diff --git a/Data/Graph.hs b/Data/Graph.hs
--- a/Data/Graph.hs
+++ b/Data/Graph.hs
@@ -75,7 +75,9 @@
 import Data.Tree (Tree(Node), Forest)
 
 -- std interfaces
+#if !MIN_VERSION_base(4,8,0)
 import Control.Applicative
+#endif
 import Control.DeepSeq (NFData(rnf))
 import Data.Maybe
 import Data.Array
diff --git a/Data/IntMap/Base.hs b/Data/IntMap/Base.hs
--- a/Data/IntMap/Base.hs
+++ b/Data/IntMap/Base.hs
@@ -216,16 +216,21 @@
     , highestBitMask
     ) where
 
+#if MIN_VERSION_base(4,8,0)
+import Control.Applicative ((<$>))
+#else
 import Control.Applicative (Applicative(pure, (<*>)), (<$>))
+import Data.Monoid (Monoid(..))
+import Data.Traversable (Traversable(traverse))
+import Data.Word (Word)
+#endif
+
 import Control.DeepSeq (NFData(rnf))
 import Control.Monad (liftM)
 import Data.Bits
 import qualified Data.Foldable as Foldable
 import Data.Maybe (fromMaybe)
-import Data.Monoid (Monoid(..))
-import Data.Traversable (Traversable(traverse))
 import Data.Typeable
-import Data.Word (Word)
 import Prelude hiding (lookup, map, filter, foldr, foldl, null)
 
 import Data.IntSet.Base (Key)
diff --git a/Data/IntSet/Base.hs b/Data/IntSet/Base.hs
--- a/Data/IntSet/Base.hs
+++ b/Data/IntSet/Base.hs
@@ -169,9 +169,11 @@
 import Data.Bits
 import qualified Data.List as List
 import Data.Maybe (fromMaybe)
+#if !MIN_VERSION_base(4,8,0)
 import Data.Monoid (Monoid(..))
-import Data.Typeable
 import Data.Word (Word)
+#endif
+import Data.Typeable
 import Prelude hiding (filter, foldr, foldl, null, map)
 
 import Data.Utils.BitUtil
diff --git a/Data/Map.hs b/Data/Map.hs
--- a/Data/Map.hs
+++ b/Data/Map.hs
@@ -45,6 +45,10 @@
 -- first argument are always preferred to the second, for example in
 -- 'union' or 'insert'.
 --
+-- /Warning/: The size of the map must not exceed @maxBound::Int@. Violation of
+-- this condition is not detected and if the size limit is exceeded, its
+-- behaviour is undefined.
+--
 -- Operation comments contain the operation time complexity in
 -- the Big-O notation (<http://en.wikipedia.org/wiki/Big_O_notation>).
 -----------------------------------------------------------------------------
diff --git a/Data/Map/Base.hs b/Data/Map/Base.hs
--- a/Data/Map/Base.hs
+++ b/Data/Map/Base.hs
@@ -270,12 +270,17 @@
     , filterLt
     ) where
 
+#if MIN_VERSION_base(4,8,0)
+import Control.Applicative ((<$>))
+#else
 import Control.Applicative (Applicative(..), (<$>))
+import Data.Monoid (Monoid(..))
+import Data.Traversable (Traversable(traverse))
+#endif
+
 import Control.DeepSeq (NFData(rnf))
 import Data.Bits (shiftL, shiftR)
 import qualified Data.Foldable as Foldable
-import Data.Monoid (Monoid(..))
-import Data.Traversable (Traversable(traverse))
 import Data.Typeable
 import Prelude hiding (lookup, map, filter, foldr, foldl, null)
 
