Nowadays I do mainly PHP7.x / Symfony projects and of all this list I would say only "ternary operator associativity" could potentially be a day to day concern,

Nowadays I do mainly PHP7.x / Symfony projects and of all this list I would say only "ternary operator associativity" could potentially be a day to day concern, and yes, empty() has gotchas. Nothing listed is false, sure, and I'm sure there's people doing complicated things with clever code like "declaring a function called __lambda_func() (which) completely breaks create_function()" but I have not encountered it in the wild, or not for a long time. Frankly I have more problems with Composer memory allocation in VM/containers than anything on this list.