[E037] Error: property `Foo::$s` cannot have type `void`
   ,-[code.php:5:16]
   |
 3 | class Foo {
   *       ^^^  
   *             
   * 
 5 |         public void $s,
   *                ^^|^ ^^  
   *                  |       
   *                  |      
   *                  `------ try using a different type
   * 
   * Note: `void`, `never`, and `callable` types are not allowed in properties
---'