fives_bad.hs

import Control.Monad
import Control.Monad.State

type CounterState = State Int

fivesWithCounter :: CounterState [Int]
fivesWithCounter = do
  modify (+1)
  fives <- fivesWithCounter
  i <- get
  return $ i:fives

main :: IO ()
main = print $ evalState take10 0
  where take10 = do
          fives <- fivesWithCounter
          return $ take 10 fives

fives_good.hs

import Control.Monad
import Control.Monad.State

type CounterState = State Int

fivesWithCounter :: CounterState [Int]
fivesWithCounter = do
  modify (+1)
  (:) <$> get <*> fivesWithCounter

main :: IO ()
main = print $ evalState (take 10 <$> fivesWithCounter) 0