diff --git a/flake.nix b/flake.nix
index e412e53..ffdfe3e 100644
--- a/flake.nix
+++ b/flake.nix
@@ -2,6 +2,7 @@
   description = "nix-filter";
 
   outputs = { self }: {
+    __functor = self.lib.__functor;
     lib = import ./default.nix;
     overlays.default = _: _: { nix-filter = self.lib; };
   };