matching: use toplevel_handler in for_tupled_function

This appears to change the function behavior with respect to the
Unused exception, but we believe that the change is correct. It makes
the code more consistent with other toplevel compilation functions.

lambda/matching.ml

@@ -3662,23 +3662,14 @@ let for_let ~scopes loc param pat body =
 (* Easy case since variables are available *)
 let for_tupled_function ~scopes loc paraml pats_act_list partial =
   let partial = check_partial_list pats_act_list partial in
-  let raise_num = next_raise_count () in
-  let omega_params = [ Patterns.omega_list paraml ] in
-  let pm =
-    { cases = pats_act_list;
-      args = List.map (fun id -> (Lvar id, Strict)) paraml;
-      default = Default_environment.(cons omega_params raise_num empty)
-    }
-  in
-  try
-    let lambda, total =
-      compile_match ~scopes None partial
-        (Context.start (List.length paraml)) pm
-    in
-    check_total ~scopes loc ~failer:Raise_match_failure
-      total lambda raise_num
-  with Unused ->
-    failure_handler ~scopes loc ~failer:Raise_match_failure ()
+  let args = List.map (fun id -> (Lvar id, Strict)) paraml in
+  let handler =
+    toplevel_handler ~scopes loc ~failer:Raise_match_failure
+      partial args pats_act_list in
+  handler (fun partial pm ->
+    compile_match ~scopes None partial
+      (Context.start (List.length paraml)) pm
+  )
 
 let flatten_pattern size p =
   match p.pat_desc with