<?php
$a = 0;
var_dump($a++ + ($a += 2));
echo "------------\n";
$a = 0;
var_dump($a++ + $a += 2);
echo "------------\n";
$a = 0;
$b = $a++;
$c = $a += 2;
var_dump($a, $b, $c, $b + $c);
echo "------------\n";
$a = 0;
$c = $a += 2;
$b = $a++;
var_dump($a, $b, $c, $b + $c);

//https://pt.stackoverflow.com/q/226847/101