Fix hlint issues for streamly-core

.hlint.ignore

@@ -1,4 +1,4 @@
-core/src/Streamly/Internal/Data/Stream/StreamK/Type.hs
+core/src/Streamly/Internal/Data/StreamK/Type.hs
 core/src/Streamly/Internal/Data/Pipe/Type.hs
 core/src/Streamly/Internal/Unicode/Stream.hs
 src/Streamly/Internal/Data/SmallArray/Type.hs
@@ -26,7 +26,6 @@ benchmark/NanoBenchmarks.hs
 benchmark/Streamly/Benchmark/Data/Array.hs
 benchmark/Streamly/Benchmark/Data/Parser.hs
 benchmark/Streamly/Benchmark/Data/ParserK.hs
-benchmark/Streamly/Benchmark/Data/Stream/StreamDK.hs
 benchmark/Streamly/Benchmark/Data/Stream/StreamK.hs
 benchmark/Streamly/Benchmark/Data/Unfold.hs
 benchmark/Streamly/Benchmark/FileSystem/Handle.hs

.hlint.yaml

@@ -9,7 +9,6 @@
 # Warnings currently triggered by your code
 - suggest: {name: "Unused LANGUAGE pragma"}
 - suggest: {name: "Eta reduce"}
-- suggest: {name: "Reduce duplication"}
 
 # Warnings currently ignored
 - ignore: {name: "Use list literal pattern"}
@@ -25,6 +24,8 @@
 - ignore: {name: "Redundant $!"}
 - ignore: {name: "Use fmap"}
 - ignore: {name: "Use ++"}
+- ignore: {name: "Replace case with maybe"} # case is more readable
+- ignore: {name: "Use mapMaybe"} # does not make any difference
 
 # Warnings ignored in specific places
 - ignore: {name: "Use mapM", within: Stream.Transform}
@@ -38,9 +39,10 @@
 - arguments:
     [ --cpp-include=src
     , --cpp-include=src/Streamly/Internal/Data/Stream
-    , --cpp-include=src/Streamly/Internal/Data/Array
+    , --cpp-include=core/src/Streamly/Internal/Data/Array
     , --cpp-include=test
     , --cpp-define=CABAL_OS_LINUX
+    , --cpp-define=linux_HOST_OS
     ]
 
 

core/src/Streamly/Internal/Data/Array/Generic.hs

@@ -138,7 +138,7 @@ write = create
 
 fromPureStream :: Stream Identity a -> Array a
 fromPureStream x =
-    unsafePerformIO $ fmap (unsafeFreeze) (MArray.fromPureStream x)
+    unsafePerformIO $ fmap unsafeFreeze (MArray.fromPureStream x)
 -- fromPureStream = runIdentity . D.fold (unsafeMakePure write)
 -- fromPureStream = fromList . runIdentity . D.toList
 

core/src/Streamly/Internal/Data/Array/Type.hs

@@ -897,7 +897,7 @@ fromPureStreamN n x =
 -- >>> fromPureStream = Array.fromList . runIdentity . Stream.toList
 --
 fromPureStream :: Unbox a => Stream Identity a -> Array a
-fromPureStream x = unsafePerformIO $ fmap (unsafeFreeze) (MA.fromPureStream x)
+fromPureStream x = unsafePerformIO $ fmap unsafeFreeze (MA.fromPureStream x)
 -- fromPureStream = runIdentity . D.fold (unsafeMakePure write)
 -- fromPureStream = fromList . runIdentity . D.toList
 

core/src/Streamly/Internal/Data/Builder.hs

@@ -19,6 +19,7 @@ where
 #if !MIN_VERSION_base(4,18,0)
 import Control.Applicative (liftA2)
 #endif
+import Data.Bifunctor (first)
 
 ------------------------------------------------------------------------------
 -- The Builder type
@@ -34,7 +35,7 @@ newtype Builder s m a =
 -- | Maps a function on the output of the fold (the type @b@).
 instance Functor m => Functor (Builder s m) where
     {-# INLINE fmap #-}
-    fmap f (Builder step1) = Builder (fmap (\ (a, s) -> (f a, s)) . step1)
+    fmap f (Builder step1) = Builder (fmap (first f) . step1)
 
 {-# INLINE fromPure #-}
 fromPure :: Applicative m => b -> Builder s m b

core/src/Streamly/Internal/Data/Fold/Combinators.hs

@@ -1337,7 +1337,7 @@ notElem a = all (/= a)
 --
 {-# INLINE and #-}
 and :: Monad m => Fold m Bool Bool
-and = all (== True)
+and = all id
 
 -- | Returns 'True' if any element is 'True', 'False' otherwise
 --
@@ -1347,7 +1347,7 @@ and = all (== True)
 --
 {-# INLINE or #-}
 or :: Monad m => Fold m Bool Bool
-or = any (== True)
+or = any id
 
 ------------------------------------------------------------------------------
 -- Grouping/Splitting
@@ -1641,9 +1641,9 @@ takeEndBySeq patArr (Fold fstep finitial fextract ffinal) =
                     SplitOnSeqKRLoop s _ _ _ -> s
         in fex st
 
-    extract state = extractFunc fextract state
+    extract = extractFunc fextract
 
-    final state = extractFunc ffinal state
+    final = extractFunc ffinal
 
 -- | Like 'takeEndBySeq' but discards the matched sequence.
 --
@@ -1802,9 +1802,9 @@ takeEndBySeq_ patArr (Fold fstep finitial fextract ffinal) =
             SplitOnSeqKR s idx rb _ -> consumeRing s idx rb (Ring.startOf rb)
             SplitOnSeqKRLoop s _ rb rh -> consumeRing s patLen rb rh
 
-    extract state = extractFunc fextract state
+    extract = extractFunc fextract
 
-    final state = extractFunc ffinal state
+    final = extractFunc ffinal
 
 ------------------------------------------------------------------------------
 -- Distributing

core/src/Streamly/Internal/Data/MutArray/Generic.hs

@@ -301,7 +301,7 @@ putIndexUnsafeWith n _arrContents# x =
 putIndexUnsafe :: forall m a. MonadIO m => Int -> MutArray a -> a -> m ()
 putIndexUnsafe i MutArray {..} x =
     assert (i >= 0 && i < arrLen)
-    putIndexUnsafeWith (i + arrStart) arrContents# x
+        (putIndexUnsafeWith (i + arrStart) arrContents# x)
 
 invalidIndex :: String -> Int -> a
 invalidIndex label i =

core/src/Streamly/Internal/Data/MutByteArray.hs

@@ -1,5 +1,3 @@
-{-# LANGUAGE TemplateHaskell #-}
-
 -- This is required as all the instances in this module are orphan instances.
 {-# OPTIONS_GHC -fno-warn-orphans #-}
 
@@ -91,28 +89,25 @@ instance Serialize a => Serialize (Maybe a) where
     {-# INLINE addSizeTo #-}
     addSizeTo acc x =
         case x of
-            Nothing -> (acc + 1)
+            Nothing -> acc + 1
-            Just field0 -> (addSizeTo (acc + 1)) field0
+            Just field0 -> addSizeTo (acc + 1) field0
 
     {-# INLINE deserializeAt #-}
     deserializeAt initialOffset arr endOffset = do
-        (i0, tag) <- ((deserializeAt initialOffset) arr) endOffset
+        (i0, tag) <- deserializeAt initialOffset arr endOffset
         case tag :: Word8 of
             0 -> pure (i0, Nothing)
-            1 -> do (i1, a0) <- ((deserializeAt i0) arr) endOffset
+            1 -> do (i1, a0) <- deserializeAt i0 arr endOffset
                     pure (i1, Just a0)
             _ -> error "Found invalid tag while peeking (Maybe a)"
 
     {-# INLINE serializeAt #-}
     serializeAt initialOffset arr val =
         case val of
-            Nothing -> do
+            Nothing -> serializeAt initialOffset arr (0 :: Word8)
-                i0 <- ((serializeAt initialOffset) arr) (0 :: Word8)
-                pure i0
             Just field0 -> do
-                i0 <- ((serializeAt initialOffset) arr) (1 :: Word8)
+                i0 <- serializeAt initialOffset arr (1 :: Word8)
-                i1 <- ((serializeAt i0) arr) field0
+                serializeAt i0 arr field0
-                pure i1
 
 -- $(Serialize.deriveSerialize ''Either)
 instance (Serialize a, Serialize b) => Serialize (Either a b) where
@@ -120,16 +115,16 @@ instance (Serialize a, Serialize b) => Serialize (Either a b) where
     {-# INLINE addSizeTo #-}
     addSizeTo acc x =
         case x of
-            Left field0 -> (addSizeTo (acc + 1)) field0
+            Left field0 -> addSizeTo (acc + 1) field0
-            Right field0 -> (addSizeTo (acc + 1)) field0
+            Right field0 -> addSizeTo (acc + 1) field0
 
     {-# INLINE deserializeAt #-}
     deserializeAt initialOffset arr endOffset = do
-        (i0, tag) <- ((deserializeAt initialOffset) arr) endOffset
+        (i0, tag) <- deserializeAt initialOffset arr endOffset
         case tag :: Word8 of
-            0 -> do (i1, a0) <- ((deserializeAt i0) arr) endOffset
+            0 -> do (i1, a0) <- deserializeAt i0 arr endOffset
                     pure (i1, Left a0)
-            1 -> do (i1, a0) <- ((deserializeAt i0) arr) endOffset
+            1 -> do (i1, a0) <- deserializeAt i0 arr endOffset
                     pure (i1, Right a0)
             _ -> error "Found invalid tag while peeking (Either a b)"
 
@@ -137,21 +132,19 @@ instance (Serialize a, Serialize b) => Serialize (Either a b) where
     serializeAt initialOffset arr val =
         case val of
             Left field0 -> do
-                i0 <- ((serializeAt initialOffset) arr) (0 :: Word8)
+                i0 <- serializeAt initialOffset arr (0 :: Word8)
-                i1 <- ((serializeAt i0) arr) field0
+                serializeAt i0 arr field0
-                pure i1
             Right field0 -> do
-                i0 <- ((serializeAt initialOffset) arr) (1 :: Word8)
+                i0 <- serializeAt initialOffset arr (1 :: Word8)
-                i1 <- ((serializeAt i0) arr) field0
+                serializeAt i0 arr field0
-                pure i1
 
 instance Serialize (Proxy a) where
 
     {-# INLINE addSizeTo #-}
-    addSizeTo acc _ = (acc + 1)
+    addSizeTo acc _ = acc + 1
 
     {-# INLINE deserializeAt #-}
-    deserializeAt initialOffset _ _ = pure ((initialOffset + 1), Proxy)
+    deserializeAt initialOffset _ _ = pure (initialOffset + 1, Proxy)
 
     {-# INLINE serializeAt #-}
     serializeAt initialOffset _ _ = pure (initialOffset + 1)
@@ -171,19 +164,19 @@ instance Serialize LiftedInteger where
     {-# INLINE addSizeTo #-}
     addSizeTo acc x =
         case x of
-            LIS field0 -> (addSizeTo (acc + 1)) field0
+            LIS field0 -> addSizeTo (acc + 1) field0
-            LIP field0 -> (addSizeTo (acc + 1)) field0
+            LIP field0 -> addSizeTo (acc + 1) field0
-            LIN field0 -> (addSizeTo (acc + 1)) field0
+            LIN field0 -> addSizeTo (acc + 1) field0
 
     {-# INLINE deserializeAt #-}
     deserializeAt initialOffset arr endOffset = do
-        (i0, tag) <- ((deserializeAt initialOffset) arr) endOffset
+        (i0, tag) <- deserializeAt initialOffset arr endOffset
         case tag :: Word8 of
-            0 -> do (i1, a0) <- ((deserializeAt i0) arr) endOffset
+            0 -> do (i1, a0) <- deserializeAt i0 arr endOffset
                     pure (i1, LIS a0)
-            1 -> do (i1, a0) <- ((deserializeAt i0) arr) endOffset
+            1 -> do (i1, a0) <- deserializeAt i0 arr endOffset
                     pure (i1, LIP a0)
-            2 -> do (i1, a0) <- ((deserializeAt i0) arr) endOffset
+            2 -> do (i1, a0) <- deserializeAt i0 arr endOffset
                     pure (i1, LIN a0)
             _ -> error "Found invalid tag while peeking (LiftedInteger)"
 
@@ -191,17 +184,14 @@ instance Serialize LiftedInteger where
     serializeAt initialOffset arr val =
         case val of
             LIS field0 -> do
-                i0 <- ((serializeAt initialOffset) arr) (0 :: Word8)
+                i0 <- serializeAt initialOffset arr (0 :: Word8)
-                i1 <- ((serializeAt i0) arr) field0
+                serializeAt i0 arr field0
-                pure i1
             LIP field0 -> do
-                i0 <- ((serializeAt initialOffset) arr) (1 :: Word8)
+                i0 <- serializeAt initialOffset arr (1 :: Word8)
-                i1 <- ((serializeAt i0) arr) field0
+                serializeAt i0 arr field0
-                pure i1
             LIN field0 -> do
-                i0 <- ((serializeAt initialOffset) arr) (2 :: Word8)
+                i0 <- serializeAt initialOffset arr (2 :: Word8)
-                i1 <- ((serializeAt i0) arr) field0
+                serializeAt i0 arr field0
-                pure i1
 
 #if __GLASGOW_HASKELL__ >= 900
 

core/src/Streamly/Internal/Data/Serialize/TH.hs

@@ -172,8 +172,7 @@ mkSizeDec (SerializeConfig {..}) headTy cons = do
             cfgRecordSyntaxWithHeader
             (typeOfType headTy cons)
     pure
-        ( maybe
+        ( foldMap
-            []
             (\x -> [PragmaD (InlineP 'addSizeTo x FunLike AllPhases)])
             cfgInlineSize
          ++ [FunD 'addSizeTo [Clause [] (NormalB sizeOfMethod) []]]
@@ -240,7 +239,7 @@ mkDeserializeExpr False False headTy tyOfTy =
                 , noBindS
                       (caseE
                            (sigE (varE _tag) (conT tagType))
-                           (map peekMatch (zip [0 ..] cons) ++ [peekErr]))
+                           (fmap peekMatch (zip [0 ..] cons) ++ [peekErr]))
                 ]
   where
     peekMatch (i, con) =
@@ -282,8 +281,7 @@ mkDeserializeDec (SerializeConfig {..}) headTy cons = do
             headTy
             (typeOfType headTy cons)
     pure
-        ( maybe
+        ( foldMap
-            []
             (\x -> [PragmaD (InlineP 'deserializeAt x FunLike AllPhases)])
             cfgInlineDeserialize
          ++
@@ -308,7 +306,7 @@ mkSerializeExprTag tagType tagVal =
     [|serializeAt
           $(varE _initialOffset)
           $(varE _arr)
-          $((sigE (litE (IntegerL (fromIntegral tagVal))) (conT tagType)))|]
+          $(sigE (litE (IntegerL (fromIntegral tagVal))) (conT tagType))|]
 
 mkSerializeExpr :: Bool -> Bool -> TypeOfType -> Q Exp
 mkSerializeExpr True False tyOfTy =
@@ -365,7 +363,7 @@ mkSerializeExpr False False tyOfTy =
                 tagType = getTagType lenCons
             caseE
                 (varE _val)
-                (map (\(tagVal, (SimpleDataCon cname fields)) ->
+                (fmap (\(tagVal, SimpleDataCon cname fields) ->
                           matchConstructor
                               cname
                               (length fields)
@@ -392,8 +390,7 @@ mkSerializeDec (SerializeConfig {..}) headTy cons = do
             cfgRecordSyntaxWithHeader
             (typeOfType headTy cons)
     pure
-        ( maybe
+        ( foldMap
-            []
             (\x -> [PragmaD (InlineP 'serializeAt x FunLike AllPhases)])
             cfgInlineSerialize
          ++

core/src/Streamly/Internal/Data/Serialize/TH/Bottom.hs

@@ -249,7 +249,7 @@ makeA i = mkName $ "a" ++ show i
 
 openConstructor :: Name -> Int -> Q Pat
 openConstructor cname numFields =
-    conP cname (map varP (map mkFieldName [0 .. (numFields - 1)]))
+    conP cname (map (varP. mkFieldName) [0 .. (numFields - 1)])
 
 matchConstructor :: Name -> Int -> Q Exp -> Q Match
 matchConstructor cname numFields exp0 =
@@ -276,9 +276,9 @@ typeOfType :: Type -> [DataCon] -> TypeOfType
 typeOfType headTy [] =
     error
         ("Attempting to get size with no constructors (" ++
-         (pprint headTy) ++ ")")
+         pprint headTy ++ ")")
 typeOfType _ [DataCon cname _ _ []] = UnitType cname
-typeOfType _ [con@(DataCon _ _ _ _)] = TheType $ simplifyDataCon con
+typeOfType _ [con@DataCon{}] = TheType $ simplifyDataCon con
 typeOfType _ cons = MultiType $ map simplifyDataCon cons
 
 isUnitType :: [DataCon] -> Bool
@@ -286,7 +286,7 @@ isUnitType [DataCon _ _ _ []] = True
 isUnitType _ = False
 
 isRecordSyntax :: SimpleDataCon -> Bool
-isRecordSyntax (SimpleDataCon _ fields) = and (isJust . fst <$> fields)
+isRecordSyntax (SimpleDataCon _ fields) = all (isJust . fst) fields
 
 --------------------------------------------------------------------------------
 -- Type casting
@@ -326,7 +326,7 @@ wListToString = fmap (chr . fromIntegral)
 shiftAdd :: Bits a => (b -> a) -> [b] -> a
 shiftAdd conv xs =
     foldl' (.|.) zeroBits $
-    map (\(j, x) -> shiftL x (j * 8)) $ zip [0 ..] $ map conv xs
+    fmap (\(j, x) -> shiftL x (j * 8)) $ zip [0 ..] $ map conv xs
 
 -- Note: This only works in little endian machines
 -- TODO:
@@ -423,7 +423,7 @@ serializeW8List :: Name -> Name -> [Word8] -> Q Exp
 serializeW8List off arr w8List = do
     [|let $(varP (makeN 0)) = $(varE off)
        in $(doE (fmap makeBind [0 .. (lenW8List - 1)] ++
-                 [noBindS ([|pure $(varE (makeN lenW8List))|])]))|]
+                 [noBindS [|pure $(varE (makeN lenW8List))|]]))|]
 
     where
 

core/src/Streamly/Internal/Data/Serialize/TH/Common.hs

@@ -40,8 +40,8 @@ mkDeserializeExprOne peeker (SimpleDataCon cname fields) =
                                        [ varE (makeI numFields)
                                        , appsE
                                              (conE cname :
-                                              (map (varE . makeA)
+                                              map (varE . makeA)
-                                                   [0 .. (numFields - 1)]))
+                                                   [0 .. (numFields - 1)])
                                        ]))
                        ]
                      ])
@@ -60,7 +60,7 @@ mkSerializeExprFields poker fields =
         _ ->
             doE
                 (fmap makeBind [0 .. (numFields - 1)] ++
-                 [noBindS ([|pure $(varE (makeI numFields))|])])
+                 [noBindS [|pure $(varE (makeI numFields))|]])
   where
     numFields = length fields
     makeBind i =

core/src/Streamly/Internal/Data/Serialize/TH/RecHeader.hs

@@ -105,7 +105,7 @@ instance forall a. Serialize a => Serialize (CompactList a) where
 
     -- {-# INLINE addSizeTo #-}
     addSizeTo acc (CompactList xs) =
-        foldl' addSizeTo (acc + (Unbox.sizeOf (Proxy :: Proxy Word8))) xs
+        foldl' addSizeTo (acc + Unbox.sizeOf (Proxy :: Proxy Word8)) xs
 
     -- Inlining this causes large compilation times for tests
     {-# INLINABLE deserializeAt #-}
@@ -175,10 +175,10 @@ mkRecSizeOfExpr :: SimpleDataCon -> Q Exp
 mkRecSizeOfExpr con = do
     n_acc <- newName "acc"
     n_x <- newName "x"
-    (lamE
+    lamE
          [varP n_acc, varP n_x]
          [|$(litIntegral hlen) +
-            $(caseE (varE n_x) [matchCons (varE n_acc) con])|])
+            $(caseE (varE n_x) [matchCons (varE n_acc) con])|]
 
     where
 
@@ -194,7 +194,7 @@ mkRecSizeOfExpr con = do
 
 headerValue :: SimpleDataCon -> [Word8]
 headerValue (SimpleDataCon _ fields) =
-    int_w8 numFields : concat (fmap lengthPrependedFieldEncoding fields)
+    int_w8 numFields : concatMap lengthPrependedFieldEncoding fields
 
     where
 
@@ -215,7 +215,7 @@ headerValue (SimpleDataCon _ fields) =
                     else
                         errorUnsupported
                             "Length of any key should be <= 255."
-         in (int_w8 (length fEnc)) : fEnc
+         in int_w8 (length fEnc) : fEnc
 
 --------------------------------------------------------------------------------
 -- Peek
@@ -232,7 +232,7 @@ serializeWithSize off arr val = do
     pure off1
 
 mkRecSerializeExpr :: Name -> SimpleDataCon -> Q Exp
-mkRecSerializeExpr initialOffset (con@(SimpleDataCon cname fields)) = do
+mkRecSerializeExpr initialOffset con@(SimpleDataCon cname fields) = do
     afterHLen <- newName "afterHLen"
     -- Encoding the header length is required.
     -- We first compare the header length encoded and the current header
@@ -264,7 +264,7 @@ mkRecSerializeExpr initialOffset (con@(SimpleDataCon cname fields)) = do
 {-# INLINE deserializeWithSize #-}
 deserializeWithSize ::
        Serialize a => Int -> MutByteArray -> Int -> IO (Int, a)
-deserializeWithSize off arr endOff = deserializeAt (off + 4) arr endOff
+deserializeWithSize off = deserializeAt (off + 4)
 
 conUpdateFuncDec :: Name -> [Field] -> Q [Dec]
 conUpdateFuncDec funcName fields = do
@@ -274,7 +274,7 @@ conUpdateFuncDec funcName fields = do
     arr <- newName "arr"
     key <- newName "key"
     method <-
-        (caseE
+        caseE
              (varE key)
              (concat
                   [ map (matchField arr endOff (prevAcc, curOff)) fnames
@@ -291,7 +291,7 @@ conUpdateFuncDec funcName fields = do
                                         , valOff + w32_int valLen)|])
                           []
                     ]
-                  ]))
+                  ])
     pure
         [ PragmaD (InlineP funcName NoInline FunLike AllPhases)
         , FunD

core/src/Streamly/Internal/Data/Serialize/Type.hs

@@ -1,3 +1,4 @@
+{- HLINT ignore -}
 -- |
 -- Module      : Streamly.Internal.Data.Serialize.Type
 -- Copyright   : (c) 2023 Composewell Technologies
@@ -190,7 +191,7 @@ deserializeChecked off arr sz =
     let next = off + Unbox.sizeOf (Proxy :: Proxy a)
      in do
         -- Keep likely path in the straight branch.
-        if (next <= sz)
+        if next <= sz
         then Unbox.peekAt off arr >>= \val -> pure (next, val)
         else error
             $ "deserializeAt: accessing array at offset = "
@@ -241,7 +242,7 @@ instance forall a. Serialize a => Serialize [a] where
 
     -- {-# INLINE addSizeTo #-}
     addSizeTo acc xs =
-        foldl' addSizeTo (acc + (Unbox.sizeOf (Proxy :: Proxy Int))) xs
+        foldl' addSizeTo (acc + Unbox.sizeOf (Proxy :: Proxy Int)) xs
 
     -- Inlining this causes large compilation times for tests
     {-# INLINABLE deserializeAt #-}

core/src/Streamly/Internal/Data/Stream/Eliminate.hs

@@ -282,7 +282,7 @@ parseBreakD (PRD.Parser pstep initial extract) stream@(Stream step state) = do
                     src  = Prelude.reverse src0
                 return (Right b, Nesting.append (fromList src) (Stream step s))
             PR.Error err -> do
-                let src = (Prelude.reverse $ getList buf) ++ x:xs
+                let src = Prelude.reverse (getList buf) ++ x:xs
                 return
                     ( Left (ParseError err)
                     , Nesting.append (fromList src) (Stream step s)
@@ -315,7 +315,7 @@ parseBreakD (PRD.Parser pstep initial extract) stream@(Stream step state) = do
                     src  = Prelude.reverse src0
                 return (Right b, fromList src)
             PR.Error err -> do
-                let src = (Prelude.reverse $ getList buf) ++ x:xs
+                let src = Prelude.reverse (getList buf) ++ x:xs
                 return (Left (ParseError err), fromList src)
 
     -- This is simplified goExtract
@@ -441,7 +441,7 @@ elem e (Stream step state) = go SPEC state
 
 {-# INLINE_NORMAL notElem #-}
 notElem :: (Monad m, Eq a) => a -> Stream m a -> m Bool
-notElem e s = fmap not (elem e s)
+notElem e s = fmap not (e `elem` s)
 
 {-# INLINE_NORMAL all #-}
 all :: Monad m => (a -> Bool) -> Stream m a -> m Bool

core/src/Streamly/Internal/Data/StreamK.hs

@@ -1,4 +1,5 @@
 {-# LANGUAGE CPP #-}
+{- HLINT ignore "Eta reduce" -}
 -- |
 -- Module      : Streamly.Internal.Data.StreamK
 -- Copyright   : (c) 2017 Composewell Technologies

core/src/Streamly/Internal/Data/Unbox.hs

@@ -5,6 +5,7 @@
 {-# LANGUAGE NoMonoLocalBinds #-}
 {-# LANGUAGE UnboxedTuples #-}
 {-# LANGUAGE UndecidableInstances #-}
+{- HLINT ignore -}
 
 -- |
 -- Module      : Streamly.Internal.Data.Unbox

core/src/Streamly/Internal/Data/Unbox/TH.hs

@@ -21,9 +21,10 @@ module Streamly.Internal.Data.Unbox.TH
 -- Imports
 --------------------------------------------------------------------------------
 
-import Data.Word (Word16, Word32, Word64, Word8)
+import Data.Bifunctor (second)
-import Data.Proxy (Proxy(..))
 import Data.List (elemIndex)
+import Data.Proxy (Proxy(..))
+import Data.Word (Word16, Word32, Word64, Word8)
 
 import Language.Haskell.TH
 import Language.Haskell.TH.Syntax
@@ -62,7 +63,7 @@ elimTV _ptv ktv (KindedTV n k) = ktv n k
 -- | Extract the type variable name from a 'TyVarBndr', ignoring the
 -- kind signature if one exists.
 tvName :: TyVarBndr_ flag -> Name
-tvName = elimTV id (\n _ -> n)
+tvName = elimTV id const
 
 -- | Get the 'Name' of a 'TyVarBndr'
 tyVarBndrName :: TyVarBndr_ flag -> Name
@@ -191,7 +192,7 @@ mkOffsetDecls tagSize fields =
                        [|$(litE (IntegerL (fromIntegral tagSize))) +
                          $(varE _initialOffset)|])
                   [])
-             (map mkOffsetExpr (zip [1 ..] fields)))
+             (fmap mkOffsetExpr (zip [1 ..] fields)))
 
