hlint police

cabal-install/Distribution/Client/Check.hs

@@ -72,10 +72,10 @@ check verbosity = do
         isDistError _                          = True
         errors = filter isDistError packageChecks
 
-    unless (null errors) $ do
+    unless (null errors) $
         putStrLn "Hackage would reject this package."
 
-    when (null packageChecks) $ do
+    when (null packageChecks) $
         putStrLn "No errors or warnings could be found in the package."
 
     return (null packageChecks)

cabal-install/Distribution/Client/Config.hs

@@ -85,7 +85,7 @@ import Data.Maybe
 import Data.Monoid
          ( Monoid(..) )
 import Control.Monad
-         ( when, foldM, liftM )
+         ( unless, foldM, liftM )
 import qualified Distribution.Compat.ReadP as Parse
          ( option )
 import qualified Text.PrettyPrint as Disp
@@ -281,15 +281,15 @@ loadConfig verbosity configFileFlag userInstallFlag = addBaseConf $ do
       writeConfigFile configFile commentConf initialConf
       return initialConf
     Just (ParseOk ws conf) -> do
-      when (not $ null ws) $ warn verbosity $
+      unless (null ws) $ warn verbosity $
         unlines (map (showPWarning configFile) ws)
       return conf
     Just (ParseFailed err) -> do
       let (line, msg) = locatedErrorMsg err
       warn verbosity $
           "Error parsing config file " ++ configFile
-        ++ maybe "" (\n -> ":" ++ show n) line ++ ":\n" ++ msg
-      warn verbosity $ "Using default configuration."
+        ++ maybe "" (\n -> ':' : show n) line ++ ":\n" ++ msg
+      warn verbosity "Using default configuration."
       initialSavedConfig
 
   where

cabal-install/Distribution/Client/Configure.hs

@@ -167,10 +167,9 @@ planLocalPackage verbosity comp configFlags configExFlags installedPkgIndex
         . addConstraints
             -- '--enable-tests' and '--enable-benchmarks' constraints from
             -- command line
-            [ PackageConstraintStanzas (packageName pkg) $ concat
-                [ if testsEnabled then [TestStanzas] else []
-                , if benchmarksEnabled then [BenchStanzas] else []
-                ]
+            [ PackageConstraintStanzas (packageName pkg) $
+                [ TestStanzas  | testsEnabled ] ++
+                [ BenchStanzas | benchmarksEnabled ]
             ]
 
         $ standardInstallPolicy

cabal-install/Distribution/Client/Dependency/Modular/Explore.hs

@@ -72,7 +72,7 @@ combine var ((k, (     d, v)) : xs) c = (\ ~(e, ys) -> (e, (k, v) : ys)) $
 
 -- | Naive backtracking exploration of the search tree. This will yield correct
 -- assignments only once the tree itself is validated.
-explore :: Alternative m => Tree a -> (Assignment -> m (Assignment, RevDepMap))
+explore :: Alternative m => Tree a -> Assignment -> m (Assignment, RevDepMap)
 explore = cata go
   where
     go (FailF _ _)           _           = A.empty
@@ -80,24 +80,25 @@ explore = cata go
     go (PChoiceF qpn _     ts) (A pa fa sa)   =
       asum $                                      -- try children in order,
       P.mapWithKey                                -- when descending ...
-        (\ k r -> r (A (M.insert qpn k pa) fa sa)) $ -- record the pkg choice
+        (\ k r -> r (A (M.insert qpn k pa) fa sa)) -- record the pkg choice
       ts
     go (FChoiceF qfn _ _ _ ts) (A pa fa sa)   =
       asum $                                      -- try children in order,
       P.mapWithKey                                -- when descending ...
-        (\ k r -> r (A pa (M.insert qfn k fa) sa)) $ -- record the flag choice
+        (\ k r -> r (A pa (M.insert qfn k fa) sa)) -- record the flag choice
       ts
     go (SChoiceF qsn _ _   ts) (A pa fa sa)   =
       asum $                                      -- try children in order,
       P.mapWithKey                                -- when descending ...
-        (\ k r -> r (A pa fa (M.insert qsn k sa))) $ -- record the flag choice
+        (\ k r -> r (A pa fa (M.insert qsn k sa))) -- record the flag choice
       ts
     go (GoalChoiceF        ts) a              =
       casePSQ ts A.empty                      -- empty goal choice is an internal error
         (\ _k v _xs -> v a)                   -- commit to the first goal choice
 
