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{-# LANGUAGE BangPatterns #-}
{-# LANGUAGE BlockArguments #-}
{-# LANGUAGE MagicHash #-}
{-# LANGUAGE StandaloneKindSignatures #-}
{-# LANGUAGE UnboxedTuples #-}
{-# LANGUAGE UnliftedDatatypes #-}
module Main where
import Data.Kind
import System.Mem (performGC)
import GHC.Exts
import GHC.IO
type U :: UnliftedType
data U = U Int# Int#
main :: IO ()
main = do
res <- IO \ s0 ->
let u :: U
u = U 97531# 86420#
in
case makeStablePtr# u s0 of
(# s1, ptr #) ->
case unIO performGC s1 of
(# s3, _ #) ->
case deRefStablePtr# ptr s3 of
(# s4, U i j #) ->
case makeStablePtr# (U 123# 456#) s4 of
(# s5, ptr' #) ->
(# s5, [ I# i, I# j, I# (eqStablePtr# ptr ptr), I# (eqStablePtr# ptr ptr') ] #)
print res
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