{-# LINE 1 "GHC/ExecutionStack/Internal.hsc" #-}------------------------------------------------------------------------------- |-- Module : GHC.ExecutionStack.Internal-- Copyright : (c) The University of Glasgow 2013-2015-- License : see libraries/base/LICENSE---- Maintainer : cvs-ghc@haskell.org-- Stability : internal-- Portability : non-portable (GHC Extensions)---- Internals of the `GHC.ExecutionStack` module---- @since 4.9.0.0-----------------------------------------------------------------------------{-# LANGUAGE MultiWayIf #-}moduleGHC.ExecutionStack.Internal(-- * InternalLocation (..),SrcLoc (..),StackTrace ,stackFrames ,stackDepth ,collectStackTrace ,showStackFrames ,invalidateDebugCache )whereimportControl.Monad (join )importData.Word importForeign.C.Types importForeign.C.String (peekCString ,CString )importForeign.Ptr (Ptr ,nullPtr ,castPtr ,plusPtr ,FunPtr )importForeign.ForeignPtr importForeign.Marshal.Alloc (allocaBytes )importForeign.Storable (Storable (..))importSystem.IO.Unsafe (unsafePerformIO ,unsafeInterleaveIO )-- N.B. See includes/rts/Libdw.h for notes on stack representation.-- | A location in the original program source.dataSrcLoc =SrcLoc {SrcLoc -> String sourceFile ::String ,SrcLoc -> Int sourceLine ::Int,SrcLoc -> Int sourceColumn ::Int}-- | Location information about an address from a backtrace.dataLocation =Location {Location -> String objectName ::String ,Location -> String functionName ::String ,Location -> Maybe SrcLoc srcLoc ::Maybe SrcLoc }-- | A chunk of backtrace framesdataChunk =Chunk {Chunk -> Word chunkFrames ::!Word,Chunk -> Ptr Chunk chunkNext ::!(Ptr Chunk ),Chunk -> Ptr Addr chunkFirstFrame ::!(Ptr Addr )}-- | The state of the execution stacknewtypeStackTrace =StackTrace (ForeignPtr StackTrace )-- | An addresstypeAddr =Ptr ()withSession ::(ForeignPtr Session ->IOa )->IO(Maybe a )withSession :: (ForeignPtr Session -> IO a) -> IO (Maybe a) withSession action :: ForeignPtr Session -> IO a action =doPtr Session ptr <-IO (Ptr Session) libdw_pool_take if|Ptr Session forall a. Ptr a nullPtr Ptr Session -> Ptr Session -> Bool forall a. Eq a => a -> a -> Bool ==Ptr Session ptr ->Maybe a -> IO (Maybe a) forall (m :: * -> *) a. Monad m => a -> m a return Maybe a forall a. Maybe a Nothing |Bool otherwise ->doForeignPtr Session fptr <-FinalizerPtr Session -> Ptr Session -> IO (ForeignPtr Session) forall a. FinalizerPtr a -> Ptr a -> IO (ForeignPtr a) newForeignPtr FinalizerPtr Session libdw_pool_release Ptr Session ptr a ret <-ForeignPtr Session -> IO a action ForeignPtr Session fptr Maybe a -> IO (Maybe a) forall (m :: * -> *) a. Monad m => a -> m a return (Maybe a -> IO (Maybe a)) -> Maybe a -> IO (Maybe a) forall a b. (a -> b) -> a -> b $ a -> Maybe a forall a. a -> Maybe a Just a ret -- | How many stack frames in the given 'StackTrace'stackDepth ::StackTrace ->IntstackDepth :: StackTrace -> Int stackDepth (StackTrace fptr :: ForeignPtr StackTrace fptr )=IO Int -> Int forall a. IO a -> a unsafePerformIO (IO Int -> Int) -> IO Int -> Int forall a b. (a -> b) -> a -> b $ ForeignPtr StackTrace -> (Ptr StackTrace -> IO Int) -> IO Int forall a b. ForeignPtr a -> (Ptr a -> IO b) -> IO b withForeignPtr ForeignPtr StackTrace fptr ((Ptr StackTrace -> IO Int) -> IO Int) -> (Ptr StackTrace -> IO Int) -> IO Int forall a b. (a -> b) -> a -> b $ \ptr :: Ptr StackTrace ptr ->Word -> Int forall a b. (Integral a, Num b) => a -> b fromIntegral (Word -> Int) -> (Word -> Word) -> Word -> Int forall b c a. (b -> c) -> (a -> b) -> a -> c . Word -> Word asWord (Word -> Int) -> IO Word -> IO Int forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b <$> ((\hsc_ptr :: Ptr StackTrace hsc_ptr ->Ptr StackTrace -> Int -> IO Word forall a b. Storable a => Ptr b -> Int -> IO a peekByteOff Ptr StackTrace hsc_ptr 0))Ptr StackTrace ptr {-# LINE 84 "GHC/ExecutionStack/Internal.hsc" #-}whereasWord :: Word -> Word asWord =Word -> Word forall a. a -> a id ::Word->WordpeekChunk ::Ptr Chunk ->IOChunk peekChunk :: Ptr Chunk -> IO Chunk peekChunk ptr :: Ptr Chunk ptr =Word -> Ptr Chunk -> Ptr Addr -> Chunk Chunk (Word -> Ptr Chunk -> Ptr Addr -> Chunk) -> IO Word -> IO (Ptr Chunk -> Ptr Addr -> Chunk) forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b <$> ((\hsc_ptr :: Ptr Chunk hsc_ptr ->Ptr Chunk -> Int -> IO Word forall a b. Storable a => Ptr b -> Int -> IO a peekByteOff Ptr Chunk hsc_ptr 0))Ptr Chunk ptr {-# LINE 90 "GHC/ExecutionStack/Internal.hsc" #-}IO (Ptr Chunk -> Ptr Addr -> Chunk) -> IO (Ptr Chunk) -> IO (Ptr Addr -> Chunk) forall (f :: * -> *) a b. Applicative f => f (a -> b) -> f a -> f b <*> ((\hsc_ptr :: Ptr Chunk hsc_ptr ->Ptr Chunk -> Int -> IO (Ptr Chunk) forall a b. Storable a => Ptr b -> Int -> IO a peekByteOff Ptr Chunk hsc_ptr 8))Ptr Chunk ptr {-# LINE 91 "GHC/ExecutionStack/Internal.hsc" #-}IO (Ptr Addr -> Chunk) -> IO (Ptr Addr) -> IO Chunk forall (f :: * -> *) a b. Applicative f => f (a -> b) -> f a -> f b <*> Ptr Addr -> IO (Ptr Addr) forall (f :: * -> *) a. Applicative f => a -> f a pure (Ptr Any -> Ptr Addr forall a b. Ptr a -> Ptr b castPtr (Ptr Any -> Ptr Addr) -> Ptr Any -> Ptr Addr forall a b. (a -> b) -> a -> b $ ((\hsc_ptr :: Ptr Chunk hsc_ptr ->Ptr Chunk hsc_ptr Ptr Chunk -> Int -> Ptr Any forall a b. Ptr a -> Int -> Ptr b `plusPtr` 16))Ptr Chunk ptr ){-# LINE 92 "GHC/ExecutionStack/Internal.hsc" #-}-- | Return a list of the chunks of a backtrace, from the outer-most to-- inner-most chunk.chunksList ::StackTrace ->IO[Chunk ]chunksList :: StackTrace -> IO [Chunk] chunksList (StackTrace fptr :: ForeignPtr StackTrace fptr )=ForeignPtr StackTrace -> (Ptr StackTrace -> IO [Chunk]) -> IO [Chunk] forall a b. ForeignPtr a -> (Ptr a -> IO b) -> IO b withForeignPtr ForeignPtr StackTrace fptr ((Ptr StackTrace -> IO [Chunk]) -> IO [Chunk]) -> (Ptr StackTrace -> IO [Chunk]) -> IO [Chunk] forall a b. (a -> b) -> a -> b $ \ptr :: Ptr StackTrace ptr ->[Chunk] -> Ptr Chunk -> IO [Chunk] go [](Ptr Chunk -> IO [Chunk]) -> IO (Ptr Chunk) -> IO [Chunk] forall (m :: * -> *) a b. Monad m => (a -> m b) -> m a -> m b =<< ((\hsc_ptr :: Ptr StackTrace hsc_ptr ->Ptr StackTrace -> Int -> IO (Ptr Chunk) forall a b. Storable a => Ptr b -> Int -> IO a peekByteOff Ptr StackTrace hsc_ptr 8))Ptr StackTrace ptr {-# LINE 98 "GHC/ExecutionStack/Internal.hsc" #-}wherego :: [Chunk] -> Ptr Chunk -> IO [Chunk] go accum :: [Chunk] accum ptr :: Ptr Chunk ptr |Ptr Chunk ptr Ptr Chunk -> Ptr Chunk -> Bool forall a. Eq a => a -> a -> Bool ==Ptr Chunk forall a. Ptr a nullPtr =[Chunk] -> IO [Chunk] forall (m :: * -> *) a. Monad m => a -> m a return [Chunk] accum |Bool otherwise =doChunk chunk <-Ptr Chunk -> IO Chunk peekChunk Ptr Chunk ptr [Chunk] -> Ptr Chunk -> IO [Chunk] go (Chunk chunk