--TEST--
$this in isset
--FILE--
<?php
var_dump(isset($this));
try {
    var_dump(isset($this->foo));
} catch (Throwable $e) {
    echo "exception\n";
}
try {
    var_dump(isset($this->foo->bar));
} catch (Throwable $e) {
    echo "exception\n";
}
try {
    var_dump(isset($this[0]));
} catch (Throwable $e) {
    echo "exception\n";
}

class A extends ArrayObject {
    public $foo = 5;
    function foo() {
        $this[0] = 5;
        var_dump(isset($this));
        var_dump(isset($this->foo));
        var_dump(isset($this[0]));
    }
}
$a = new A();
$a->foo();
?>
--EXPECT--
bool(false)
exception
exception
exception
bool(true)
bool(true)
bool(true)