Cleanup GHC macros (because min version is 8.8.4) (#3281)

* Drop min_version_ghc (8.8.4 is min supported)

* Drop conditional glasgow_haskell cpp

* Inline some imports (review feedback)

* Drop hie-compat 8.6 (review feedback)

* Dropping more ghc 8.6 related code and docs

* Eval: Include tests that were broken for 8.6

Author: andys8

docs/contributing/contributing.md

@@ -64,8 +64,6 @@ To create binaries:
 * `nix build .#haskell-language-server-884` - GHC 8.8.4
 * `nix build .#haskell-language-server-901` - GHC 9.0.1
 
-GHC 8.6.5 is not supported here because `nixpkgs-unstable` no longer maintains the corresponding packages set.
-
 ## Testing
 
 The tests make use of the [Tasty](https://github.com/feuerbach/tasty) test framework.

docs/contributing/plugin-tutorial.md

@@ -34,7 +34,7 @@ And here is the gist of the algorithm:
 
 ## Setup
 
-To get started, let’s fetch the HLS repo and build it. You need at least GHC 8.6 for this:
+To get started, let’s fetch the HLS repo and build it. You need at least GHC 8.8 for this:
 
 ```
 git clone --recursive http://github.com/haskell/haskell-language-server hls

docs/installation.md

@@ -157,7 +157,7 @@ Homebrew users can install `haskell-language-server` using the following command
 brew install haskell-language-server
 ```
 
-This formula contains HLS binaries compiled with GHC versions available via Homebrew; at the moment those are: 8.6.5, 8.8.4, 8.10.7.
+This formula contains HLS binaries compiled with GHC versions available via Homebrew; at the moment those are: 8.8.4, 8.10.7.
 
 You need to provide your own GHC/Cabal/Stack as required by your project, possibly via Homebrew.
 

ghcide-bench/ghcide-bench.cabal

@@ -12,7 +12,7 @@ synopsis:           An LSP client for running performance experiments on HLS
 description:        An LSP client for running performance experiments on HLS
 homepage:           https://github.com/haskell/haskell-language-server/tree/master/ghcide#readme
 bug-reports:        https://github.com/haskell/haskell-language-server/issues
-tested-with:        GHC == 8.6.5 || == 8.8.4 || == 8.10.7 || == 9.0.2 || == 9.2.3 || == 9.2.4
+tested-with:        GHC == 8.8.4 || == 8.10.7 || == 9.0.2 || == 9.2.3 || == 9.2.4
 
 source-repository head
     type:     git

ghcide/README.md

@@ -98,7 +98,7 @@ If you can't get `ghcide` working outside the editor, see [this setup troublesho
 
 ### Optimal project setup
 
-`ghcide` has been designed to handle projects with hundreds or thousands of modules. If `ghci` can handle it, then `ghcide` should be able to handle it. The only caveat is that this currently requires GHC >= 8.6, and that the first time a module is loaded in the editor will trigger generation of support files in the background if those do not already exist.
+`ghcide` has been designed to handle projects with hundreds or thousands of modules. If `ghci` can handle it, then `ghcide` should be able to handle it. The only caveat is that this currently requires GHC >= 8.8, and that the first time a module is loaded in the editor will trigger generation of support files in the background if those do not already exist.
 
 ### Using with VS Code
 

ghcide/ghcide.cabal

@@ -99,7 +99,7 @@ library
         unliftio-core,
         ghc-boot-th,
         ghc-boot,
-        ghc >= 8.6,
+        ghc >= 8.8,
         ghc-check >=0.5.0.8,
         ghc-paths,
         cryptohash-sha1 >=0.11.100 && <0.12,
@@ -363,7 +363,7 @@ test-suite ghcide-tests
         text,
         text-rope,
         unordered-containers,
-    if (impl(ghc >= 8.6) && impl(ghc < 9.2))
+    if impl(ghc < 9.2)
       build-depends:
           record-dot-preprocessor,
           record-hasfield

ghcide/src/Development/IDE/Core/Compile.hs

@@ -1181,9 +1181,7 @@ getModSummaryFromImports env fp modTime contents = do
         msrModSummary =
             ModSummary
                 { ms_mod          = modl
-#if MIN_VERSION_ghc(8,8,0)
                 , ms_hie_date     = Nothing
-#endif
 #if MIN_VERSION_ghc(9,3,0)
                 , ms_dyn_obj_date    = Nothing
                 , ms_ghc_prim_import = ghc_prim_import

ghcide/src/Development/IDE/Core/Rules.hs

@@ -62,9 +62,6 @@ module Development.IDE.Core.Rules(
     DisplayTHWarning(..),
     ) where
 
