I got the following error in the console, when using a translation within a twig file (not sure if it's only in twig):

Cannot declare class Locale, because the name is already in use.

Exception trace:
 () at /var/www/domains/rsaleads/vendor/symfony/symfony/src/Symfony/Component/Intl/Resources/stubs/Locale.php:23

Info about environment:

PHP 7.0.13-1+deb.sury.org~xenial+1 (cli) ( NTS )
Symfony 3.0.1