php-fig/fig-standards — pull request #222 by drak (2013-10-30 09:11:21+00:00)
Title: Use non-contravertial CS

Way back in the beginning of discussions we talked about not using any CS that was specifically omitted from PSR-2 so we don't endorse rival views.

This means

if (! isset($array[$key)) {
// ...
}

Should be written either as

if (isset($array[$key) === false) {
// ...
}

Or

if (false !== isset($array[$key)) {
// ...
}

I chose the latter simply because that is what is used a few lines up already.