diff --git a/Data/Map/Lazy.hs b/Data/Map/Lazy.hs
--- a/Data/Map/Lazy.hs
+++ b/Data/Map/Lazy.hs
@@ -44,6 +44,10 @@
 -- first argument are always preferred to the second, for example in
 -- 'union' or 'insert'.
 --
+-- /Warning/: The size of the map must not exceed @maxBound::Int@. Violation of
+-- this condition is not detected and if the size limit is exceeded, its
+-- behaviour is undefined.
+--
 -- Operation comments contain the operation time complexity in
 -- the Big-O notation (<http://en.wikipedia.org/wiki/Big_O_notation>).
 -----------------------------------------------------------------------------
diff --git a/Data/Map/Strict.hs b/Data/Map/Strict.hs
--- a/Data/Map/Strict.hs
+++ b/Data/Map/Strict.hs
@@ -44,6 +44,10 @@
 -- first argument are always preferred to the second, for example in
 -- 'union' or 'insert'.
 --
+-- /Warning/: The size of the map must not exceed @maxBound::Int@. Violation of
+-- this condition is not detected and if the size limit is exceeded, its
+-- behaviour is undefined.
+--
 -- Operation comments contain the operation time complexity in
 -- the Big-O notation (<http://en.wikipedia.org/wiki/Big_O_notation>).
 --
diff --git a/Data/Sequence.hs b/Data/Sequence.hs
--- a/Data/Sequence.hs
+++ b/Data/Sequence.hs
@@ -16,7 +16,8 @@
 -- Module      :  Data.Sequence
 -- Copyright   :  (c) Ross Paterson 2005
 --                (c) Louis Wasserman 2009
---                (c) David Feuer, Ross Paterson, and Milan Straka 2014
+--                (c) Bertram Felgenhauer, David Feuer, Ross Paterson, and
+--                    Milan Straka 2014
 -- License     :  BSD-style
 -- Maintainer  :  libraries@haskell.org
 -- Stability   :  experimental
@@ -29,7 +30,7 @@
 --
 -- An amortized running time is given for each operation, with /n/ referring
 -- to the length of the sequence and /i/ being the integral index used by
--- some operations.  These bounds hold even in a persistent (shared) setting.
+-- some operations. These bounds hold even in a persistent (shared) setting.
 --
 -- The implementation uses 2-3 finger trees annotated with sizes,
 -- as described in section 4.2 of
@@ -40,9 +41,16 @@
 --      <http://staff.city.ac.uk/~ross/papers/FingerTree.html>
 --
 -- /Note/: Many of these operations have the same names as similar
--- operations on lists in the "Prelude".  The ambiguity may be resolved
+-- operations on lists in the "Prelude". The ambiguity may be resolved
 -- using either qualification or the @hiding@ clause.
 --
+-- /Warning/: The size of a 'Seq' must not exceed @maxBound::Int@.  Violation
+-- of this condition is not detected and if the size limit is exceeded, the
+-- behaviour of the sequence is undefined.  This is unlikely to occur in most
+-- applications, but some care may be required when using '><', '<*>', '*>', or
+-- '>>', particularly repeatedly and particularly in combination with
+-- 'replicate' or 'fromFunction'.
+--
 -----------------------------------------------------------------------------
 
 module Data.Sequence (
@@ -147,6 +155,9 @@
 
 import Prelude hiding (
     Functor(..),
+#if MIN_VERSION_base(4,8,0)
+    Applicative, foldMap, Monoid,
+#endif
     null, length, take, drop, splitAt, foldl, foldl1, foldr, foldr1,
     scanl, scanl1, scanr, scanr1, replicate, zip, zipWith, zip3, zipWith3,
     takeWhile, dropWhile, iterate, reverse, filter, mapM, sum, all)
@@ -175,6 +186,7 @@
 
 -- Array stuff, with GHC.Arr on GHC
 import Data.Array (Ix, Array)
+import qualified Data.Array
 #ifdef __GLASGOW_HASKELL__
 import qualified GHC.Arr
 #endif
@@ -338,15 +350,18 @@
                        (Deep s (squashL pr prm) mm (squashR sfm sf)))
            (fmap (fmap lastf) sfm)
 
