diff --git a/monad-loops.cabal b/monad-loops.cabal
--- a/monad-loops.cabal
+++ b/monad-loops.cabal
@@ -1,5 +1,5 @@
 name:                   monad-loops
-version:                0.3.1.0
+version:                0.3.1.1
 stability:              provisional
 license:                BSD3
 license-file:           LICENSE
diff --git a/src/Control/Monad/Loops.hs b/src/Control/Monad/Loops.hs
--- a/src/Control/Monad/Loops.hs
+++ b/src/Control/Monad/Loops.hs
@@ -289,13 +289,13 @@
 -- twist.  Rather than returning a list, it returns any MonadPlus type of your
 -- choice.
 unfoldrM' :: (Monad m, MonadPlus f) => (a -> m (Maybe (b,a))) -> a -> m (f b)
-unfoldrM' f z = go
-    where go = do
+unfoldrM' f z = go z
+    where go z = do
             x <- f z
             case x of
                 Nothing         -> return mzero
                 Just (x, z)     -> do
-                        xs <- go
+                        xs <- go z
                         return (return x `mplus` xs)
 
 {-# SPECIALIZE concatM :: [a -> IO a] -> (a -> IO a) #-}