Ticket #828 (closed bug: fixed)
ghc -e 'Control.Monad.Fix.mfix error' panics
Just for the record, a low priority bug...
Folk on IRC found this obscure torture test:
Depending on how you run it it gives different errors.
Compiling a module main = mfix error works fine:
ghc foo.hs -o foo ./foo foo: <<loop>>
It exits with a non-zero exit code as expected.
ghci fares a little worse but ok:
Prelude> Control.Monad.Fix.mfix error *** Exception: *** Exception: <<loop>>
So actually the only way that goes wrong is ghc -e :
ghc -e 'Control.Monad.Fix.mfix error' *** Exception: ghc-6.4.2: panic! (the `impossible' happened, GHC version 6.4.2): <<loop>> Please report this as a compiler bug. See: http://www.haskell.org/ghc/reportabug
Same behaviour with recent ghc-6.5.
So I'd guess it's just the catching of errors in ghc -e that's not quite right, probably because of the way that tring to generate the error message generates an error.