[ruby-talk:5978] Garbage collection bug: unknown data type 40

The following is a program that makes ruby crash with the error
message:

./bicapitalize.rb:19: [BUG] gc_sweep(): unknown data type 40
ruby 1.6.1 (2000-09-27) [i586-linux-gnu]
Aborted

Here is the program:
-----------------------------------------------------------------
#! /usr/bin/ruby

srand

$aGlobalVar = []

def doit! text
  text.downcase!
  nothing text
  bicapitalize! text
end

def nothing text
  for i in 0...$aGlobalVar.length
  end
end

def bicapitalize! text
  text.gsub!(/[a-z]/) { |m| rand < .3 ? m.upcase : m }
end

STDIN.each_line { |line|
  doit! line
  print line
}
print "\n"
------------------------------------------------------------------

This program should be run as a unix filter taking input from stdin
and writing to stdout. With a sufficiently large input, the error
message will appear. At least on my machine:

[jo@bogon ruby]$ cat /etc/mandrake-release
Linux Mandrake release 7.2 (Odyssey) for i586

[jo@bogon ruby]$ uname -a
Linux bogon.jonett 2.2.17-21mdk #1 Thu Oct 5 13:16:08 CEST 2000 i686 unknown

[jo@bogon ruby]$ rpm -q ruby
ruby-1.6.1-2mdk


 -Jo
-- 
Hours and hours of sheer boredom, punctuated by lunch.