    {-# LANGUAGE FlexibleContexts #-}
    {-# LANGUAGE ViewPatterns #-}
    -----------------------------------------------------------------------------
    -- |
    -- This module rexposes wrapped parsers from the GHC API. Along with
    -- returning the parse result, the corresponding annotations are also
    -- returned such that it is then easy to modify the annotations and print
    -- the result.
    --
    ----------------------------------------------------------------------------
    module Language.Haskell.GHC.ExactPrint.Parsers (
            -- * Utility
              Parser
            , ParseResult
            , withDynFlags
            , CppOptions(..)
            , defaultCppOptions
            , LibDir

            -- * Module Parsers
            , parseModule
            , parseModuleFromString
            , parseModuleWithOptions
            , parseModuleWithCpp

            -- * Basic Parsers
            , parseExpr
            , parseImport
            , parseType
            , parseDecl
            , parsePattern
            , parseStmt

            , parseWith

            -- * Internal

            , ghcWrapper

            , initDynFlags
            , initDynFlagsPure
            , parseModuleFromStringInternal
            , parseModuleEpAnnsWithCpp
            , parseModuleEpAnnsWithCppInternal
            , postParseTransform
            ) where

    import Language.Haskell.GHC.ExactPrint.Preprocess

    -- import Control.Monad.RWS
    import Data.Functor (void)

    import qualified GHC hiding (parseModule)
    import qualified Control.Monad.IO.Class as GHC
    import qualified GHC.Data.FastString    as GHC
    import qualified GHC.Data.StringBuffer  as GHC
    import qualified GHC.Driver.Config.Parser as GHC
    import qualified GHC.Driver.Errors.Types as GHC
    import qualified GHC.Driver.Session     as GHC
    import qualified GHC.Parser             as GHC
    import qualified GHC.Parser.Header      as GHC
    import qualified GHC.Parser.Lexer       as GHC
    import qualified GHC.Parser.PostProcess as GHC
    import qualified GHC.Types.SrcLoc       as GHC

    import qualified GHC.LanguageExtensions as LangExt

    -- ---------------------------------------------------------------------

    -- | Wrapper function which returns Annotations along with the parsed
    -- element.
    parseWith :: GHC.DynFlags
              -> FilePath
              -> GHC.P w
              -> String
              -> ParseResult w
    parseWith :: forall w. DynFlags -> FilePath -> P w -> FilePath -> ParseResult w
    parseWith DynFlags
    dflags FilePath
    fileName P w
    parser FilePath
    s =
      case P w -> DynFlags -> FilePath -> FilePath -> ParseResult w
    forall a. P a -> DynFlags -> FilePath -> FilePath -> ParseResult a
    runParser P w
    parser DynFlags
    dflags FilePath
    fileName FilePath
    s of
        GHC.PFailed PState
    pst
          -> ErrorMessages -> ParseResult w
    forall a b. a -> Either a b
    Left (PsMessage -> GhcMessage
    GHC.GhcPsMessage (PsMessage -> GhcMessage) -> Messages PsMessage -> ErrorMessages
    forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
    <$> PState -> Messages PsMessage
    GHC.getPsErrorMessages PState
    pst)
        GHC.POk PState
    _ w
    pmod
          -> w -> ParseResult w
    forall a b. b -> Either a b
    Right w
    pmod

    parseWithECP :: (GHC.DisambECP w)
              => GHC.DynFlags
              -> FilePath
              -> GHC.P GHC.ECP
              -> String
              -> ParseResult (GHC.LocatedA w)
    parseWithECP :: forall w.
    DisambECP w =>
    DynFlags
    -> FilePath -> P ECP -> FilePath -> ParseResult (LocatedA w)
    parseWithECP DynFlags
    dflags FilePath
    fileName P ECP
    parser FilePath
    s =
        case P (LocatedA w)
    -> DynFlags -> FilePath -> FilePath -> ParseResult (LocatedA w)
    forall a. P a -> DynFlags -> FilePath -> FilePath -> ParseResult a
    runParser (P ECP
    parser P ECP -> (ECP -> P (LocatedA w)) -> P (LocatedA w)
    forall a b. P a -> (a -> P b) -> P b
    forall (m :: * -> *) a b. Monad m => m a -> (a -> m b) -> m b
    >>= \ECP
    p -> PV (LocatedA w) -> P (LocatedA w)
    forall a. PV a -> P a
    GHC.runPV (PV (LocatedA w) -> P (LocatedA w))
    -> PV (LocatedA w) -> P (LocatedA w)
    forall a b. (a -> b) -> a -> b
    $ ECP -> forall b. DisambECP b => PV (LocatedA b)
    GHC.unECP ECP
    p) DynFlags
    dflags FilePath
    fileName FilePath
    s of
          GHC.PFailed PState
    pst
            -> ErrorMessages -> ParseResult (LocatedA w)
    forall a b. a -> Either a b
    Left (PsMessage -> GhcMessage
    GHC.GhcPsMessage (PsMessage -> GhcMessage) -> Messages PsMessage -> ErrorMessages
    forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
    <$> PState -> Messages PsMessage
    GHC.getPsErrorMessages PState
    pst)
          GHC.POk PState
    _ LocatedA w
    pmod
            -> LocatedA w -> ParseResult (LocatedA w)
    forall a b. b -> Either a b
    Right LocatedA w
    pmod

