diff --git a/compat/GHC/Driver/Monad.hs b/compat/GHC/Driver/Monad.hs
new file mode 100644
index 0000000..400e560
--- /dev/null
+++ b/compat/GHC/Driver/Monad.hs
@@ -0,0 +1,2 @@
+module GHC.Driver.Monad (module GhcMonad) where
+import GhcMonad
diff --git a/compat/GHC/Driver/Session.hs b/compat/GHC/Driver/Session.hs
new file mode 100644
index 0000000..41916b7
--- /dev/null
+++ b/compat/GHC/Driver/Session.hs
@@ -0,0 +1,2 @@
+module GHC.Driver.Session (module DynFlags) where
+import DynFlags
diff --git a/compat/GHC/Hs/Type.hs b/compat/GHC/Hs/Type.hs
new file mode 100644
index 0000000..208ee5d
--- /dev/null
+++ b/compat/GHC/Hs/Type.hs
@@ -0,0 +1,9 @@
+{-# LANGUAGE CPP #-}
+module GHC.Hs.Type
+#if MIN_VERSION_ghc(8,10,0)
+(module GHC.Hs.Types) where
+import GHC.Hs.Types
+#else
+(module HsTypes) where
+import HsTypes
+#endif
diff --git a/compat/GHC/Hs/Types.hs b/compat/GHC/Hs/Types.hs
deleted file mode 100644
index c2dc3e8..0000000
--- a/compat/GHC/Hs/Types.hs
+++ /dev/null
@@ -1,2 +0,0 @@
-module GHC.Hs.Types (module HsTypes) where
-import HsTypes
diff --git a/compat/GHC/Utils/Outputable.hs b/compat/GHC/Utils/Outputable.hs
new file mode 100644
index 0000000..69bc10b
--- /dev/null
+++ b/compat/GHC/Utils/Outputable.hs
@@ -0,0 +1,2 @@
+module GHC.Utils.Outputable (module Outputable) where
+import Outputable
diff --git a/package.yaml b/package.yaml
index 00be81f..6b98e1b 100644
--- a/package.yaml
+++ b/package.yaml
@@ -30,7 +30,7 @@ description: |
 
 dependencies:
 - base >= 4.7 && < 5
-- ghc >= 8.4 && < 8.11
+- ghc >= 8.4 && < 9.2
 
 default-extensions:
 - DataKinds
diff --git a/src/GHC/SourceGen/Binds.hs b/src/GHC/SourceGen/Binds.hs
index 71a171f..ff59e17 100644
--- a/src/GHC/SourceGen/Binds.hs
+++ b/src/GHC/SourceGen/Binds.hs
@@ -4,6 +4,7 @@
 -- license that can be found in the LICENSE file or at
 -- https://developers.google.com/open-source/licenses/bsd
 
+{-# LANGUAGE CPP #-}
 -- | This module provides combinators for constructing Haskell declarations.
 module GHC.SourceGen.Binds
     (  -- * Bindings
@@ -53,6 +54,7 @@ import GHC.Hs.Expr
 import GHC.Hs.Types
 import GhcPlugins (isSymOcc)
 import TcEvidence (HsWrapper(WpHole))
+#endif
 
 import GHC.SourceGen.Binds.Internal
 import GHC.SourceGen.Name
@@ -288,7 +290,10 @@ stmt e =
 -- > =====
 -- > bvar "x" <-- var "act"
 (<--) :: Pat' -> HsExpr' -> Stmt'
-p <-- e = withPlaceHolder $ noExt BindStmt (builtPat p) (builtLoc e) noSyntaxExpr noSyntaxExpr
+p <-- e = withPlaceHolder $ noExt BindStmt (builtPat p) (builtLoc e)
+#if !MIN_VERSION_ghc(9,0,0)
+         noSyntaxExpr noSyntaxExpr
+#endif
 infixl 1 <--
 
 -- | Syntax types which can declare/define pattern bindings.
diff --git a/src/GHC/SourceGen/Binds/Internal.hs b/src/GHC/SourceGen/Binds/Internal.hs
index 255f41d..444a273 100644
--- a/src/GHC/SourceGen/Binds/Internal.hs
+++ b/src/GHC/SourceGen/Binds/Internal.hs
@@ -7,12 +7,18 @@
 {-# LANGUAGE CPP #-}
 module GHC.SourceGen.Binds.Internal where
 