 -- | Version of 'explore' that returns a 'Log'.
-exploreLog :: Tree (Maybe (ConflictSet QPN)) -> (Assignment -> Log Message (Assignment, RevDepMap))
+exploreLog :: Tree (Maybe (ConflictSet QPN))
+              -> Assignment -> Log Message (Assignment, RevDepMap)
 exploreLog = cata go
   where
     go (FailF c fr)          _           = failWith (Failure c fr)

cabal-install/Distribution/Client/Dependency/Modular/IndexConversion.hs

@@ -114,10 +114,10 @@ convGPD os arch cid pi
     PInfo
       (maybe []    (convCondTree os arch cid pi fds (const True)          ) libs    ++
        concatMap   (convCondTree os arch cid pi fds (const True)     . snd) exes    ++
-      (prefix (Stanza (SN pi TestStanzas))
-        (L.map     (convCondTree os arch cid pi fds (const True)     . snd) tests)) ++
-      (prefix (Stanza (SN pi BenchStanzas))
-        (L.map     (convCondTree os arch cid pi fds (const True)     . snd) benchs)))
+      prefix (Stanza (SN pi TestStanzas))
+        (L.map     (convCondTree os arch cid pi fds (const True)     . snd) tests) ++
+      prefix (Stanza (SN pi BenchStanzas))
+        (L.map     (convCondTree os arch cid pi fds (const True)     . snd) benchs))
       fds
       [] -- TODO: add encaps
       Nothing

cabal-install/Distribution/Client/Dependency/Modular/Package.hs

@@ -2,6 +2,7 @@ module Distribution.Client.Dependency.Modular.Package
   (module Distribution.Client.Dependency.Modular.Package,
    module Distribution.Package) where
 
+import Control.Arrow (first)
 import Data.List as L
 import Data.Map as M
 
@@ -45,7 +46,7 @@ showI (I v (Inst (InstalledPackageId i))) = showVer v ++ "/installed" ++ shortId
   where
     -- A hack to extract the beginning of the package ABI hash
     shortId = snip (splitAt 4) (++ "...") .
-              snip ((\ (x, y) -> (reverse x, y)) . break (=='-') . reverse) ('-':)
+              snip (first reverse . break (=='-') . reverse) ('-':)
     snip p f xs = case p xs of
                     (ys, zs) -> (if L.null zs then id else f) ys
 
@@ -82,7 +83,7 @@ data Q a = Q PP a
   deriving (Eq, Ord, Show)
 
 -- | Standard string representation of a qualified entity.
-showQ :: (a -> String) -> (Q a -> String)
+showQ :: (a -> String) -> Q a -> String
 showQ showa (Q [] x) = showa x
 showQ showa (Q pp x) = showPP pp ++ "." ++ showa x
 

cabal-install/Distribution/Client/Index.hs

@@ -62,18 +62,18 @@ index verbosity indexFlags path' = do
   let runRemoveSource = not . null $ refsToRemove
   let runList         = fromFlagOrDefault False (indexList indexFlags)
 
-  unless (or [runInit, runLinkSource, runRemoveSource, runList]) $ do
+  unless (or [runInit, runLinkSource, runRemoveSource, runList]) $
     die "no arguments passed to the 'index' command"
 
   path <- validateIndexPath path'
 
-  when runInit $ do
+  when runInit $
     createEmpty verbosity path
 
-  when runLinkSource $ do
+  when runLinkSource $
     addBuildTreeRefs verbosity path refsToAdd
 
-  when runRemoveSource $ do
+  when runRemoveSource $
     removeBuildTreeRefs verbosity path refsToRemove
 
   when runList $ do
@@ -84,7 +84,7 @@ index verbosity indexFlags path' = do
 buildTreeRefFromPath :: FilePath -> IO (Maybe BuildTreeRef)
 buildTreeRefFromPath dir = do
   dirExists <- doesDirectoryExist dir
-  when (not dirExists) $ do
+  unless dirExists $
     die $ "directory '" ++ dir ++ "' does not exist"
   _ <- findPackageDesc dir
   return . Just $ BuildTreeRef { buildTreePath = dir }
@@ -103,7 +103,7 @@ readBuildTreePath entry = case Tar.entryContent entry of
 readBuildTreePaths :: Tar.Entries -> [FilePath]
 readBuildTreePaths =
   catMaybes
-  . Tar.foldrEntries (\e r -> (readBuildTreePath e):r)
+  . Tar.foldrEntries (\e r -> readBuildTreePath e : r)
   [] error
 