    -- ---------------------------------------------------------------------

    runParser :: GHC.P a -> GHC.DynFlags -> FilePath -> String -> GHC.ParseResult a
    runParser :: forall a. P a -> DynFlags -> FilePath -> FilePath -> ParseResult a
    runParser P a
    parser DynFlags
    flags FilePath
    filename FilePath
    str = P a -> PState -> ParseResult a
    forall a. P a -> PState -> ParseResult a
    GHC.unP P a
    parser PState
    parseState
        where
          location :: RealSrcLoc
    location = FastString -> Int -> Int -> RealSrcLoc
    GHC.mkRealSrcLoc (FilePath -> FastString
    GHC.mkFastString FilePath
    filename) Int
    1 Int
    1
          buffer :: StringBuffer
    buffer = FilePath -> StringBuffer
    GHC.stringToStringBuffer FilePath
    str
          parseState :: PState
    parseState = ParserOpts -> StringBuffer -> RealSrcLoc -> PState
    GHC.initParserState (DynFlags -> ParserOpts
    GHC.initParserOpts DynFlags
    flags) StringBuffer
    buffer RealSrcLoc
    location

    -- ---------------------------------------------------------------------

    -- | Provides a safe way to consume a properly initialised set of
    -- 'DynFlags'.
    --
    -- @
    -- myParser fname expr = withDynFlags (\\d -> parseExpr d fname expr)
    -- @
    withDynFlags :: LibDir -> (GHC.DynFlags -> a) -> IO a
    withDynFlags :: forall a. FilePath -> (DynFlags -> a) -> IO a
    withDynFlags FilePath
    libdir DynFlags -> a
    action = FilePath -> Ghc a -> IO a
    forall a. FilePath -> Ghc a -> IO a
    ghcWrapper FilePath
    libdir (Ghc a -> IO a) -> Ghc a -> IO a
    forall a b. (a -> b) -> a -> b
    $ do
      DynFlags
    dflags <- Ghc DynFlags
    forall (m :: * -> *). GhcMonad m => m DynFlags
    GHC.getSessionDynFlags
      Ghc () -> Ghc ()
    forall (f :: * -> *) a. Functor f => f a -> f ()
    void (Ghc () -> Ghc ()) -> Ghc () -> Ghc ()
    forall a b. (a -> b) -> a -> b
    $ DynFlags -> Ghc ()
    forall (m :: * -> *).
    (HasCallStack, GhcMonad m) =>
    DynFlags -> m ()
    GHC.setSessionDynFlags DynFlags
    dflags
      a -> Ghc a
    forall a. a -> Ghc a
    forall (m :: * -> *) a. Monad m => a -> m a
    return (DynFlags -> a
    action DynFlags
    dflags)

    -- ---------------------------------------------------------------------

    parseFile :: GHC.DynFlags -> FilePath -> String -> GHC.ParseResult (GHC.Located (GHC.HsModule GHC.GhcPs))
    parseFile :: DynFlags
    -> FilePath -> FilePath -> ParseResult (Located (HsModule GhcPs))
    parseFile = P (Located (HsModule GhcPs))
    -> DynFlags
    -> FilePath
    -> FilePath
    -> ParseResult (Located (HsModule GhcPs))
    forall a. P a -> DynFlags -> FilePath -> FilePath -> ParseResult a
    runParser P (Located (HsModule GhcPs))
    GHC.parseModule

    -- ---------------------------------------------------------------------

    type LibDir = FilePath

    type ParseResult a = Either GHC.ErrorMessages a

    type Parser a = GHC.DynFlags -> FilePath -> String
                    -> ParseResult a

    parseExpr :: Parser (GHC.LHsExpr GHC.GhcPs)
    parseExpr :: Parser (LHsExpr GhcPs)
    parseExpr DynFlags
    df FilePath
    fp = DynFlags
    -> FilePath
    -> P ECP
    -> FilePath
    -> ParseResult (LocatedA (HsExpr GhcPs))
    forall w.
    DisambECP w =>
    DynFlags
    -> FilePath -> P ECP -> FilePath -> ParseResult (LocatedA w)
    parseWithECP DynFlags
    df FilePath
    fp P ECP
    GHC.parseExpression

    parseImport :: Parser (GHC.LImportDecl GHC.GhcPs)
    parseImport :: Parser (LImportDecl GhcPs)
    parseImport DynFlags
    df FilePath
    fp = DynFlags
    -> FilePath
    -> P (GenLocated SrcSpanAnnA (ImportDecl GhcPs))
    -> FilePath
    -> ParseResult (GenLocated SrcSpanAnnA (ImportDecl GhcPs))
    forall w. DynFlags -> FilePath -> P w -> FilePath -> ParseResult w
    parseWith DynFlags
    df FilePath
    fp P (GenLocated SrcSpanAnnA (ImportDecl GhcPs))
    GHC.parseImport

    parseType :: Parser (GHC.LHsType GHC.GhcPs)
    parseType :: Parser (LHsType GhcPs)
    parseType DynFlags
    df FilePath
    fp = DynFlags
    -> FilePath
    -> P (GenLocated SrcSpanAnnA (HsType GhcPs))
    -> FilePath
    -> ParseResult (GenLocated SrcSpanAnnA (HsType GhcPs))
    forall w. DynFlags -> FilePath -> P w -> FilePath -> ParseResult w
    parseWith DynFlags
    df FilePath
    fp P (GenLocated SrcSpanAnnA (HsType GhcPs))
    GHC.parseType

