Description:
------------
As per https://3v4l.org/aULpq , in PHP 7 this no longer seems to work:

<?php
function test($a, $b)
{
    $a **= $b;
}

class testClass
{
    public $a;
    private $b;

    function __construct()
    {
        $this->a = 98;
        $this->b = 4;
        $this->a **= $this->b;
    }
}

test(7, 3);
$a = new testClass;
echo $a->a;
?>

In PHP 5.6 (and HHVM), this correction produces: 92236816 whereas in PHP 7 it produces:

Fatal error: Invalid opcode 167/8/1. in /in/aULpq on line 18