private function validatePhpdoc($config): void
    {
        // Check that dirs key exists
        if (! Validator::key('phpdoc', Validator::arrayType())->validate($config)) {
            throw new InvalidConfigException('"phpdoc" parameter is not an array.');
        }
        // Validate each phpdoc
        if (! Validator::arrayVal()
            ->each(Validator::stringType(), Validator::stringType())->validate($config['phpdoc'])
        ) {
            throw new InvalidConfigException('Some annotation in "phpdoc" parameter are not strings.');
        }
    }