    -- safe, see D1007
    parseDecl :: Parser (GHC.LHsDecl GHC.GhcPs)
    parseDecl :: Parser (LHsDecl GhcPs)
    parseDecl DynFlags
    df FilePath
    fp = DynFlags
    -> FilePath
    -> P (GenLocated SrcSpanAnnA (HsDecl GhcPs))
    -> FilePath
    -> ParseResult (GenLocated SrcSpanAnnA (HsDecl GhcPs))
    forall w. DynFlags -> FilePath -> P w -> FilePath -> ParseResult w
    parseWith DynFlags
    df FilePath
    fp P (GenLocated SrcSpanAnnA (HsDecl GhcPs))
    GHC.parseDeclaration

    parseStmt :: Parser (GHC.ExprLStmt GHC.GhcPs)
    parseStmt :: Parser (ExprLStmt GhcPs)
    parseStmt DynFlags
    df FilePath
    fp = DynFlags
    -> FilePath
    -> P (GenLocated
            SrcSpanAnnA (StmtLR GhcPs GhcPs (LocatedA (HsExpr GhcPs))))
    -> FilePath
    -> ParseResult
         (GenLocated
            SrcSpanAnnA (StmtLR GhcPs GhcPs (LocatedA (HsExpr GhcPs))))
    forall w. DynFlags -> FilePath -> P w -> FilePath -> ParseResult w
    parseWith DynFlags
    df FilePath
    fp P (GenLocated
         SrcSpanAnnA (StmtLR GhcPs GhcPs (LocatedA (HsExpr GhcPs))))
    GHC.parseStatement

    parsePattern :: Parser (GHC.LPat GHC.GhcPs)
    parsePattern :: Parser (LPat GhcPs)
    parsePattern DynFlags
    df FilePath
    fp = DynFlags
    -> FilePath
    -> P (GenLocated SrcSpanAnnA (Pat GhcPs))
    -> FilePath
    -> ParseResult (GenLocated SrcSpanAnnA (Pat GhcPs))
    forall w. DynFlags -> FilePath -> P w -> FilePath -> ParseResult w
    parseWith DynFlags
    df FilePath
    fp P (GenLocated SrcSpanAnnA (Pat GhcPs))
    GHC.parsePattern

    -- ---------------------------------------------------------------------
    --

    -- | This entry point will also work out which language extensions are
    -- required and perform CPP processing if necessary.
    --
    -- @
    -- parseModule = parseModuleWithCpp defaultCppOptions
    -- @
    --
    -- Note: 'GHC.ParsedSource' is a synonym for 'GHC.Located' ('GHC.HsModule' 'GhcPs')
    parseModule :: LibDir -> FilePath -> IO (ParseResult GHC.ParsedSource)
    parseModule :: FilePath -> FilePath -> IO (ParseResult (Located (HsModule GhcPs)))
    parseModule FilePath
    libdir FilePath
    file = FilePath
    -> CppOptions
    -> FilePath
    -> IO (ParseResult (Located (HsModule GhcPs)))
    parseModuleWithCpp FilePath
    libdir CppOptions
    defaultCppOptions FilePath
    file

    -- | This entry point will work out which language extensions are
    -- required but will _not_ perform CPP processing.
    -- In contrast to `parseModoule` the input source is read from the provided
    -- string; the `FilePath` parameter solely exists to provide a name
    -- in source location annotations.
    parseModuleFromString
      :: LibDir -- GHC libdir
      -> FilePath
      -> String
      -> IO (ParseResult GHC.ParsedSource)
    parseModuleFromString :: FilePath
    -> FilePath
    -> FilePath
    -> IO (ParseResult (Located (HsModule GhcPs)))
    parseModuleFromString FilePath
    libdir FilePath
    fp FilePath
    s = FilePath
    -> Ghc (ParseResult (Located (HsModule GhcPs)))
    -> IO (ParseResult (Located (HsModule GhcPs)))
    forall a. FilePath -> Ghc a -> IO a
    ghcWrapper FilePath
    libdir (Ghc (ParseResult (Located (HsModule GhcPs)))
     -> IO (ParseResult (Located (HsModule GhcPs))))
    -> Ghc (ParseResult (Located (HsModule GhcPs)))
    -> IO (ParseResult (Located (HsModule GhcPs)))
    forall a b. (a -> b) -> a -> b
    $ do
      DynFlags
    dflags <- FilePath -> FilePath -> Ghc DynFlags
    forall (m :: * -> *).
    GhcMonad m =>
    FilePath -> FilePath -> m DynFlags
    initDynFlagsPure FilePath
    fp FilePath
    s
      ParseResult (Located (HsModule GhcPs))
    -> Ghc (ParseResult (Located (HsModule GhcPs)))
    forall a. a -> Ghc a
    forall (m :: * -> *) a. Monad m => a -> m a
    return (ParseResult (Located (HsModule GhcPs))
     -> Ghc (ParseResult (Located (HsModule GhcPs))))
    -> ParseResult (Located (HsModule GhcPs))
    -> Ghc (ParseResult (Located (HsModule GhcPs)))
    forall a b. (a -> b) -> a -> b
    $ Parser (Located (HsModule GhcPs))
    parseModuleFromStringInternal DynFlags
    dflags FilePath
    fp FilePath
    s

