Assertion during enum compilation

### Description

The following code:

```php
<?php
enum y : string {
    case y = __FILE__;
}
```

Resulted in this output:
```
Zend/zend_compile.c:9712: zend_compile_const_expr_magic_const: Assertion `ast->attr == T_CLASS_C' failed.
Aborted (core dumped)
```

I'm not sure what this should produce. PHP-8.1 parser passes this code.


### PHP Version

master

### Operating System

*