# ruby -wc says syntax ok
# ruby -w says blah.rb:2: undefined local variable or method `index' for main:Object (NameError)
if index < 0 and $VERBOSE
  $stderr.puts "warning: index is a negative number"
  if $DEBUG
    $stderr.puts "index value: #{index.inspect}"
    $stderr.puts "array state: #{array.inspect}"
  end
end
~~~~~~~~~~
