"Segmentation fault ruby 1.8.6" "i686-linux" "patchlevel 230"

When I reported #512 "ActionView::TemplateError" "wrong argument type" "expected Proc", I tried to reproduce the issue in order to provide the full stack trace. Instead I got this:

$ ./script/server -e test -p 2000
=> Booting Mongrel (use 'script/server webrick' to force WEBrick)
=> Rails 2.1.0 application starting on http://0.0.0.0:2000
=> Call with -d to detach
=> Ctrl-C to shutdown server
** Starting Mongrel listening at 0.0.0.0:2000
** Starting Rails with test environment...
** Rails loaded.
** Loading any Rails specific GemPlugins
** Signals ready.  TERM => stop.  USR2 => restart.  INT => stop (no restart).
** Rails signals registered.  HUP => reload (without restart).  It might not work well.
** Mongrel 1.1.5 available at 0.0.0.0:2000
** Use CTRL-C to stop.
/usr/local/lib/ruby/gems/1.8/gems/actionpack-2.1.0/lib/action_view/helpers/form_tag_helper.rb:431: [BUG] Segmentation fault
ruby 1.8.6 (2008-06-20) [i686-linux]

Aborted
$ ruby -v
ruby 1.8.6 (2008-06-20 patchlevel 230) [i686-linux]
$