(module bug_unbound_in_instance_method
  (class Describe
    (param a)
    (method describe
      (type (fn-type (params (borrow a)) (ret (con Str))))))
  (instance
    (class Describe)
    (type (con Int))
    (method describe
      (body
        (lam
          (params (typed n (con Int)))
          (ret (con Str))
          (body (app format_label "n=" (app int_to_str n)))))))
  (fn main
    (type (fn-type (params) (ret (con Unit)) (effects IO)))
    (params)
    (body (do io/print_str (app describe 5)))))