Strange this error is append with PHP version doesn’t not support this syntax. Array can be used in Const since PHP 5.6 and Array can be used in Define since PHP 7. (You can read PHP documentation)
Are you sure your PHP version is the same in all folders on your server ? Sometime people use PHP 7 on admin folder and PHP 5 in others. This can be configured in htaccess for example.
Check on Prestashop back office -> Advanced Parameters -> Informations. You can read PHP version running with Prestashop.
Ask your hosting provider : tell him your error and link to PHP documentation https://www.tutorialspoint.com/php7/php7_constant_arrays.htm
About your current PHP version and current PrestaShop version : you should not use PHP 7.2 with Prestashop 1.7.4, we know about issue with it. You can use PHP 7.1 max : https://devdocs.prestashop.com/1.7/basics/installation/system-requirements/