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{-# OPTIONS -XRecursiveDo #-}
-- test that we have all the promised instances
module Main(main) where
import Control.Monad.Fix
import qualified Control.Monad.ST as SST
import qualified Control.Monad.ST.Lazy as LST
generic :: MonadFix m => m [Int]
generic = mdo xs <- return (1:xs)
return (take 4 xs)
io :: IO [Int]
io = generic
sst :: SST.ST s [Int]
sst = generic
lst :: LST.ST s [Int]
lst = generic
mb :: Maybe [Int]
mb = generic
ls :: [[Int]]
ls = generic
main :: IO ()
main = do
print =<< io
print $ SST.runST sst
print $ LST.runST lst
print $ mb
print $ ls
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