ontaining disallowed items
</li>
</ul>

<p>
So this is the only area where you have to distinguish different types of structs by looking at their implementation. Unfortunately, most structs that you migth want to use for persistent memory are disallowed because they contain references. This includes Nation, ForeignUnit, and Location. You have to fall back to IDs and single values here. The same of course counts for reference types like City. Also, this is the only part of your code that has to be unsafe. It