PHP 8.0 comes with enhancements improvements and new features

htmlspecialchars($string, ENT_COMPAT | ENT_HTML401, 'UTF-8', false);

htmlspecialchars($string, double_encode: false);

class PostsController
{
    /**
     * @Route("/api/posts/{id}", methods={"GET"})
     */
    public function get($id) { /* ... */ }
}

class PostsController
{
    #[Route("/api/posts/{id}", methods: ["GET"])]
    public function get($id) { /* ... */ }
}

class Point {
  public float $x;
  public float $y;
  public float $z;
  public function __construct(
    float $x = 0.0,
    float $y = 0.0,
    float $z = 0.0,
  ) {
    $this->x = $x;
    $this->y = $y;
    $this->z = $z;
  }
}

class Point {
  public function __construct(
    public float $x = 0.0,
    public float $y = 0.0,
    public float $z = 0.0,
  ) {}
}

class Number {
  /** @var int|float */
  private $number;
  /**
   * @param float|int $number
   */
  public function __construct($number) {
    $this->number = $number;
  }
}
new Number('NaN'); // Ok

class Number {
  public function __construct(
    private int|float $number
  ) {}
}
new Number('NaN'); // TypeError

switch (8.0) {
  case '8.0':
    $result = "Oh no!";
    break;
  case 8.0:
    $result = "This is what I expected";
    break;
}
echo $result;
//> Oh no!

echo match (8.0) {
  '8.0' => "Oh no!",
  8.0 => "This is what I expected",
};
//> This is what I expected

$country =  null;
if ($session !== null) {
  $user = $session->user;
  if ($user !== null) {
    $address = $user->getAddress();
    if ($address !== null) {
      $country = $address->country;
    }
  }
}

$country = $session?->user?->getAddress()?->country;

0 == 'foobar' // true

0 == 'foobar' // false

strlen([]); // Warning: strlen() expects parameter 1 to be string, array given
array_chunk([], -1); // Warning: array_chunk(): Size parameter expected to be greater than 0

strlen([]); // TypeError: strlen(): Argument #1 ($str) must be of type string, array given
array_chunk([], -1); // ValueError: array_chunk(): Argument #2 ($length) must be greater than 0