    -- | Internal part of 'parseModuleFromString'.
    parseModuleFromStringInternal :: Parser GHC.ParsedSource
    parseModuleFromStringInternal :: Parser (Located (HsModule GhcPs))
    parseModuleFromStringInternal DynFlags
    dflags FilePath
    fileName FilePath
    str =
      let (FilePath
    str1, [LEpaComment]
    lp) = FilePath -> (FilePath, [LEpaComment])
    stripLinePragmas FilePath
    str
          res :: Either
      ErrorMessages ([LEpaComment], DynFlags, Located (HsModule GhcPs))
    res        = case P (Located (HsModule GhcPs))
    -> DynFlags
    -> FilePath
    -> FilePath
    -> ParseResult (Located (HsModule GhcPs))
    forall a. P a -> DynFlags -> FilePath -> FilePath -> ParseResult a
    runParser P (Located (HsModule GhcPs))
    GHC.parseModule DynFlags
    dflags FilePath
    fileName FilePath
    str1 of
            GHC.PFailed PState
    pst
              -> ErrorMessages
    -> Either
         ErrorMessages ([LEpaComment], DynFlags, Located (HsModule GhcPs))
    forall a b. a -> Either a b
    Left (PsMessage -> GhcMessage
    GHC.GhcPsMessage (PsMessage -> GhcMessage) -> Messages PsMessage -> ErrorMessages
    forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
    <$> PState -> Messages PsMessage
    GHC.getPsErrorMessages PState
    pst)
            GHC.POk     PState
    _  Located (HsModule GhcPs)
    pmod
              -> ([LEpaComment], DynFlags, Located (HsModule GhcPs))
    -> Either
         ErrorMessages ([LEpaComment], DynFlags, Located (HsModule GhcPs))
    forall a b. b -> Either a b
    Right ([LEpaComment]
    lp, DynFlags
    dflags, Located (HsModule GhcPs)
    pmod)
      in  Either
      ErrorMessages ([LEpaComment], DynFlags, Located (HsModule GhcPs))
    -> ParseResult (Located (HsModule GhcPs))
    forall a.
    Either a ([LEpaComment], DynFlags, Located (HsModule GhcPs))
    -> Either a (Located (HsModule GhcPs))
    postParseTransform Either
      ErrorMessages ([LEpaComment], DynFlags, Located (HsModule GhcPs))
    res

    parseModuleWithOptions :: LibDir -- ^ GHC libdir
                           -> FilePath
                           -> IO (ParseResult GHC.ParsedSource)
    parseModuleWithOptions :: FilePath -> FilePath -> IO (ParseResult (Located (HsModule GhcPs)))
    parseModuleWithOptions FilePath
    libdir FilePath
    fp =
      FilePath
    -> CppOptions
    -> FilePath
    -> IO (ParseResult (Located (HsModule GhcPs)))
    parseModuleWithCpp FilePath
    libdir CppOptions
    defaultCppOptions FilePath
    fp

    -- | Parse a module with specific instructions for the C pre-processor.
    parseModuleWithCpp
      :: LibDir -- ^ GHC libdir
      -> CppOptions
      -> FilePath -- ^ File to be parsed
      -> IO (ParseResult GHC.ParsedSource)
    parseModuleWithCpp :: FilePath
    -> CppOptions
    -> FilePath
    -> IO (ParseResult (Located (HsModule GhcPs)))
    parseModuleWithCpp FilePath
    libdir CppOptions
    cpp FilePath
    fp = do
      Either
      ErrorMessages ([LEpaComment], DynFlags, Located (HsModule GhcPs))
    res <- FilePath
    -> CppOptions
    -> FilePath
    -> IO
         (Either
            ErrorMessages ([LEpaComment], DynFlags, Located (HsModule GhcPs)))
    parseModuleEpAnnsWithCpp FilePath
    libdir CppOptions
    cpp FilePath
    fp
      ParseResult (Located (HsModule GhcPs))
    -> IO (ParseResult (Located (HsModule GhcPs)))
    forall a. a -> IO a
    forall (m :: * -> *) a. Monad m => a -> m a
    return (ParseResult (Located (HsModule GhcPs))
     -> IO (ParseResult (Located (HsModule GhcPs))))
    -> ParseResult (Located (HsModule GhcPs))
    -> IO (ParseResult (Located (HsModule GhcPs)))
    forall a b. (a -> b) -> a -> b
    $ Either
      ErrorMessages ([LEpaComment], DynFlags, Located (HsModule GhcPs))
    -> ParseResult (Located (HsModule GhcPs))
    forall a.
    Either a ([LEpaComment], DynFlags, Located (HsModule GhcPs))
    -> Either a (Located (HsModule GhcPs))
    postParseTransform Either
      ErrorMessages ([LEpaComment], DynFlags, Located (HsModule GhcPs))
    res

