Cannot escape from a black hole in ghci 6.10.1

[Simon Marlow]

Ahn, Ki Yung wrote:
> Dear GHC users
> 
> I have both GHC 6.8.2 (debian unstable package) and
> GHC 6.8.10 (binary distribution from ghc homepage) installed.
> 
> I was able to escape from a black hole in ghci 6.8.2 with Ctrl-C.
> For example,
> 
> GHCi, version 6.8.2: http://www.haskell.org/ghc/  :? for help
> Loading package base ... linking ... done.
> Prelude> let x = x + x
> Prelude> x
> ^CInterrupted.
> Prelude> x
> *** Exception: stack overflow
> Prelude>
> 
> Interestingly, you will get a stack overflow when you try to escape from
> the black home for the second time.
> 
> In ghci 6.10.1, I am not able to escape from a black hole with Ctrl-C.
> 
> 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.
> Prelude> let x = x + x
> Prelude> x
> ^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C ... (doesn't work)
> 
> You can't escape from the black hole and ghci will start
> eating up your memory unless kill the ghci process.
> Now the black hole behaves like a real black hole :-)
> 
> Is this a ticketed bug, or should we make a new ticket?

Yes, this is the same bug as #2783 (fixed yesterday) and probably also
#2780 (I still have to test the fix against that program).  It'll be fixed
in 6.10.2.

Cheers,
	Simon