Fixed some uses of Map.lookup that used the old system of it working with any monad (in GHC 6.10, it's always Maybe)

flow/FlowAlgorithms.hs

@@ -151,7 +151,9 @@ flowAlgorithm funcs nodes (startNode, startVal)
                  "Nodes still to process: " ++ show workList
                  ++ " " ++ userErrLabel funcs node)
                  (filtNodes $ nodesToProcess funcs node)
-               nodeVal <- Map.lookup node vals
+               nodeVal <- case Map.lookup node vals of
+                 Nothing -> throwError "Could not find node during flowAlgorithm"
+                 Just x -> return x
                if total /= nodeVal
                  -- If the value has changed, that will cascade to affect all
                  -- its dependents, so add all

transformations/SimplifyExprs.hs

@@ -380,7 +380,9 @@ pullUp pullUpArraysInsideRecords = pass "Pull up definitions"
              ets <- sequence [astTypeOf e | e <- es']
 
              ps <- get
-             rts <- Map.lookup (A.nameName n) (csFunctionReturns ps)
+             rts <- case Map.lookup (A.nameName n) (csFunctionReturns ps) of
+               Nothing -> dieP m "Could not find function returns"
+               Just x -> return x
              specs <- sequence [makeNonceVariable "return_actual" m t A.Original | t <- rts]
              sequence_ [addPulled $ (m, Left spec) | spec <- specs]