regex-dna failure golf

test.pl

use v6;

sub my-subst($self, $matcher, $replacement,
				   :ii(:$samecase), :ss(:$samespace),
				   :$SET_CALLER_DOLLAR_SLASH, *%options) {
	my $matches := $self.match($matcher, |%options);
	return $self unless $matches;
	if $matches ~~ Match {
		$matches := ($matches,).list;
	}
	else {
		$matches := $matches.list;
	}
	my $caller_dollar_slash := pir::find_caller_lex__Ps('$/');
	my $prev = 0;
	my $result = '';
my $i = 0;
	while $matches {
say ++$i;
		my $m = $matches.shift;
		$result ~= $self.substr($prev, $m.from - $prev);

		$caller_dollar_slash = $m if $SET_CALLER_DOLLAR_SLASH;
		my $real_replacement = ~($replacement ~~ Callable ?? $replacement($m) !! $replacement);
		$real_replacement    = $real_replacement.samecase(~$m) if $samecase;
		$real_replacement    = $real_replacement.samespace(~$m) if $samespace;
		$result ~= $real_replacement;
		$prev = $m.to;
	}
	$result ~= $self.substr($prev);
	$result;
}

my $string = 'abc' x 10000;
my %hash = :a(1), :b(2), :c(3);
$string = my-subst($string, /(<[abc]>)/, -> $/ { %hash{$0} }, :global);