+#if MIN_VERSION_ghc(9,0,0)
+import GHC.Types.Basic (Origin(Generated))
+import GHC.Data.Bag (listToBag)
+import GHC.Types.SrcLoc (Located)
+#else
 import BasicTypes (Origin(Generated))
 import Bag (listToBag)
+import SrcLoc (Located)
+#endif
 import GHC.Hs.Binds
 import GHC.Hs.Decls
 import GHC.Hs.Expr (MatchGroup(..), Match(..), GRHSs(..))
-import SrcLoc (Located)
 
 #if !MIN_VERSION_ghc(8,6,0)
 import PlaceHolder (PlaceHolder(..))
diff --git a/src/GHC/SourceGen/Decl.hs b/src/GHC/SourceGen/Decl.hs
index 22d7c27..da0737b 100644
--- a/src/GHC/SourceGen/Decl.hs
+++ b/src/GHC/SourceGen/Decl.hs
@@ -49,14 +49,21 @@ module GHC.SourceGen.Decl
     , patSynBind
     ) where
 
+#if MIN_VERSION_ghc(9,0,0)
+import GHC.Types.Basic (LexicalFixity(Prefix))
+import GHC.Data.Bag (listToBag)
+import GHC.Types.SrcLoc (Located, LayoutInfo(..))
+#else
 import BasicTypes (LexicalFixity(Prefix))
+import Bag (listToBag)
+import SrcLoc (Located)
+#endif
 #if !MIN_VERSION_ghc(8,6,0)
 import BasicTypes (DerivStrategy(..))
 #endif
-import Bag (listToBag)
 import GHC.Hs.Binds
 import GHC.Hs.Decls
-import GHC.Hs.Types
+import GHC.Hs.Type
     ( ConDeclField(..)
     , FieldOcc(..)
     , HsConDetails(..)
@@ -71,8 +78,10 @@ import GHC.Hs.Types
 #endif
     , SrcStrictness(..)
     , SrcUnpackedness(..)
+#if MIN_VERSION_ghc(9,0,0)
+    , hsUnrestricted
+#endif
     )
-import SrcLoc (Located)
 
 #if MIN_VERSION_ghc(8,10,0)
 import GHC.Hs.Extension (NoExtField(NoExtField))
@@ -154,7 +163,9 @@ class'
 class' context name vars decls
     = noExt TyClD $ ClassDecl
             { tcdCtxt = builtLoc $ map builtLoc context
-#if MIN_VERSION_ghc(8,10,0)
+#if MIN_VERSION_ghc(9,0,0)
+            , tcdCExt = NoLayoutInfo
+#elif MIN_VERSION_ghc(8,10,0)
             , tcdCExt = NoExtField
 #elif MIN_VERSION_ghc(8,6,0)
             , tcdCExt = NoExt
@@ -306,10 +317,10 @@ data' = newOrDataType DataType
 --
 -- > Foo a Int
 -- > =====
--- > conDecl "Foo" [field (var "a"), field (var "Int")]
+-- > prefixCon "Foo" [field (var "a"), field (var "Int")]
 prefixCon :: OccNameStr -> [Field] -> ConDecl'
 prefixCon name fields = renderCon98Decl name
-    $ PrefixCon $ map renderField fields
+    $ PrefixCon $ map (hsUnrestricted . renderField) fields
 
 -- | Declares a Haskell-98-style infix constructor for a data or type
 -- declaration.
@@ -319,7 +330,7 @@ prefixCon name fields = renderCon98Decl name
 -- > infixCon (field (var "A" @@ var "b")) ":+:" (field (Var "C" @@ var "d"))
 infixCon :: Field -> OccNameStr -> Field -> ConDecl'
 infixCon f name f' = renderCon98Decl name
-    $ InfixCon (renderField f) (renderField f')
+    $ InfixCon (hsUnrestricted $ renderField f) (hsUnrestricted $ renderField f')
 
 -- | Declares Haskell-98-style record constructor for a data or type
 -- declaration.
@@ -371,6 +382,11 @@ strict f = f { strictness = SrcStrict }
 lazy :: Field -> Field
 lazy f = f { strictness = SrcLazy }
 
+#if !MIN_VERSION_ghc(9,0,0)
+hsUnrestricted :: a -> a
+hsUnrestricted = id
+#endif
+
 renderField :: Field -> Located HsType'
 -- TODO: parenthesizeTypeForApp is an overestimate in the case of
 -- rendering an infix or record type.
diff --git a/src/GHC/SourceGen/Expr.hs b/src/GHC/SourceGen/Expr.hs
index b8f0267..e5700ff 100644
--- a/src/GHC/SourceGen/Expr.hs
+++ b/src/GHC/SourceGen/Expr.hs
@@ -31,9 +31,14 @@ module GHC.SourceGen.Expr
 import GHC.Hs.Expr
 import GHC.Hs.Extension (GhcPs)
 import GHC.Hs.Pat (HsRecField'(..), HsRecFields(..))
-import GHC.Hs.Types (FieldOcc(..), AmbiguousFieldOcc(..))
+import GHC.Hs.Type (FieldOcc(..), AmbiguousFieldOcc(..))
+import GHC.Hs.Utils (mkHsIf)
 import Data.String (fromString)
+#if MIN_VERSION_ghc(9,0,0)
+import GHC.Types.SrcLoc (unLoc, GenLocated(..), Located)
+#else
 import SrcLoc (unLoc, GenLocated(..), Located)
+#endif
 
 import GHC.SourceGen.Binds.Internal
 import GHC.SourceGen.Binds
@@ -68,7 +73,7 @@ lambdaCase :: [RawMatch] -> HsExpr'
 lambdaCase = noExt HsLamCase . matchGroup CaseAlt
 
 if' :: HsExpr' -> HsExpr' -> HsExpr' -> HsExpr'
-if' x y z = noExt HsIf Nothing (builtLoc x) (builtLoc y) (builtLoc z)
+if' x y z = mkHsIf (builtLoc x) (builtLoc y) (builtLoc z)
 
 -- | A MultiWayIf expression.
 --
@@ -94,7 +99,12 @@ multiIf = noExtOrPlaceHolder HsMultiIf . map builtLoc
 -- > =====
 -- > do' [bvar "x" <-- var "act", stmt $ var "return" @@ var "x"]
 do' :: [Stmt'] -> HsExpr'
-do' = withPlaceHolder . noExt HsDo DoExpr
+do' = withPlaceHolder
+#if MIN_VERSION_ghc(9,0,0)
+        . noExt HsDo (DoExpr Nothing)
+#else
+        . noExt HsDo DoExpr
+#endif
         . builtLoc . map (builtLoc . parenthesizeIfLet)
   where
   -- Put parentheses around a "let" in a do-binding, to avoid:
@@ -120,7 +130,12 @@ do' = withPlaceHolder . noExt HsDo DoExpr
 -- >          ]
 listComp :: HsExpr' -> [Stmt'] -> HsExpr'
 listComp lastExpr stmts =
-    let lastStmt = noExt LastStmt (builtLoc lastExpr) False noSyntaxExpr
+    let lastStmt = noExt LastStmt (builtLoc lastExpr) ret noSyntaxExpr
+#if MIN_VERSION_ghc(9,0,0)
+        ret = Nothing
+#else
+        ret = False
+#endif
      in withPlaceHolder . noExt HsDo ListComp . builtLoc . map builtLoc $
             stmts ++ [lastStmt]
 
diff --git a/src/GHC/SourceGen/Expr/Internal.hs b/src/GHC/SourceGen/Expr/Internal.hs
index fc171ae..0ecf23c 100644
--- a/src/GHC/SourceGen/Expr/Internal.hs
+++ b/src/GHC/SourceGen/Expr/Internal.hs
@@ -8,7 +8,11 @@
 module GHC.SourceGen.Expr.Internal where
 
 import GHC.Hs.Expr
+#if MIN_VERSION_ghc(9,0,0)
+import GHC.Types.SrcLoc (Located, unLoc)
+#else
 import SrcLoc (Located, unLoc)
+#endif
 
 import GHC.SourceGen.Lit.Internal
 import GHC.SourceGen.Syntax.Internal
diff --git a/src/GHC/SourceGen/Lit.hs b/src/GHC/SourceGen/Lit.hs
index 2904aa7..0c00195 100644
--- a/src/GHC/SourceGen/Lit.hs
+++ b/src/GHC/SourceGen/Lit.hs
@@ -6,6 +6,7 @@
 
 -- | This module provides combinators for constructing Haskell literals,
 -- which may be used in either patterns or expressions.
+{-# LANGUAGE CPP #-}
 module GHC.SourceGen.Lit
     ( HsLit'
     , HsOverLit'
@@ -16,12 +17,16 @@ module GHC.SourceGen.Lit
     , frac
     ) where
 
