method iterator and CArrays.md

Here's another interesting one. Take this class:

class Path {
  has cairo_path_t $.path handles <data num_data>;
  has $!index = 0;

  submethod BUILD (:$!path) { }

  method AT-POS(|) {
    die 'Sorry! Cairo::Path is an iterated list, not an array.'
  }

  method get_data(Int $i) {
    #nativecast( CArray[cairo_path_data_t], $!path.data[$i] );
    nativecast( CArray[Pointer], $!path.data[$i] );
  }

  method iterator {
    my $oc = self;
    my $path = $!path;

    say 'Iterator';
    class :: does Iterator {
      has $.index is rw = 0;

      method pull-one {
        say 'Pulling';
        my $r := $path.num_data > $.index ??
          $oc.get_data($.index) !! IterationEnd;
        $.index += $r.header.length;
        say "Iterator: { $r.^name }";
        $r;
      }
    }.new;
  }

  method new (cairo_path_t $path) {
    self.bless(:$path);
  }

  method destroy {
    $!path.destroy;
  }
}

So you would expect that this:

my $p = $path.iterator.pull-one;

Would pull the first element from $!path. It doesn't. Instead, I get the following:

Iterator
Pulling
Unknown element type in CArray
  in method <anon> at /home/cbwood/Projects/rakudobrew/moar-master/install/share/perl6/sources/8660F65A7B3492675BB3B2058DB30E411A4C4E54 (NativeCall::Types) line 163
  in method get_data at /home/cbwood/Projects/p6-Pango/../cairo-p6/lib/Cairo.pm6 (Cairo) line 1565
  in method pull-one at /home/cbwood/Projects/p6-Pango/../cairo-p6/lib/Cairo.pm6 (Cairo) line 1580
  in sub fancy_cairo_stroke at t/02-twisted.t line 15
  in sub draw_dream at t/02-twisted.t line 276
  in sub MAIN at t/02-twisted.t line 295
  in block <unit> at t/02-twisted.t line 290

Now I know for a fact that CArray[Pointer] is valid, so why is this error popping up?