Fix hlint issues in benchmarks

.hlint.ignore

@@ -31,6 +31,7 @@ benchmark/Streamly/Benchmark/Data/Stream/StreamK.hs
 benchmark/Streamly/Benchmark/Data/Unfold.hs
 benchmark/Streamly/Benchmark/FileSystem/Handle.hs
 benchmark/Streamly/Benchmark/Prelude/Async.hs
+benchmark/Streamly/Benchmark/Prelude/Concurrent.hs
 benchmark/Streamly/Benchmark/Prelude/Merge.hs
 benchmark/Streamly/Benchmark/Prelude/Parallel.hs
 benchmark/Streamly/Benchmark/Prelude/Rate.hs

benchmark/Streamly/Benchmark/Data/Fold.hs

@@ -269,13 +269,13 @@ unzip = Stream.fold $ FL.lmap (\a -> (a, a)) (FL.unzip FL.sum FL.length)
 {-# INLINE unzipWithFstM #-}
 unzipWithFstM :: Monad m => Stream m Int -> m (Int, Int)
 unzipWithFstM = do
-    let f = \a -> return (a + 1, a)
+    let f a = return (a + 1, a)
     Stream.fold (FL.unzipWithFstM f FL.sum FL.length)
 
 {-# INLINE unzipWithMinM #-}
 unzipWithMinM :: Monad m => Stream m Int -> m (Int, Int)
 unzipWithMinM = do
-    let f = \a -> return (a + 1, a)
+    let f a = return (a + 1, a)
     Stream.fold (FL.unzipWithMinM f FL.sum FL.length)
 
 -------------------------------------------------------------------------------

benchmark/Streamly/Benchmark/Data/Serialize.hs

@@ -1,4 +1,5 @@
 {-# LANGUAGE TemplateHaskell #-}
+{- HLINT ignore -}
 
 #undef FUSION_CHECK
 #ifdef FUSION_CHECK
@@ -18,6 +19,7 @@ module Main (main) where
 -------------------------------------------------------------------------------
 
 import Control.DeepSeq (NFData(..), deepseq)
+import Control.Monad (when, void)
 import GHC.Generics (Generic)
 import System.Random (randomRIO)
 #ifndef USE_UNBOX
@@ -264,13 +266,13 @@ $(deriveSerialize [d|instance Serialize a => Serialize (BinTree a)|])
 instance NFData a => NFData (BinTree a) where
   {-# INLINE rnf #-}
   rnf (Leaf a) = rnf a `seq` ()
-  rnf (Tree l r) = rnf l `seq` rnf r `seq` ()
+  rnf (Tree l r) = rnf l `seq` rnf r
 
 instance Arbitrary a => Arbitrary (BinTree a) where
   arbitrary = oneof [Leaf <$> arbitrary, Tree <$> arbitrary <*> arbitrary]
 
 mkBinTree :: (Arbitrary a) => Int -> IO (BinTree a)
-mkBinTree = go (generate $ arbitrary)
+mkBinTree = go (generate arbitrary)
 
     where
 
@@ -295,16 +297,14 @@ getSize = addSizeTo 0
 -- Common helpers
 -------------------------------------------------------------------------------
 
+{- HLINT ignore "Eta reduce" -}
 -- Parts of "f" that are dependent on val will not be optimized out.
 {-# INLINE loop #-}
 loop :: Int -> (a -> IO b) -> a -> IO ()
 loop count f val = go count val
     where
 
-    go n x = do
+    go n x = when (n > 0) $ f x >> go (n-1) x
-        if n > 0
-        then f x >> go (n-1) x
-        else return ()
 
 -- The first arg of "f" is the environment which is not threaded around in the
 -- loop.
@@ -313,10 +313,7 @@ loopWith :: Int -> (e -> a -> IO b) -> e -> a -> IO ()
 loopWith count f e val = go count val
     where
 