    -- ---------------------------------------------------------------------

    -- | Low level function which is used in the internal tests.
    -- It is advised to use 'parseModule' or 'parseModuleWithCpp' instead of
    -- this function.
    parseModuleEpAnnsWithCpp
      :: LibDir -- ^ GHC libdir
      -> CppOptions
      -> FilePath -- ^ File to be parsed
      -> IO
           ( Either
               GHC.ErrorMessages
               ([GHC.LEpaComment], GHC.DynFlags, GHC.ParsedSource)
           )
    parseModuleEpAnnsWithCpp :: FilePath
    -> CppOptions
    -> FilePath
    -> IO
         (Either
            ErrorMessages ([LEpaComment], DynFlags, Located (HsModule GhcPs)))
    parseModuleEpAnnsWithCpp FilePath
    libdir CppOptions
    cppOptions FilePath
    file = FilePath
    -> Ghc
         (Either
            ErrorMessages ([LEpaComment], DynFlags, Located (HsModule GhcPs)))
    -> IO
         (Either
            ErrorMessages ([LEpaComment], DynFlags, Located (HsModule GhcPs)))
    forall a. FilePath -> Ghc a -> IO a
    ghcWrapper FilePath
    libdir (Ghc
       (Either
          ErrorMessages ([LEpaComment], DynFlags, Located (HsModule GhcPs)))
     -> IO
          (Either
             ErrorMessages ([LEpaComment], DynFlags, Located (HsModule GhcPs))))
    -> Ghc
         (Either
            ErrorMessages ([LEpaComment], DynFlags, Located (HsModule GhcPs)))
    -> IO
         (Either
            ErrorMessages ([LEpaComment], DynFlags, Located (HsModule GhcPs)))
    forall a b. (a -> b) -> a -> b
    $ do
      DynFlags
    dflags <- FilePath -> Ghc DynFlags
    forall (m :: * -> *). GhcMonad m => FilePath -> m DynFlags
    initDynFlags FilePath
    file
      CppOptions
    -> DynFlags
    -> FilePath
    -> Ghc
         (Either
            ErrorMessages ([LEpaComment], DynFlags, Located (HsModule GhcPs)))
    forall (m :: * -> *).
    GhcMonad m =>
    CppOptions
    -> DynFlags
    -> FilePath
    -> m (Either
            ErrorMessages ([LEpaComment], DynFlags, Located (HsModule GhcPs)))
    parseModuleEpAnnsWithCppInternal CppOptions
    cppOptions DynFlags
    dflags FilePath
    file

    -- | Internal function. Default runner of GHC.Ghc action in IO.
    ghcWrapper :: LibDir -> GHC.Ghc a -> IO a
    ghcWrapper :: forall a. FilePath -> Ghc a -> IO a
    ghcWrapper FilePath
    libdir Ghc a
    a =
      FatalMessager -> FlushOut -> IO a -> IO a
    forall (m :: * -> *) a.
    ExceptionMonad m =>
    FatalMessager -> FlushOut -> m a -> m a
    GHC.defaultErrorHandler FatalMessager
    GHC.defaultFatalMessager FlushOut
    GHC.defaultFlushOut
        (IO a -> IO a) -> IO a -> IO a
    forall a b. (a -> b) -> a -> b
    $ Maybe FilePath -> Ghc a -> IO a
    forall a. Maybe FilePath -> Ghc a -> IO a
    GHC.runGhc (FilePath -> Maybe FilePath
    forall a. a -> Maybe a
    Just FilePath
    libdir) Ghc a
    a

