Doctrine\Common\Proxy\ProxyGenerator::getParameterType PHP Method

    private function getParameterType(ClassMetadata $class, \ReflectionMethod $method, \ReflectionParameter $parameter)
    {
        if (method_exists($parameter, 'hasType')) {
            if (!$parameter->hasType()) {
                return '';
            }
            return $this->formatType($parameter->getType(), $parameter->getDeclaringFunction(), $parameter);
        }
        // For PHP 5.x, we need to pick the type hint in the old way (to be removed for PHP 7.0+)
        if ($parameter->isArray()) {
            return 'array';
        }
        if ($parameter->isCallable()) {
            return 'callable';
        }
        try {
            $parameterClass = $parameter->getClass();
            if ($parameterClass) {
                return '\\' . $parameterClass->getName();
            }
        } catch (\ReflectionException $previous) {
            throw UnexpectedValueException::invalidParameterTypeHint($class->getName(), $method->getName(), $parameter->getName(), $previous);
        }
        return null;
    }