diff --git a/bytecomp/matching.ml b/bytecomp/matching.ml
index afec0f5..94797d8 100644
--- a/bytecomp/matching.ml
+++ b/bytecomp/matching.ml
@@ -2484,21 +2484,44 @@ and compile_no_test divide up_ctx repr partial ctx to_match =
 (* The entry points *)

 (*
-   If there is a guard in a matching, then
-   set exhaustiveness info to Partial.
-   (because of side effects in guards, assume the worst)
+   If there is a guard in a matching or a lazy pattern,
+   then set exhaustiveness info to Partial.
+   (because of side effects, assume the worst)
 *)

-let check_partial pat_act_list partial =
+let rec is_lazy p = match p.pat_desc with
+| Tpat_alias (p, _ ,_ ) ->
+    is_lazy p
+| Tpat_tuple pats ->
+    List.exists is_lazy pats
+| Tpat_record (lpats,_) ->
+    List.exists
+      (fun (_, _, p) -> is_lazy p)
+      lpats
+| Tpat_construct (_, _, pats,_) ->
+    List.exists is_lazy pats
+| Tpat_array pats ->
+    List.exists is_lazy pats
+| Tpat_variant (_, Some p, _) ->
+    is_lazy p
+| Tpat_or (p, q, _) ->
+    is_lazy p || is_lazy q
+| Tpat_lazy p -> true
+| Tpat_constant _ | Tpat_var _
+| Tpat_any | Tpat_variant (_,None,_) -> false
+
+let check_partial is_lazy pat_act_list partial =
   if
     List.exists
-      (fun (_,lam) -> is_guarded lam)
+      (fun (pats, lam) -> is_guarded lam || is_lazy pats)
        pat_act_list
   then begin
     Partial
   end else
     partial

+let check_partial_list = check_partial (List.exists is_lazy)
+let check_partial = check_partial is_lazy

 (* have toplevel handler when appropriate *)

@@ -2561,7 +2584,7 @@ let for_let loc param pat body =

 (* Easy case since variables are available *)
 let for_tupled_function loc paraml pats_act_list partial =
-  let partial = check_partial pats_act_list partial in
+  let partial = check_partial_list pats_act_list partial in
   let raise_num = next_raise_count () in
   let omegas = [List.map (fun _ -> omega) paraml] in
   let pm =