3 files changed, 19 insertions, 2 deletions
diff --git a/plugins/extraction/mlutil.ml b/plugins/extraction/mlutil.ml
index 2b6122cd3..321af2946 100644
--- a/plugins/extraction/mlutil.ml
+++ b/plugins/extraction/mlutil.ml
@@ -285,13 +285,13 @@ let type_simpl = type_expand (fun _ -> None)
 (*s Generating a signature from a ML type. *)
 
 let type_to_sign env t = match type_expand env t with
-  | Tdummy d -> Kill d
+  | Tdummy d when not (conservative_types ()) -> Kill d
   | _ -> Keep
 
 let type_to_signature env t =
   let rec f = function
     | Tmeta {contents = Some t} -> f t
-    | Tarr (Tdummy d, b) -> Kill d :: f b
+    | Tarr (Tdummy d, b) when not (conservative_types ())  -> Kill d :: f b
     | Tarr (_, b) -> Keep :: f b
     | _ -> []
   in f (type_expand env t)
diff --git a/plugins/extraction/table.ml b/plugins/extraction/table.ml
index d785fdde9..3fb183995 100644
--- a/plugins/extraction/table.ml
+++ b/plugins/extraction/table.ml
@@ -533,6 +533,19 @@ let _ = declare_int_option
                           | None -> chg_flag 0
                           | Some i -> chg_flag (max i 0))}
 
+(* This option controls whether "dummy lambda" are removed when a
+   toplevel constant is defined. *)
+let conservative_types_ref = ref false
+let conservative_types () = !conservative_types_ref
+
+let _ = declare_bool_option
+  {optsync = true;
+   optdepr = false;
+   optname = "Extraction Conservative Types";
+   optkey = ["Extraction"; "Conservative"; "Types"];
+   optread = (fun () -> !conservative_types_ref);
+   optwrite = (fun b -> conservative_types_ref := b) }
+
 
 (*s Extraction Lang *)
 
diff --git a/plugins/extraction/table.mli b/plugins/extraction/table.mli
index 060abf804..b17f83715 100644
--- a/plugins/extraction/table.mli
+++ b/plugins/extraction/table.mli
@@ -132,6 +132,10 @@ type opt_flag =
 
 val optims :  unit -> opt_flag
 
+(*s Controls whether dummy lambda are removed *)
+
+val conservative_types : unit -> bool
+
 (*s Target language. *)
 
 type lang = Ocaml | Haskell | Scheme