diff --git a/Acme/Missiles.hs b/Acme/Missiles.hs
--- a/Acme/Missiles.hs
+++ b/Acme/Missiles.hs
@@ -14,9 +14,9 @@
 ) where
 
 import Control.Concurrent (forkIO, threadDelay)
-import Control.Monad (void)
+import Foreign.Marshal.Error (void)
 
--- | Cause serious international side-effects.
+-- | Cause serious international side effects.
 launchMissiles :: IO ()
 launchMissiles =
     void $ forkIO $ do
diff --git a/acme-missiles.cabal b/acme-missiles.cabal
--- a/acme-missiles.cabal
+++ b/acme-missiles.cabal
@@ -1,5 +1,5 @@
 name:                acme-missiles
-version:             0.1.0.0
+version:             0.1.1
 synopsis:            Cause serious international side effects.
 description:
     The highly effectful 'launchMissiles' action, as mentioned in /Beautiful concurrency/,