    -- | Internal function. Exposed if you want to muck with DynFlags
    -- before parsing.
    parseModuleEpAnnsWithCppInternal
      :: GHC.GhcMonad m
      => CppOptions
      -> GHC.DynFlags
      -> FilePath
      -> m
           ( Either
               GHC.ErrorMessages
               ([GHC.LEpaComment], GHC.DynFlags, GHC.ParsedSource)
           )
    parseModuleEpAnnsWithCppInternal :: forall (m :: * -> *).
    GhcMonad m =>
    CppOptions
    -> DynFlags
    -> FilePath
    -> m (Either
            ErrorMessages ([LEpaComment], DynFlags, Located (HsModule GhcPs)))
    parseModuleEpAnnsWithCppInternal CppOptions
    cppOptions DynFlags
    dflags FilePath
    file = do
      let useCpp :: Bool
    useCpp = Extension -> DynFlags -> Bool
    GHC.xopt Extension
    LangExt.Cpp DynFlags
    dflags
      (FilePath
    fileContents, [LEpaComment]
    injectedComments, DynFlags
    dflags') <-
        if Bool
    useCpp
          then do
            (FilePath
    contents,DynFlags
    dflags1) <- CppOptions -> FilePath -> m (FilePath, DynFlags)
    forall (m :: * -> *).
    GhcMonad m =>
    CppOptions -> FilePath -> m (FilePath, DynFlags)
    getPreprocessedSrcDirect CppOptions
    cppOptions FilePath
    file
            [LEpaComment]
    cppComments <- CppOptions -> FilePath -> m [LEpaComment]
    forall (m :: * -> *).
    GhcMonad m =>
    CppOptions -> FilePath -> m [LEpaComment]
    getCppTokensAsComments CppOptions
    cppOptions FilePath
    file
            (FilePath, [LEpaComment], DynFlags)
    -> m (FilePath, [LEpaComment], DynFlags)
    forall a. a -> m a
    forall (m :: * -> *) a. Monad m => a -> m a
    return (FilePath
    contents,[LEpaComment]
    cppComments,DynFlags
    dflags1)
          else do
            FilePath
    txt <- IO FilePath -> m FilePath
    forall a. IO a -> m a
    forall (m :: * -> *) a. MonadIO m => IO a -> m a
    GHC.liftIO (IO FilePath -> m FilePath) -> IO FilePath -> m FilePath
    forall a b. (a -> b) -> a -> b
    $ FilePath -> IO FilePath
    readFileGhc FilePath
    file
            let (FilePath
    contents1,[LEpaComment]
    lp) = FilePath -> (FilePath, [LEpaComment])
    stripLinePragmas FilePath
    txt
            (FilePath, [LEpaComment], DynFlags)
    -> m (FilePath, [LEpaComment], DynFlags)
    forall a. a -> m a
    forall (m :: * -> *) a. Monad m => a -> m a
    return (FilePath
    contents1,[LEpaComment]
    lp,DynFlags
    dflags)
      Either
      ErrorMessages ([LEpaComment], DynFlags, Located (HsModule GhcPs))
    -> m (Either
            ErrorMessages ([LEpaComment], DynFlags, Located (HsModule GhcPs)))
    forall a. a -> m a
    forall (m :: * -> *) a. Monad m => a -> m a
    return (Either
       ErrorMessages ([LEpaComment], DynFlags, Located (HsModule GhcPs))
     -> m (Either
             ErrorMessages ([LEpaComment], DynFlags, Located (HsModule GhcPs))))
    -> Either
         ErrorMessages ([LEpaComment], DynFlags, Located (HsModule GhcPs))
    -> m (Either
            ErrorMessages ([LEpaComment], DynFlags, Located (HsModule GhcPs)))
    forall a b. (a -> b) -> a -> b
    $
        case DynFlags
    -> FilePath -> FilePath -> ParseResult (Located (HsModule GhcPs))
    parseFile DynFlags
    dflags' FilePath
    file FilePath
    fileContents of
          GHC.PFailed PState
    pst
            -> ErrorMessages
    -> Either
         ErrorMessages ([LEpaComment], DynFlags, Located (HsModule GhcPs))
    forall a b. a -> Either a b
    Left (PsMessage -> GhcMessage
    GHC.GhcPsMessage (PsMessage -> GhcMessage) -> Messages PsMessage -> ErrorMessages
    forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
    <$> PState -> Messages PsMessage
    GHC.getPsErrorMessages PState
    pst)
          GHC.POk PState
    _ Located (HsModule GhcPs)
    pmod
            -> ([LEpaComment], DynFlags, Located (HsModule GhcPs))
    -> Either
         ErrorMessages ([LEpaComment], DynFlags, Located (HsModule GhcPs))
    forall a b. b -> Either a b
    Right (([LEpaComment], DynFlags, Located (HsModule GhcPs))
     -> Either
          ErrorMessages ([LEpaComment], DynFlags, Located (HsModule GhcPs)))
    -> ([LEpaComment], DynFlags, Located (HsModule GhcPs))
    -> Either
         ErrorMessages ([LEpaComment], DynFlags, Located (HsModule GhcPs))
    forall a b. (a -> b) -> a -> b
    $ ([LEpaComment]
    injectedComments, DynFlags
    dflags', Located (HsModule GhcPs) -> Located (HsModule GhcPs)
    fixModuleTrailingComments Located (HsModule GhcPs)
    pmod)

    -- | Internal function. Exposed if you want to muck with DynFlags
    -- before parsing. Or after parsing.
    postParseTransform
      :: Either a ([GHC.LEpaComment], GHC.DynFlags, GHC.ParsedSource)
      -> Either a (GHC.ParsedSource)
    postParseTransform :: forall a.
    Either a ([LEpaComment], DynFlags, Located (HsModule GhcPs))
    -> Either a (Located (HsModule GhcPs))
    postParseTransform Either a ([LEpaComment], DynFlags, Located (HsModule GhcPs))
    parseRes = (([LEpaComment], DynFlags, Located (HsModule GhcPs))
     -> Located (HsModule GhcPs))
    -> Either a ([LEpaComment], DynFlags, Located (HsModule GhcPs))
    -> Either a (Located (HsModule GhcPs))
    forall a b. (a -> b) -> Either a a -> Either a b
    forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
    fmap ([LEpaComment], DynFlags, Located (HsModule GhcPs))
    -> Located (HsModule GhcPs)
    forall {a} {b}.
    (a, b, Located (HsModule GhcPs)) -> Located (HsModule GhcPs)
    mkAnns Either a ([LEpaComment], DynFlags, Located (HsModule GhcPs))
    parseRes
      where
        -- TODO:AZ perhaps inject the comments into the parsedsource here already
        mkAnns :: (a, b, Located (HsModule GhcPs)) -> Located (HsModule GhcPs)
    mkAnns (a
    _cs, b
    _, Located (HsModule GhcPs)
    m) = Located (HsModule GhcPs) -> Located (HsModule GhcPs)
    fixModuleTrailingComments Located (HsModule GhcPs)
    m

