[E018] Error: case `A\B\C\D\E\Foo::Baz` of backed enum `Foo` must have a value
   ,-[code.php:7:14]
   |
 5 | enum Foo: int {
   *      ^^^  
   *            
   * 
 7 |      case Baz;
   *           ^^^|  
   *              `-- try adding a value
   *                 
   *                  
---'