(module test_22c_user_class_e2e
  (data IntBox
    (ctor MkIntBox (con Int)))
  (class Foo
    (param a)
    (method foo
      (type (fn-type (params (borrow a)) (ret (own (con Int)))))))
  (instance
    (class Foo)
    (type (con IntBox))
    (method foo
      (body (lam (params (typed b a)) (ret (con Int)) (body (match b
        (case (pat-ctor MkIntBox v) v)))))))
  (fn main
    (type (fn-type (params) (ret (own (con Unit))) (effects IO)))
    (params)
    (body (app print (app foo (term-ctor IntBox MkIntBox 42))))))