Chunk -> [Chunk] -> [Chunk] forall a. a -> [a] -> [a] :[Chunk] accum )(Chunk -> Ptr Chunk chunkNext Chunk chunk )-- | Unpack the given 'Location' in the Haskell representationpeekLocation ::Ptr Location ->IOLocation peekLocation :: Ptr Location -> IO Location peekLocation ptr :: Ptr Location ptr =doletpeekCStringPtr ::CString ->IOString peekCStringPtr :: CString -> IO String peekCStringPtr p :: CString p |CString p CString -> CString -> Bool forall a. Eq a => a -> a -> Bool /=CString forall a. Ptr a nullPtr =CString -> IO String peekCString (CString -> IO String) -> CString -> IO String forall a b. (a -> b) -> a -> b $ CString -> CString forall a b. Ptr a -> Ptr b castPtr CString p |Bool otherwise =String -> IO String forall (m :: * -> *) a. Monad m => a -> m a return ""String objFile <-CString -> IO String peekCStringPtr (CString -> IO String) -> IO CString -> IO String forall (m :: * -> *) a b. Monad m => (a -> m b) -> m a -> m b =<< ((\hsc_ptr :: Ptr Location hsc_ptr ->Ptr Location -> Int -> IO CString forall a b. Storable a => Ptr b -> Int -> IO a peekByteOff Ptr Location hsc_ptr 0))Ptr Location ptr {-# LINE 113 "GHC/ExecutionStack/Internal.hsc" #-}function<-peekCStringPtr=<<((\hsc_ptr->peekByteOffhsc_ptr8))ptr{-# LINE 114 "GHC/ExecutionStack/Internal.hsc" #-}srcFile<-peekCStringPtr=<<((\hsc_ptr->peekByteOffhsc_ptr16))ptr{-# LINE 115 "GHC/ExecutionStack/Internal.hsc" #-}lineNo<-((\hsc_ptr->peekByteOffhsc_ptr24))ptr::IOWord32{-# LINE 116 "GHC/ExecutionStack/Internal.hsc" #-}colNo<-((\hsc_ptr->peekByteOffhsc_ptr28))ptr::IOWord32{-# LINE 117 "GHC/ExecutionStack/Internal.hsc" #-}let_srcLoc|nullsrcFile=Nothing|otherwise=Just$SrcLoc{sourceFile=srcFile,sourceLine=fromIntegrallineNo,sourceColumn=fromIntegralcolNo}Location -> IO Location forall (m :: * -> *) a. Monad m => a -> m a return Location :: String -> String -> Maybe SrcLoc -> Location Location {objectName :: String objectName =String objFile ,functionName :: String functionName =String function ,srcLoc :: Maybe SrcLoc srcLoc =Maybe SrcLoc _srcLoc }-- | The size in bytes of a 'locationSize'locationSize ::IntlocationSize :: Int locationSize =(32){-# LINE 131 "GHC/ExecutionStack/Internal.hsc" #-}-- | List the frames of a stack trace.stackFrames ::StackTrace ->Maybe [Location ]stackFrames :: StackTrace -> Maybe [Location] stackFrames st :: StackTrace st @(StackTrace fptr :: ForeignPtr StackTrace fptr )=IO (Maybe [Location]) -> Maybe [Location] forall a. IO a -> a unsafePerformIO (IO (Maybe [Location]) -> Maybe [Location]) -> IO (Maybe [Location]) -> Maybe [Location] forall a b. (a -> b) -> a -> b $ (ForeignPtr Session -> IO [Location]) -> IO (Maybe [Location]) forall a. (ForeignPtr Session -> IO a) -> IO (Maybe a) withSession ((ForeignPtr Session -> IO [Location]) -> IO (Maybe [Location])) -> (ForeignPtr Session -> IO [Location]) -> IO (Maybe [Location]) forall a b. (a -> b) -> a -> b $ \sess :: ForeignPtr Session sess ->do[Chunk] chunks <-StackTrace -> IO [Chunk] chunksList StackTrace st ForeignPtr Session -> [Chunk] -> IO [Location] go ForeignPtr Session sess ([Chunk] -> [Chunk] forall a. [a] -> [a] reverse [Chunk] chunks )wherego ::ForeignPtr Session ->[Chunk ]->IO[Location ]go :: ForeignPtr Session -> [Chunk] -> IO [Location] go _[]=[Location] -> IO [Location] forall (m :: * -> *) a. Monad m => a -> m a return []go sess :: ForeignPtr