Basic borrowing is in place, but more is needed:
- if the borrowed value lives in mutable memory, we need to increase (temporarily) the ref count of boxes (or else prohibit this mutable memory from being changed and/or prohibit the borrowing).
- evec/estr borrowing does not type check nor trans. Not sure why the former doesn't work but the latter is just unimplemented.
Basic borrowing is in place, but more is needed: