I wrote the following haskell program and hugs reported an internal compiler error when I tried to load it. The syntax is invalid but I would expect a sensible error message rather than the internal error which I got. Cheers, Neil. falcon:tmp$ cat foo.hs class Foo x where foo :: x instance Foo () where foo ? falcon:tmp$ hugs foo.hs __ __ __ __ ____ ___ _________________________________________ || || || || || || ||__ Hugs 98: Based on the Haskell 98 standard ||___|| ||__|| ||__|| __|| Copyright (c) 1994-2005 ||---|| ___|| World Wide Web: http://haskell.org/hugs || || Bugs: http://hackage.haskell.org/trac/hugs || || Version: September 2006 _________________________________________ Haskell 98 mode: Restart with command line option -98 to enable extensions INTERNAL ERROR: parseInput Please report this Hugs bug to http://hackage.haskell.org/trac/hugs Hugs>