[php-src] Issue #12631: Method to check if method overwritten in child class

Issue: https://github.com/php/php-src/issues/12631 Author: foremtehan ### Description It would be great if we could have a method that checks whether the child class overwritten the parent class's method https://3v4l.org/hTQWO As you can see in the above script, The method_exists return true even the method not overwritten in the child class, Not that passing static::class, self::class and $this don't solve the problem