Session sess (chunk :: Chunk chunk :chunks :: [Chunk] chunks )=do[Location] this <-ForeignPtr Session -> Chunk -> IO [Location] iterChunk ForeignPtr Session sess Chunk chunk [Location] rest <-IO [Location] -> IO [Location] forall a. IO a -> IO a unsafeInterleaveIO (ForeignPtr Session -> [Chunk] -> IO [Location] go ForeignPtr Session sess [Chunk] chunks )[Location] -> IO [Location] forall (m :: * -> *) a. Monad m => a -> m a return ([Location] this [Location] -> [Location] -> [Location] forall a. [a] -> [a] -> [a] ++ [Location] rest ){- Here we lazily lookup the location information associated with each address as this can be rather costly. This does mean, however, that if the set of loaded modules changes between the time that we capture the stack and the time we reach here, we may end up with nonsense (mostly likely merely unknown symbols). I think this is a reasonable price to pay, however, as module loading/unloading is a rather rare event. Morover, we stand to gain a great deal by lazy lookups as the stack frames may never even be requested, meaning the only effort wasted is the collection of the stack frames themselves. The only slightly tricky thing here is to ensure that the ForeignPtr stays alive until we reach the end. -}iterChunk ::ForeignPtr Session ->Chunk ->IO[Location ]iterChunk :: ForeignPtr Session -> Chunk -> IO [Location] iterChunk sess :: ForeignPtr Session sess chunk :: Chunk chunk =Word -> Ptr Addr -> IO [Location] iterFrames (Chunk -> Word chunkFrames Chunk chunk )(Chunk -> Ptr Addr chunkFirstFrame Chunk chunk )whereiterFrames ::Word->Ptr Addr ->IO[Location ]iterFrames :: Word -> Ptr Addr -> IO [Location] iterFrames 0_=[Location] -> IO [Location] forall (m :: * -> *) a. Monad m => a -> m a return []iterFrames n :: Word n frame :: Ptr Addr frame =doAddr pc <-Ptr Addr -> IO Addr forall a. Storable a => Ptr a -> IO a peek Ptr Addr frame ::IOAddr Maybe Location mframe <-Addr -> IO (Maybe Location) lookupFrame Addr pc [Location] rest <-IO [Location] -> IO [Location] forall a. IO a -> IO a unsafeInterleaveIO (Word -> Ptr Addr -> IO [Location] iterFrames (Word n Word -> Word -> Word forall a. Num a => a -> a -> a - 1)Ptr Addr forall a. Ptr a frame' )[Location] -> IO [Location] forall (m :: * -> *) a. Monad m => a -> m a return ([Location] -> IO [Location]) -> [Location] -> IO [Location] forall a b. (a -> b) -> a -> b $ [Location] -> (Location -> [Location]) -> Maybe Location -> [Location] forall b a. b -> (a -> b) -> Maybe a -> b maybe [Location] rest (Location -> [Location] -> [Location] forall a. a -> [a] -> [a] :[Location] rest )Maybe Location mframe whereframe' :: Ptr b frame' =Ptr Addr frame Ptr Addr -> Int -> Ptr b forall a b. Ptr a -> Int -> Ptr b `plusPtr` Addr -> Int forall a. Storable a => a -> Int sizeOf (Addr forall a. HasCallStack => a undefined ::Addr )lookupFrame ::Addr ->IO(Maybe Location )lookupFrame :: Addr -> IO (Maybe Location) lookupFrame pc :: Addr pc =ForeignPtr StackTrace -> (Ptr StackTrace -> IO (Maybe Location)) -> IO (Maybe Location) forall a b. ForeignPtr a -> (Ptr a -> IO b) -> IO b withForeignPtr ForeignPtr StackTrace fptr ((Ptr StackTrace -> IO (Maybe Location)) -> IO (Maybe Location)) -> (Ptr StackTrace -> IO (Maybe Location)) -> IO (Maybe Location) forall a b. (a -> b) -> a -> b $ IO (Maybe Location) -> Ptr StackTrace -> IO (Maybe Location) forall