--- At the bottom
+-- At the bottom. Note that these appendTree0 calls are very cheap, because in
+-- each case, one of the arguments is guaranteed to be Empty or Single.
 aptyMiddle firstf
            lastf
            map23
            fs
            (Deep s pr m sf)
-      = (fmap (fmap firstf) m `snocTree` fmap firstf (digitToNode sf))
-        `appendTree0` middle `appendTree0`
-        (fmap lastf (digitToNode pr) `consTree`  fmap (fmap lastf) m)
+      = fmap (fmap firstf) m `appendTree0`
+        ((fmap firstf (digitToNode sf)
+            `consTree` middle)
+            `snocTree` fmap lastf (digitToNode pr))
+        `appendTree0`  fmap (fmap lastf) m
     where middle = case trimTree $ mapMulFT s (\(Elem f) -> fmap (fmap (map23 f)) converted) fs of
                      (firstMapped, restMapped, lastMapped) ->
                         Deep (size firstMapped + size restMapped + size lastMapped)
@@ -469,17 +484,16 @@
 -- | /O(log n)/ (incremental) Rejigger a finger tree so the digits are all ones
 -- and twos.
 thin :: Sized a => FingerTree a -> FingerTree a
--- Note that 'thin' may call itself at most once before passing the job on to
--- 'thin12'. 'thin12' will produce a 'Deep' constructor immediately before
--- calling 'thin'.
+-- Note that 'thin12' will produce a 'Deep' constructor immediately before
+-- recursively calling 'thin'.
 thin Empty = Empty
 thin (Single a) = Single a
 thin t@(Deep s pr m sf) =
   case pr of
     One{} -> thin12 t
     Two{} -> thin12 t
-    Three a b c  -> thin $ Deep s (One a) (node2 b c `consTree` m) sf
-    Four a b c d -> thin $ Deep s (Two a b) (node2 c d `consTree` m) sf
+    Three a b c  -> thin12 $ Deep s (One a) (node2 b c `consTree` m) sf
+    Four a b c d -> thin12 $ Deep s (Two a b) (node2 c d `consTree` m) sf
 
 thin12 :: Sized a => FingerTree a -> FingerTree a
 thin12 (Deep s pr m sf@One{}) = Deep s pr (thin m) sf
@@ -626,13 +640,13 @@
 deep pr m sf    =  Deep (size pr + size m + size sf) pr m sf
 
 {-# INLINE pullL #-}
-pullL :: Sized a => Int -> FingerTree (Node a) -> Digit a -> FingerTree a
+pullL :: Int -> FingerTree (Node a) -> Digit a -> FingerTree a
 pullL s m sf = case viewLTree m of
     Nothing2        -> digitToTree' s sf
     Just2 pr m'     -> Deep s (nodeToDigit pr) m' sf
 
