Revert subst in branches of matches

Actually, it could be moved in susbt_in_problem,
hence doing it only once (on the deltas), instead
of replacing multiple times like now (useless).

(cherry picked from commit bd3a8ee424e495ab4003f6d4cb88579f29e3bc3a)

diff --git a/ocaml/num.ml b/ocaml/num.ml
index 66e8a2df7ccb6ebd3e3cf98f741b043d910c5bbe..56ae90ac24d254b9db91ee7d7dacaaffd77e483c 100644 (file)
--- a/ocaml/num.ml
+++ b/ocaml/num.ml
@@ -230,13 +230,16 @@ and subst truelam delift_by_one what (with_what : nf) (where : nf) =
    | `N _ as x -> x
    | `Match(t,v,bs_lift,bs,args) ->
        let bs_lift = bs_lift + if delift_by_one then -1 else 0 in
-       (* let l' = l - bs_lift  in *)
-       (* let with_what' = lift l' (with_what :> nf) in *)
+       (* Warning! It now applies again the substitution in branches of matches.
+          But careful, it does it many times, for every occurrence of
+          the match. This is okay because what does not occur in with_what. *)
+       let l' = l - bs_lift  in
+       let with_what' = lift l' (with_what :> nf) in
        (* The following line should be the identity when delift_by_one = true because we
           are assuming the ts to not contain lambda-bound variables. *)
-       (* bs := List.map (fun (n,t) -> n,subst truelam false what with_what' t) !bs ; *)
+       bs := List.map (fun (n,t) -> n,subst truelam false what with_what' t) !bs ;
        let body = cast_to_i_num_var (aux_i_num_var l t) in
-       mk_match body v bs_lift bs (List.map (aux l) args)
+       mk_match body v bs_lift bs (List.map (aux l) (args :> nf list))
  and aux l(*lift*) =
 (*function iii -> let res = match iii with*)
   function