a b. a -> b -> a const (IO (Maybe Location) -> Ptr StackTrace -> IO (Maybe Location)) -> IO (Maybe Location) -> Ptr StackTrace -> IO (Maybe Location) forall a b. (a -> b) -> a -> b $ doInt -> (Ptr Location -> IO (Maybe Location)) -> IO (Maybe Location) forall a b. Int -> (Ptr a -> IO b) -> IO b allocaBytes Int locationSize ((Ptr Location -> IO (Maybe Location)) -> IO (Maybe Location)) -> (Ptr Location -> IO (Maybe Location)) -> IO (Maybe Location) forall a b. (a -> b) -> a -> b $ \buf :: Ptr Location buf ->doCInt ret <-ForeignPtr Session -> (Ptr Session -> IO CInt) -> IO CInt forall a b. ForeignPtr a -> (Ptr a -> IO b) -> IO b withForeignPtr ForeignPtr Session sess ((Ptr Session -> IO CInt) -> IO CInt) -> (Ptr Session -> IO CInt) -> IO CInt forall a b. (a -> b) -> a -> b $ \sessPtr :: Ptr Session sessPtr ->Ptr Session -> Ptr Location -> Addr -> IO CInt libdw_lookup_location Ptr Session sessPtr Ptr Location buf Addr pc caseCInt ret of0->Location -> Maybe Location forall a. a -> Maybe a Just (Location -> Maybe Location) -> IO Location -> IO (Maybe Location) forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b <$> Ptr Location -> IO Location peekLocation Ptr Location buf _->Maybe Location -> IO (Maybe Location) forall (m :: * -> *) a. Monad m => a -> m a return Maybe Location forall a. Maybe a Nothing -- | A LibdwSession from the runtime systemdataSession foreignimportccallunsafe"libdwPoolTake"libdw_pool_take ::IO(Ptr Session )foreignimportccallunsafe"&libdwPoolRelease"libdw_pool_release ::FunPtr (Ptr Session ->IO())foreignimportccallunsafe"libdwPoolClear"libdw_pool_clear ::IO()foreignimportccallunsafe"libdwLookupLocation"libdw_lookup_location ::Ptr Session ->Ptr Location ->Addr ->IOCInt foreignimportccallunsafe"libdwGetBacktrace"libdw_get_backtrace ::Ptr Session ->IO(Ptr StackTrace )foreignimportccallunsafe"&backtraceFree"backtrace_free ::FunPtr (Ptr StackTrace ->IO())-- | Get an execution stack.collectStackTrace ::IO(Maybe StackTrace )collectStackTrace :: IO (Maybe StackTrace) collectStackTrace =(Maybe (Maybe StackTrace) -> Maybe StackTrace) -> IO (Maybe (Maybe StackTrace)) -> IO (Maybe StackTrace) forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b fmap Maybe (Maybe StackTrace) -> Maybe StackTrace forall (m :: * -> *) a. Monad m => m (m a) -> m a join (IO (Maybe (Maybe StackTrace)) -> IO (Maybe StackTrace)) -> IO (Maybe (Maybe StackTrace)) -> IO (Maybe StackTrace) forall a b. (a -> b) -> a -> b $ (ForeignPtr Session -> IO (Maybe StackTrace)) -> IO (Maybe (Maybe StackTrace)) forall a. (ForeignPtr Session -> IO a) -> IO (Maybe a) withSession ((ForeignPtr Session -> IO (Maybe StackTrace)) -> IO (Maybe (Maybe StackTrace))) -> (ForeignPtr Session -> IO (Maybe StackTrace)) -> IO (Maybe (Maybe StackTrace)) forall a b. (a -> b) -> a -> b $ \sess :: ForeignPtr Session sess ->doPtr StackTrace st <-ForeignPtr Session -> (Ptr Session -> IO (Ptr StackTrace)) -> IO (Ptr StackTrace) forall a b. ForeignPtr a -> (Ptr a -> IO b) -> IO b withForeignPtr ForeignPtr Session sess Ptr Session -> IO (Ptr StackTrace) libdw_get_backtrace if|Ptr StackTrace st Ptr StackTrace -> Ptr StackTrace -> Bool forall a. Eq a => a -> a -> Bool ==Ptr StackTrace forall a. Ptr a nullPtr ->Maybe StackTrace -> IO (Maybe StackTrace) forall (m :: * -> *) a. Monad m => a -> m a return Maybe StackTrace forall a. Maybe a