I've not run into too many, you just have to be careful around re-entrancy from Wren->C->Wren, and slot allocation in foreign constructors. There's some big st

I've not run into too many, you just have to be careful around re-entrancy from Wren->C->Wren, and slot allocation in foreign constructors. There's some big stuff in the pipeline, so I'm sure it'll be enhanced soon enough.