 -- | Given a path to a tar archive, extract all references to local build trees.
@@ -135,7 +135,7 @@ validateIndexPath path' = do
    if (== ".tar") . takeExtension $ path
      then return path
      else do dirExists <- doesDirectoryExist path
-             unless dirExists $ do
+             unless dirExists $
                die $ "directory does not exist: '" ++ path ++ "'"
              return $ path </> defaultIndexFileName
 
@@ -163,7 +163,7 @@ addBuildTreeRefs verbosity path l' = do
   -- Add only those paths that aren't already in the index.
   treesToAdd <- mapM buildTreeRefFromPath (l \\ treesInIndex)
   let entries = map writeBuildTreeRef (catMaybes treesToAdd)
-  when (not . null $ entries) $ do
+  unless (null entries) $ do
     offset <-
       fmap (Tar.foldrEntries (\e acc -> Tar.entrySizeInBytes e + acc) 0 error
             . Tar.read) $ BS.readFile path
@@ -194,7 +194,7 @@ removeBuildTreeRefs verbosity path l' = do
     where
       p l entry = case readBuildTreePath entry of
         Nothing    -> True
-        (Just pth) -> not $ any (== pth) l
+        (Just pth) -> pth `notElem` l
 
 -- | List the local build trees that are referred to from the index.
 listBuildTreeRefs :: Verbosity -> FilePath -> IO [FilePath]
@@ -205,7 +205,7 @@ listBuildTreeRefs verbosity path = do
   pkgIndex <- fmap packageIndex . getSourcePackages verbosity $ [repo]
   let buildTreeRefs = [ pkgPath | (LocalUnpackedPackage pkgPath) <-
                            map packageSource . allPackages $ pkgIndex ]
-  when (null buildTreeRefs) $ do
+  when (null buildTreeRefs) $
     notice verbosity $ "Index file '" ++ path
       ++ "' has no references to local build trees."
   return buildTreeRefs
@@ -214,5 +214,5 @@ listBuildTreeRefs verbosity path = do
 checkIndexExists :: FilePath -> IO ()
 checkIndexExists path = do
   indexExists <- doesFileExist path
-  when (not indexExists) $ do
+  unless indexExists $
     die $ "index does not exist: '" ++ path ++ "'"

cabal-install/Distribution/Client/IndexUtils.hs

@@ -55,7 +55,7 @@ import Distribution.Simple.Utils
          ( die, warn, info, fromUTF8, findPackageDesc )
 
 import Data.Char   (isAlphaNum)
-import Data.Maybe  (catMaybes, fromMaybe)
+import Data.Maybe  (mapMaybe, fromMaybe)
 import Data.List   (isPrefixOf)
 import Data.Monoid (Monoid(..))
 import qualified Data.Map as Map
@@ -165,7 +165,7 @@ readRepoIndex verbosity repo =
   in handleNotFound $ do
     warnIfIndexIsOld indexFile
     whenCacheOutOfDate indexFile cacheFile $ do
-      info verbosity $ "Updating the index cache file..."
+      info verbosity "Updating the index cache file..."
       updatePackageIndexCacheFile indexFile cacheFile
     readPackageIndexCacheFile mkAvailablePackage indexFile cacheFile
 
@@ -212,7 +212,7 @@ readRepoIndex verbosity repo =
 updateRepoIndexCache :: Verbosity -> Repo -> IO ()
 updateRepoIndexCache verbosity repo =
     whenCacheOutOfDate indexFile cacheFile $ do
-      info verbosity $ "Updating the index cache file..."
+      info verbosity "Updating the index cache file..."
       updatePackageIndexCacheFile indexFile cacheFile
   where
     indexFile = repoLocalDir repo </> "00-index.tar"
@@ -338,8 +338,7 @@ extractPrefs entry = case Tar.entryContent entry of
   _ -> Nothing
 
 parsePreferredVersions :: String -> [Dependency]
-parsePreferredVersions = catMaybes
-                       . map simpleParse
+parsePreferredVersions = mapMaybe simpleParse
                        . filter (not . isPrefixOf "--")
                        . lines
 
