Strange behavior when using stable names inside ghci?

27 Jun 2012


      Hi,
  The program below when loaded in ghci prints always False, and when
compiled with ghc it prints True. I'm using ghc-7.4.1 and I cannot
quite explain such behavior. Any hints?

Thanks in advance,
Facundo

{-# LANGUAGE GADTs #-}
import System.Mem.StableName
import Unsafe.Coerce
import GHC.Conc

data D where
   D :: a -> b -> D

main = do
  putStr "type enter"
  s <- getLine
  let i = fromEnum$ head$ s++"0"
      d = D i i
  case d of
    D a b -> do
        let a' = a
        sn0 <- pseq a'$ makeStableName a'
        sn1 <- pseq b$ makeStableName b
        print (sn0==unsafeCoerce sn1)

Strange behavior when using stable names inside ghci?

Facundo Domínguez