.devcontainer/Dockerfile

@@ -0,0 +1,35 @@
+ARG UBUNTU_TAG=20.04
+FROM ubuntu:"$UBUNTU_TAG"
+
+ENV LANG=C.UTF-8
+RUN \
+    apt-get update && \
+    apt-get install --assume-yes curl gcc git libgmp-dev libtinfo-dev make sudo
+
+ARG GHCUP_VERSION=0.1.17.3
+RUN \
+    curl --output /usr/local/bin/ghcup "https://downloads.haskell.org/~ghcup/$GHCUP_VERSION/x86_64-linux-ghcup-$GHCUP_VERSION" && \
+    chmod +x /usr/local/bin/ghcup && \
+    ghcup --version
+
+ARG USER_NAME=haskell
+RUN \
+    useradd --create-home --shell "$( which bash )" "$USER_NAME" && \
+    echo "$USER_NAME ALL=(ALL) NOPASSWD: ALL" | tee "/etc/sudoers.d/$USER_NAME"
+USER "$USER_NAME"
+ENV PATH="/home/$USER_NAME/.cabal/bin:/home/$USER_NAME/.ghcup/bin:$PATH"
+
+ARG GHC_VERSION=9.0.1
+RUN \
+    ghcup install ghc "$GHC_VERSION" --set && \
+    ghc --version
+
+ARG CABAL_VERSION=3.6.2.0
+RUN \
+    ghcup install cabal "$CABAL_VERSION" --set && \
+    cabal --version
+
+ARG HLS_VERSION=1.4.0
+RUN \
+    ghcup install hls "$HLS_VERSION" --set && \
+    haskell-language-server-wrapper --version

.devcontainer/devcontainer.json

@@ -0,0 +1,6 @@
+{
+    "build": {
+        "dockerfile": "Dockerfile"
+    },
+    "postCreateCommand": "cabal update"
+}

.vscode/extensions.json

@@ -0,0 +1,5 @@
+{
+    "recommendations": [
+        "haskell.haskell"
+    ]
+}

brittany.cabal

@@ -91,8 +91,8 @@ library {
     -fno-warn-redundant-constraints
   }
   build-depends:
-    { base >=4.12 && <4.15
+    { base >=4.12 && <4.16
-    , ghc >=8.6.1 && <8.11
+    , ghc >=8.6.1 && <8.11 || >=9.0 && <9.1
     , ghc-paths >=0.1.0.9 && <0.2
     , ghc-exactprint >=0.5.8 && <0.6.5
     , transformers >=0.5.2.0 && <0.6
@@ -118,7 +118,7 @@ library {
     , semigroups >=0.18.2 && <0.20
     , cmdargs >=0.10.14 && <0.11
     , czipwith >=1.0.1.0 && <1.1
-    , ghc-boot-th >=8.6.1 && <8.11
+    , ghc-boot-th >=8.6.1 && <8.11 || >=9.0 && <9.1
     , filepath >=1.4.1.0 && <1.5
     , random >= 1.1 && <1.3
     }

cabal.project

@@ -0,0 +1,12 @@
+packages: .
+
+allow-newer:
+    , butcher:base
+    , data-tree-print:base
+    , multistate:base
+
+-- https://github.com/lspitzner/czipwith/pull/2
+source-repository-package
+    type: git
+    location: https://github.com/mithrandi/czipwith
+    tag: b6245884ae83e00dd2b5261762549b37390179f8

src/Language/Haskell/Brittany/Internal/Config/Types.hs

@@ -340,16 +340,16 @@ data ExactPrintFallbackMode
                                  -- A PROGRAM BY TRANSFORMING IT.
   deriving (Show, Generic, Data)
 
-instance CFunctor CDebugConfig
-instance CFunctor CLayoutConfig
-instance CFunctor CErrorHandlingConfig
-instance CFunctor CForwardOptions
-instance CFunctor CPreProcessorConfig
-instance CFunctor CConfig
-
 deriveCZipWith ''CDebugConfig
 deriveCZipWith ''CLayoutConfig
 deriveCZipWith ''CErrorHandlingConfig
 deriveCZipWith ''CForwardOptions
 deriveCZipWith ''CPreProcessorConfig
 deriveCZipWith ''CConfig
+
+instance CFunctor CDebugConfig
+instance CFunctor CLayoutConfig
+instance CFunctor CErrorHandlingConfig
+instance CFunctor CForwardOptions
+instance CFunctor CPreProcessorConfig
+instance CFunctor CConfig

src/Language/Haskell/Brittany/Internal/ExactPrintUtils.hs

@@ -20,6 +20,22 @@ import           Language.Haskell.Brittany.Internal.Utils
 import           Data.Data
 import           Data.HList.HList
 