 {-# INLINE pullR #-}
-pullR :: Sized a => Int -> Digit a -> FingerTree (Node a) -> FingerTree a
+pullR :: Int -> Digit a -> FingerTree (Node a) -> FingerTree a
 pullR s pr m = case viewRTree m of
     Nothing2        -> digitToTree' s pr
     Just2 m' sf     -> Deep s pr m' (nodeToDigit sf)
@@ -856,17 +870,14 @@
     4 -> deepA two emptyTree two
     5 -> deepA three emptyTree two
     6 -> deepA three emptyTree three
-    7 -> deepA four emptyTree three
-    8 -> deepA four emptyTree four
     _ -> case n `quotRem` 3 of
            (q,0) -> deepA three (applicativeTree (q - 2) mSize' n3) three
-           (q,1) -> deepA four  (applicativeTree (q - 2) mSize' n3) three
-           (q,_) -> deepA four  (applicativeTree (q - 2) mSize' n3) four
+           (q,1) -> deepA two (applicativeTree (q - 1) mSize' n3) two
+           (q,_) -> deepA three (applicativeTree (q - 1) mSize' n3) two
   where
     one = fmap One m
     two = liftA2 Two m m
     three = liftA3 Three m m m
-    four = liftA3 Four m m m <*> m
     deepA = liftA3 (Deep (n * mSize))
     mSize' = 3 * mSize
     n3 = liftA3 (Node3 mSize') m m m
@@ -1639,6 +1650,10 @@
 fromArray :: Ix i => Array i a -> Seq a
 #ifdef __GLASGOW_HASKELL__
 fromArray a = fromFunction (GHC.Arr.numElements a) (GHC.Arr.unsafeAt a)
+ where
+  -- The following definition uses (Ix i) constraing, which is needed for the
+  -- other fromArray definition.
+  _ = Data.Array.rangeSize (Data.Array.bounds a)
 #else
 fromArray a = fromList2 (Data.Array.rangeSize (Data.Array.bounds a)) (Data.Array.elems a)
 #endif
@@ -1825,7 +1840,7 @@
 {-# SPECIALIZE tailsTree :: (FingerTree (Node a) -> Node b) -> FingerTree (Node a) -> FingerTree (Node b) #-}
 -- | Given a function to apply to tails of a tree, applies that function
 -- to every tail of the specified tree.
-tailsTree :: (Sized a, Sized b) => (FingerTree a -> b) -> FingerTree a -> FingerTree b
+tailsTree :: Sized a => (FingerTree a -> b) -> FingerTree a -> FingerTree b
 tailsTree _ Empty = Empty
 tailsTree f (Single x) = Single (f (Single x))
 tailsTree f (Deep n pr m sf) =
@@ -1840,7 +1855,7 @@
 {-# SPECIALIZE initsTree :: (FingerTree (Node a) -> Node b) -> FingerTree (Node a) -> FingerTree (Node b) #-}
 -- | Given a function to apply to inits of a tree, applies that function
 -- to every init of the specified tree.
-initsTree :: (Sized a, Sized b) => (FingerTree a -> b) -> FingerTree a -> FingerTree b
+initsTree :: Sized a => (FingerTree a -> b) -> FingerTree a -> FingerTree b
 initsTree _ Empty = Empty
 initsTree f (Single x) = Single (f (Single x))
 initsTree f (Deep n pr m sf) =
@@ -2335,7 +2350,7 @@
         toPQ cmp (\ (Elem x) -> PQueue x Nil) xs
 
 -- | fromList2, given a list and its length, constructs a completely
--- balanced Seq whose elements are that list using the applicativeTree
+-- balanced Seq whose elements are that list using the replicateA
 -- generalization.
 fromList2 :: Int -> [a] -> Seq a
 fromList2 n = execState (replicateA n (State ht))
diff --git a/Data/Set.hs b/Data/Set.hs
--- a/Data/Set.hs
+++ b/Data/Set.hs
@@ -38,6 +38,10 @@
 -- 'union' or 'insert'.  Of course, left-biasing can only be observed
 -- when equality is an equivalence relation instead of structural
 -- equality.
+--
+-- /Warning/: The size of the set must not exceed @maxBound::Int@. Violation of
+-- this condition is not detected and if the size limit is exceeded, its
+-- behaviour is undefined.
 -----------------------------------------------------------------------------
 
 module Data.Set (
diff --git a/Data/Set/Base.hs b/Data/Set/Base.hs
--- a/Data/Set/Base.hs
+++ b/Data/Set/Base.hs
@@ -45,6 +45,10 @@
 -- 'union' or 'insert'.  Of course, left-biasing can only be observed
 -- when equality is an equivalence relation instead of structural
 -- equality.
+--
+-- /Warning/: The size of the set must not exceed @maxBound::Int@. Violation of
+-- this condition is not detected and if the size limit is exceeded, its
+-- behaviour is undefined.
 -----------------------------------------------------------------------------
 
 -- [Note: Using INLINABLE]
@@ -192,7 +196,9 @@
 import Prelude hiding (filter,foldl,foldr,null,map)
 import qualified Data.List as List
 import Data.Bits (shiftL, shiftR)
+#if !MIN_VERSION_base(4,8,0)
 import Data.Monoid (Monoid(..))
+#endif
 import qualified Data.Foldable as Foldable
 import Data.Typeable
 import Control.DeepSeq (NFData(rnf))
diff --git a/Data/Tree.hs b/Data/Tree.hs
--- a/Data/Tree.hs
+++ b/Data/Tree.hs
@@ -34,13 +34,19 @@
     unfoldTreeM_BF, unfoldForestM_BF,
     ) where
 
