(module own_return_provenance_let

  (data Box
    (doc "Heap cell holding one Int.")
    (ctor Box (con Int)))

  (fn passthrough
    (doc "Already rejected today (consume-while-borrowed): own-return aliases a borrowed binder through a let.")
    (type
      (fn-type
        (params (borrow (con Box)))
        (ret (own (con Box)))))
    (params b)
    (body (let y b y))))