-import BasicTypes (FractionalLit(..))
-import BasicTypes(IntegralLit(..), SourceText(..))
+#if MIN_VERSION_ghc(9,0,0)
+import GHC.Types.Basic (FractionalLit(..), IntegralLit(..), SourceText(..))
+import GHC.Data.FastString (fsLit)
+#else
+import BasicTypes (FractionalLit(..), IntegralLit(..), SourceText(..))
+import FastString (fsLit)
+#endif
 import GHC.Hs.Lit
 import GHC.Hs.Expr (noExpr, noSyntaxExpr, HsExpr(..))
 import GHC.Hs.Pat (Pat(..))
-import FastString (fsLit)
 
 import GHC.SourceGen.Lit.Internal
 import GHC.SourceGen.Syntax.Internal
diff --git a/src/GHC/SourceGen/Lit/Internal.hs b/src/GHC/SourceGen/Lit/Internal.hs
index ca4e9e9..7dad501 100644
--- a/src/GHC/SourceGen/Lit/Internal.hs
+++ b/src/GHC/SourceGen/Lit/Internal.hs
@@ -4,10 +4,14 @@
 -- license that can be found in the LICENSE file or at
 -- https://developers.google.com/open-source/licenses/bsd
 
+{-# LANGUAGE CPP #-}
 module GHC.SourceGen.Lit.Internal where
 
-import BasicTypes (SourceText(NoSourceText), FractionalLit(..))
-import BasicTypes (IntegralLit(..))
+#if MIN_VERSION_ghc(9,0,0)
+import GHC.Types.Basic (SourceText(NoSourceText), FractionalLit(..), IntegralLit(..))
+#else
+import BasicTypes (SourceText(NoSourceText), FractionalLit(..), IntegralLit(..))
+#endif
 import GHC.Hs.Lit
 import GHC.SourceGen.Syntax.Internal
 
diff --git a/src/GHC/SourceGen/Module.hs b/src/GHC/SourceGen/Module.hs
index ab0d316..dffb1c4 100644
--- a/src/GHC/SourceGen/Module.hs
+++ b/src/GHC/SourceGen/Module.hs
@@ -34,7 +34,13 @@ import GHC.Hs
     , ImportDeclQualifiedStyle(..)
 #endif
     )
+#if MIN_VERSION_ghc(9,0,0)
+import GHC.Types.SrcLoc (LayoutInfo(..))
+import GHC.Unit.Module (IsBootInterface(..))
+import GHC.Types.Name.Reader (RdrName)
+#else
 import RdrName (RdrName)
+#endif
 
 import GHC.SourceGen.Syntax.Internal
 import GHC.SourceGen.Name
@@ -54,6 +60,9 @@ module' name exports imports decls = HsModule
     , hsmodDecls = fmap builtLoc decls
     , hsmodDeprecMessage = Nothing
     , hsmodHaddockModHeader = Nothing
+#if MIN_VERSION_ghc(9,0,0)
+    , hsmodLayout = NoLayoutInfo
+#endif
     }
 
 qualified' :: ImportDecl' -> ImportDecl'
@@ -71,7 +80,13 @@ as' d m = d { ideclAs = Just (builtLoc $ unModuleNameStr m) }
 import' :: ModuleNameStr -> ImportDecl'
 import' m = noSourceText (noExt ImportDecl)
             (builtLoc $ unModuleNameStr m)
-            Nothing False False
+            Nothing
+#if MIN_VERSION_ghc(9,0,0)
+            NotBoot
+#else
+            False
+#endif
+            False
 #if MIN_VERSION_ghc(8,10,0)
             NotQualified
 #else
@@ -89,7 +104,13 @@ hiding d ies = d
 
 -- | Adds the @{-# SOURCE #-}@ pragma to an import.
 source :: ImportDecl' -> ImportDecl'
-source d = d { ideclSource = True }
+source d = d { ideclSource =
+#if MIN_VERSION_ghc(9,0,0)
+    IsBoot
+#else
+    True
+#endif
+}
 
 -- | Exports all methods and/or constructors.
 --
diff --git a/src/GHC/SourceGen/Name.hs b/src/GHC/SourceGen/Name.hs
index 7eec70d..3fa6056 100644
--- a/src/GHC/SourceGen/Name.hs
+++ b/src/GHC/SourceGen/Name.hs
@@ -9,6 +9,7 @@
 --
 -- These types are all instances of 'Data.String.IsString'.  For ease of use,
 -- we recommend enabling the @OverloadedStrings@ extension.
+{-# LANGUAGE CPP #-}
 module GHC.SourceGen.Name
     ( -- * RdrNameStr
       RdrNameStr(..)
@@ -27,11 +28,18 @@ module GHC.SourceGen.Name
     , moduleNameStrToString
     ) where
 
