diff --git a/checks/ArrayUsageCheck.hs b/checks/ArrayUsageCheck.hs
index 9f4b721..17a8b06 100644
--- a/checks/ArrayUsageCheck.hs
+++ b/checks/ArrayUsageCheck.hs
@@ -16,7 +16,7 @@ You should have received a copy of the GNU General Public License along
 with this program.  If not, see <http://www.gnu.org/licenses/>.
 -}
 
-module ArrayUsageCheck (BackgroundKnowledge(..), checkArrayUsage, FlattenedExp(..), makeEquations, VarMap) where
+module ArrayUsageCheck (BackgroundKnowledge(..), checkArrayUsage, FlattenedExp(..), onlyConst, makeEquations, VarMap) where
 
 import Control.Monad.Error
 import Control.Monad.State
@@ -43,12 +43,6 @@ checkArrayUsage :: forall m. (Die m, CSMR m, MonadIO m) => (Meta, ParItems Usage
 checkArrayUsage (m,p) = mapM_ (checkIndexes m) $ Map.toList $
     groupArrayIndexes $ transformParItems nodeVars p
   where
-    -- Gets all the items inside a ParItems and returns them in a flat list.
-    flattenParItems :: ParItems a -> [a]
-    flattenParItems (SeqItems xs) = xs
-    flattenParItems (ParItems ps) = concatMap flattenParItems ps
-    flattenParItems (RepParItem _ p) = flattenParItems p
-
     -- Takes a ParItems Vars, and returns a map from array-variable-name to a list of writes and a list of reads for that array.
     -- Returns (array name, list of written-to indexes, list of read-from indexes)
     groupArrayIndexes :: ParItems Vars -> Map.Map String (ParItems ([A.Expression], [A.Expression]))
@@ -202,6 +196,7 @@ data FlattenedExp
     -- ^ A modulo, with the given top and bottom (in that order)
   | Divide (Set.Set FlattenedExp) (Set.Set FlattenedExp)
     -- ^ An integer division, with the given top and bottom (in that order)
+  deriving (Show)
 
 instance Eq FlattenedExp where
   a == b = EQ == compare a b
diff --git a/checks/UsageCheckUtils.hs b/checks/UsageCheckUtils.hs
index acc5723..01d0e23 100644
--- a/checks/UsageCheckUtils.hs
+++ b/checks/UsageCheckUtils.hs
@@ -16,7 +16,7 @@ You should have received a copy of the GNU General Public License along
 with this program.  If not, see <http://www.gnu.org/licenses/>.
 -}
 
-module UsageCheckUtils (customVarCompare, Decl(..), emptyVars, foldUnionVars, getVarActual, getVarProc, labelFunctions, mapUnionVars, ParItems(..), processVarW, transformParItems, UsageLabel(..), Var(..), Vars(..), vars) where
+module UsageCheckUtils (customVarCompare, Decl(..), emptyVars, flattenParItems, foldUnionVars, getVarActual, getVarProc, labelFunctions, mapUnionVars, ParItems(..), processVarW, transformParItems, UsageLabel(..), Var(..), Vars(..), vars) where
 
 import Data.Generics hiding (GT)
 import Data.List
@@ -71,6 +71,7 @@ data ParItems a
   = SeqItems [a] -- ^ A list of items that happen only in sequence (i.e. none are in parallel with each other)
   | ParItems [ParItems a] -- ^ A list of items that are all in parallel with each other
   | RepParItem A.Replicator (ParItems a) -- ^ A list of replicated items that happen in parallel
+  deriving (Show)
 
 data UsageLabel = Usage
   {nodeRep :: Maybe A.Replicator
@@ -82,6 +83,13 @@ transformParItems f (SeqItems xs) = SeqItems $ map f xs
 transformParItems f (ParItems ps) = ParItems $ map (transformParItems f) ps
 transformParItems f (RepParItem r p) = RepParItem r (transformParItems f p)
 
+-- Gets all the items inside a ParItems and returns them in a flat list.
+flattenParItems :: ParItems a -> [a]
+flattenParItems (SeqItems xs) = xs
+flattenParItems (ParItems ps) = concatMap flattenParItems ps
+flattenParItems (RepParItem _ p) = flattenParItems p
+
+
 emptyVars :: Vars
 emptyVars = Vars Set.empty Set.empty Set.empty