By default after installation of php7 the display_erros is setting to off.
How to modifi it in php.ini configuration?
If you are using linux probably in /etc/php/7.0/apache2/php.ini (if you are using php directly from terminal you need to change the /etc/php/7.0/cli/php.ini)
change it to
In addition, change the error_reporting to the correct value, i use E_ALL in my developing server!
Now, restart apache and voilá