+#if MIN_VERSION_ghc(9,0,0)
+import           GHC.Driver.Session ( getDynFlags )
+import           GHC ( runGhc, GenLocated(L), moduleNameString )
+import qualified GHC.Driver.Session    as GHC
+import qualified GHC                   as GHC hiding (parseModule)
+import qualified GHC.Parser            as GHC
+import qualified GHC.Types.SrcLoc      as GHC
+import qualified GHC.Data.FastString   as GHC
+import qualified GHC.Parser.Lexer      as GHC
+import qualified GHC.Data.StringBuffer as GHC
+import qualified GHC.Utils.Outputable  as GHC
+import qualified GHC.Driver.CmdLine    as GHC
+import           GHC.Hs
+import           GHC.Data.Bag
+import           GHC.Types.SrcLoc ( SrcSpan, Located )
+#else
 import           DynFlags ( getDynFlags )
 import           GHC ( runGhc, GenLocated(L), moduleNameString )
 import qualified DynFlags      as GHC
@@ -41,6 +57,7 @@ import           HsSyn
 #endif
 
 import           SrcLoc ( SrcSpan, Located )
+#endif
 
 
 import qualified Language.Haskell.GHC.ExactPrint            as ExactPrint
@@ -153,7 +170,11 @@ commentAnnFixTransformGlob ast = do
       annsMap = Map.fromListWith
         (flip const)
         [ (GHC.realSrcSpanEnd span, annKey)
+#if MIN_VERSION_ghc(9,0,0)
+        | (GHC.RealSrcSpan span _, annKey) <- Foldable.toList nodes
+#else
         | (GHC.RealSrcSpan span, annKey) <- Foldable.toList nodes
+#endif
         ]
   nodes `forM_` (snd .> processComs annsMap)
  where
@@ -168,9 +189,14 @@ commentAnnFixTransformGlob ast = do
           :: (ExactPrint.Comment, ExactPrint.DeltaPos)
           -> ExactPrint.TransformT Identity Bool
         processCom comPair@(com, _) =
+#if MIN_VERSION_ghc(9,0,0)
+          case GHC.realSrcSpanStart $ ExactPrint.commentIdentifier com of
+            comLoc -> case Map.lookupLE comLoc annsMap of
+#else
           case GHC.srcSpanStart $ ExactPrint.commentIdentifier com of
             GHC.UnhelpfulLoc{}    -> return True -- retain comment at current node.
             GHC.RealSrcLoc comLoc -> case Map.lookupLE comLoc annsMap of
+#endif
               Just (_, annKey2) | loc1 /= loc2 -> case (con1, con2) of
                 (ExactPrint.CN "RecordCon", ExactPrint.CN "HsRecField") ->
                   move $> False
@@ -179,8 +205,13 @@ commentAnnFixTransformGlob ast = do
                where
                 ExactPrint.AnnKey annKeyLoc1 con1 = annKey1
                 ExactPrint.AnnKey annKeyLoc2 con2 = annKey2
+#if MIN_VERSION_ghc(9,0,0)
+                loc1                              = GHC.realSrcSpanStart annKeyLoc1
+                loc2                              = GHC.realSrcSpanStart annKeyLoc2
+#else
                 loc1                              = GHC.srcSpanStart annKeyLoc1
                 loc2                              = GHC.srcSpanStart annKeyLoc2
+#endif
                 move = ExactPrint.modifyAnnsT $ \anns ->
                   let
                     ann2  = Data.Maybe.fromJust $ Map.lookup annKey2 anns
@@ -271,12 +302,20 @@ moveTrailingComments astFrom astTo = do
 -- elements to the relevant annotations. Avoids quadratic behaviour a trivial
 -- implementation would have.
 extractToplevelAnns
+#if MIN_VERSION_ghc(9,0,0)
+  :: Located HsModule
+#else
   :: Located (HsModule GhcPs)
+#endif
   -> ExactPrint.Anns
   -> Map ExactPrint.AnnKey ExactPrint.Anns
 extractToplevelAnns lmod anns = output
  where
+#if MIN_VERSION_ghc(9,0,0)
+  (L _ (HsModule _ _ _ _ ldecls _ _)) = lmod
+#else
   (L _ (HsModule _ _ _ ldecls _ _)) = lmod
+#endif
   declMap1 :: Map ExactPrint.AnnKey ExactPrint.AnnKey
   declMap1 = Map.unions $ ldecls <&> \ldecl ->
     Map.fromSet (const (ExactPrint.mkAnnKey ldecl)) (foldedAnnKeys ldecl)

