--- a/t/re/reg_mesg.t	2018-05-21 20:29:23.000000000 +0800
+++ b/t/re/reg_mesg-change.t	2019-04-11 09:54:59.622000000 +0800
@@ -122,6 +122,8 @@ my $tab_hex = sprintf "%02X", ord("\t");
 #
 # The first set are those that should be fatal errors.
 
+my $bug133423 = "(?[(?^:(?[\\\x00]))\\]\x00|2[^^]\x80\x80\x80\x80\x80\x80\x80\x80\x80\x80\x80\x80\x80\x80\x80\x80\x80\x80\x80\x80\x80\x80\x80\x80\x80\x80\x80\x80\x80\x80\x80\x80\x80\x80])R.\\670";
+
 my @death =
 (
  '/[[=foo=]]/' => 'POSIX syntax [= =] is reserved for future extensions {#} m/[[=foo=]{#}]/',