config = {
-      packageOverrides = pkgs: pkgs // { guile = pkgs.guile_1_9; };
+      packageOverrides = (pkgs: pkgs // { guile = pkgs.guile_1_9; });
     };
   };