-O Bug

[Simon Marlow]

> Compiling the program
> 
> >main =
> >  do
> >  _ <- compute "_"
> >  return ()
> >
> >compute :: String -> String
> >compute ("hd"++_) = "_"
> 
> with 
> 
> ghc -c Bug.lhs
> 
> results in the obvious errors
> but compiling with
> 
> ghc -O -c Bug.lhs
> 
> rather results in
> 
> <<loop>>
> 
> which looks to me like a bug in ghc.
> I tried this with
> ghc 4.08,4.08.1 and egcs 1.1.2 on solaris and linux

Thanks for the report.  Yes, it does look like a bug, and one in the
typechecker.  The Keeper of the Typechecker (namely Simon) is away for
the week, but we'll hopefully get back to you next week with some more
info.

Cheers,
	Simon