Thanks for looking into this so quickly.  After you have confirmed that the fix
works, could you please tell me whether I have to worry about this bug for
normal day-to-day work with 6.5?  The compiler appears to work just fine in most
cases but I'm conerned that it could produce incorrect output so that finalized
programs don't work right.  Is this possible or likely?

I don't know whether this would have caught the problem, but you might
consider running the eweasel tests before a final release with a version of the compiler
that has preconditions enabled on all classes.  Or maybe you already do this.