-    go n x = do
+    go n x = when (n > 0) $ f e x >> go (n-1) x
-        if n > 0
-        then f e x >> go (n-1) x
-        else return ()
 
 benchSink :: NFData b => String -> Int -> (Int -> IO b) -> Benchmark
 benchSink name times f = bench name (nfIO (randomRIO (times, times) >>= f))
@@ -342,7 +339,7 @@ pokeTimesWithSize val times = do
 
 {-# INLINE poke #-}
 poke :: SERIALIZE_CLASS a => MutByteArray -> a -> IO ()
-poke arr val = SERIALIZE_OP 0 arr val >> return ()
+poke arr val = void (SERIALIZE_OP 0 arr val)
 
 {-# INLINE pokeTimes #-}
 pokeTimes :: SERIALIZE_CLASS a => a -> Int -> IO ()
@@ -356,7 +353,7 @@ encode :: SERIALIZE_CLASS a => a -> IO ()
 encode val = do
     let n = getSize val
     arr <- MBA.new n
-    SERIALIZE_OP 0 arr val >> return ()
+    void (SERIALIZE_OP 0 arr val)
 
 {-# INLINE encodeTimes #-}
 encodeTimes :: SERIALIZE_CLASS a => a -> Int -> IO ()

benchmark/Streamly/Benchmark/Data/Serialize/TH.hs

@@ -18,7 +18,7 @@ import Control.DeepSeq (NFData(..))
 genLargeRecord :: String -> Int -> Q [Dec]
 genLargeRecord tyName numFields =
     sequence
-        ([ dataD
+        [ dataD
                (pure [])
                (mkName tyName)
                []
@@ -28,7 +28,7 @@ genLargeRecord tyName numFields =
          , mkValueSigDec
          , mkValueDec
          , nfDataInstance tyName
-         ])
+         ]
 
     where
 
@@ -64,7 +64,7 @@ genLargeRecord tyName numFields =
                        (foldl
                             (\b a -> [|$(b) $(a)|])
                             (conE (mkName tyName))
-                            (const (conE '()) <$> [0 .. (numFields - 1)])))
+                            (conE '() <$ [0 .. (numFields - 1)])))
                   []
             ]
     mkCon nm = recC (mkName nm) (mkField <$> [0 .. (numFields - 1)])

benchmark/Streamly/Benchmark/Data/Stream/Eliminate.hs

@@ -132,12 +132,14 @@ foldableAny :: Int -> Int -> Bool
 foldableAny value n =
     Prelude.any (> (value + 1)) (sourceUnfoldr value n :: Stream Identity Int)
 
+{- HLINT ignore "Use all"-}
 {-# INLINE foldableAnd #-}
 foldableAnd :: Int -> Int -> Bool
 foldableAnd value n =
     Prelude.and $ fmap
         (<= (value + 1)) (sourceUnfoldr value n :: Stream Identity Int)
 
+{- HLINT ignore "Use any"-}
 {-# INLINE foldableOr #-}
 foldableOr :: Int -> Int -> Bool
 foldableOr value n =

benchmark/Streamly/Benchmark/Data/Stream/StreamKAlt.hs

@@ -452,4 +452,4 @@ o_1_space =
     ]
 
 main :: IO ()
-main = defaultMain $ concat [o_1_space]
+main = defaultMain [o_1_space]

benchmark/Streamly/Benchmark/Data/Stream/ToStreamK.hs

@@ -120,7 +120,7 @@ fromFoldable streamLen n = S.fromFoldable [n..n+streamLen]
 {-# INLINE fromFoldableM #-}
 fromFoldableM :: Monad m => Int -> Int -> Stream m Int
 fromFoldableM streamLen n =
-    Prelude.foldr S.consM S.nil (Prelude.fmap return [n..n+streamLen])
+    Prelude.foldr (S.consM . return) S.nil [n .. n + streamLen]
 
 {-
 {-# INLINABLE concatMapFoldableWith #-}