Debugging <<loop>> error message in haskell

Hello i am encountering this error message in a Haskell program and i do not know where is the loop coming from.There are almost no IO methods so that i can hook myself to them and print the partial result in the terminal.

I start with a file , i read it and then there are only pure methods.How can i debug this ?

Is there a way to attach to methods or create a helper that can do the following:

Having a method method::a->b how can i somehow wrap it in a iomethod::(a->b)->IO (a->b) to be able to test in in GHCI (i want to insert some putStrLn-s etc ?

P.S My data suffer transformations IO a(->b->c->d->......)->IO x and i do not know how to debug the part that is in the parathesis (that is the code that contains the pure methods)

Types and typeclass definitions and implementations

data TCPFile=Rfile (Maybe Readme) | Dfile  Samples | Empty
data Header=Header { ftype::Char}

newtype Samples=Samples{values::[Maybe Double]}deriving(Show)

data Readme=Readme{ maxClients::Int, minClients::Int,stepClients::Int,maxDelay::Int,minDelay::Int,stepDelay::Int}deriving(Show)

data FileData=FileData{ header::Header,rawContent::Text}

(>>?)::Maybe a->(a->Maybe b)->Maybe b
(Just t) >>? f=f t
Nothing >>? _=Nothing

class TextEncode a where
fromText::Text-> a


getHeader::TCPFile->Header
getHeader (Rfile _ ) = Header { ftype='r'}
getHeader (Dfile _ )= Header{ftype='d'}
getHeader _ = Header {ftype='e'}


instance Show TCPFile where
show (Rfile t)="Rfile " ++"{"++content++"}" where
    content=case t of
        Nothing->""
        Just c -> show c
show (Dfile c)="Dfile " ++"{"++show c ++ "}"

instance TextEncode Samples where
    fromText text=Samples  (map (readMaybe.unpack) cols) where
             cols=splitOn (pack ",") text



instance TextEncode Readme where
    fromText txt =let len= length dat
                      dat= case len of 
                            6 ->Prelude.take 6 .readData $ txt
                            _ ->[0,0,0,0,0,0] in 
            Readme{maxClients=Prelude.head dat,minClients=dat!!1,stepClients=dat!!2,maxDelay=dat!!3,minDelay=dat!!4,stepDelay=dat!!5} where




instance TextEncode TCPFile where
    fromText  = textToFile

Main

module Main where 
import Data.Text(Text,pack,unpack)
import Data.Text.IO(readFile,writeFile)
import TCPFile(TCPFile)

main::IO()
main=do
    dat<-readTcpFile "test.txt"
    print dat

readTcpFile::FilePath->IO TCPFile
readTcpFile path =fromText <$> Data.Text.IO.readFile path  

textToFile::Text->TCPFile
textToFile input=case readHeader input >>? (\h -> Just (FileData h input)) >>?  makeFile of
    Just r -> r
    Nothing ->Empty



readHeader::Text->Maybe Header
readHeader txt=case Data.Text.head txt of 
    'r' ->Just (Header{ ftype='r'})
    'd' ->Just (Header {ftype ='d'})
    _  -> Nothing

makeFile::FileData->Maybe TCPFile
makeFile fd= case ftype.header $ fd of
        'r'->Just (Rfile (Just (fromText . rawContent $ fd)))
        'd'->Just (Dfile (fromText . rawContent $ fd))
        _  ->Nothing 


readData::Text->[Int]
readData =catMaybes . maybeValues where
    maybeValues=mvalues.split.filterText "{}"

#all the methods under this line  are used in the above method

mvalues::[Text]->[Maybe Int]
mvalues arr=map (\x->(readMaybe::String->Maybe Int).unpack $ x) arr

split::Text->[Text]
split =splitOn (pack ",")

filterText::[Char]->Text->Text
filterText chars tx=Data.Text.filter (\x -> not (x `elem` chars)) tx

I want first to clean the Text from given characters , in our case }{ then split it by ,.After the text is split by commas i want to parse them, and create either a Rfile which contains 6 integers , either a Dfile (datafile) which contains any given number of integers.

Input I have a file with the following content: r,1.22,3.45,6.66,5.55,6.33,2.32} and i am running runghc main 2>err.hs

Expected Output : Rfile (Just (Readme 1.22 3.45 6.66 5.55 6.33 2.32))