internal error: main thread has been GC'd

when compiling the following program with ghc 6.2.1

count :: (?c :: Integer) => IO ()
count = do y <- return ?c
           putStr ((show ?c)++"\n")
           let ?c = y+1 in count 

main = let ?c=0 in count

compiles fine with ghc: --make  -fglasgow-exts test.hs
While running, wenn pressing control-c to break, it
tells me:

a.out: internal error: main thread has been GC'd
    Please report this as a bug to
glasgow-haskell-bugs@haskell.org,
    or http://www.sourceforge.net/projects/ghc/

Trac metadata

Trac field	Value
Version	None
Type	Bug
TypeOfFailure	OtherFailure
Priority	normal
Resolution	ResolvedFixed
Component	Runtime System
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