@@ -507,7 +506,7 @@ showIndexCacheEntry entry = case entry of
    CachePreference dep    -> "pref-ver: " ++ display dep
 
 readIndexCache :: BSS.ByteString -> [IndexCacheEntry]
-readIndexCache = catMaybes . map readIndexCacheEntry . BSS.lines
+readIndexCache = mapMaybe readIndexCacheEntry . BSS.lines
 
 showIndexCache :: [IndexCacheEntry] -> String
 showIndexCache = unlines . map showIndexCacheEntry

cabal-install/Distribution/Client/Init.hs

@@ -48,7 +48,7 @@ import Control.Monad
   ( (>=>), join )
 #endif
 import Control.Arrow
-  ( (&&&) )
+  ( (&&&), (***) )
 
 import Text.PrettyPrint hiding (mode, cat)
 
@@ -59,7 +59,7 @@ import Distribution.Version
 import Distribution.Verbosity
   ( Verbosity )
 import Distribution.ModuleName
-  ( ModuleName, fromString )
+  ( ModuleName, fromString )  -- And for the Text instance
 import Distribution.InstalledPackageInfo
   ( InstalledPackageInfo, sourcePackageId, exposed )
 import qualified Distribution.Package as P
@@ -74,8 +74,6 @@ import Distribution.Client.Init.Heuristics
 
 import Distribution.License
   ( License(..), knownLicenses )
-import Distribution.ModuleName
-  ( ) -- for the Text instance
 
 import Distribution.ReadE
   ( runReadE, readP_to_E )
@@ -186,7 +184,8 @@ getLicense flags = do
 --   darcs repo.
 getAuthorInfo :: InitFlags -> IO InitFlags
 getAuthorInfo flags = do
-  (authorName, authorEmail)  <- (\(a,e) -> (flagToMaybe a, flagToMaybe e)) `fmap` guessAuthorNameMail
+  (authorName, authorEmail)  <-
+    (flagToMaybe *** flagToMaybe) `fmap` guessAuthorNameMail
   authorName'  <-     return (flagToMaybe $ author flags)
                   ?>> maybePrompt flags (promptStr "Author name" authorName)
                   ?>> return authorName
@@ -237,9 +236,9 @@ getLibOrExec :: InitFlags -> IO InitFlags
 getLibOrExec flags = do
   isLib <-     return (flagToMaybe $ packageType flags)
            ?>> maybePrompt flags (either (const Library) id `fmap`
-                                   (promptList "What does the package build"
-                                               [Library, Executable]
-                                               Nothing display False))
+                                   promptList "What does the package build"
+                                   [Library, Executable]
+                                   Nothing display False)
            ?>> return (Just Library)
 
   return $ flags { packageType = maybeToFlag isLib }
@@ -250,13 +249,9 @@ getLanguage flags = do
   lang <-     return (flagToMaybe $ language flags)
           ?>> maybePrompt flags
                 (either UnknownLanguage id `fmap`
-                  (promptList "What base language is the package written in"
-                    [Haskell2010, Haskell98]
-                    (Just Haskell2010)
-                    display
-                    True
-                  )
-                )
+                  promptList "What base language is the package written in"
+                  [Haskell2010, Haskell98]
+                  (Just Haskell2010) display True)
           ?>> return (Just Haskell2010)
 
   return $ flags { language = maybeToFlag lang }
@@ -264,7 +259,7 @@ getLanguage flags = do
 -- | Ask whether to generate explanatory comments.
 getGenComments :: InitFlags -> IO InitFlags
 getGenComments flags = do
-  genComments <-     return (not <$> (flagToMaybe $ noComments flags))
+  genComments <-     return (not <$> flagToMaybe (noComments flags))
                  ?>> maybePrompt flags (promptYesNo promptMsg (Just False))
                  ?>> return (Just False)
   return $ flags { noComments = maybeToFlag (fmap not genComments) }
@@ -275,7 +270,7 @@ getGenComments flags = do
 getSrcDir :: InitFlags -> IO InitFlags
 getSrcDir flags = do
   srcDirs <-     return (sourceDirs flags)
-             ?>> Just `fmap` (guessSourceDirs flags)
+             ?>> Just `fmap` guessSourceDirs flags
 
   return $ flags { sourceDirs = srcDirs }
 
@@ -283,8 +278,8 @@ getSrcDir flags = do
 --   moment just looks to see whether there is a directory called 'src'.
 guessSourceDirs :: InitFlags -> IO [String]
 guessSourceDirs flags = do
-  dir      <- fromMaybe getCurrentDirectory
-                (fmap return . flagToMaybe $ packageDir flags)
+  dir      <-
+    maybe getCurrentDirectory return . flagToMaybe $ packageDir flags
   srcIsDir <- doesDirectoryExist (dir </> "src")
   if srcIsDir
     then return ["src"]
@@ -293,8 +288,7 @@ guessSourceDirs flags = do
 -- | Get the list of exposed modules and extra tools needed to build them.
 getModulesBuildToolsAndDeps :: PackageIndex -> InitFlags -> IO InitFlags
 getModulesBuildToolsAndDeps pkgIx flags = do
-  dir <- fromMaybe getCurrentDirectory
-                   (fmap return . flagToMaybe $ packageDir flags)
+  dir <- maybe getCurrentDirectory return . flagToMaybe $ packageDir flags
 
   -- XXX really should use guessed source roots.
   sourceFiles <- scanForModules dir
@@ -359,7 +353,7 @@ chooseDep flags (m, Just ps)
       grps  -> do message flags ("\nWarning: multiple packages found providing "
                                  ++ display m
                                  ++ ": " ++ intercalate ", " (map (display . P.pkgName . head) grps))
-                  message flags ("You will need to pick one and manually add it to the Build-depends: field.")
+                  message flags "You will need to pick one and manually add it to the Build-depends: field."
                   return Nothing
   where
     pkgGroups = groupBy ((==) `on` P.pkgName) (map sourcePackageId ps)
@@ -447,7 +441,7 @@ promptListOptional pr choices =
   $ promptList pr (Nothing : map Just choices) (Just Nothing)
                (maybe "(none)" display) True
   where
-    rearrange = either (Just . Left) (maybe Nothing (Just . Right))
+    rearrange = either (Just . Left) (fmap Right)
 
 -- | Create a prompt from a list of items.
 promptList :: Eq t
@@ -461,8 +455,7 @@ promptList pr choices def displayItem other = do
   putStrLn $ pr ++ ":"
   let options1 = map (\c -> (Just c == def, displayItem c)) choices
       options2 = zip ([1..]::[Int])
-                     (options1 ++ if other then [(False, "Other (specify)")]
-                                           else [])
+                     (options1 ++ [(False, "Other (specify)") | other])
   mapM_ (putStrLn . \(n,(i,s)) -> showOption n i ++ s) options2
   promptList' displayItem (length options2) choices def other
  where showOption n i | n < 10 = " " ++ star i ++ " " ++ rest
@@ -598,7 +591,7 @@ findNewName oldName = findNewName' 0
 generateCabalFile :: String -> InitFlags -> String
 generateCabalFile fileName c =
   renderStyle style { lineLength = 79, ribbonsPerLine = 1.1 } $
-  (if (minimal c /= Flag True)
+  (if minimal c /= Flag True
     then showComment (Just $ "Initial " ++ fileName ++ " generated by cabal "
                           ++ "init.  For further documentation, see "
                           ++ "http://haskell.org/cabal/users-guide/")
@@ -670,12 +663,12 @@ generateCabalFile fileName c =
 
        , case packageType c of
            Flag Executable ->
-             text "\nexecutable" <+> text (fromMaybe "" . flagToMaybe $ packageName c) $$ (nest 2 $ vcat
+             text "\nexecutable" <+> text (fromMaybe "" . flagToMaybe $ packageName c) $$ nest 2 (vcat
              [ fieldS "main-is" NoFlag (Just ".hs or .lhs file containing the Main module.") True
 
