class Test 
{
   // ... another stuff
   public function getValueFromCookie(): string
   {
      $cookies = new Cookies(false);
      if ($cookies->has("CookieName")) {
         $cookie = $cookies->get("CookieName"); // this cause an fatal error
         // ... logic with $cookie
      }
   }
}

class Cookies extends AbstractInjectionAware implements CookiesInterface
{

    /**
     * Gets a cookie from the bag
     */
    public function get(string! name) -> <CookieInterface>
    {
        var container, encryption, cookie;

        /**
         * Gets cookie from the cookies service. They will be sent with response.
         */
        if fetch cookie, this->cookies[name] {
            return cookie;
        }

        /**
         * Create the cookie if the it does not exist.
         * It's value come from $_COOKIE with request, so it shouldn't be saved
         * to _cookies property, otherwise it will always be resent after get.
         */

        // ======================
        // ==> Here it's the line that cause the error, because this->container is null, so called the
        // method get produces a fatal error
        let cookie = <CookieInterface> this->container->get("Phalcon\\Http\\Cookie", [name]),
            container = this->container;

        // ==> Here it's ok, check if container it's an object, but it must be evaluated before
        if typeof container == "object" {
            /**
             * Pass the DI to created cookies
             */
            cookie->setDi(container);

            let encryption = this->useEncryption;

            /**
             * Enable encryption in the cookie
             */
            if encryption {
                cookie->useEncryption(encryption);
                cookie->setSignKey(this->signKey);
            }
        }

        return cookie;
    }
}

class Test 
{
   // ... another stuff
   public function getValueFromCookie(): string
   {
      $cookies = new Cookies(false);
      $cookies->setDI(Di::getDefault()); // this avoid the fatal error
      if ($cookies->has("CookieName")) {
         $cookie = $cookies->get("CookieName"); 
         // ... logic with $cookie
      }
   }
}