    fixModuleTrailingComments :: GHC.ParsedSource -> GHC.ParsedSource
    fixModuleTrailingComments :: Located (HsModule GhcPs) -> Located (HsModule GhcPs)
    fixModuleTrailingComments (GHC.L SrcSpan
    l HsModule GhcPs
    p) = SrcSpan -> HsModule GhcPs -> Located (HsModule GhcPs)
    forall l e. l -> e -> GenLocated l e
    GHC.L SrcSpan
    l HsModule GhcPs
    p'
      where
        an' :: EpAnn AnnsModule
    an' = case XModulePs -> EpAnn AnnsModule
    GHC.hsmodAnn (XModulePs -> EpAnn AnnsModule) -> XModulePs -> EpAnn AnnsModule
    forall a b. (a -> b) -> a -> b
    $ HsModule GhcPs -> XCModule GhcPs
    forall p. HsModule p -> XCModule p
    GHC.hsmodExt HsModule GhcPs
    p of
          (GHC.EpAnn Anchor
    a AnnsModule
    an EpAnnComments
    ocs) -> Anchor -> AnnsModule -> EpAnnComments -> EpAnn AnnsModule
    forall ann. Anchor -> ann -> EpAnnComments -> EpAnn ann
    GHC.EpAnn Anchor
    a AnnsModule
    an (AnnList -> EpAnnComments -> EpAnnComments
    rebalance (AnnsModule -> AnnList
    GHC.am_decls AnnsModule
    an) EpAnnComments
    ocs)
          EpAnn AnnsModule
    unused -> EpAnn AnnsModule
    unused
        p' :: HsModule GhcPs
    p' = HsModule GhcPs
    p { GHC.hsmodExt = (GHC.hsmodExt p){ GHC.hsmodAnn = an' } }
        -- p'  = error $ "fixModuleTrailingComments: an'=" ++ showAst an'

        rebalance :: GHC.AnnList -> GHC.EpAnnComments -> GHC.EpAnnComments
        rebalance :: AnnList -> EpAnnComments -> EpAnnComments
    rebalance AnnList
    al EpAnnComments
    cs = EpAnnComments
    cs'
          where
            cs' :: EpAnnComments
    cs' = case AnnList -> Maybe AddEpAnn
    GHC.al_close AnnList
    al of
              Just (GHC.AddEpAnn AnnKeywordId
    _ (GHC.EpaSpan RealSrcSpan
    ss Maybe BufSpan
    _)) ->
                let
                  pc :: [LEpaComment]
    pc = EpAnnComments -> [LEpaComment]
    GHC.priorComments EpAnnComments
    cs
                  fc :: [LEpaComment]
    fc = EpAnnComments -> [LEpaComment]
    GHC.getFollowingComments EpAnnComments
    cs
                  bf :: GenLocated Anchor e -> Bool
    bf (GHC.L Anchor
    anc e
    _) = Anchor -> RealSrcSpan
    GHC.anchor Anchor
    anc RealSrcSpan -> RealSrcSpan -> Bool
    forall a. Ord a => a -> a -> Bool
    > RealSrcSpan
    ss
                  ([LEpaComment]
    prior,[LEpaComment]
    f) = (LEpaComment -> Bool)
    -> [LEpaComment] -> ([LEpaComment], [LEpaComment])
    forall a. (a -> Bool) -> [a] -> ([a], [a])
    break LEpaComment -> Bool
    forall {e}. GenLocated Anchor e -> Bool
    bf [LEpaComment]
    fc
                  cs'' :: EpAnnComments
    cs'' = [LEpaComment] -> [LEpaComment] -> EpAnnComments
    GHC.EpaCommentsBalanced ([LEpaComment]
    pc [LEpaComment] -> [LEpaComment] -> [LEpaComment]
    forall a. Semigroup a => a -> a -> a
    <> [LEpaComment]
    prior) [LEpaComment]
    f
                in EpAnnComments
    cs''
              Maybe AddEpAnn
    _ -> EpAnnComments
    cs

    -- | Internal function. Initializes DynFlags value for parsing.
    --
    -- Passes "-hide-all-packages" to the GHC API to prevent parsing of
    -- package environment files. However this only works if there is no
    -- invocation of `setSessionDynFlags` before calling `initDynFlags`.
    -- See ghc tickets #15513, #15541.
    initDynFlags :: GHC.GhcMonad m => FilePath -> m GHC.DynFlags
    initDynFlags :: forall (m :: * -> *). GhcMonad m => FilePath -> m DynFlags
    initDynFlags FilePath
    file = do
      -- Based on GHC backpack driver doBackPack
      DynFlags
    dflags0         <- m DynFlags
    forall (m :: * -> *). GhcMonad m => m DynFlags
    GHC.getSessionDynFlags
      let parser_opts0 :: ParserOpts
    parser_opts0 = DynFlags -> ParserOpts
    GHC.initParserOpts DynFlags
    dflags0
      (Messages PsMessage
    _, [Located FilePath]
    src_opts)   <- IO (Messages PsMessage, [Located FilePath])
    -> m (Messages PsMessage, [Located FilePath])
    forall a. IO a -> m a
    forall (m :: * -> *) a. MonadIO m => IO a -> m a
    GHC.liftIO (IO (Messages PsMessage, [Located FilePath])
     -> m (Messages PsMessage, [Located FilePath]))
    -> IO (Messages PsMessage, [Located FilePath])
    -> m (Messages PsMessage, [Located FilePath])
    forall a b. (a -> b) -> a -> b
    $ ParserOpts
    -> FilePath -> IO (Messages PsMessage, [Located FilePath])
    GHC.getOptionsFromFile ParserOpts
    parser_opts0 FilePath
    file
      (DynFlags
    dflags1, [Located FilePath]
    _, [Warn]
    _) <- DynFlags
    -> [Located FilePath] -> m (DynFlags, [Located FilePath], [Warn])
    forall (m :: * -> *).
    MonadIO m =>
    DynFlags
    -> [Located FilePath] -> m (DynFlags, [Located FilePath], [Warn])
    GHC.parseDynamicFilePragma DynFlags
    dflags0 [Located FilePath]
    src_opts
      -- Turn this on last to avoid T10942
      let dflags2 :: DynFlags
    dflags2 = DynFlags
    dflags1 DynFlags -> GeneralFlag -> DynFlags
    `GHC.gopt_set` GeneralFlag
    GHC.Opt_KeepRawTokenStream
      -- Prevent parsing of .ghc.environment.* "package environment files"
      (DynFlags
    dflags3, [Located FilePath]
    _, [Warn]
    _) <- DynFlags
    -> [Located FilePath] -> m (DynFlags, [Located FilePath], [Warn])
    forall (m :: * -> *).
    MonadIO m =>
    DynFlags
    -> [Located FilePath] -> m (DynFlags, [Located FilePath], [Warn])
    GHC.parseDynamicFlagsCmdLine
        DynFlags
    dflags2
        [FilePath -> Located FilePath
    forall e. e -> Located e
    GHC.noLoc FilePath
    "-hide-all-packages"]
      ()
    _ <- DynFlags -> m ()
    forall (m :: * -> *).
    (HasCallStack, GhcMonad m) =>
    DynFlags -> m ()
    GHC.setSessionDynFlags DynFlags
    dflags3
      DynFlags -> m DynFlags
    forall a. a -> m a
    forall (m :: * -> *) a. Monad m => a -> m a
    return DynFlags
    dflags3

