>>     However, the situation is complicated by the fact that not all foreign
>>     statuses are errors. Hence it would be misleading to make &foreign a
>>     subtype or &error. We could make it a subtype of &conditon as you
>>     suggest, but then foreign errors are not a subtype of &error.

> True, which is why I didn't want to introduce a new type, allowing
> foreign-status objects to belong to &error (or its parent
> &serious-condition) or just &condition depending on their semantics.

We could have &foreign (a subtype of &condition) and &foreign-error (a
subtype of &error) separately, and `foreign-status?` would test for
either of those. It's a bit iffy, but could be worse?