Nothing |Bool otherwise ->StackTrace -> Maybe StackTrace forall a. a -> Maybe a Just (StackTrace -> Maybe StackTrace) -> (ForeignPtr StackTrace -> StackTrace) -> ForeignPtr StackTrace -> Maybe StackTrace forall b c a. (b -> c) -> (a -> b) -> a -> c . ForeignPtr StackTrace -> StackTrace StackTrace (ForeignPtr StackTrace -> Maybe StackTrace) -> IO (ForeignPtr StackTrace) -> IO (Maybe StackTrace) forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b <$> FinalizerPtr StackTrace -> Ptr StackTrace -> IO (ForeignPtr StackTrace) forall a. FinalizerPtr a -> Ptr a -> IO (ForeignPtr a) newForeignPtr FinalizerPtr StackTrace backtrace_free Ptr StackTrace st -- | Free the cached debug data.invalidateDebugCache ::IO()invalidateDebugCache :: IO () invalidateDebugCache =IO () libdw_pool_clear -- | Render a stacktrace as a stringshowStackFrames ::[Location ]->ShowS showStackFrames :: [Location] -> ShowS showStackFrames frames :: [Location] frames =String -> ShowS showString "Stack trace:\n"ShowS -> ShowS -> ShowS forall b c a. (b -> c) -> (a -> b) -> a -> c . (ShowS -> ShowS -> ShowS) -> ShowS -> [ShowS] -> ShowS forall (t :: * -> *) a b. Foldable t => (a -> b -> b) -> b -> t a -> b foldr ShowS -> ShowS -> ShowS forall b c a. (b -> c) -> (a -> b) -> a -> c (.) ShowS forall a. a -> a id ((Location -> ShowS) -> [Location] -> [ShowS] forall a b. (a -> b) -> [a] -> [b] map Location -> ShowS showFrame [Location] frames )whereshowFrame :: Location -> ShowS showFrame loc :: Location loc =String -> ShowS showString " "ShowS -> ShowS -> ShowS forall b c a. (b -> c) -> (a -> b) -> a -> c . Location -> ShowS showLocation Location loc ShowS -> ShowS -> ShowS forall b c a. (b -> c) -> (a -> b) -> a -> c . Char -> ShowS showChar '\n'-- | Render a 'Location' as a stringshowLocation ::Location ->ShowS showLocation :: Location -> ShowS showLocation loc :: Location loc =String -> ShowS showString (Location -> String functionName Location loc )ShowS -> ShowS -> ShowS forall b c a. (b -> c) -> (a -> b) -> a -> c . ShowS -> (SrcLoc -> ShowS) -> Maybe SrcLoc -> ShowS forall b a. b -> (a -> b) -> Maybe a -> b maybe ShowS forall a. a -> a id SrcLoc -> ShowS showSrcLoc (Location -> Maybe SrcLoc srcLoc Location loc )ShowS -> ShowS -> ShowS forall b c a. (b -> c) -> (a -> b) -> a -> c . String -> ShowS showString " in "ShowS -> ShowS -> ShowS forall b c a. (b -> c) -> (a -> b) -> a -> c . String -> ShowS showString (Location -> String objectName Location loc )whereshowSrcLoc ::SrcLoc ->ShowS showSrcLoc :: SrcLoc -> ShowS showSrcLoc sloc :: SrcLoc sloc =String -> ShowS showString " ("ShowS -> ShowS -> ShowS forall b c a. (b -> c) -> (a -> b) -> a -> c . String -> ShowS showString (SrcLoc -> String sourceFile SrcLoc sloc )ShowS -> ShowS -> ShowS forall b c a. (b -> c) -> (a -> b) -> a -> c . String -> ShowS showString ":"ShowS -> ShowS -> ShowS forall b c a. (b -> c) -> (a -> b) -> a -> c . Int -> ShowS forall a. Show a => a -> ShowS shows (SrcLoc -> Int sourceLine SrcLoc sloc )ShowS -> ShowS -> ShowS forall b c a. (b -> c) -> (a -> b) -> a -> c . String -> ShowS showString "."ShowS -> ShowS -> ShowS forall b c a. (b -> c) -> (a -> b) -> a -> c . Int -> ShowS forall a. Show a => a -> ShowS shows (SrcLoc -> Int sourceColumn SrcLoc sloc )ShowS -> ShowS -> ShowS forall b c a. (b -> c) -> (a -> b) -> a -> c . String -> ShowS showString ")"