[simonbyrne]

I'm not sure I understand: why would the C interop limit the design of the GC?

I didn't say Julia programmers don't have to worry about types, my comment was only about type annotations, though they are obviously related. Perhaps a better way to phrase it is: by worrying a little bit about types, you can generally avoid the need for type annotations. Hopefully as the tooling around the language matures, we can reduce the amount of worrying required.