3 files changed, 20 insertions, 0 deletions
diff --git a/compiler/Language/Haskell/Syntax/Expr.hs b/compiler/Language/Haskell/Syntax/Expr.hs
index 6f5150a1b4..b4d7b24dea 100644
--- a/compiler/Language/Haskell/Syntax/Expr.hs
+++ b/compiler/Language/Haskell/Syntax/Expr.hs
@@ -404,7 +404,9 @@ data HsExpr p
 
   -- For details on above see note [exact print annotations] in GHC.Parser.Annotation
   | HsPar       (XPar p)
+               !(LHsToken "(" p)
                 (LHsExpr p)  -- ^ Parenthesised expr; see Note [Parens in HsSyn]
+               !(LHsToken ")" p)
 
   | SectionL    (XSectionL p)
                 (LHsExpr p)    -- operand; see Note [Sections in HsSyn]
@@ -928,7 +930,9 @@ data HsCmd id
        -- For details on above see note [exact print annotations] in GHC.Parser.Annotation
 
   | HsCmdPar    (XCmdPar id)
+               !(LHsToken "(" id)
                 (LHsCmd id)                     -- parenthesised command
+               !(LHsToken ")" id)
     -- ^ - 'GHC.Parser.Annotation.AnnKeywordId' : 'GHC.Parser.Annotation.AnnOpen' @'('@,
     --             'GHC.Parser.Annotation.AnnClose' @')'@
 
diff --git a/compiler/Language/Haskell/Syntax/Extension.hs b/compiler/Language/Haskell/Syntax/Extension.hs
index f414968a6e..2f9b9d7583 100644
--- a/compiler/Language/Haskell/Syntax/Extension.hs
+++ b/compiler/Language/Haskell/Syntax/Extension.hs
@@ -4,6 +4,7 @@
 {-# LANGUAGE DeriveDataTypeable      #-}
 {-# LANGUAGE EmptyCase               #-}
 {-# LANGUAGE EmptyDataDeriving       #-}
+{-# LANGUAGE StandaloneDeriving      #-}
 {-# LANGUAGE FlexibleContexts        #-}
 {-# LANGUAGE FlexibleInstances       #-}
 {-# LANGUAGE GADTs                   #-}
@@ -22,6 +23,7 @@ module Language.Haskell.Syntax.Extension where
 
 import GHC.Prelude
 
+import GHC.TypeLits (Symbol, KnownSymbol)
 import Data.Data hiding ( Fixity )
 import Data.Kind (Type)
 import GHC.Utils.Outputable
@@ -693,3 +695,14 @@ type family NoGhcTc (p :: Type)
 -- =====================================================================
 -- End of Type family definitions
 -- =====================================================================
+
+
+
+-- =====================================================================
+-- Token information
+
+type LHsToken tok p = XRec p (HsToken tok)
+
+data HsToken (tok :: Symbol) = HsTok
+
+deriving instance KnownSymbol tok => Data (HsToken tok)
diff --git a/compiler/Language/Haskell/Syntax/Pat.hs b/compiler/Language/Haskell/Syntax/Pat.hs
index c7829d833c..75dc7ddd00 100644
--- a/compiler/Language/Haskell/Syntax/Pat.hs
+++ b/compiler/Language/Haskell/Syntax/Pat.hs
@@ -9,6 +9,7 @@
 {-# LANGUAGE UndecidableInstances #-} -- Wrinkle in Note [Trees That Grow]
                                       -- in module Language.Haskell.Syntax.Extension
 {-# LANGUAGE ViewPatterns #-}
+{-# LANGUAGE DataKinds #-}
 {-
 (c) The University of Glasgow 2006
 (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
@@ -74,7 +75,9 @@ data Pat p
     -- For details on above see note [exact print annotations] in GHC.Parser.Annotation
 
   | ParPat      (XParPat p)
+               !(LHsToken "(" p)
                 (LPat p)                -- ^ Parenthesised pattern
+               !(LHsToken ")" p)
                                         -- See Note [Parens in HsSyn] in GHC.Hs.Expr
     -- ^ - 'GHC.Parser.Annotation.AnnKeywordId' : 'GHC.Parser.Annotation.AnnOpen' @'('@,
     --                                    'GHC.Parser.Annotation.AnnClose' @')'@