Hal\Pattern\Resolver\Creational\Singleton\SingletonResolver::resolve PHP Method

    public function resolve(ResolvedClass $resolved)
    {
        $class = $resolved->getClass();
        $pattern = new Singleton($class->getFullname());
        $methods = $class->getMethods();
        // private construct ?
        if (isset($methods['__construct']) && $methods['__construct']->getVisibility() !== ReflectedMethod::VISIBILITY_PUBLIC) {
            // static method ?
            foreach ($methods as $method) {
                if ($method->getState() === ReflectedMethod::STATE_STATIC) {
                    // call itself ?
                    $deps = $method->getReturns();
                    foreach ($deps as $dep) {
                        if (in_array($dep->getType(), array('\\self', '\\static', $class->getFullname()))) {
                            // yes, class is a singleton
                            $resolved->pushPattern($pattern);
                            return;
                        }
                    }
                }
            }
        }
    }