              , generateBuildInfo Executable c
              ])
-           Flag Library    -> text "\nlibrary" $$ (nest 2 $ vcat
+           Flag Library    -> text "\nlibrary" $$ nest 2 (vcat
              [ fieldS "exposed-modules" (listField (exposedModules c))
                       (Just "Modules exported by the library.")
                       True
@@ -733,15 +726,15 @@ generateCabalFile fileName c =
                         (False, _, _)     -> ($$ text "")
                       $
                       comment f <> text s <> colon
-                                <> text (take (20 - length s) (repeat ' '))
+                                <> text (replicate (20 - length s) ' ')
                                 <> text (fromMaybe "" . flagToMaybe $ f)
    comment NoFlag    = text "-- "
    comment (Flag "") = text "-- "
    comment _         = text ""
 
    showComment :: Maybe String -> Doc
-   showComment (Just t) = vcat . map text
-                        . map ("-- "++) . lines
+   showComment (Just t) = vcat
+                        . map (text . ("-- "++)) . lines
                         . renderStyle style {
                             lineLength = 76,
                             ribbonsPerLine = 1.05
@@ -774,6 +767,6 @@ message _ s = putStrLn s
 
 #if MIN_VERSION_base(3,0,0)
 #else
-(>=>)       :: Monad m => (a -> m b) -> (b -> m c) -> (a -> m c)
+(>=>)       :: Monad m => (a -> m b) -> (b -> m c) -> a -> m c
 f >=> g     = \x -> f x >>= g
 #endif

cabal-install/Distribution/Client/Init/Heuristics.hs

@@ -37,7 +37,7 @@ import Data.Char   ( isUpper, isLower, isSpace )
 import Data.Either ( partitionEithers )
 #endif
 import Data.List   ( isPrefixOf )
-import Data.Maybe  ( catMaybes )
+import Data.Maybe  ( mapMaybe, catMaybes, maybeToList )
 import Data.Monoid ( mempty, mappend )
 import qualified Data.Set as Set ( fromList, toList )
 import System.Directory ( getDirectoryContents, doesDirectoryExist, doesFileExist,
@@ -104,13 +104,13 @@ findImports :: FilePath -> SourceFileEntry -> IO SourceFileEntry
 findImports projectRoot sf = do
   s <- readFile (sfToFileName projectRoot sf)
 
-  let modules = catMaybes
-              . map ( getModName
-                    . drop 1
-                    . filter (not . null)
-                    . dropWhile (/= "import")
-                    . words
-                    )
+  let modules = mapMaybe
+                ( getModName
+                . drop 1
+                . filter (not . null)
+                . dropWhile (/= "import")
+                . words
+                )
               . filter (not . ("--" `isPrefixOf`)) -- poor man's comment filtering
               . lines
               $ s
@@ -148,7 +148,7 @@ neededBuildPrograms :: [SourceFileEntry] -> [String]
 neededBuildPrograms entries =
     [ handler
     | ext <- nubSet (map fileExtension entries)
-    , handler <- maybe [] (:[]) (lookup ext knownSuffixHandlers)
+    , handler <- maybeToList (lookup ext knownSuffixHandlers)
     ]
 
 -- |Guess author and email
@@ -173,7 +173,7 @@ guessAuthorNameMail =
 
 -- |Get list of categories used in hackage. NOTE: Very slow, needs to be cached
 knownCategories :: SourcePackageDb -> [String]
-knownCategories (SourcePackageDb sourcePkgIndex _) = nubSet $
+knownCategories (SourcePackageDb sourcePkgIndex _) = nubSet
     [ cat | pkg <- map head (allPackagesByName sourcePkgIndex)
           , let catList = (PD.category . PD.packageDescription . packageDescription) pkg
           , cat <- splitString ',' catList

cabal-install/Distribution/Client/InstallSymlink.hs

@@ -234,6 +234,6 @@ makeRelative a b = assert (isAbsolute a && isAbsolute b) $
       bs = splitPath b
       commonLen = length $ takeWhile id $ zipWith (==) as bs
    in joinPath $ [ ".." | _  <- drop commonLen as ]
-              ++ [  b'  | b' <- drop commonLen bs ]
+              ++ drop commonLen bs
 
 #endif

cabal-install/Distribution/Client/PackageIndex.hs

@@ -63,7 +63,7 @@ import qualified Data.Array as Array
 import Data.Array ((!))
 import Data.List (groupBy, sortBy, nub, isInfixOf)
 import Data.Monoid (Monoid(..))
-import Data.Maybe (isJust, isNothing, fromMaybe)
+import Data.Maybe (isJust, isNothing, fromMaybe, catMaybes)
 
 import Distribution.Package
          ( PackageName(..), PackageIdentifier(..)
@@ -90,7 +90,7 @@ newtype PackageIndex pkg = PackageIndex
   deriving (Show, Read)
 
