Steps to reproduce the issue

Brand new (Alpha4) installation with blog sample data installed, nothing else changed
In the admin menu select "Articles" and click on the first article (Your Template).

Expected result

Editor (should be TinyMCE, since I haven't changed any settings) shows up with the article in it

Actual result

No content displayed, only the error and stack trace below

( ! ) Fatal error: Cannot use Joomla\CMS\Language\Multilanguage as Multilanguage because the name is already in use in /home/mark/public_html/Development/J4_Alpha/administrator/components/com_content/Helper/PreviewHelper.php on line 18
Call Stack

Time Memory Function Location

1 0.0001 355792 {main}( ) .../index.php:0
2 0.0002 356272 require_once( '/home/mark/public_html/Development/J4_Alpha/administrator/includes/app.php' ) .../index.php:36
3 0.0193 1534768 Joomla\CMS\Application\AdministratorApplication->execute( ) .../app.php:38
4 0.0426 2195656 Joomla\CMS\Application\AdministratorApplication->doExecute( ) .../CMSApplication.php:238
5 0.0492 2552296 Joomla\CMS\Application\AdministratorApplication->dispatch( ) .../AdministratorApplication.php:149
6 0.0520 2645016 Joomla\CMS\Component\ComponentHelper::renderComponent( ) .../AdministratorApplication.php:106
7 0.0588 2798800 Joomla\CMS\Dispatcher\Dispatcher->dispatch( ) .../ComponentHelper.php:350
8 0.0595 2812704 Joomla\Component\Content\Administrator\Controller\DisplayController->execute( ) .../Dispatcher.php:161
9 0.0595 2812704 Joomla\Component\Content\Administrator\Controller\DisplayController->display( ) .../BaseController.php:710
10 0.0597 2812704 Joomla\Component\Content\Administrator\Controller\DisplayController->display( ) .../DisplayController.php:59
11 0.0609 2847248 Joomla\Component\Content\Administrator\View\Article\HtmlView->display( ) .../BaseController.php:672
12 0.0877 3027592 Joomla\Component\Content\Administrator\View\Article\HtmlView->addToolbar( ) .../HtmlView.php:106
13 0.1010 3229216 spl_autoload_call ( ) .../HtmlView.php:186
14 0.1010 3229312 JClassLoader->loadClass( ) .../HtmlView.php:186
15 0.1010 3229312 Composer\Autoload\ClassLoader->loadClass( ) .../loader.php:55
16 0.1010 3229472 Composer\Autoload\includeFile( ) .../ClassLoader.php:322

System information (as much as possible)

Localhost, Linux (Fedora 27).
PHP 7.1.21
MySQLi 5.5.5-10.2.17-MariaDB
Caching Disabled
Gzip Disabled
Users 1
Articles 6

Additional comments

While I have looked around the admin panel and looked at a couple of the pages, and displayed the welcome page of the front end, I have changed nothing. This is a completely fresh install.