+#if MIN_VERSION_ghc(9,0,0)
+import GHC.Data.FastString (unpackFS)
+import GHC.Unit.Module (moduleNameString)
+import GHC.Types.Name.Occurrence (OccName, occNameFS, occNameSpace, isVarNameSpace)
+import GHC.Types.Name (Name, nameOccName)
+#else
 import FastString (unpackFS)
 import Module (moduleNameString)
-import GHC.SourceGen.Name.Internal
 import OccName (OccName, occNameFS, occNameSpace, isVarNameSpace)
 import Name (Name, nameOccName)
+#endif
+import GHC.SourceGen.Name.Internal
 
 unqual :: OccNameStr -> RdrNameStr
 unqual = UnqualStr
diff --git a/src/GHC/SourceGen/Name/Internal.hs b/src/GHC/SourceGen/Name/Internal.hs
index 7d7e16d..19773cb 100644
--- a/src/GHC/SourceGen/Name/Internal.hs
+++ b/src/GHC/SourceGen/Name/Internal.hs
@@ -4,16 +4,25 @@
 -- license that can be found in the LICENSE file or at
 -- https://developers.google.com/open-source/licenses/bsd
 
+{-# LANGUAGE CPP #-}
 module GHC.SourceGen.Name.Internal where
 
 import Data.Char (isAlphaNum, isUpper)
 import Data.List (intercalate)
 import Data.String (IsString(..))
+#if MIN_VERSION_ghc(9,0,0)
+import GHC.Data.FastString (FastString, fsLit)
+import GHC.Unit.Module (mkModuleNameFS, ModuleName, moduleNameString)
+import GHC.Types.Name.Occurrence
+import GHC.Types.Name.Reader
+import GHC.Types.SrcLoc (Located)
+#else
 import FastString (FastString, fsLit)
 import Module (mkModuleNameFS, ModuleName, moduleNameString)
-import RdrName
 import OccName
+import RdrName
 import SrcLoc (Located)
+#endif
 
 import GHC.SourceGen.Syntax.Internal (builtLoc)
 
diff --git a/src/GHC/SourceGen/Overloaded.hs b/src/GHC/SourceGen/Overloaded.hs
index fc8f1f0..d5d5885 100644
--- a/src/GHC/SourceGen/Overloaded.hs
+++ b/src/GHC/SourceGen/Overloaded.hs
@@ -18,8 +18,7 @@ module GHC.SourceGen.Overloaded
     , BVar(..)
     ) where
 
-import BasicTypes (Boxity(..))
-import GHC.Hs.Types
+import GHC.Hs.Type
     ( HsType(..)
     , HsTyVarBndr(..)
     )
@@ -34,10 +33,20 @@ import GHC.Hs
     , HsTupArg(..)
     , HsTupleSort(..)
     )
+#if MIN_VERSION_ghc(9,0,0)
+import GHC.Types.Basic (Boxity(..))
+import GHC.Core.DataCon (dataConName)
+import GHC.Types.Name.Reader (RdrName(..), nameRdrName)
+import GHC.Types.SrcLoc (Located)
+import GHC.Builtin.Types (consDataCon_RDR, nilDataCon, unitDataCon)
+import GHC.Types.Var (Specificity(..))
+#else
+import BasicTypes (Boxity(..))
 import DataCon (dataConName)
 import RdrName (RdrName(..), nameRdrName)
 import SrcLoc (Located)
 import TysWiredIn (consDataCon_RDR, nilDataCon, unitDataCon)
+#endif
 
 import GHC.SourceGen.Expr.Internal
 import GHC.SourceGen.Name.Internal
@@ -241,8 +250,16 @@ instance Var HsType' where
 instance BVar HsType' where
     bvar = var . UnqualStr
 
+#if MIN_VERSION_ghc(9,0,0)
+instance BVar HsTyVarBndr' where
+    bvar = noExt UserTyVar () . typeRdrName . UnqualStr
+
+instance BVar HsTyVarBndrS' where
+    bvar = noExt UserTyVar SpecifiedSpec . typeRdrName . UnqualStr
+#else
 instance BVar HsTyVarBndr' where
     bvar = noExt UserTyVar . typeRdrName . UnqualStr
+#endif
 
 instance Var IE' where
     var n = noExt IEVar $ builtLoc $ IEName $ exportRdrName n
diff --git a/src/GHC/SourceGen/Pat.hs b/src/GHC/SourceGen/Pat.hs
index f28f118..83a8196 100644
--- a/src/GHC/SourceGen/Pat.hs
+++ b/src/GHC/SourceGen/Pat.hs
@@ -18,13 +18,13 @@ module GHC.SourceGen.Pat
     , sigP
     ) where
 
