unableToBuildType(type: NSURL)

[wildthink]

The objCClassWrapper case is not supported in createInstance(...). Specifically, URL and NSURL were both tried.
Interestingly, it does work if the property is Optional.

(lldb) po kind
Runtime.Kind.objCClassWrapper

[wickwirew]

Taking a look now. As a temporary work around you should be able to make URL conform to DefaultConstructor, and you can tell it how to construct a default value for the object.

[wildthink]

Hey @wickwirew
So far I've learned that URL is a little exceptional in that it doesn't like to be empty.
But I did experiment with the Factory in my own fork (https://github.com/wildthink/Runtime) that is working but I have not yet done a lot of testing on it. I'm not sure this is a good solution; the Swift Runtime system is still new to me.