src/Language/Haskell/Brittany/Internal/LayouterBasics.hs

@@ -99,6 +99,15 @@ import Language.Haskell.Brittany.Internal.Types
 import Language.Haskell.Brittany.Internal.Utils
 import Language.Haskell.Brittany.Internal.ExactPrintUtils
 
+#if MIN_VERSION_ghc(9,0,0)
+import GHC.Types.Name.Reader ( RdrName(..) )
+import           GHC ( Located, runGhc, GenLocated(L), moduleNameString )
+import qualified GHC.Types.SrcLoc as GHC
+import           GHC.Types.Name.Occurrence ( occNameString )
+import           GHC.Types.Name ( getOccString )
+import           GHC ( moduleName )
+import           GHC.Parser.Annotation ( AnnKeywordId(..) )
+#else
 import           RdrName ( RdrName(..) )
 import           GHC ( Located, runGhc, GenLocated(L), moduleNameString )
 import qualified SrcLoc        as GHC
@@ -106,6 +115,7 @@ import           OccName ( occNameString )
 import           Name ( getOccString )
 import           Module ( moduleName )
 import           ApiAnnotation ( AnnKeywordId(..) )
+#endif
 
 import           Data.Data
 import           Data.Generics.Schemes
@@ -299,7 +309,13 @@ filterAnns ast =
 -- b) after (in source code order) the node.
 hasAnyCommentsBelow :: Data ast => GHC.Located ast -> ToBriDocM Bool
 hasAnyCommentsBelow ast@(L l _) =
+#if MIN_VERSION_ghc(9,0,0)
+  case l of
+    GHC.RealSrcSpan rss _ -> List.any (\(c, _) -> ExactPrint.commentIdentifier c > rss)
+    GHC.UnhelpfulSpan _ -> const False
+#else
   List.any (\(c, _) -> ExactPrint.commentIdentifier c > l)
+#endif
     <$> astConnectedComments ast
 
 hasCommentsBetween

src/Language/Haskell/Brittany/Internal/Layouters/Type.hs

@@ -30,10 +30,17 @@ import           GHC.Hs
 #else
 import           HsSyn
 #endif
+#if MIN_VERSION_ghc(9,0,0)
+import           GHC.Types.Name
+import           GHC.Utils.Outputable ( ftext, showSDocUnsafe )
+import           GHC.Types.Basic
+import qualified GHC.Types.SrcLoc
+#else
 import           Name
 import           Outputable ( ftext, showSDocUnsafe )
 import           BasicTypes
 import qualified SrcLoc
+#endif
 
