In that case, chromatic's code simplifies to

use B::Deparse qw( );

my $deparse = B::Deparse->new();

sub lives_ok(&;$) {
   my ($code, $desc) = @_;
   $desc = $deparse->coderef2text($code)
      if !defined($desc);
   return Text::Exception::lives_ok($code, $desc);
}
[download]

Be careful to avoid accidently overriding your own functions with those from the module you are extending.