While upgrading an app to Symfony 3.3 + Symfony Flex, I'm facing some issues. All of them look reasonable to me, except this one:

Fatal error: Uncaught Symfony\Component\DependencyInjection\Exception\EnvParameterException:

Environment variables "DATABASE_URL" are never used. Please, check your
container's configuration.

I think it's crazy to throw a fatal error just because I'm not using a defined env var. Could we please change this behavior? Thanks!