 import           DataTreePrint
 
@@ -56,7 +63,11 @@ layoutType ltype@(L _ typ) = docWrapNode ltype $ case typ of
         ]
       NotPromoted -> docWrapNode name $ docLit t
 #if MIN_VERSION_ghc(8,10,1)
+#if MIN_VERSION_ghc(9,0,0)
+  HsForAllTy _ tele (L _ (HsQualTy _ (L _ cntxts) typ2)) -> let bndrs = hsf_vis_bndrs tele in do
+#else
   HsForAllTy _ _ bndrs (L _ (HsQualTy _ (L _ cntxts) typ2)) -> do
+#endif
 #else
   HsForAllTy _ bndrs (L _ (HsQualTy _ (L _ cntxts) typ2)) -> do
 #endif
@@ -146,7 +157,11 @@ layoutType ltype@(L _ typ) = docWrapNode ltype $ case typ of
           )
       ]
 #if MIN_VERSION_ghc(8,10,1)
+#if MIN_VERSION_ghc(9,0,0)
+  HsForAllTy _ tele typ2 -> let bndrs = hsf_vis_bndrs tele in do
+#else
   HsForAllTy _ _ bndrs typ2 -> do
+#endif
 #else
   HsForAllTy _ bndrs typ2 -> do
 #endif
@@ -254,7 +269,11 @@ layoutType ltype@(L _ typ) = docWrapNode ltype $ case typ of
             ]
           )
       ]
+#if MIN_VERSION_ghc(9,0,0)
+  HsFunTy _ _ typ1 typ2 -> do
+#else
   HsFunTy _ typ1 typ2 -> do
+#endif
     typeDoc1 <- docSharedWrapper layoutType typ1
     typeDoc2 <- docSharedWrapper layoutType typ2
     let maybeForceML = case typ2 of
@@ -642,11 +661,20 @@ layoutType ltype@(L _ typ) = docWrapNode ltype $ case typ of
 #endif
 
 layoutTyVarBndrs
+#if MIN_VERSION_ghc(9,0,0)
+  :: [LHsTyVarBndr flag GhcPs]
+#else
   :: [LHsTyVarBndr GhcPs]
+#endif
   -> ToBriDocM [(Text, Maybe (ToBriDocM BriDocNumbered))]
 layoutTyVarBndrs = mapM $ \case
+#if MIN_VERSION_ghc(9,0,0)
+  (L _ (UserTyVar _ _ name)) -> return $ (lrdrNameToText name, Nothing)
+  (L _ (KindedTyVar _ _ lrdrName kind)) -> do
+#else
   (L _ (UserTyVar _ name)) -> return $ (lrdrNameToText name, Nothing)
   (L _ (KindedTyVar _ lrdrName kind)) -> do
+#endif
     d <- docSharedWrapper layoutType kind
     return $ (lrdrNameToText lrdrName, Just $ d)
   (L _ (XTyVarBndr{})) -> error "brittany internal error: XTyVarBndr"

src/Language/Haskell/Brittany/Internal/Prelude.hs

@@ -14,8 +14,16 @@ import GHC.Hs.Extension               as E ( GhcPs )
 import HsExtension                    as E ( GhcPs )
 #endif /* ghc-8.10.1 */
 
+#if MIN_VERSION_ghc(9,0,0)
+import GHC.Types.Name.Reader          as E ( RdrName )
+#else
 import RdrName                        as E ( RdrName )
-#if MIN_VERSION_ghc(8,8,0)
+#endif
+
+#if MIN_VERSION_ghc(9,0,0)
+-- Does not exist in GHC >= 9.0.1.
+-- https://gitlab.haskell.org/ghc/ghc/-/issues/17494
+#elif MIN_VERSION_ghc(8,8,0)
 import qualified GHC                       ( dL, HasSrcSpan, SrcSpanLess )
 #endif
 import qualified GHC                       ( Located )
@@ -404,7 +412,10 @@ todo :: a
 todo = error "todo"
 
 
-#if MIN_VERSION_ghc(8,8,0)
+#if MIN_VERSION_ghc(9,0,0)
+ghcDL :: a -> a
+ghcDL = id
+#elif MIN_VERSION_ghc(8,8,0)
 ghcDL :: GHC.HasSrcSpan a => a -> GHC.Located (GHC.SrcSpanLess a)
 ghcDL = GHC.dL
 #else              /* ghc-8.6 */

src/Language/Haskell/Brittany/Internal/Utils.hs

@@ -46,11 +46,20 @@ import           Data.Generics.Aliases
 import qualified Text.PrettyPrint as PP
 import           Text.PrettyPrint ( ($+$), (<+>) )
 
