diff --git a/library/Potoki/Core/Produce.hs b/library/Potoki/Core/Produce.hs
--- a/library/Potoki/Core/Produce.hs
+++ b/library/Potoki/Core/Produce.hs
@@ -9,8 +9,8 @@
 
 instance Applicative Produce where
   pure x = Produce $ do
-    refX <- newIORef (Just x)
-    return (A.maybeRef refX, pure ())
+    refX <- liftIO (newIORef (Just x))
+    return (A.maybeRef refX)
   (<*>) (Produce leftManaged) (Produce rightManaged) =
     Produce ((<*>) <$> leftManaged <*> rightManaged)
 
diff --git a/potoki-core.cabal b/potoki-core.cabal
--- a/potoki-core.cabal
+++ b/potoki-core.cabal
@@ -1,7 +1,7 @@
 name:
   potoki-core
 version:
-  0.9
+  0.9.1
 synopsis:
   Low-level components of "potoki"
 description: