Lint code in PRs and when committing to master (#6790)

* Remove unused LANGUAGE pragmata

* Apply HLint suggestions

* Configure HLint to ignore some warnings

* Lint code when committing to master

10 files changed, 15 insertions, 20 deletions

diff --git a/src/Text/Pandoc/Readers/BibTeX.hs b/src/Text/Pandoc/Readers/BibTeX.hs
index c367e75a1..b7285e306 100644
--- a/src/Text/Pandoc/Readers/BibTeX.hs
+++ b/src/Text/Pandoc/Readers/BibTeX.hs
@@ -26,7 +26,6 @@ import Text.Pandoc.Builder (setMeta, cite, str)
 import Data.Text (Text)
 import Citeproc (Lang(..), parseLang)
 import Citeproc.Locale (getLocale)
-import Data.Maybe (fromMaybe)
 import Text.Pandoc.Error (PandocError(..))
 import Text.Pandoc.Class (PandocMonad, lookupEnv)
 import Text.Pandoc.Citeproc.BibTeX as BibTeX
@@ -49,7 +48,7 @@ readBibLaTeX = readBibTeX' BibTeX.Biblatex
 
 readBibTeX' :: PandocMonad m => Variant -> ReaderOptions -> Text -> m Pandoc
 readBibTeX' variant _opts t = do
-  lang <- fromMaybe (Lang "en" (Just "US")) . fmap parseLang
+  lang <- maybe (Lang "en" (Just "US")) parseLang
              <$> lookupEnv "LANG"
   locale <- case getLocale lang of
                Left e  -> throwError $ PandocCiteprocError e
@@ -67,4 +66,3 @@ readBibTeX' variant _opts t = do
                                             , citationHash = 0}]
                                             (str "[@*]"))
                         $ Pandoc nullMeta []
-
diff --git a/src/Text/Pandoc/Readers/DocBook.hs b/src/Text/Pandoc/Readers/DocBook.hs
index 190ba1d31..115ac617c 100644
--- a/src/Text/Pandoc/Readers/DocBook.hs
+++ b/src/Text/Pandoc/Readers/DocBook.hs
@@ -1046,7 +1046,7 @@ parseEntry cn el = do
           _ -> 1
   let colSpan = toColSpan el
   let align = toAlignment el
-  (fmap (cell align 1 colSpan) . (parseMixed plain) . elContent) el
+  (fmap (cell align 1 colSpan) . parseMixed plain . elContent) el
 
 getInlines :: PandocMonad m => Element -> DB m Inlines
 getInlines e' = trimInlines . mconcat <$>
diff --git a/src/Text/Pandoc/Readers/Docx.hs b/src/Text/Pandoc/Readers/Docx.hs
index 31c0660fd..00de6a0cd 100644
--- a/src/Text/Pandoc/Readers/Docx.hs
+++ b/src/Text/Pandoc/Readers/Docx.hs
@@ -1,7 +1,6 @@
 {-# LANGUAGE CPP               #-}
 {-# LANGUAGE OverloadedStrings #-}
 {-# LANGUAGE PatternGuards     #-}
-{-# LANGUAGE MultiWayIf        #-}
 {-# LANGUAGE FlexibleContexts  #-}
 {-# LANGUAGE ViewPatterns      #-}
 {- |
@@ -417,7 +416,7 @@ parPartToInlines' (BookMark _ anchor) =
           (modify $ \s -> s { docxAnchorMap = M.insert anchor prevAnchor anchorMap})
         return mempty
       Nothing -> do
-        exts <- readerExtensions <$> asks docxOptions
+        exts <- asks (readerExtensions . docxOptions)
         let newAnchor =
               if not inHdrBool && anchor `elem` M.elems anchorMap
               then uniqueIdent exts [Str anchor]
@@ -462,7 +461,7 @@ makeHeaderAnchor' (Header n (ident, classes, kvs) ils)
   | (c:_) <- filter isAnchorSpan ils
   , (Span (anchIdent, ["anchor"], _) cIls) <- c = do
     hdrIDMap <- gets docxAnchorMap
-    exts <- readerExtensions <$> asks docxOptions
+    exts <- asks (readerExtensions . docxOptions)
     let newIdent = if T.null ident
                    then uniqueIdent exts ils (Set.fromList $ M.elems hdrIDMap)
                    else ident
@@ -475,7 +474,7 @@ makeHeaderAnchor' (Header n (ident, classes, kvs) ils)
 makeHeaderAnchor' (Header n (ident, classes, kvs) ils) =
   do
     hdrIDMap <- gets docxAnchorMap
-    exts <- readerExtensions <$> asks docxOptions
+    exts <- asks (readerExtensions . docxOptions)
     let newIdent = if T.null ident
                    then uniqueIdent exts ils (Set.fromList $ M.elems hdrIDMap)
                    else ident
@@ -736,4 +735,3 @@ docxToOutput opts (Docx (Document _ body)) =
 addAuthorAndDate :: T.Text -> Maybe T.Text -> [(T.Text, T.Text)]
 addAuthorAndDate author mdate =
   ("author", author) : maybe [] (\date -> [("date", date)]) mdate
-
diff --git a/src/Text/Pandoc/Readers/Docx/Combine.hs b/src/Text/Pandoc/Readers/Docx/Combine.hs
index 427a73dbe..46112af19 100644
--- a/src/Text/Pandoc/Readers/Docx/Combine.hs
+++ b/src/Text/Pandoc/Readers/Docx/Combine.hs
@@ -109,7 +109,7 @@ ilModifierAndInnards ils = case viewl $ unMany ils of
     Underline lst     -> Just (Modifier underline, lst)
     Superscript lst   -> Just (Modifier superscript, lst)
     Subscript lst     -> Just (Modifier subscript, lst)
-    Link attr lst tgt -> Just (Modifier $ linkWith attr (fst tgt) (snd tgt), lst)
+    Link attr lst tgt -> Just (Modifier $ uncurry (linkWith attr) tgt, lst)
     Span attr lst     -> Just (AttrModifier spanWith attr, lst)
     _                 -> Nothing
   _ -> Nothing
diff --git a/src/Text/Pandoc/Readers/EPUB.hs b/src/Text/Pandoc/Readers/EPUB.hs
index 5d7984512..5e3326e6d 100644
--- a/src/Text/Pandoc/Readers/EPUB.hs
+++ b/src/Text/Pandoc/Readers/EPUB.hs
@@ -26,7 +26,7 @@ import qualified Data.ByteString.Lazy as BL (ByteString)
 import Data.List (isInfixOf)
 import qualified Data.Text as T
 import qualified Data.Map as M (Map, elems, fromList, lookup)
-import Data.Maybe (fromMaybe, mapMaybe)
+import Data.Maybe (mapMaybe)
 import qualified Data.Text.Lazy as TL
 import qualified Data.Text.Lazy.Encoding as TL
 import Network.URI (unEscapeString)
@@ -139,8 +139,7 @@ parseManifest content coverId = do
   where
     findCover e = maybe False (isInfixOf "cover-image")
                   (findAttr (emptyName "properties") e)
-               || fromMaybe False
-                  (liftM2 (==) coverId (findAttr (emptyName "id") e))
+               || Just True == liftM2 (==) coverId (findAttr (emptyName "id") e)
     parseItem e = do
       uid <- findAttrE (emptyName "id") e
       href <- findAttrE (emptyName "href") e
@@ -191,7 +190,7 @@ getManifest archive = do
   let rootdir = dropFileName manifestFile
   --mime <- lookup "media-type" as
   manifest <- findEntryByPathE manifestFile archive
-  fmap ((,) rootdir) (parseXMLDocE . UTF8.toStringLazy . fromEntry $ manifest)
+  (rootdir,) <$> (parseXMLDocE . UTF8.toStringLazy . fromEntry $ manifest)
 