    -- | Requires GhcMonad constraint because there is
    -- no pure variant of `parseDynamicFilePragma`. Yet, in constrast to
    -- `initDynFlags`, it does not (try to) read the file at filepath, but
    -- solely depends on the module source in the input string.
    --
    -- Passes "-hide-all-packages" to the GHC API to prevent parsing of
    -- package environment files. However this only works if there is no
    -- invocation of `setSessionDynFlags` before calling `initDynFlagsPure`.
    -- See ghc tickets #15513, #15541.
    initDynFlagsPure :: GHC.GhcMonad m => FilePath -> String -> m GHC.DynFlags
    initDynFlagsPure :: forall (m :: * -> *).
    GhcMonad m =>
    FilePath -> FilePath -> m DynFlags
    initDynFlagsPure FilePath
    fp FilePath
    s = do
      -- AZ Note: "I" below appears to be Lennart Spitzner
      -- I was told we could get away with using the unsafeGlobalDynFlags.
      -- as long as `parseDynamicFilePragma` is impure there seems to be
      -- no reason to use it.
      DynFlags
    dflags0 <- m DynFlags
    forall (m :: * -> *). GhcMonad m => m DynFlags
    GHC.getSessionDynFlags
      let parser_opts0 :: ParserOpts
    parser_opts0 = DynFlags -> ParserOpts
    GHC.initParserOpts DynFlags
    dflags0
      let (Messages PsMessage
    _, [Located FilePath]
    pragmaInfo) = ParserOpts
    -> StringBuffer
    -> FilePath
    -> (Messages PsMessage, [Located FilePath])
    GHC.getOptions ParserOpts
    parser_opts0 (FilePath -> StringBuffer
    GHC.stringToStringBuffer (FilePath -> StringBuffer) -> FilePath -> StringBuffer
    forall a b. (a -> b) -> a -> b
    $ FilePath
    s) FilePath
    fp
      (DynFlags
    dflags1, [Located FilePath]
    _, [Warn]
    _) <- DynFlags
    -> [Located FilePath] -> m (DynFlags, [Located FilePath], [Warn])
    forall (m :: * -> *).
    MonadIO m =>
    DynFlags
    -> [Located FilePath] -> m (DynFlags, [Located FilePath], [Warn])
    GHC.parseDynamicFilePragma DynFlags
    dflags0 [Located FilePath]
    pragmaInfo
      -- Turn this on last to avoid T10942
      let dflags2 :: DynFlags
    dflags2 = DynFlags
    dflags1 DynFlags -> GeneralFlag -> DynFlags
    `GHC.gopt_set` GeneralFlag
    GHC.Opt_KeepRawTokenStream
      -- Prevent parsing of .ghc.environment.* "package environment files"
      (DynFlags
    dflags3, [Located FilePath]
    _, [Warn]
    _) <- DynFlags
    -> [Located FilePath] -> m (DynFlags, [Located FilePath], [Warn])
    forall (m :: * -> *).
    MonadIO m =>
    DynFlags
    -> [Located FilePath] -> m (DynFlags, [Located FilePath], [Warn])
    GHC.parseDynamicFlagsCmdLine
        DynFlags
    dflags2
        [FilePath -> Located FilePath
    forall e. e -> Located e
    GHC.noLoc FilePath
    "-hide-all-packages"]
      ()
    _ <- DynFlags -> m ()
    forall (m :: * -> *).
    (HasCallStack, GhcMonad m) =>
    DynFlags -> m ()
    GHC.setSessionDynFlags DynFlags
    dflags3
      DynFlags -> m DynFlags
    forall a. a -> m a
    forall (m :: * -> *) a. Monad m => a -> m a
    return DynFlags
    dflags3

    -- ---------------------------------------------------------------------