Yes, but where?!? -- Directive d not applicable for type Str

#/usr/bin/perl6

my ($index, $newIndex) = (5, 1);
my ($indexF, $newIndexF);

sub readFile {
    my $indexFH = open (my $fn = sprintf "index_split_%03d.html", $index++), :r
        or die "Can't open file '$fn': $!";

    $indexF = $indexFH.slurp-rest;
    $indexFH.close;
}

sub writeFile {
    my $newIndexFH = open (sprintf "newinidex_split_%03d.html", $newIndex++), :w;
    $newIndexFH.print($newIndex);
    $newIndexFH.close;

    say "Wrote new index file $newIndex.";
}

readFile() && $newIndexF = $indexF if !$newIndexF.defined;

repeat {
    readFile();
    if ($index ~~ /'<h1>'/) {
        writeFile();
        $newIndexF = $index;
        next;
    }

    $newIndexF ~~ s| '</p>' \v '</body>' \v '</html>' $||;
    $newIndexF ~~ s!('.' | '!' | '?')$$|$\0 !!;
    $indexF ~~s |^^.+?\<p.+?\>||;
    $index ~= $newIndexF;
} until $newIndex > 418;

writeFile();


===
Output
===

$ perl6 reSplit.pl
Directive d not applicable for type Str
  in any  at /home/cbwood/.rakudobrew/moar-nom/install/share/perl6/runtime/CORE.setting.moarvm line 1
  in any panic at /home/cbwood/.rakudobrew/moar-nom/install/share/nqp/lib/NQPHLL.moarvm line 1