-#if !MIN_VERSION_ghc(8,8,0)
-import           Control.Applicative                          (liftA2)
-#endif
 import           Control.Concurrent.Async                     (concurrently)
 import           Control.Concurrent.Strict
 import           Control.DeepSeq

ghcide/src/Development/IDE/Core/Tracing.hs

@@ -37,25 +37,16 @@ import           OpenTelemetry.Eventlog            (SpanInFlight (..), addEvent,
                                                     beginSpan, endSpan, setTag,
                                                     withSpan)
 
-#if MIN_VERSION_ghc(8,8,0)
-otTracedProvider :: MonadUnliftIO m => PluginId -> ByteString -> m a -> m a
-otTracedGarbageCollection :: (MonadMask f, MonadIO f, Show a) => ByteString -> f [a] -> f [a]
-withEventTrace :: (MonadMask m, MonadIO m) => String -> ((ByteString -> m ()) -> m a) -> m a
-#else
-otTracedProvider :: MonadUnliftIO m => PluginId -> String -> m a -> m a
-otTracedGarbageCollection :: (MonadMask f, MonadIO f, Show a) => String -> f [a] -> f [a]
-withEventTrace :: (MonadMask m, MonadIO m) => String -> ((ByteString -> m ()) -> m a) -> m a
-#endif
 
-withTrace :: (MonadMask m, MonadIO m) =>
-    String -> ((String -> String -> m ()) -> m a) -> m a
+withTrace :: (MonadMask m, MonadIO m) => String -> ((String -> String -> m ()) -> m a) -> m a
 withTrace name act
   | userTracingEnabled
   = withSpan (fromString name) $ \sp -> do
       let setSpan' k v = setTag sp (fromString k) (fromString v)
       act setSpan'
   | otherwise = act (\_ _ -> pure ())
 
+withEventTrace :: (MonadMask m, MonadIO m) => String -> ((ByteString -> m ()) -> m a) -> m a
 withEventTrace name act
   | userTracingEnabled
   = withSpan (fromString name) $ \sp -> do
@@ -125,6 +116,7 @@ otTracedAction key file mode result act
         (\sp -> act (liftIO . setTag sp "diagnostics" . encodeUtf8 . showDiagnostics ))
   | otherwise = act (\_ -> return ())
 
+otTracedGarbageCollection :: (MonadMask f, MonadIO f, Show a) => ByteString -> f [a] -> f [a]
 otTracedGarbageCollection label act
   | userTracingEnabled = fst <$>
       generalBracket
@@ -138,6 +130,7 @@ otTracedGarbageCollection label act
         (const act)
   | otherwise = act
 
+otTracedProvider :: MonadUnliftIO m => PluginId -> ByteString -> m a -> m a
 otTracedProvider (PluginId pluginName) provider act
   | userTracingEnabled = do
     runInIO <- askRunInIO
@@ -146,4 +139,3 @@ otTracedProvider (PluginId pluginName) provider act
         runInIO act
   | otherwise = act
 
-

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

@@ -228,18 +228,8 @@ import           DynFlags                              hiding (ExposePackage)
 import           HscTypes
 import           MkIface                               hiding (writeIfaceFile)
 
-#if MIN_VERSION_ghc(8,8,0)
 import           StringBuffer                          (hPutStringBuffer)
-#endif
 import qualified SysTools
-
-#if !MIN_VERSION_ghc(8,8,0)
-import qualified EnumSet
-import           SrcLoc                                (RealLocated)
-
-import           Foreign.ForeignPtr
-import           System.IO
-#endif
 #endif
 
 import           Compat.HieAst                         (enrichHie)
@@ -385,13 +375,6 @@ corePrepExpr _ = GHC.corePrepExpr
 simplifyExpr df _ = GHC.simplifyExpr df
 #endif
 
-#if !MIN_VERSION_ghc(8,8,0)
-hPutStringBuffer :: Handle -> StringBuffer -> IO ()
-hPutStringBuffer hdl (StringBuffer buf len cur)
-    = withForeignPtr (plusForeignPtr buf cur) $ \ptr ->
-             hPutBuf hdl ptr len
-#endif
-
 #if MIN_VERSION_ghc(9,2,0)
 type ErrMsg  = MsgEnvelope DecoratedSDoc
 #endif
@@ -445,12 +428,7 @@ hieExportNames = nameListFromAvails . hie_exports
 type NameCacheUpdater = NameCache
 #else
 upNameCache :: IORef NameCache -> (NameCache -> (NameCache, c)) -> IO c
-#if MIN_VERSION_ghc(8,8,0)
 upNameCache = updNameCache
-#else
-upNameCache ref upd_fn
-  = atomicModifyIORef' ref upd_fn
-#endif
 #endif
 
 #if !MIN_VERSION_ghc(9,0,1)
@@ -480,27 +458,15 @@ addIncludePathsQuote path x = x{includePaths = f $ includePaths x}
     where f i = i{includePathsQuote = path : includePathsQuote i}
 
 setHieDir :: FilePath -> DynFlags -> DynFlags
-setHieDir _f d =
-#if MIN_VERSION_ghc(8,8,0)
-    d { hieDir     = Just _f}
-#else
-    d
-#endif
+setHieDir _f d = d { hieDir = Just _f}
 
 dontWriteHieFiles :: DynFlags -> DynFlags
-dontWriteHieFiles d =
-#if MIN_VERSION_ghc(8,8,0)
-    gopt_unset d Opt_WriteHie
-#else
-    d
-#endif
+dontWriteHieFiles d = gopt_unset d Opt_WriteHie
 
 setUpTypedHoles ::DynFlags -> DynFlags
 setUpTypedHoles df
   = flip gopt_unset Opt_AbstractRefHoleFits    -- too spammy
-#if MIN_VERSION_ghc(8,8,0)
   $ flip gopt_unset Opt_ShowDocsOfHoleFits     -- not used
-#endif
   $ flip gopt_unset Opt_ShowMatchesOfHoleFits  -- nice but broken (forgets module qualifiers)
   $ flip gopt_unset Opt_ShowProvOfHoleFits     -- not used
   $ flip gopt_unset Opt_ShowTypeAppOfHoleFits  -- not used
@@ -533,12 +499,6 @@ disableWarningsAsErrors :: DynFlags -> DynFlags
 disableWarningsAsErrors df =
     flip gopt_unset Opt_WarnIsError $ foldl' wopt_unset_fatal df [toEnum 0 ..]
 
-#if !MIN_VERSION_ghc(8,8,0)
-wopt_unset_fatal :: DynFlags -> WarningFlag -> DynFlags
-wopt_unset_fatal dfs f
-    = dfs { fatalWarningFlags = EnumSet.delete f (fatalWarningFlags dfs) }
-#endif
-
 isQualifiedImport :: ImportDecl a -> Bool
 #if MIN_VERSION_ghc(8,10,0)
 isQualifiedImport ImportDecl{ideclQualified = NotQualified} = False
@@ -606,8 +566,7 @@ generatedNodeInfo = sourceNodeInfo -- before ghc 9.0, we don't distinguish the s
 #endif
 
 data GhcVersion
-  = GHC86
-  | GHC88
+  = GHC88
   | GHC810
   | GHC90
   | GHC92
@@ -628,8 +587,6 @@ ghcVersion = GHC90
 ghcVersion = GHC810
 #elif MIN_VERSION_GLASGOW_HASKELL(8,8,0,0)
 ghcVersion = GHC88
-#elif MIN_VERSION_GLASGOW_HASKELL(8,6,0,0)
-ghcVersion = GHC86
 #endif
 
 runUnlit :: Logger -> DynFlags -> [Option] -> IO ()