Thank you for a nicely characterised bug report. GHC should never crash! I've created a trac ticket http://hackage.haskell.org/trac/ghc/ticket/3049 Simon | -----Original Message----- | From: glasgow-haskell-users-bounces@haskell.org [mailto:glasgow-haskell-users- | bounces@haskell.org] On Behalf Of Ben Franksen | Sent: 24 February 2009 19:50 | To: glasgow-haskell-users@haskell.org | Subject: Bug in STM with data invariants | | My ghc(i) crashes when using STM data invariants. This little piece of code | demonstrates the problem: | | module Bug where | | import Control.Concurrent.STM | | test = do | x <- atomically $ do | v <- newTVar 0 | always $ return True -- remove this line and all is fine | return v | atomically (readTVar x) >>= print | | This is what ghci makes of it: | | ben@sarun> ghci Bug.hs | GHCi, version 6.10.1: http://www.haskell.org/ghc/ :? for help | Loading package ghc-prim ... linking ... done. | Loading package integer ... linking ... done. | Loading package base ... linking ... done. | [1 of 1] Compiling Bug ( Bug.hs, interpreted ) | Ok, modules loaded: Bug. | *Bug> test | Loading package syb ... linking ... done. | Loading package array-0.2.0.0 ... linking ... done. | Loading package stm-2.1.1.2 ... linking ... done. | zsh: segmentation fault ghci Bug.hs | | I am using ghc-6.10.1 freshly installed from source with just a 'cabal | install stm' thrown after it. | | BTW, the documentation for Control.Concurrent.STM.TVar lists... nothing. | Similar with Control.Monad.STM. Well, at least the source link works, so | one isn't completely lost... :-) | | Cheers | Ben | | _______________________________________________ | Glasgow-haskell-users mailing list | Glasgow-haskell-users@haskell.org | http://www.haskell.org/mailman/listinfo/glasgow-haskell-users