Steps to reproduce the issue

Attempt to Install latest branch of Joomla after composer install and npm install

Expected result

Go to Joomla install process

Actual result

Fatal error: Cannot use Joomla\CMS\Factory as Factory because the name is already in use in C:\xxx\joomla-cms\libraries\src\Document\HtmlDocument.php on line 18

System information (as much as possible)

PHP 7.1.20

Additional comments

Each Document class uses Joomla\CMS\Factory, Factory is already assigned to Joomla\CMS\Document\Factory.

I updated the use statement to use Joomla\CMS\Factory as FactoryCMS and updated each reference to FactoryCMS in each of the Document classes which seems to fix it. I'm not sure if making this change has caused other side effects?