[E033] Error: readonly property `Foo\Bar\Baz::$foo` cannot have a default value
   ,-[code.php:6:34]
   |
 5 | final class Baz {
   *             ^^^  
   *                   
 6 |      public readonly string $foo = "foo";
   *             ^^^^^^^^        ^^^^ |  
   *                                  |   
   *                                  |  
   *                                  |   
   *                                  |  
   *                                  `-- try removing this `=`
---'