Fatal error: Uncaught Error: Call to undefined function Composer\Autoload\array_merge() in /var/www/html/vendor/composer/ClassLoader.php:258 Stack trace: #0 /var/www/html/vendor/magento/framework/Autoload/ClassLoaderWrapper.php(35): Composer\Autoload\ClassLoader->addPsr4('Magento\\', Array, true) #1 /var/www/html/vendor/magento/framework/Autoload/Populator.php(26): Magento\Framework\Autoload\ClassLoaderWrapper->addPsr4('Magento\\', Array, true) #2 /var/www/html/vendor/magento/framework/App/Bootstrap.php(141): Magento\Framework\Autoload\Populator::populateMappings(Object(Magento\Framework\Autoload\ClassLoaderWrapper), Object(Magento\Framework\App\Filesystem\DirectoryList)) #3 /var/www/html/app/bootstrap.php(45): Magento\Framework\App\Bootstrap::populateAutoloader('/var/www/html', Array) #4 /var/www/html/pub/index.php(12): require('/var/www/html/a...') #5 {main} thrown in /var/www/html/vendor/composer/ClassLoader.php on line 258