[ ghc-Bugs-1373450 ] Nested 'atomically' should raise an exception

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Bugs item #1373450, was opened at 2005-12-05 10:48
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Category: Runtime System
Group: None
Status: Open
Resolution: None
Priority: 5
Submitted By: Simon Peyton Jones (simonpj)
Assigned to: Nobody/Anonymous (nobody)
Summary: Nested 'atomically' should raise an exception

Initial Comment:
Using 'atomically' inside an unsafePerformIO, inside 
another 'atomically' should raise an exception.  
Currently, it seg-faults.

Here's an example:

    import Control.Concurrent.STM
    import System.IO.Unsafe (unsafePerformIO)

    {-# NOINLINE var #-}
    var :: TVar ()
    var = unsafePerformIO (atomically (newTVar ()))

    main = atomically (readTVar var)

Simon

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