+#if MIN_VERSION_base(4,8,0)
+import Control.Applicative ((<$>))
+import Data.Foldable (toList)
+#else
 import Control.Applicative (Applicative(..), (<$>))
-import Control.Monad (liftM)
+import Data.Foldable (Foldable(foldMap), toList)
 import Data.Monoid (Monoid(..))
+import Data.Traversable (Traversable(traverse))
+#endif
+
+import Control.Monad (liftM)
 import Data.Sequence (Seq, empty, singleton, (<|), (|>), fromList,
             ViewL(..), ViewR(..), viewl, viewr)
-import Data.Foldable (Foldable(foldMap), toList)
-import Data.Traversable (Traversable(traverse))
 import Data.Typeable
 import Control.DeepSeq (NFData(rnf))
 
@@ -51,7 +57,6 @@
 #if MIN_VERSION_base(4,8,0)
 import Data.Coerce
 #endif
-
 
 -- | Multi-way trees, also known as /rose trees/.
 data Tree a = Node {
diff --git a/benchmarks/IntMap.hs b/benchmarks/IntMap.hs
--- a/benchmarks/IntMap.hs
+++ b/benchmarks/IntMap.hs
@@ -4,7 +4,6 @@
 import Control.DeepSeq
 import Control.Exception (evaluate)
 import Control.Monad.Trans (liftIO)
-import Criterion.Config
 import Criterion.Main
 import Data.List (foldl')
 import qualified Data.IntMap as M
@@ -13,9 +12,8 @@
 
 main = do
     let m = M.fromAscList elems :: M.IntMap Int
-    defaultMainWith
-        defaultConfig
-        (liftIO . evaluate $ rnf [m])
+    evaluate $ rnf [m]
+    defaultMain
         [ bench "lookup" $ whnf (lookup keys) m
         , bench "insert" $ whnf (ins elems) M.empty
         , bench "insertWith empty" $ whnf (insWith elems) M.empty
diff --git a/benchmarks/IntSet.hs b/benchmarks/IntSet.hs
--- a/benchmarks/IntSet.hs
+++ b/benchmarks/IntSet.hs
@@ -5,7 +5,6 @@
 import Control.DeepSeq
 import Control.Exception (evaluate)
 import Control.Monad.Trans (liftIO)
-import Criterion.Config
 import Criterion.Main
 import Data.List (foldl')
 import qualified Data.IntSet as S
@@ -14,9 +13,8 @@
     let s = S.fromAscList elems :: S.IntSet
         s_even = S.fromAscList elems_even :: S.IntSet
         s_odd = S.fromAscList elems_odd :: S.IntSet
-    defaultMainWith
-        defaultConfig
-        (liftIO . evaluate $ rnf [s, s_even, s_odd])
+    evaluate $ rnf [s, s_even, s_odd]
+    defaultMain
         [ bench "member" $ whnf (member elems) s
         , bench "insert" $ whnf (ins elems) S.empty
         , bench "map" $ whnf (S.map (+ 1)) s
diff --git a/benchmarks/Makefile b/benchmarks/Makefile
--- a/benchmarks/Makefile
+++ b/benchmarks/Makefile
@@ -1,10 +1,12 @@
 all:
 
 bench-%: %.hs force
-	ghc -O2 -DTESTING $< -i../$(TOP) -o $@ -outputdir tmp -rtsopts
+	ghc -O2 -DTESTING $< -I../include -i../$(TOP) -o $@ -outputdir tmp -rtsopts
 
+.PRECIOUS: bench-%
+
 bench-%.csv: bench-%
-	./bench-$* $(BENCHMARK) -v -u bench-$*.csv
+	./bench-$* "$(BENCHMARK)" -v1 --csv bench-$*.csv
 
