Be compatible with OCaml 4.14

lib/ptt_aggregate.ml

@@ -89,9 +89,9 @@ let to_recipients ~info recipients =
   let by_domains, by_ipaddrs = aggregate_by_domains ~info recipients in
   let by_domains = List.map (fun (domain, locals) ->
     let domain = `Domain domain in
-    Ptt_sendmail.{ domain; locals }) (By_domain.to_list by_domains) in
+    Ptt_sendmail.{ domain; locals }) (By_domain.bindings by_domains) in
   let by_ipaddrs = List.map (fun (ipaddr, locals) ->
     let domain = `Ipaddr ipaddr in
     let locals = (locals :> [ `Some of Emile.local list | `Postmaster | `All]) in
-    Ptt_sendmail.{ domain; locals }) (By_ipaddr.to_list by_ipaddrs) in
+    Ptt_sendmail.{ domain; locals }) (By_ipaddr.bindings by_ipaddrs) in
   List.rev_append by_domains by_ipaddrs

lib/ptt_common.ml

@@ -53,7 +53,7 @@ let recipients_are_reachable ~info dns resolver recipients =
           | Ok domain_name -> Set.add domain_name acc
           | Error _ -> raise (Invalid_recipients value))
       Set.empty recipients
-    |> Set.to_list in
+    |> Set.elements in
   let ( let* ) = Lwt.bind in
   let mail_exchange_are_reachable { Dns.Mx.mail_exchange; _ } =
     let* result = resolver.gethostbyname dns mail_exchange in
@@ -64,7 +64,7 @@ let recipients_are_reachable ~info dns resolver recipients =
     let* result = resolver.getmxbyname dns domain in
     match result with
     | Ok mxs ->
-        let lst = Dns.Rr_map.Mx_set.to_list mxs in
+        let lst = Dns.Rr_map.Mx_set.elements mxs in
         let lst = List.sort Dns.Mx.compare lst in
         Lwt_list.exists_p mail_exchange_are_reachable lst
     | Error _ -> Lwt.return false in

lib/ptt_map.ml

@@ -62,4 +62,4 @@ let expand ~info t recipients =
         | None -> []
       else [ recipient ]) recipients
   |> List.concat
-  |> Set.of_list |> Set.to_list
+  |> Set.of_list |> Set.elements

lib/ptt_sendmail.ml

@@ -171,14 +171,14 @@ module Make
                 | Error (`Msg msg) ->
                   warn_about_an_unreachable_mail_exchange ~domain ~mail_exchange msg;
                   Lwt.return acc end in
-            resolve (Dns.Rr_map.Mx_set.to_list mxs) >|= Mxs.vs >|= Result.ok
+            resolve (Dns.Rr_map.Mx_set.elements mxs) >|= Mxs.vs >|= Result.ok
         | Error _ as err -> Lwt.return err end >>= function
     | Error _ -> no_mail_exchange_service elt
     | Ok mxs ->
       if Mxs.is_empty mxs
       then no_mail_exchange_service elt
       else
-        let mxs = Mxs.to_list mxs in
+        let mxs = Mxs.bindings mxs in
         let rec go = function
           | [] ->
               (* NOTE(dinosaure): we verified that [mxs] contains at least one
@@ -207,7 +207,7 @@ module Make
     | None -> Lwt.return_unit
 
   let v
-    : type a. resolver:_ -> ?pool:pool -> info:Ptt_common.info -> Tls.Config.client -> _
+    : resolver:_ -> ?pool:pool -> info:Ptt_common.info -> Tls.Config.client -> _
     = fun ~resolver ?pool ~info tls ->
     let stream, push = Lwt_stream.create () in
     { stream; push; info; resolver; tls; pool }, push

ptt-bin.opam

@@ -11,7 +11,7 @@ homepage: "https://github.com/mirage/ptt"
 doc: "https://mirage.github.io/ptt/"
 bug-reports: "https://github.com/mirage/ptt/issues"
 depends: [
-  "ocaml"             {>= "4.07.0"}
+  "ocaml"             {>= "4.14.0"}
   "dune"
   "ptt"               {= version}
   "bos"

ptt.opam

@@ -11,7 +11,7 @@ homepage: "https://github.com/mirage/ptt"
 doc: "https://mirage.github.io/ptt/"
 bug-reports: "https://github.com/mirage/ptt/issues"
 depends: [
-  "ocaml"             {>= "4.07.0"}
+  "ocaml"             {>= "4.14.0"}
   "dune"
   "mrmime"
   "digestif"