private function getTypesContent()
    {
        if (null === $this->typesContent) {
            $name = $this->getTag()->getName();

            if (!$this->supportTypes()) {
                throw new \RuntimeException('This tag does not support types.');
            }

            $matchingResult = Preg::match(
                '{^(?:\s*\*|/\*\*)\s*@'.$name.'\s+'.self::REGEX_TYPES.'(?:[ \t].*)?$}sx',
                $this->lines[0]->getContent(),
                $matches
            );

            $this->typesContent = 1 === $matchingResult
                ? $matches['types']
                : '';
        }

        return $this->typesContent;
    }