     where
 
@@ -271,7 +272,7 @@ mkPeekExpr headTy cons =
                 , noBindS
                       (caseE
                            (sigE (varE _tag) (conT tagType))
-                           (map peekMatch (zip [0 ..] cons) ++ [peekErr]))
+                           (fmap peekMatch (zip [0 ..] cons) ++ [peekErr]))
                 ]
 
     where
@@ -303,7 +304,7 @@ mkPokeExprTag tagType tagVal = pokeTag
         [|pokeAt
               $(varE _initialOffset)
               $(varE _arr)
-              $((sigE (litE (IntegerL (fromIntegral tagVal))) (conT tagType)))|]
+              $(sigE (litE (IntegerL (fromIntegral tagVal))) (conT tagType))|]
 
 mkPokeExprFields :: Int -> [Field] -> Q Exp
 mkPokeExprFields tagSize fields = do
@@ -326,7 +327,7 @@ mkPokeExprFields tagSize fields = do
 mkPokeMatch :: Name -> Int -> Q Exp -> Q Match
 mkPokeMatch cname numFields exp0 =
     match
-        (conP cname (map varP (map mkFieldName [0 .. (numFields - 1)])))
+        (conP cname (map (varP . mkFieldName) [0 .. (numFields - 1)]))
         (normalB exp0)
         []
 
@@ -339,15 +340,15 @@ mkPokeExpr headTy cons =
                    $(lift (pprint headTy)) ++ ")")|]
         -- XXX We don't gaurentee encoded equivalilty for Unbox. Does it still
         -- make sense to encode a default value for unit constructor?
-        [(DataCon _ _ _ [])] -> [|pure ()|] -- mkPokeExprTag ''Word8 0
+        [DataCon _ _ _ []] -> [|pure ()|] -- mkPokeExprTag ''Word8 0
-        [(DataCon cname _ _ fields)] ->
+        [DataCon cname _ _ fields] ->
             caseE
                 (varE _val)
                 [mkPokeMatch cname (length fields) (mkPokeExprFields 0 fields)]
         _ ->
             caseE
                 (varE _val)
-                (map (\(tagVal, (DataCon cname _ _ fields)) ->
+                (fmap (\(tagVal, DataCon cname _ _ fields) ->
                           mkPokeMatch
                               cname
                               (length fields)
@@ -466,7 +467,7 @@ deriveUnbox mDecs = do
     mapType f v = f v
 
     modifyConVariables f con =
-        con { dcFields = map (\(a, b) -> (a, mapType f b)) (dcFields con) }
+        con { dcFields = map (second (mapType f)) (dcFields con) }
 
     mkInst mo preds headTyWC methods =
         pure [InstanceD mo preds headTyWC methods]

core/src/Streamly/Internal/Data/Unfold.hs

@@ -519,7 +519,7 @@ replicateM = Unfold step inject
 
     where
 
-    inject seed = pure seed
+    inject = pure
 
     {-# INLINE_LATE step #-}
     step (i, action) =

core/src/Streamly/Internal/Unicode/Parser.hs

@@ -340,7 +340,7 @@ number =  Parser (\s a -> return $ step s a) initial (return . extract)
     step SPInitial val =
         case val of
           '+' -> Continue 0 (SPSign 1)
-          '-' -> Continue 0 $ (SPSign (-1))
+          '-' -> Continue 0 (SPSign (-1))
           _ -> do
               let num = ord val - 48
               if num >= 0 && num <= 9
@@ -481,7 +481,7 @@ doubleParser =  Parser (\s a -> return $ step s a) initial (return . extract)
     step DPInitial val =
         case val of
           '+' -> Continue 0 (DPSign 1)
-          '-' -> Continue 0 $ (DPSign (-1))
+          '-' -> Continue 0 (DPSign (-1))
           _ -> do
               let num = ord val - 48
               if num >= 0 && num <= 9

core/src/Streamly/Internal/Unicode/String.hs

@@ -1,4 +1,4 @@
-{-# LANGUAGE TemplateHaskell #-}
+{-# LANGUAGE TemplateHaskellQuotes #-}
 {-# LANGUAGE CPP #-}
 -- |
 -- Module      : Streamly.Internal.Unicode.String