tp_jit_01.php

<?php
class Foo {
    public ?string $p;
}
$a = new Foo;
$ref = &$a->p;
$ref[] = "bar";
echo "OPS!\n";

tp_jit_o2.php

<?php
$a = new class {
	public int $foo = 1;
};

$_ = [&$a->foo];

$_[0] += 1;
var_dump($a->foo);
$_[0] .= "1";
var_dump($a->foo);

$_[0] .= "e50";
var_dump($a->foo);

tp_jit_o3.php

<?php
$a = new class {
	public int $foo = 1;
};

$_ = &$a->foo;

$_ += 1;
var_dump($a->foo);
$_ .= "1";
var_dump($a->foo);
$_ .= "e50";
var_dump($a->foo);