Fix pre-Semigroup-Monoid stuff

containers/src/Data/IntSet/Internal.hs

@@ -1256,11 +1256,20 @@ foldMap :: Monoid a => (Key -> a) -> IntSet -> a
 foldMap f = \t ->  -- Use lambda t to be inlinable with one argument only.
   case t of
     Bin p l r
+#if MIN_VERSION_base(4,11,0)
       | signBranch p -> go r <> go l  -- handle negative numbers
       | otherwise -> go l <> go r
+#else
+      | signBranch p -> go r `mappend` go l  -- handle negative numbers
+      | otherwise -> go l `mappend` go r
+#endif
     _ -> go t
   where
+#if MIN_VERSION_base(4,11,0)
     go (Bin _ l r) = go l <> go r
+#else
+    go (Bin _ l r) = go l `mappend` go r
+#endif
     go (Tip kx bm) = foldMapBits kx f bm
     go Nil = mempty
 {-# INLINE foldMap #-}
@@ -1688,7 +1697,11 @@ foldlBits :: Int -> (a -> Int -> a) -> a -> Nat -> a
 foldl'Bits :: Int -> (a -> Int -> a) -> a -> Nat -> a
 foldrBits :: Int -> (Int -> a -> a) -> a -> Nat -> a
 foldr'Bits :: Int -> (Int -> a -> a) -> a -> Nat -> a
+#if MIN_VERSION_base(4,11,0)
 foldMapBits :: Semigroup a => Int -> (Int -> a) -> Nat -> a
+#else
+foldMapBits :: Monoid a => Int -> (Int -> a) -> Nat -> a
+#endif
 takeWhileAntitoneBits :: Int -> (Int -> Bool) -> Nat -> Nat
 
 {-# INLINE lowestBitSet #-}
@@ -1758,7 +1771,11 @@ foldMapBits prefix f bitmap = go (prefix + bi0) (bitmap `xor` bitmask0)
     bitmask0 = lowestBitMask bitmap
     bi0 = countTrailingZeros bitmask0
     go !x 0 = f x
+#if MIN_VERSION_base(4,11,0)
     go !x bm = f x <> go (prefix + bi) (bm `xor` bitmask)
+#else
+    go !x bm = f x `mappend` go (prefix + bi) (bm `xor` bitmask)
+#endif
       where
         bitmask = lowestBitMask bm
         bi = countTrailingZeros bitmask
@@ -1841,7 +1858,11 @@ foldMapBits prefix f bm = go x0 (x0 + 1) ((bm `shiftRL` lb) `shiftRL` 1)
     x0 = prefix + lb
     go !x !_ 0 = f x
     go !x !bi n
+#if MIN_VERSION_base(4,11,0)
       | n `testBit` 0 = f x <> go bi (bi + 1) (n `shiftRL` 1)
+#else
+      | n `testBit` 0 = f x `mappend` go bi (bi + 1) (n `shiftRL` 1)
+#endif
       | otherwise = go x (bi + 1) (n `shiftRL` 1)
 
 takeWhileAntitoneBits prefix predicate = foldl'Bits prefix f 0 -- Does not use antitone property