memory leak with Lwt.catch

tail.ml

open Lwt

let do_something i =
  let x = Random.int 100 in
  Lwt_io.printlf "%i: x = %i"  i x >>= fun () ->
  if (x < 2)
  then Lwt.fail (Failure "kaboom")
  else Lwt.return ()

let rec loop1 i =
    Lwt.catch
      (fun () ->
       do_something i >>= fun () ->
       loop1 (i+1))
      (fun exn ->
       Lwt_io.printlf "%s" (Printexc.to_string exn) >>= fun () ->
       loop1 (i+1)
      )

let rec loop2 i =
  Lwt.catch
    (fun () -> do_something i)
    (fun exn -> Lwt_io.printlf "%s" (Printexc.to_string exn))
  >>= fun () ->
  loop2 (i+1)


let main () = loop2 0


let () = Lwt_main.run (main());;

If you run it with loop1, the memory keeps on growing.
The annotations (C-c C-f) tell you the recursive call on line 14 is a tail call.