Zephir not incrementing correctly?

greeting.zep

namespace Utils;

class Greeting
{
    protected counter1 = 0;
    protected counter2 = 0;
    protected counter3 = 0;
    protected revcounter1 = 5;
    protected revcounter2 = 5;
    protected revcounter3 = 5;
    protected name = "";

    public function __construct(string! name = "world")
    {
        let this->name = name;
    }

    public function speakLoop(int times = 5) -> void
    {
        while times {
            echo "hello " . this->name . "!\n";
            let this->counter1++;
            let this->counter2 += 1;
            let this->counter3 = this->counter3 + 1;
            let this->revcounter1--;
            let this->revcounter2 -= 1;
            let this->revcounter3 = this->revcounter3 - 1;
            let times -= 1;
        }
    }
}

result

class Utils\Greeting#1 (7) {
  protected $counter1 =>
  int(0)
  protected $counter2 =>
  int(0)
  protected $counter3 =>
  int(0)
  protected $revcounter1 =>
  int(5)
  protected $revcounter2 =>
  int(5)
  protected $revcounter3 =>
  int(5)
  protected $name =>
  string(4) "Andy"
}

hello Andy!
hello Andy!
hello Andy!
hello Andy!
hello Andy!

class Utils\Greeting#1 (7) {
  protected $counter1 =>
  int(0)
  protected $counter2 =>
  int(1)
  protected $counter3 =>
  int(5)
  protected $revcounter1 =>
  int(5)
  protected $revcounter2 =>
  int(1)
  protected $revcounter3 =>
  int(0)
  protected $name =>
  string(4) "Andy"
}

test.php

<?php

$g = new \Utils\Greeting('Andy');

var_dump($g);
$g->speakLoop(5);
var_dump($g);