PHP: Copy On Write and Assign By Reference perform different on PHP5 and PHP7

Question

We have a piece of simple code:

1    

On PHP5, it outputs 8, because:

Answer 1

I'd say the way it works in PHP7 is the right way. It's bad to implicitly change the way operators work depending whether operand is referenced anywhere or not.

This is the best thing about PHP7 being completely rewritten: no clumsy/bug-driven-development v4/v5 code will work.