GHCi doesn't run computations in a new thread
A broken QuickCheck property cause ghci to panic after
reloading the module. Seen in stable and head branch.
paprika$ ghci T.hs
*Main> do_test
test : *
(0)
*Main> :reload
ghc-6.5: panic! (the `impossible' happened, GHC version
6.5):
<<loop>>
Please report it as a compiler bug to
glasgow-haskell-bugs@haskell.org,
or http://sourceforge.net/projects/ghc/.
Changing the property to check for empty lists causes
the test to pass, and reload to work fine.
-- Don Stewart
Edited by Simon Marlow