> Can nil be somehow made illegal for owned refs only? Well we can enforce that every access like `r.field` is always guarded by a `r != nil` check. This currently seems to be the best solution which only recently became available with our precise control flow graphs in the compiler.
> Since immutable would be annotated to the ref type, it seems misplaced and/or > like a misnomer to me: We don't want the ref to be immutable but the object > it refers to, and the immutability is conditional. How about one of these: Ok, agreed. How about `.restricted`?
