Cleanup CPPs, begin deprecation of GHC 9.4

Closes #4529.

Also,
- update flake lock
- some girl scout changes while trying to understand some code

Author: dschrempf

.github/workflows/supported-ghc-versions.json

@@ -1 +1 @@
-["9.12", "9.10", "9.8", "9.6", "9.4"]
+["9.12", "9.10", "9.8", "9.6"]

flake.lock

@@ -14,7 +14,7 @@ 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 ==9.10.1 || ==9.8.2 || ==9.6.5 || ==9.4.8
+tested-with:        GHC == {9.12.2, 9.10.1, 9.8.4, 9.6.7}
 extra-source-files:
   CHANGELOG.md
   README.md

ghcide/ghcide.cabal

@@ -32,11 +32,9 @@ import           GHC.Types.SrcLoc
 
 -- See Note [Guidelines For Using CPP In GHCIDE Import Statements]
 
-#if MIN_VERSION_ghc(9,5,0)
 import           GHC.Unit.Home.ModInfo
 import           GHC.Unit.Module.Location          (ModLocation (..))
 import           GHC.Unit.Module.WholeCoreBindings
-#endif
 
 -- Orphan instance for Shake.hs
 -- https://hub.darcs.net/ross/transformers/issue/86
@@ -68,13 +66,10 @@ instance NFData Unlinked where
   rnf (DotA f)           = rnf f
   rnf (DotDLL f)         = rnf f
   rnf (BCOs a b)         = seqCompiledByteCode a `seq` liftRnf rwhnf b
-#if MIN_VERSION_ghc(9,5,0)
   rnf (CoreBindings wcb) = rnf wcb
   rnf (LoadedBCOs us)    = rnf us
 #endif
-#endif
 
-#if MIN_VERSION_ghc(9,5,0)
 instance NFData WholeCoreBindings where
 #if MIN_VERSION_ghc(9,11,0)
   rnf (WholeCoreBindings bs m ml f) = rnf bs `seq` rnf m `seq` rnf ml `seq` rnf f
@@ -88,7 +83,6 @@ instance NFData ModLocation where
 #else
     rnf (ModLocation mf f1 f2 f3 f4 f5) = rnf mf `seq` rnf f1 `seq` rnf f2 `seq` rnf f3 `seq` rnf f4 `seq` rnf f5
 #endif
-#endif
 
 instance Show PackageFlag where show = unpack . printOutputable
 instance Show InteractiveImport where show = unpack . printOutputable
@@ -103,12 +97,6 @@ instance NFData SB.StringBuffer where rnf = rwhnf
 instance Show Module where
     show = moduleNameString . moduleName
 
-
-#if !MIN_VERSION_ghc(9,5,0)
-instance (NFData l, NFData e) => NFData (GenLocated l e) where
-    rnf (L l e) = rnf l `seq` rnf e
-#endif
-
 instance Show ModSummary where
     show = show . ms_mod
 
@@ -191,11 +179,6 @@ instance NFData Type where
 instance Show a => Show (Bag a) where
     show = show . bagToList
 
-#if !MIN_VERSION_ghc(9,5,0)
-instance NFData HsDocString where
-    rnf = rwhnf
-#endif
-
 instance Show ModGuts where
     show _ = "modguts"
 instance NFData ModGuts where
@@ -204,11 +187,7 @@ instance NFData ModGuts where
 instance NFData (ImportDecl GhcPs) where
     rnf = rwhnf
 
-#if MIN_VERSION_ghc(9,5,0)
 instance (NFData (HsModule a)) where
-#else
-instance (NFData HsModule) where
-#endif
   rnf = rwhnf
 
 instance Show OccName where show = unpack . printOutputable
@@ -239,10 +218,8 @@ instance NFData UnitId where
 instance NFData NodeKey where
   rnf = rwhnf
 
-#if MIN_VERSION_ghc(9,5,0)
 instance NFData HomeModLinkable where
   rnf = rwhnf
-#endif
 
 instance NFData (HsExpr (GhcPass Renamed)) where
     rnf = rwhnf
@@ -261,16 +238,3 @@ instance NFData Extension where
 
 instance NFData (UniqFM Name [Name]) where
   rnf (ufmToIntMap -> m) = rnf m
-
-#if !MIN_VERSION_ghc(9,5,0)
-instance NFData DuplicateRecordFields where
-  rnf DuplicateRecordFields   = ()
-  rnf NoDuplicateRecordFields = ()
-
-instance NFData FieldSelectors where
-  rnf FieldSelectors   = ()
-  rnf NoFieldSelectors = ()
-
-instance NFData FieldLabel where
-  rnf (FieldLabel a b c d) = rnf a `seq` rnf b `seq` rnf c `seq` rnf d
-#endif

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

@@ -14,7 +14,7 @@ copyright:          The Haskell IDE Team
 license:            Apache-2.0
 license-file:       LICENSE
 build-type:         Simple
-tested-with:        GHC ==9.10.1 || ==9.8.2 || ==9.6.5 || ==9.4.8
+tested-with:        GHC == {9.12.2, 9.10.1, 9.8.4, 9.6.7}
 extra-source-files:
   README.md
   ChangeLog.md

haskell-language-server.cabal

@@ -3,7 +3,10 @@
 {-# LANGUAGE RecordWildCards   #-}
 {-# LANGUAGE ViewPatterns      #-}
 
-module Ide.Plugin.ConfigUtils where
+module Ide.Plugin.ConfigUtils (
+  pluginsToDefaultConfig,
+  pluginsToVSCodeExtensionSchema
+  ) where
 
 import           Control.Lens                  (at, (&), (?~))
 import qualified Data.Aeson                    as A
@@ -31,10 +34,10 @@ pluginsToDefaultConfig :: IdePlugins a -> A.Value
 pluginsToDefaultConfig IdePlugins {..} =
   -- Use '_Object' and 'at' to get at the "plugin" key
   -- and actually set it.
-  A.toJSON defaultConfig & _Object . at "plugin" ?~ elems
+  A.toJSON defaultConfig & _Object . at "plugin" ?~ pluginSpecificDefaultConfigs
   where
-    defaultConfig@Config {} = def
-    elems = A.object $ mconcat $ singlePlugin <$> ipMap
+    defaultConfig = def :: Config
+    pluginSpecificDefaultConfigs = A.object $ mconcat $ singlePlugin <$> ipMap
     -- Splice genericDefaultConfig and dedicatedDefaultConfig
     -- Example:
     --
@@ -48,6 +51,7 @@ pluginsToDefaultConfig IdePlugins {..} =
     --     }
     --   }
     -- }
+    singlePlugin :: PluginDescriptor ideState -> [A.Pair]
     singlePlugin PluginDescriptor {pluginConfigDescriptor = ConfigDescriptor {..}, ..} =
       let x = genericDefaultConfig <> dedicatedDefaultConfig
        in [fromString (T.unpack pId) A..= A.object x | not $ null x]
@@ -66,8 +70,8 @@ pluginsToDefaultConfig IdePlugins {..} =
                         <> nubOrd (mconcat
                             (handlersToGenericDefaultConfig configInitialGenericConfig <$> handlers))
             in case x of
-                    -- if the plugin has only one capability, we produce globalOn instead of the specific one;
-                    -- otherwise we don't produce globalOn at all
+                    -- If the plugin has only one capability, we produce globalOn instead of the specific one;
+                    -- otherwise we omit globalOn
                     [_] -> ["globalOn" A..= plcGlobalOn configInitialGenericConfig]
                     _   -> x
         -- Example: