Hi all, I think my grammar's thing rule should have captured $+{thing}. It didn't. What did I miss?

use Test::More tests => 1;
use Data::Dumper;
'cow' =~ /
  (?:
    # Grammar rules go here...
    (?<thing> .+ )
  ){0}

  # Invoke grammar here
  ^(?&thing)
/x
  or die "Didn't match";

my $got = Dumper({
    '%+' => {%+},
    '@+' => [@+],
    '@-' => [@-],
});
my $expected = Dumper({
    '%+' => {
        thing => 'cow'
    },
    '@-' => [ 0, 0 ],
    '@+' => [ 3, 3 ],
});
is( $got, $expected );
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Test results:

#   Failed test at bin/ooga.pl line 24.
#          got: '$VAR1 = {
#           '%+' => {},
#           '@-' => [
#                     '0'
#                   ],
#           '@+' => [
#                     '1',
#                     undef
#                   ]
#         };
# '
#     expected: '$VAR1 = {
#           '%+' => {
#                     'thing' => 'cow'
#                   },
#           '@-' => [
#                     0,
#                     0
#                   ],
#           '@+' => [
#                     3,
#                     3
#                   ]
#         };
# '
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