-import GHC.Hs.Types
+import GHC.Hs.Type
 import GHC.Hs.Pat hiding (LHsRecField')
 
 import GHC.SourceGen.Name.Internal
 import GHC.SourceGen.Pat.Internal
 import GHC.SourceGen.Syntax.Internal
-import GHC.SourceGen.Type.Internal (sigWcType)
+import GHC.SourceGen.Type.Internal (patSigType)
 
 -- | A wild pattern (@_@).
 wildP :: Pat'
@@ -44,7 +44,13 @@ v `asP` p = noExt AsPat (valueRdrName v) $ builtPat $ parenthesize p
 -- > =====
 -- > conP "A" [bvar "b", bvar "c"]
 conP :: RdrNameStr -> [Pat'] -> Pat'
-conP c xs = ConPatIn (valueRdrName c) $ PrefixCon
+conP c xs =
+#if MIN_VERSION_ghc(9,0,0)
+  noExt ConPat
+#else
+  ConPatIn
+#endif
+  (valueRdrName c) $ PrefixCon
                 $ map (builtPat . parenthesize) xs
 
 -- | A pattern constructor with no arguments.
@@ -56,8 +62,13 @@ conP_ :: RdrNameStr -> Pat'
 conP_ c = conP c []
 
 recordConP :: RdrNameStr -> [(RdrNameStr, Pat')] -> Pat'
-recordConP c fs
-    = ConPatIn (valueRdrName c)
+recordConP c fs =
+#if MIN_VERSION_ghc(9,0,0)
+  noExt ConPat
+#else
+  ConPatIn
+#endif
+  (valueRdrName c)
         $ RecCon $ HsRecFields (map mkRecField fs) Nothing -- No ".."
   where
     mkRecField :: (RdrNameStr, Pat') -> LHsRecField' LPat'
@@ -92,9 +103,9 @@ lazyP = noExt LazyPat . builtPat . parenthesize
 -- > sigPat (bvar "x") (var "y")
 sigP :: Pat' -> HsType' -> Pat'
 #if MIN_VERSION_ghc(8,8,0)
-sigP p t = noExt SigPat (builtPat p) (sigWcType t)
+sigP p t = noExt SigPat (builtPat p) (patSigType t)
 #elif MIN_VERSION_ghc(8,6,0)
-sigP p t = SigPat (sigWcType t) (builtPat p)
+sigP p t = SigPat (patSigType t) (builtPat p)
 #else
-sigP p t = SigPatIn (builtPat p) (sigWcType t)
+sigP p t = SigPatIn (builtPat p) (patSigType t)
 #endif
diff --git a/src/GHC/SourceGen/Pat/Internal.hs b/src/GHC/SourceGen/Pat/Internal.hs
index 01677f8..fdff839 100644
--- a/src/GHC/SourceGen/Pat/Internal.hs
+++ b/src/GHC/SourceGen/Pat/Internal.hs
@@ -2,11 +2,16 @@
 module GHC.SourceGen.Pat.Internal where
 
 import GHC.Hs.Pat (Pat(..))
+#if MIN_VERSION_ghc(9,0,0)
+import GHC.Hs.Type (HsConDetails(..))
+import GHC.Types.SrcLoc (unLoc)
+#else
 import GHC.Hs.Types (HsConDetails(..))
+import SrcLoc (unLoc)
+#endif
 
 import GHC.SourceGen.Lit.Internal (litNeedsParen, overLitNeedsParen)
 import GHC.SourceGen.Syntax.Internal
-import SrcLoc (unLoc)
 
 -- Note: GHC>=8.6 inserts parentheses automatically when pretty-printing patterns.
 -- When we stop supporting lower versions, we may be able to simplify this.
@@ -24,9 +29,14 @@ needsPar (NPat _ l _ _) = overLitNeedsParen $ unLoc l
 needsPar (LitPat l) = litNeedsParen l
 needsPar (NPat l _ _ _) = overLitNeedsParen $ unLoc l
 #endif
+#if MIN_VERSION_ghc(9,0,0)
+needsPar (ConPat _ _ (PrefixCon xs)) = not $ null xs
+needsPar (ConPat _ _ (InfixCon _ _)) = True
+#else
 needsPar (ConPatIn _ (PrefixCon xs)) = not $ null xs
 needsPar (ConPatIn _ (InfixCon _ _)) = True
 needsPar ConPatOut{} = True
+#endif
 #if MIN_VERSION_ghc(8,6,0)
 needsPar SigPat{} = True
 #else
diff --git a/src/GHC/SourceGen/Pretty.hs b/src/GHC/SourceGen/Pretty.hs
index 783fe46..d0c9148 100644
--- a/src/GHC/SourceGen/Pretty.hs
+++ b/src/GHC/SourceGen/Pretty.hs
@@ -11,15 +11,15 @@ module GHC.SourceGen.Pretty
     , hPutPpr
     ) where
 
