diff --git a/Simulation/Aivika/IO/Generator.hs b/Simulation/Aivika/IO/Generator.hs
--- a/Simulation/Aivika/IO/Generator.hs
+++ b/Simulation/Aivika/IO/Generator.hs
@@ -87,7 +87,7 @@
   newGenerator tp =
     case tp of
       SimpleGenerator ->
-        MWC.uniform <$> MWC.withSystemRandom (return :: MWC.GenIO -> IO MWC.GenIO) >>= newRandomGenerator01
+        MWC.uniform <$> MWC.createSystemRandom >>= newRandomGenerator01
       SimpleGeneratorWithSeed x ->
         MWC.uniform <$> MWC.initialize (singleton x) >>= newRandomGenerator01
       CustomGenerator g ->
diff --git a/Simulation/Aivika/Trans/DoubleLinkedList.hs b/Simulation/Aivika/Trans/DoubleLinkedList.hs
--- a/Simulation/Aivika/Trans/DoubleLinkedList.hs
+++ b/Simulation/Aivika/Trans/DoubleLinkedList.hs
@@ -211,10 +211,10 @@
                              (Nothing, Nothing) ->
                                do writeRef (listHead x) Nothing
                                   writeRef (listTail x) Nothing
-                             (Nothing, head' @ (Just item')) ->
+                             (Nothing, head'@(Just item')) ->
                                do writeRef (itemPrev item') Nothing
                                   writeRef (listHead x) head'
-                             (tail' @ (Just item'), Nothing) ->
+                             (tail'@(Just item'), Nothing) ->
                                do writeRef (itemNext item') Nothing
                                   writeRef (listTail x) tail'
                              (Just prev', Just next') ->
diff --git a/Simulation/Aivika/Trans/Internal/Cont.hs b/Simulation/Aivika/Trans/Internal/Cont.hs
--- a/Simulation/Aivika/Trans/Internal/Cont.hs
+++ b/Simulation/Aivika/Trans/Internal/Cont.hs
@@ -821,7 +821,7 @@
           invokeEvent p $ writeRef rc Nothing
           case c of
             Nothing -> return Nothing
-            z @ (Just c) ->
+            z@(Just c) ->
               do f <- invokeEvent p $
                       contPreemptionBegun $
                       contId $ contAux c
diff --git a/Simulation/Aivika/Trans/Stream.hs b/Simulation/Aivika/Trans/Stream.hs
--- a/Simulation/Aivika/Trans/Stream.hs
+++ b/Simulation/Aivika/Trans/Stream.hs
@@ -323,7 +323,7 @@
 -- | Replace the 'Left' values.
 replaceLeftStream :: MonadDES m => Stream m (Either a b) -> Stream m c -> Stream m (Either c b)
 {-# INLINABLE replaceLeftStream #-}
-replaceLeftStream (Cons sab) (ys0 @ ~(Cons sc)) = Cons z where
+replaceLeftStream (Cons sab) (ys0@(Cons sc)) = Cons z where
   z = do (a, xs) <- sab
          case a of
            Left _ ->
@@ -335,7 +335,7 @@
 -- | Replace the 'Right' values.
 replaceRightStream :: MonadDES m => Stream m (Either a b) -> Stream m c -> Stream m (Either a c)
 {-# INLINABLE replaceRightStream #-}
-replaceRightStream (Cons sab) (ys0 @ ~(Cons sc)) = Cons z where
+replaceRightStream (Cons sab) (ys0@(Cons sc)) = Cons z where
   z = do (a, xs) <- sab
          case a of
            Right _ ->
diff --git a/aivika-transformers.cabal b/aivika-transformers.cabal
--- a/aivika-transformers.cabal
+++ b/aivika-transformers.cabal
@@ -1,5 +1,5 @@
 name:            aivika-transformers
-version:         5.9
+version:         5.9.1
 synopsis:        Transformers for the Aivika simulation library
 description:
     This package is a generalization of the aivika [1] simulation library
@@ -173,11 +173,11 @@
                      array >= 0.3.0.0,
                      containers >= 0.4.0.0,
                      random >= 1.0.0.3,
-                     mwc-random >= 0.13.0.0,
+                     mwc-random >= 0.13.1.0,
                      vector >= 0.10.0.1,
                      semigroups >= 0.10,
                      exceptions >= 0.9.0,
-                     aivika >= 5.9
+                     aivika >= 5.9.1
 
     other-extensions:   FlexibleContexts,
                         FlexibleInstances,