 instance Package pkg => Monoid (PackageIndex pkg) where
-  mempty  = PackageIndex (Map.empty)
+  mempty  = PackageIndex Map.empty
   mappend = merge
   --save one mappend with empty in the common case:
   mconcat [] = mempty
@@ -466,9 +466,8 @@ dependencyGraph :: PackageFixedDeps pkg
                     PackageIdentifier -> Maybe Graph.Vertex)
 dependencyGraph index = (graph, vertexToPkg, pkgIdToVertex)
   where
-    graph = Array.listArray bounds
-              [ [ v | Just v <- map pkgIdToVertex (depends pkg) ]
-              | pkg <- pkgs ]
+    graph = Array.listArray bounds $
+            map (catMaybes . map pkgIdToVertex . depends) pkgs
     vertexToPkg vertex = pkgTable ! vertex
     pkgIdToVertex = binarySearch 0 topBound
 

cabal-install/Distribution/Client/ParseUtils.hs

@@ -23,7 +23,7 @@ import qualified Text.PrettyPrint as Disp
 
 --FIXME: replace this with something better
 parseFields :: [FieldDescr a] -> a -> [ParseUtils.Field] -> ParseResult a
-parseFields fields initial = foldM setField initial
+parseFields fields = foldM setField
   where
     fieldMap = Map.fromList
       [ (name, f) | f@(FieldDescr name _ _) <- fields ]

cabal-install/Distribution/Client/Setup.hs

@@ -56,12 +56,9 @@ import Distribution.Simple.Program
          ( defaultProgramConfiguration )
 import Distribution.Simple.Command hiding (boolOpt)
 import qualified Distribution.Simple.Setup as Cabal
-         ( configureCommand, buildCommand, sdistCommand, haddockCommand
-         , buildOptions, defaultBuildFlags )
 import Distribution.Simple.Setup
-         ( ConfigFlags(..), BuildFlags(..), SDistFlags(..), HaddockFlags(..) )
-import Distribution.Simple.Setup
-         ( Flag(..), toFlag, fromFlag, flagToMaybe, flagToList
+         ( ConfigFlags(..), BuildFlags(..), SDistFlags(..), HaddockFlags(..)
+         , Flag(..), toFlag, fromFlag, flagToMaybe, flagToList
          , optionVerbosity, boolOpt, trueArg, falseArg )
 import Distribution.Simple.InstallDirs
          ( PathTemplate, toPathTemplate, fromPathTemplate )
@@ -826,11 +823,10 @@ installOptions showOrParseArgs =
                       (map (fmap show) . flagToList))
       ] ++ case showOrParseArgs of      -- TODO: remove when "cabal install" avoids
           ParseArgs ->
-            option [] ["only"]
+            [ option [] ["only"]
               "Only installs the package in the current directory."
               installOnly (\v flags -> flags { installOnly = v })
-              trueArg
-             : []
+              trueArg ]
           _ -> []
 
 instance Monoid InstallFlags where
@@ -1422,7 +1418,7 @@ liftOptions :: (b -> a) -> (a -> b -> b)
             -> [OptionField a] -> [OptionField b]
 liftOptions get set = map (liftOption get set)
 
-yesNoOpt :: ShowOrParseArgs -> MkOptDescr (b -> Flag Bool) (Flag Bool -> (b -> b)) b
+yesNoOpt :: ShowOrParseArgs -> MkOptDescr (b -> Flag Bool) (Flag Bool -> b -> b) b
 yesNoOpt ShowArgs sf lf = trueArg sf lf
 yesNoOpt _        sf lf = boolOpt' flagToMaybe Flag (sf, lf) ([], map ("no-" ++) lf) sf lf
 

cabal-install/Distribution/Client/Tar.hs

@@ -114,7 +114,7 @@ extractTarGzFile :: FilePath -- ^ Destination directory
                  -> FilePath -- ^ Expected subdir (to check for tarbombs)
                  -> FilePath -- ^ Tarball
                 -> IO ()
-extractTarGzFile dir expected tar = do
+extractTarGzFile dir expected tar =
   unpack dir . checkTarbomb expected . read . GZipUtils.maybeDecompress =<< BS.readFile tar
 
 --
@@ -363,7 +363,7 @@ splitLongPath path =
     Right (name, [])         -> Right (TarPath name "")
     Right (name, first:rest) -> case packName prefixMax remainder of