 .PHONY: force clean veryclean
 force:
diff --git a/benchmarks/Map.hs b/benchmarks/Map.hs
--- a/benchmarks/Map.hs
+++ b/benchmarks/Map.hs
@@ -4,7 +4,6 @@
 import Control.DeepSeq
 import Control.Exception (evaluate)
 import Control.Monad.Trans (liftIO)
-import Criterion.Config
 import Criterion.Main
 import Data.List (foldl')
 import qualified Data.Map as M
@@ -15,9 +14,8 @@
     let m = M.fromAscList elems :: M.Map Int Int
         m_even = M.fromAscList elems_even :: M.Map Int Int
         m_odd = M.fromAscList elems_odd :: M.Map Int Int
-    defaultMainWith
-        defaultConfig
-        (liftIO . evaluate $ rnf [m, m_even, m_odd])
+    evaluate $ rnf [m, m_even, m_odd]
+    defaultMain
         [ bench "lookup absent" $ whnf (lookup evens) m_odd
         , bench "lookup present" $ whnf (lookup evens) m_even
         , bench "insert absent" $ whnf (ins elems_even) m_odd
diff --git a/benchmarks/Sequence.hs b/benchmarks/Sequence.hs
--- a/benchmarks/Sequence.hs
+++ b/benchmarks/Sequence.hs
@@ -3,6 +3,7 @@
 
 import Control.Applicative
 import Control.DeepSeq
+import Control.Exception (evaluate)
 import Criterion.Main
 import Data.List (foldl')
 import qualified Data.Sequence as S
@@ -14,19 +15,19 @@
         s100 = S.fromList [1..100] :: S.Seq Int
         s1000 = S.fromList [1..1000] :: S.Seq Int
         s10000 = S.fromList [1..10000] :: S.Seq Int
-    rnf [s10, s100, s1000, s10000] `seq` return ()
+    evaluate $ rnf [s10, s100, s1000, s10000]
     let g = mkStdGen 1
     let rlist n = map (`mod` (n+1)) (take 10000 (randoms g)) :: [Int]
         r10 = rlist 10
         r100 = rlist 100
         r1000 = rlist 1000
         r10000 = rlist 10000
-    rnf [r10, r100, r1000, r10000] `seq` return ()
+    evaluate $ rnf [r10, r100, r1000, r10000]
     let u10 = S.replicate 10 () :: S.Seq ()
         u100 = S.replicate 100 () :: S.Seq ()
         u1000 = S.replicate 1000 () :: S.Seq ()
         u10000 = S.replicate 10000 () :: S.Seq ()
-    rnf [u10, u100, u1000, u10000] `seq` return ()
+    evaluate $ rnf [u10, u100, u1000, u10000]
     defaultMain
       [ bgroup "splitAt/append"
          [ bench "10" $ nf (shuffle r10) s10
diff --git a/benchmarks/Set.hs b/benchmarks/Set.hs
--- a/benchmarks/Set.hs
+++ b/benchmarks/Set.hs
@@ -6,7 +6,6 @@
 import Control.DeepSeq
 import Control.Exception (evaluate)
 import Control.Monad.Trans (liftIO)
-import Criterion.Config
 import Criterion.Main
 import Data.List (foldl')
 import qualified Data.Set as S
@@ -15,9 +14,8 @@
     let s = S.fromAscList elems :: S.Set Int
         s_even = S.fromAscList elems_even :: S.Set Int
         s_odd = S.fromAscList elems_odd :: S.Set Int
-    defaultMainWith
-        defaultConfig
-        (liftIO . evaluate $ rnf [s, s_even, s_odd])
+    evaluate $ rnf [s, s_even, s_odd]
+    defaultMain
         [ bench "member" $ whnf (member elems) s
         , bench "insert" $ whnf (ins elems) S.empty
         , bench "map" $ whnf (S.map (+ 1)) s
diff --git a/containers.cabal b/containers.cabal
--- a/containers.cabal
+++ b/containers.cabal
@@ -1,5 +1,5 @@
 name: containers
-version: 0.5.6.2
+version: 0.5.6.3
 license: BSD3
 license-file: LICENSE
 maintainer: fox@ucw.cz