 -- Fixup
 
diff --git a/src/Text/Pandoc/Readers/Markdown.hs b/src/Text/Pandoc/Readers/Markdown.hs
index d8296ea61..64a2db288 100644
--- a/src/Text/Pandoc/Readers/Markdown.hs
+++ b/src/Text/Pandoc/Readers/Markdown.hs
@@ -1918,7 +1918,7 @@ note = try $ do
           -- notes, to avoid infinite looping with notes inside
           -- notes:
           let contents' = runF contents st{ stateNotes' = M.empty }
-          let addCitationNoteNum (c@Citation{}) =
+          let addCitationNoteNum c@Citation{} =
                 c{ citationNoteNum = noteNum }
           let adjustCite (Cite cs ils) =
                 Cite (map addCitationNoteNum cs) ils
diff --git a/src/Text/Pandoc/Readers/Metadata.hs b/src/Text/Pandoc/Readers/Metadata.hs
index 0d49a7fa8..b9a8653d5 100644
--- a/src/Text/Pandoc/Readers/Metadata.hs
+++ b/src/Text/Pandoc/Readers/Metadata.hs
@@ -70,7 +70,7 @@ yamlBsToRefs :: PandocMonad m
              -> ParserT Text ParserState m (F [MetaValue])
 yamlBsToRefs pMetaValue idpred bstr =
   case YAML.decodeNode' YAML.failsafeSchemaResolver False False bstr of
-       Right (YAML.Doc o@(YAML.Mapping _ _ _):_)
+       Right (YAML.Doc o@YAML.Mapping{}:_)
                 -> case lookupYAML "references" o of
                      Just (YAML.Sequence _ _ ns) -> do
                        let g n = case lookupYAML "id" n of
diff --git a/src/Text/Pandoc/Readers/Odt/ContentReader.hs b/src/Text/Pandoc/Readers/Odt/ContentReader.hs
index 24391dbf0..43c44e7e9 100644
--- a/src/Text/Pandoc/Readers/Odt/ContentReader.hs
+++ b/src/Text/Pandoc/Readers/Odt/ContentReader.hs
@@ -25,6 +25,7 @@ module Text.Pandoc.Readers.Odt.ContentReader
 
 import Control.Applicative hiding (liftA, liftA2, liftA3)
 import Control.Arrow
+import Control.Monad ((<=<))
 
 import qualified Data.ByteString.Lazy as B
 import Data.Foldable (fold)
@@ -352,11 +353,11 @@ modifierFromStyleDiff propertyTriple  =
 
     lookupPreviousValue f = lookupPreviousStyleValue (fmap f . textProperties)
 
-    lookupPreviousValueM f = lookupPreviousStyleValue ((f =<<).textProperties)
+    lookupPreviousValueM f = lookupPreviousStyleValue (f <=< textProperties)
 
     lookupPreviousStyleValue f (ReaderState{..},_,mFamily)
       =     findBy f (extendedStylePropertyChain styleTrace styleSet)
-        <|> ( f =<< fmap (lookupDefaultStyle' styleSet) mFamily         )
+        <|> (f . lookupDefaultStyle' styleSet =<< mFamily)
 
 
 type ParaModifier = Blocks -> Blocks
diff --git a/src/Text/Pandoc/Readers/Odt/Generic/Utils.hs b/src/Text/Pandoc/Readers/Odt/Generic/Utils.hs
index 146f35319..6dc56a0d9 100644
--- a/src/Text/Pandoc/Readers/Odt/Generic/Utils.hs
+++ b/src/Text/Pandoc/Readers/Odt/Generic/Utils.hs
@@ -1,4 +1,3 @@
-{-# LANGUAGE TypeOperators #-}
 {-# LANGUAGE ViewPatterns  #-}
 {- |
    Module      : Text.Pandoc.Reader.Odt.Generic.Utils
diff --git a/src/Text/Pandoc/Readers/Txt2Tags.hs b/src/Text/Pandoc/Readers/Txt2Tags.hs
index 5c5b3c4e9..474e4fac0 100644
--- a/src/Text/Pandoc/Readers/Txt2Tags.hs
+++ b/src/Text/Pandoc/Readers/Txt2Tags.hs
@@ -464,7 +464,7 @@ macro = try $ do
   name <- string "%%" *> oneOfStringsCI (map fst commands)
   optional (try $ enclosed (char '(') (char ')') anyChar)
   lookAhead (spaceChar <|> oneOf specialChars <|> newline)
-  maybe (return mempty) (\f -> B.str <$> asks f) (lookup name commands)
+  maybe (return mempty) (\f -> asks (B.str . f)) (lookup name commands)
   where
     commands = [ ("date", date), ("mtime", mtime)
                , ("infile", T.pack . infile), ("outfile", T.pack . outfile)]