Since 2016-12-28, the «var/generation» folder has been renamed to «generated/code» in Magento 2.2

dmitrii_fediuk (Dmitrii Fediuk) January 20, 2017, 11:48pm 2

See also:

How to fix the «Can’t create directory ‘generated/code’ in Magento/Framework/Code/Generator.php» Magento 2.2 issue?