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