-import DynFlags
-import GhcMonad
-import Outputable
+import GHC.Driver.Monad
+import GHC.Driver.Session
+import GHC.Utils.Outputable
 import System.IO
 
 hPutPpr :: Outputable a => Handle -> a -> Ghc ()
 hPutPpr h x = do
     dflags <- getDynFlags
-    liftIO $ printForUser dflags h neverQualify $ ppr x
+    liftIO $ printForUser dflags h neverQualify AllTheWay $ ppr x
 
 putPpr :: Outputable a => a -> Ghc ()
 putPpr = hPutPpr stdout
diff --git a/src/GHC/SourceGen/Syntax/Internal.hs b/src/GHC/SourceGen/Syntax/Internal.hs
index 4b477ba..c9190b3 100644
--- a/src/GHC/SourceGen/Syntax/Internal.hs
+++ b/src/GHC/SourceGen/Syntax/Internal.hs
@@ -38,6 +38,9 @@ import GHC.Hs
 #if !MIN_VERSION_ghc(8,8,0)
     , LHsRecField
     , LHsRecUpdField
+#endif
+#if MIN_VERSION_ghc(9,0,0)
+    , HsPatSigType
 #endif
     )
 import GHC.Hs.Binds (Sig, HsLocalBinds)
@@ -48,10 +51,17 @@ import BasicTypes (DerivStrategy)
 #endif
 import GHC.Hs.Decls (HsDerivingClause)
 import GHC.Hs.Pat
+#if MIN_VERSION_ghc(9,0,0)
+import GHC.Types.Name.Reader (RdrName)
+import GHC.Types.SrcLoc (SrcSpan, Located, GenLocated(..), mkGeneralSrcSpan)
+#else
 import RdrName (RdrName)
 import SrcLoc (SrcSpan, Located, GenLocated(..), mkGeneralSrcSpan)
+#endif
 
-#if MIN_VERSION_ghc(8,8,0)
+#if MIN_VERSION_ghc(9,0,0)
+import GHC.Types.Basic (PromotionFlag(..))
+#elif MIN_VERSION_ghc(8,8,0)
 import BasicTypes (PromotionFlag(..))
 #else
 import GHC.Hs.Types (Promoted(..))
@@ -65,6 +75,10 @@ import GHC.Hs.Extension (NoExt(NoExt))
 import PlaceHolder(PlaceHolder(..))
 #endif
 
+#if MIN_VERSION_ghc(9,0,0)
+import GHC.Types.Var (Specificity)
+#endif
+
 import GHC.Hs.Extension (GhcPs)
 
 #if MIN_VERSION_ghc(8,6,0)
@@ -194,15 +208,29 @@ type IE' = IE GhcPs
 -- Instances:
 --
 -- * 'GHC.SourceGen.Overloaded.BVar'
+#if MIN_VERSION_ghc(9,0,0)
+type HsTyVarBndr' = HsTyVarBndr () GhcPs
+type HsTyVarBndrS' = HsTyVarBndr Specificity GhcPs
+#else
 type HsTyVarBndr' = HsTyVarBndr GhcPs
+type HsTyVarBndrS' = HsTyVarBndr GhcPs
+#endif
 
 type HsLit' = HsLit GhcPs
+#if MIN_VERSION_ghc(9,0,0)
+type HsModule' = HsModule
+#else
 type HsModule' = HsModule GhcPs
+#endif
 type HsBind' = HsBind GhcPs
 type HsLocalBinds' = HsLocalBinds GhcPs
 type HsValBinds' = HsValBinds GhcPs
 type Sig' = Sig GhcPs
+#if MIN_VERSION_ghc(9,0,0)
+type HsMatchContext' = HsMatchContext GhcPs
+#else
 type HsMatchContext' = HsMatchContext RdrName
+#endif
 type Match' = Match GhcPs
 type MatchGroup' = MatchGroup GhcPs
 type GRHS' = GRHS GhcPs
@@ -228,3 +256,9 @@ type DerivStrategy' = DerivStrategy GhcPs
 #else
 type DerivStrategy' = DerivStrategy
 #endif
+
+#if MIN_VERSION_ghc(9,0,0)
+type HsPatSigType' = HsPatSigType GhcPs
+#else
+type HsPatSigType' = LHsSigWcType'
+#endif
diff --git a/src/GHC/SourceGen/Type.hs b/src/GHC/SourceGen/Type.hs
index 6c4cf0c..63c8b9a 100644
--- a/src/GHC/SourceGen/Type.hs
+++ b/src/GHC/SourceGen/Type.hs
@@ -22,7 +22,11 @@ module GHC.SourceGen.Type
     ) where
 