+#if MIN_VERSION_ghc(9,0,0)
+import qualified GHC.Utils.Outputable as GHC
+import qualified GHC.Driver.Session   as GHC
+import qualified GHC.Data.FastString  as GHC
+import qualified GHC.Types.SrcLoc     as GHC
+import           GHC.Types.Name.Occurrence as OccName ( occNameString )
+#else
 import qualified Outputable    as GHC
 import qualified DynFlags      as GHC
 import qualified FastString    as GHC
 import qualified SrcLoc        as GHC
 import           OccName ( occNameString )
+#endif
+
 import qualified Data.ByteString as B
 
 import           DataTreePrint

stack.yaml

@@ -1,4 +1,18 @@
-resolver: nightly-2020-12-09
+resolver: nightly-2021-10-20
 
 extra-deps:
-  - data-tree-print-0.1.0.2
+- butcher-1.3.3.2@sha256:0be5b914f648ec9c63cb88730d983602aef829a7c8c31343952e4642e6b52a84,3150
+- data-tree-print-0.1.0.2@sha256:d845e99f322df70e0c06d6743bf80336f5918d5423498528beb0593a2afc1703,1620
+- multistate-0.8.0.3@sha256:49d600399f3a4bfd8c8ba2e924c6592e84915b63c52970818982baa274cd9ac3,3588
+
+# https://github.com/lspitzner/czipwith/pull/2
+- git: https://github.com/mithrandi/czipwith
+  commit: b6245884ae83e00dd2b5261762549b37390179f8
+
+# In the dependencies for butcher-1.3.3.2:
+#     base-4.15.0.0 from stack configuration does not match >=4.11 && <4.15
+# In the dependencies for data-tree-print-0.1.0.2:
+#     base-4.15.0.0 from stack configuration does not match >=4.8 && <4.15
+# In the dependencies for multistate-0.8.0.3:
+#     base-4.15.0.0 from stack configuration does not match >=4.11 && <4.15
+allow-newer: true

stack.yaml.lock

@@ -4,16 +4,41 @@
 #   https://docs.haskellstack.org/en/stable/lock_files
 
 packages:
+- completed:
+    hackage: butcher-1.3.3.2@sha256:0be5b914f648ec9c63cb88730d983602aef829a7c8c31343952e4642e6b52a84,3150
+    pantry-tree:
+      size: 1197
+      sha256: 96fe696234de07e4d9253d80ddf189f8cfaf2e262e977438343a6069677a39d2
+  original:
+    hackage: butcher-1.3.3.2@sha256:0be5b914f648ec9c63cb88730d983602aef829a7c8c31343952e4642e6b52a84,3150
 - completed:
     hackage: data-tree-print-0.1.0.2@sha256:d845e99f322df70e0c06d6743bf80336f5918d5423498528beb0593a2afc1703,1620
     pantry-tree:
       size: 272
       sha256: b8778eb1b16fddb91b2eed2b25f33a89d1e4f7a533160de4ccbf226f82456135
   original:
-    hackage: data-tree-print-0.1.0.2
+    hackage: data-tree-print-0.1.0.2@sha256:d845e99f322df70e0c06d6743bf80336f5918d5423498528beb0593a2afc1703,1620
+- completed:
+    hackage: multistate-0.8.0.3@sha256:49d600399f3a4bfd8c8ba2e924c6592e84915b63c52970818982baa274cd9ac3,3588
+    pantry-tree:
+      size: 2143
+      sha256: 73b47c11a753963b033b79209a66490013da35854dd1064b3633dd23c3fa5650
+  original:
+    hackage: multistate-0.8.0.3@sha256:49d600399f3a4bfd8c8ba2e924c6592e84915b63c52970818982baa274cd9ac3,3588
+- completed:
+    name: czipwith
+    version: 1.0.1.3
+    git: https://github.com/mithrandi/czipwith
+    pantry-tree:
+      size: 964
+      sha256: 239a37e26558e6272c07dc280ee07a83407ed6b86000047ddb979726c23818c4
+    commit: b6245884ae83e00dd2b5261762549b37390179f8
+  original:
+    git: https://github.com/mithrandi/czipwith
+    commit: b6245884ae83e00dd2b5261762549b37390179f8
 snapshots:
 - completed:
-    size: 556768
+    size: 589241
-    url: https://raw.githubusercontent.com/commercialhaskell/stackage-snapshots/master/nightly/2020/12/9.yaml
+    url: https://raw.githubusercontent.com/commercialhaskell/stackage-snapshots/master/nightly/2021/10/20.yaml
-    sha256: bca31ebf05f842be9dd24410eca84f296da1860369a82eb7466f447a76cca762
+    sha256: 69b52866fbe539d7de306ef34c4482323f7b846e0d7348188152dea980a11547
-  original: nightly-2020-12-09
+  original: nightly-2021-10-20