Hlint hints. (#1227)

Co-authored-by: mergify[bot] <37929162+mergify[bot]@users.noreply.github.com>

Author: peterwicksstringfield

GenChangelogs.hs

@@ -24,7 +24,7 @@ main = do
 
   prs <- github' $ pullRequestsForR "haskell" "haskell-language-server" stateClosed FetchAll
   let prsAfterLastTag = either (error . show)
-                        (foldMap (\pr -> if inRange pr then [pr] else []))
+                        (foldMap (\pr -> [pr | inRange pr]))
                         prs
       inRange pr
         | Just mergedDate <- simplePullRequestMergedAt pr = mergedDate > lastDate

ghcide/.hlint.yaml

@@ -11,7 +11,6 @@
 - ignore: {name: "Redundant do"}
 - ignore: {name: "Avoid lambda"}
 - ignore: {name: "Use newtype instead of data"}
-- ignore: {name: "Use fromMaybe"}
 - ignore: {name: "Use unless"}
 - ignore: {name: "Move brackets to avoid $"}
 - ignore: {name: "Eta reduce"}
@@ -25,6 +24,21 @@
 - ignore: {name: "Use uncurry"}
 - ignore: {name: "Avoid lambda using `infix`"}
 
+# Gives at least one suggestion we don't like.
+- ignore: {name: "Use <=<"}
+- ignore: {name: "Use zipFrom"}
+- ignore: {name: "Use zipWithFrom"}
+
+# We are using the "redundant" return/pure to assign a name. We do not want to
+# delete it. In particular, this is not an improvement:
+# Found:
+#   do options <- somethingComplicated
+#      pure options
+# Perhaps:
+#   do somethingComplicated
+- ignore: {name: "Redundant return"}
+- ignore: {name: "Redundant pure"}
+
 # Off by default hints we like
 - warn: {name: Use module export list}
 
@@ -107,7 +121,7 @@
   # Things that are unsafe in Haskell base library
   - {name: unsafeInterleaveIO, within: [Development.IDE.LSP.LanguageServer]}
   - {name: unsafeDupablePerformIO, within: []}
-  - {name: unsafeCoerce, within: []}
+  - {name: unsafeCoerce, within: [Ide.Plugin.Eval.Code]}
   # Things that are a bit dangerous in the GHC API
   - {name: nameModule, within: []}
 

ghcide/session-loader/Development/IDE/Session.hs

@@ -123,7 +123,7 @@ getInitialGhcLibDirDefault = do
         hPutStrLn stderr $ "Couldn't load cradle for libdir: " ++ show (err,dir,hieYaml,cradle)
         pure Nothing
       CradleNone -> do
-        hPutStrLn stderr $ "Couldn't load cradle (CradleNone)"
+        hPutStrLn stderr "Couldn't load cradle (CradleNone)"
         pure Nothing
 
 -- | Sets `unsafeGlobalDynFlags` on using the hie-bios cradle and returns the GHC libdir

ghcide/src/Development/IDE/GHC/ExactPrint.hs

@@ -5,8 +5,6 @@
 {-# LANGUAGE RankNTypes         #-}
 {-# LANGUAGE TypeFamilies       #-}
 
-{- HLINT ignore "Use zipFrom" -}
-
 module Development.IDE.GHC.ExactPrint
     ( Graft(..),
       graft,

ghcide/src/Development/IDE/Spans/AtPoint.hs

@@ -158,7 +158,7 @@ documentHighlight hf rf pos = pure highlights
     ns = concat $ pointCommand hf pos (rights . M.keys . nodeIdentifiers . nodeInfo)
     highlights = do
       n <- ns
-      ref <- maybe [] id (M.lookup (Right n) rf)
+      ref <- fromMaybe [] (M.lookup (Right n) rf)
       pure $ makeHighlight ref
     makeHighlight (sp,dets) =
       DocumentHighlight (realSrcSpanToRange sp) (Just $ highlightType $ identInfo dets)
@@ -266,12 +266,12 @@ typeLocationsAtPoint hiedb lookupModule _ideOptions pos (HAR _ ast _ _ hieKind)
             HQualTy a b -> getTypes [a,b]
             HCastTy a -> getTypes [a]
             _ -> []
-        in fmap nubOrd $ concatMapM (fmap (maybe [] id) . nameToLocation hiedb lookupModule) (getTypes ts)
+        in fmap nubOrd $ concatMapM (fmap (fromMaybe []) . nameToLocation hiedb lookupModule) (getTypes ts)
     HieFresh ->
       let ts = concat $ pointCommand ast pos getts
           getts x = nodeType ni  ++ (mapMaybe identType $ M.elems $ nodeIdentifiers ni)
             where ni = nodeInfo x
-        in fmap nubOrd $ concatMapM (fmap (maybe [] id) . nameToLocation hiedb lookupModule) (getTypes ts)
+        in fmap nubOrd $ concatMapM (fmap (fromMaybe []) . nameToLocation hiedb lookupModule) (getTypes ts)
 
 namesInType :: Type -> [Name]
 namesInType (TyVarTy n)      = [Var.varName n]

hls-plugin-api/src/Ide/PluginUtils.hs

@@ -135,7 +135,7 @@ clientSupportsDocumentChanges caps =
         WorkspaceEditClientCapabilities mDc _ _ <- _workspaceEdit wCaps
         mDc
   in
-    fromMaybe False supports
+    Just True == supports
 
 -- ---------------------------------------------------------------------
 
@@ -214,7 +214,7 @@ allLspCmdIds' pid mp = mkPlugin (allLspCmdIds pid) (Just . pluginCommands)
 
 
 allLspCmdIds :: T.Text -> [(PluginId, [PluginCommand ideState])] -> [T.Text]
-allLspCmdIds pid commands = concat $ map go commands
+allLspCmdIds pid commands = concatMap go commands
   where
     go (plid, cmds) = map (mkLspCmdId pid plid . commandId) cmds
 

hls-plugin-api/src/Ide/Types.hs

@@ -1,7 +1,6 @@
 {-# LANGUAGE GADTs #-}
 {-# LANGUAGE OverloadedStrings #-}
 {-# LANGUAGE ScopedTypeVariables #-}
-{-# LANGUAGE TupleSections #-}
 {-# LANGUAGE FlexibleContexts #-}
 {-# LANGUAGE PolyKinds #-}
 {-# LANGUAGE ViewPatterns #-}

install/src/Cabal.hs

@@ -96,7 +96,7 @@ getProjectFile ver = do
             else "cabal.project"
 
 checkCabal_ :: [String] -> Action ()
-checkCabal_ args = checkCabal args >> return ()
+checkCabal_ args = void $ checkCabal args
 
 -- | check `cabal` has the required version
 checkCabal :: [String] -> Action String

install/src/Env.hs

@@ -54,7 +54,7 @@ findInstalledGhcs = do
     -- sort by version to make it coherent with getHlsVersions
     $ sortBy (comparing fst)
     -- nub by version. knownGhcs takes precedence.
-    $ nubBy ((==) `on` fst)
+    $ nubOrdBy (compare `on` fst)
     -- filter out stack provided GHCs (assuming that stack programs path is the default one in linux)
     $ filter (not . isInfixOf ".stack" . snd) (knownGhcs ++ availableGhcs)
 

install/src/Print.hs

@@ -25,7 +25,7 @@ printInStars = liftIO . putStrLn . embedInStars
 
 -- | Trim whitespace of both ends of a string
 trim :: String -> String
-trim = dropWhileEnd isSpace . dropWhile isSpace
+trim = trimEnd . trimStart
 
 -- | Trim the whitespace of the stdout of a command
 trimmedStdout :: Stdout String -> String