What’s new in PHP 8.2

null, false, true ― standalone types

Wiki: https://wiki.php.net/rfc/null-false-standalone-types
Wiki: https://wiki.php.net/rfc/true-type

class Falsy
{
	public function alwaysFalse(): false { /* ... */ *}

	public function alwaysTrue(): true { /* ... */ *}

	public function alwaysNull(): null { /* ... */ *}
}

Dynamic properties of a class are deprecated

Doc: https://www.php.net/manual/ru/migration82.deprecated.php#migration82.deprecated.core.dynamic-properties
Wiki: https://wiki.php.net/rfc/deprecate_dynamic_properties

To help avoid errors and typos, it is no longer recommended to define dynamic properties.

Use the attribute #[\AllowDynamicProperties] on the class when you need to allow dynamic properties.

In stdClass instances dynamic properties are still allowed.

class User {
	public $name;
}

$user = new User();
$user->last_name = 'Doe'; // Deprecated notice

$user = new stdClass();
$user->last_name = 'Doe'; // Allowed

This change does not affect the use of magic methods __get()/__set().

Constants in traits

Doc: https://www.php.net/manual/ru/migration82.new-features.php#migration82.new-features.core.constant-in-traits
Wiki: https://wiki.php.net/rfc/constants_in_traits

You cannot access a constant via the trait name, but you can through the class that uses this trait:

trait Foo {
	public const CONSTANT = 1;
}

class Bar {
	use Foo;
}

var_dump( Bar::CONSTANT ); // 1
var_dump( Foo::CONSTANT ); // Error

—

Note embeded into: PHP 5.3 - 8.5 — Syntax, What's New