Enable more hints for HLint. (#489)

* Enable `Fuse foldr/map` hint for HLint.
* Enable `Use :` hint for HLint.
* Enable `Use camelCase` hint for HLint.
* Enable `Use concatMap` hint for HLint.
* Enable `Use fmap` hint for HLint.
* Enable `Use maybe` hint for HLint.
* Enable `Use newtype instead of data` hint for HLint.
* Enable `Use replicate` hint for HLint.
* Disable `Use fmap` hint for HLint.
* Update code to satisfy HLint.

.hlint.yaml

@@ -13,15 +13,8 @@
 # Warnings currently triggered by existing code.
 - ignore: {name: "Avoid lambda"} # 1 hint
 - ignore: {name: "Eta reduce"} # 1 hint
-- ignore: {name: "Fuse foldr/map"} # 1 hint
-- ignore: {name: "Use :"} # 2 hints
 - ignore: {name: "Use <$"} # 1 hint
 - ignore: {name: "Use <$>"} # 1 hint
 - ignore: {name: "Use ?~"} # 5 hints
-- ignore: {name: "Use camelCase"} # 3 hints
-- ignore: {name: "Use concatMap"} # 1 hint
 - ignore: {name: "Use fmap"} # 10 hints
 - ignore: {name: "Use lambda-case"} # 3 hints
-- ignore: {name: "Use maybe"} # 1 hint
-- ignore: {name: "Use newtype instead of data"} # 1 hint
-- ignore: {name: "Use replicate"} # 1 hint

proto-lens-protoc/app/Data/ProtoLens/Compiler/Generate.hs

@@ -424,12 +424,11 @@ generatePrisms env oneofInfo =
                -- Case deconstruction
             @@ lambda [bvar "p__"] (
                     case' (var "p__") $
-                       [ match [conP (unqual consName) [bvar "p__val"]]
-                             $ var "Prelude.Just" @@ var "p__val"
-                       ]
+                       match [conP (unqual consName) [bvar "p__val"]]
+                             (var "Prelude.Just" @@ var "p__val")
                        -- We want to generate the otherwise case
                        -- depending on the amount of sum type cases there are
-                       ++ otherwiseCase
+                       : otherwiseCase
                     )
         generatePrism :: [RawMatch] -> OneofCase -> [HsDecl']
         generatePrism otherwiseCase oneofCase =
@@ -812,15 +811,14 @@ oneofRecordField env oneofInfo
         -- since oneofs don't have a notion of a "default" case.
         -- data Foo = Foo { _Foo'bar = Maybe Foo'Bar }
         -- type instance Field "maybe'bar" Foo = Maybe Foo'Bar
-        [LensInstance
+        LensInstance
           { lensSymbol = "maybe'" <> overloadedName
                                         (oneofFieldName oneofInfo)
           , lensFieldType =
                 var "Prelude.Maybe" @@ var (unqual $ oneofTypeName oneofInfo)
           , lensExp = var "Prelude.id"
           }
-         ]
-         ++ concat
+        : concat
           -- Generate the same lenses for each sub-field of the oneof
           -- as if they were proto2 optional fields.
           -- type instance Field "bar" Foo = Bar
@@ -1089,7 +1087,7 @@ fieldTypeDescriptorExpr = \case
 -- instance NFData Bar where
 --    rnf = \x -> deepseq (_Bar'foo x) (deepseq (_Bar'bar x) ())
 messageRnfExpr :: MessageInfo OccNameStr -> HsExpr'
-messageRnfExpr msg = lambda [bvar "x__"] $ foldr (@@) unit (map seqField fieldNames)
+messageRnfExpr msg = lambda [bvar "x__"] $ foldr ((@@) . seqField) unit fieldNames
   where
     fieldNames = messageUnknownFields msg
                 : map (haskellRecordFieldName . fieldName . plainFieldInfo)

proto-lens-protoc/app/Data/ProtoLens/Compiler/Generate/Commented.hs

@@ -2,7 +2,6 @@
 -- | Enables pretty-printing Haddock comments along with top-level declarations.
 module Data.ProtoLens.Compiler.Generate.Commented where
 
-import Data.Maybe (fromMaybe)
 import GHC.SourceGen
 #if MIN_VERSION_ghc(9,0,0)
 import GHC.Utils.Outputable (Outputable(..), SDoc, (<+>), ($+$), vcat, empty, text)
@@ -47,8 +46,10 @@ data CommentedModule = CommentedModule
 
 getModuleName :: CommentedModule -> ModuleName
 getModuleName m =
-    fromMaybe (error "getModuleName: No explicit name")
-        $ fmap unLoc $ hsmodName $ moduleHeader m
+    maybe
+        (error "getModuleName: No explicit name")
+        unLoc
+        (hsmodName $ moduleHeader m)
 
 instance Outputable CommentedModule where
     ppr m =

proto-lens-setup/src/Data/ProtoLens/Setup.hs

@@ -240,7 +240,7 @@ generateSources root l files = withSystemTempDirectory "protoc-out" $ \tmpDir ->
     -- Generate .hs files for all active components into a single temporary
     -- directory.
     let activeModules = collectActiveModules l
-    let allModules = Set.fromList . concat . map snd $ activeModules
+    let allModules = Set.fromList . concatMap snd $ activeModules
     let usedInComponent f = ModuleName.fromString (protoModuleName f)
                           `Set.member` allModules
     generateProtosWithImports (root : importDirs) tmpDir

proto-lens-tests/tests/decode_delimited_test.hs

@@ -16,8 +16,8 @@ import Proto.DecodeDelimited_Fields
 import System.IO (openBinaryFile, hClose, IOMode(ReadMode))
 import System.IO.Temp (withSystemTempFile)
 
-filename_template :: String
-filename_template = "test_decode_delimited"
+filenameTemplate :: String
+filenameTemplate = "test_decode_delimited"
 
 main :: IO ()
 main = testMain
@@ -28,13 +28,13 @@ main = testMain
     foo1 = defMessage & a .~ 42 & b .~ "hello" :: Foo
     foo2 = defMessage
         & a .~ 43
-        & b .~ (T.pack . take 300 . repeat $ 'x') :: Foo
+        & b .~ (T.pack . replicate 300 $ 'x') :: Foo
 
 testWithMessage :: (Eq msg, Show msg, Message msg) => msg -> IO ()
 testWithMessage msg =
   let bs = runBuilder . buildMessageDelimited $ msg
   in
-    withSystemTempFile filename_template $ \fname h -> do
+    withSystemTempFile filenameTemplate $ \fname h -> do
         B.hPut h bs
         hClose h
         h' <- openBinaryFile fname ReadMode

proto-lens-tests/tests/proto3_optional_test.hs

@@ -117,6 +117,10 @@ instance HasField Foo "maybe'_nonsynth" (Maybe ()) where
     fieldOf _ = lens (const Nothing) const
 #endif
 
+-- Ignore lint suggestions which test generated type names.
+{- HLINT ignore Foo'_tracked -}
+{- HLINT ignore Foo'_nonsynth -}
+
 -- We should not generate a data type or constructor for the synthetic oneof.
 data Foo'_tracked = Foo'Tracked Int32
 #if 0