 import Data.String (fromString)
-import GHC.Hs.Types
+import GHC.Hs.Type
+#if MIN_VERSION_ghc(9,0,0)
+import GHC.Parser.Annotation
+import GHC.Types.Var (Specificity(..))
+#endif
 
 import GHC.SourceGen.Syntax.Internal
 import GHC.SourceGen.Lit.Internal (noSourceText)
@@ -56,7 +60,11 @@ tuplePromotedTy = withPlaceHolders (noExt HsExplicitTupleTy) . map builtLoc
 -- > =====
 -- > var "a" --> var "b"
 (-->) :: HsType' -> HsType' -> HsType'
-a --> b = noExt HsFunTy (parenthesizeTypeForFun $ builtLoc a) (builtLoc b)
+a --> b = noExt HsFunTy
+#if MIN_VERSION_ghc(9,0,0)
+         (HsUnrestrictedArrow NormalSyntax)
+#endif
+         (parenthesizeTypeForFun $ builtLoc a) (builtLoc b)
 
 infixr 0 -->
 
@@ -65,12 +73,15 @@ infixr 0 -->
 -- > forall a . T a
 -- > =====
 -- > forall' [bvar "a"] $ var "T" @@ var "a"
-forall' :: [HsTyVarBndr'] -> HsType' -> HsType'
+forall' :: [HsTyVarBndrS'] -> HsType' -> HsType'
 forall' ts = noExt HsForAllTy
-#if MIN_VERSION_ghc(8,10,0)
+#if MIN_VERSION_ghc(9,0,0)
+        (mkHsForAllInvisTele (map builtLoc ts))
+#elif MIN_VERSION_ghc(8,10,0)
         ForallInvis  -- "Invisible" forall, i.e., with a dot
+        (map builtLoc ts)
 #endif
-        (map builtLoc ts) . builtLoc
+        . builtLoc
 
 -- | Qualify a type with constraints.
 --
@@ -87,6 +98,9 @@ infixr 0 ==>
 -- > x :: A
 -- > =====
 -- > kindedVar "x" (var "A")
-kindedVar :: OccNameStr -> HsType' -> HsTyVarBndr'
-kindedVar v t = noExt KindedTyVar (typeRdrName $  UnqualStr v)
-                        (builtLoc t)
+kindedVar :: OccNameStr -> HsType' -> HsTyVarBndrS'
+kindedVar v t = noExt KindedTyVar
+#if MIN_VERSION_ghc(9,0,0)
+                SpecifiedSpec
+#endif
+                (typeRdrName $ UnqualStr v) (builtLoc t)
diff --git a/src/GHC/SourceGen/Type/Internal.hs b/src/GHC/SourceGen/Type/Internal.hs
index 6a0cd2c..4ea4f14 100644
--- a/src/GHC/SourceGen/Type/Internal.hs
+++ b/src/GHC/SourceGen/Type/Internal.hs
@@ -7,8 +7,13 @@
 {-# LANGUAGE CPP #-}
 module GHC.SourceGen.Type.Internal where
 
+#if MIN_VERSION_ghc(9,0,0)
+import GHC.Hs.Type as Types
+import GHC.Types.SrcLoc (Located, unLoc)
+#else
 import GHC.Hs.Types as Types
 import SrcLoc (Located, unLoc)
+#endif
 
 import GHC.SourceGen.Syntax.Internal
 
@@ -62,3 +67,10 @@ sigWcType = noExt (withPlaceHolder Types.HsWC) . sigType
 
 wcType :: HsType' -> LHsWcType'
 wcType = noExt (withPlaceHolder Types.HsWC) . builtLoc
+
+patSigType :: HsType' -> HsPatSigType'
+#if MIN_VERSION_ghc(9,0,0)
+patSigType = mkHsPatSigType . builtLoc
+#else
+patSigType = sigWcType
+#endif