Example of using the #[Friend] attribute from the PHP Language extensions library

Friend attribute example.php

// Example of the #[Friend] attribute available from https://github.com/DaveLiddament/php-language-extensions

class Person {

  #[Friend(PersonBuilder::class)]
  public function __construct() {}
}

class PersonBuilder {
  public function build(): Person {
    // OK: PersonBuilder is a friend of Person::__construct
    return new Person():
  }
}

class AnotherClass {
  public function doSomething(): void {
    // Error: Person::__construct can only be called by its friend: PersonBuilder
    $person = new Person();
  }
}