diff --git a/src/Data/Array/Accelerate/AST/Partitioned.hs b/src/Data/Array/Accelerate/AST/Partitioned.hs
index a901073ed..6d78fbebf 100644
--- a/src/Data/Array/Accelerate/AST/Partitioned.hs
+++ b/src/Data/Array/Accelerate/AST/Partitioned.hs
@@ -118,7 +118,7 @@ data SOA arg appendto result where
 
 soaShrink :: forall args expanded f
            . (forall a. Show (f a))
-          => (forall l r g. f (g l) -> f (g r) -> f (g (l,r))) 
+          => (forall l r g. f (g l) -> f (g r) -> f (g (l,r)))
           -> SOAs args expanded -> PreArgs f expanded -> PreArgs f args
 soaShrink _ SOArgsNil ArgsNil = ArgsNil
 soaShrink f (SOArgsCons soas soa) args = case go soa args of (arg :>: args') -> arg :>: soaShrink f soas args'
@@ -212,7 +212,7 @@ data Cluster op args where
 -- datatype describing how to combine the arguments of two fused clusters
 data Fusion largs rars args where
   EmptyF :: Fusion () () ()
-  Vertical :: ArrayR (Array sh e) 
+  Vertical :: ArrayR (Array sh e)
            -> Fusion l r a
            -> Fusion (Out sh e -> l) (In sh e -> r) (Var' sh -> a)
   Horizontal :: Fusion l r a
@@ -407,12 +407,12 @@ onZipped :: (f a -> f b -> f c) -> (g a -> g b -> g c) -> (Both f g a -> Both f
 onZipped f g (Both fa ga) (Both fb gb) = Both (f fa fb) (g ga gb)
 
 -- assumes that the arguments are already sorted!
-fuse :: MakesILP op 
+fuse :: MakesILP op
      => LabelledArgsOp op env l -> LabelledArgsOp op env r -> PreArgs f l -> PreArgs f r -> Clustered op l -> Clustered op r
      -> (forall sh e. f (Out sh e) -> f (In sh e) -> f (Var' sh))
      -> (forall args. PreArgs f args -> Clustered op args -> result)
      -> result
-fuse labl labr largs rargs (Clustered cl bl) (Clustered cr br) c k = fuse' labl labr (zipArgs largs bl) (zipArgs rargs br) cl cr (onZipped c combineBackendClusterArg) 
+fuse labl labr largs rargs (Clustered cl bl) (Clustered cr br) c k = fuse' labl labr (zipArgs largs bl) (zipArgs rargs br) cl cr (onZipped c combineBackendClusterArg)
   $ \args c' -> k (mapArgs fst' args) (Clustered c' $ mapArgs snd' args)
 
 -- assumes that the arguments are already sorted!
@@ -435,8 +435,10 @@ mkFused (l'@(LOp l ((Arr (TupRsingle (C.Const (ELabel llab))), lls))lop) :>: ls)
   | (llab,lop) <  (rlab,rop) = mkFused ls (r':>:rs) $ \f -> k (addleft l f)
   | (llab,lop) >  (rlab,rop) = mkFused (l':>:ls) rs $ \f -> k (addright r f)
   | otherwise = error "simple math, the truth cannot be questioned"
-mkFused ((LOp _ ((Arr TupRpair{}, _))_) :>: _) _ _ = error "not soa'd array"
-mkFused _ ((LOp _ ((Arr TupRpair{}, _))_) :>: _) _ = error "not soa'd array"
+mkFused ((LOp l@(ArgArray Mut _ _ _) _ _) :>: ls) rs k = mkFused ls rs $ \f -> k (addleft l f)
+mkFused ls ((LOp r@(ArgArray Mut _ _ _) _ _) :>: rs) k = mkFused ls rs $ \f -> k (addright r f)
+mkFused ((LOp _ (Arr TupRpair{}, _)_) :>: _) _ _ = error "not soa'd array"
+mkFused _ ((LOp _ (Arr TupRpair{}, _)_) :>: _) _ = error "not soa'd array"
 
 addleft :: Arg env arg -> Fusion left right args -> Fusion (arg->left) right (arg->args)
 addleft (ArgVar _          ) f = IntroL  f
@@ -469,7 +471,7 @@ singleton l largs op k = mkSOAs (mapArgs (\(LOp a _ _) -> a) largs) $ \soas ->
 -- (subargsId $ sort $ soaExpand splitLabelledArgsOp soas largs)
 
 sortArgs :: LabelledArgs env args -> (forall sorted. SortedArgs args sorted -> r) -> r
-sortArgs args k = 
+sortArgs args k =
   -- if nub ls /= ls then error "not sure if this works" -- this means that some arguments have identical sets of labels. This should only be a problem if two array arguments share labelsets.
   -- else 
     k $ SA
@@ -489,11 +491,11 @@ mkSOAs ArgsNil k = k SOArgsNil
 mkSOAs (a:>:args) k = mkSOAs args $ \soas -> mkSOA a $ \soa -> k (SOArgsCons soas soa)
 
 mkSOA :: Arg env arg -> (forall result. SOA arg toappend result -> r) -> r
-mkSOA     (ArgArray In  (ArrayR shr (TupRpair tl tr)) sh (TupRpair bufl bufr)) k = 
+mkSOA     (ArgArray In  (ArrayR shr (TupRpair tl tr)) sh (TupRpair bufl bufr)) k =
   mkSOA   (ArgArray In  (ArrayR shr tr              ) sh bufr                ) $ \soar ->
     mkSOA (ArgArray In  (ArrayR shr tl              ) sh bufl                ) $ \soal ->
       k (SOArgTup soar soal)
-mkSOA     (ArgArray Out (ArrayR shr (TupRpair tl tr)) sh (TupRpair bufl bufr)) k = 
+mkSOA     (ArgArray Out (ArrayR shr (TupRpair tl tr)) sh (TupRpair bufl bufr)) k =
   mkSOA   (ArgArray Out (ArrayR shr tr              ) sh bufr                ) $ \soar ->
     mkSOA (ArgArray Out (ArrayR shr tl              ) sh bufl                ) $ \soal ->
       k (SOArgTup soar soal)