2 files changed, 19 insertions, 2 deletions
diff --git a/engine/proofview.ml b/engine/proofview.ml
index 22271dd02..639f48e77 100644
--- a/engine/proofview.ml
+++ b/engine/proofview.ml
@@ -710,13 +710,19 @@ let partition_unifiable sigma l =
 (** Shelves the unifiable goals under focus, i.e. the goals which
     appear in other goals under focus (the unfocused goals are not
     considered). *)
-let shelve_unifiable =
+let shelve_unifiable_informative =
   let open Proof in
   Pv.get >>= fun initial ->
   let (u,n) = partition_unifiable initial.solution initial.comb in
   Comb.set n >>
   InfoL.leaf (Info.Tactic (fun () -> Pp.str"shelve_unifiable")) >>
-  Shelf.modify (fun gls -> gls @ CList.map drop_state u)
+  let u = CList.map drop_state u in
+  Shelf.modify (fun gls -> gls @ u) >>
+  tclUNIT u
+
+let shelve_unifiable =
+  let open Proof in
+  shelve_unifiable_informative >>= fun _ -> tclUNIT ()
 
 (** [guard_no_unifiable] returns the list of unifiable goals if some
     goals are unifiable (see {!shelve_unifiable}) in the current focus. *)
@@ -1035,6 +1041,8 @@ module Unsafe = struct
 
   let advance = Evarutil.advance
 
+  let undefined = undefined
+
   let mark_as_unresolvable p gl =
     { p with solution = mark_in_evm ~goal:false p.solution gl }
 
diff --git a/engine/proofview.mli b/engine/proofview.mli
index e7be66552..1905686fe 100644
--- a/engine/proofview.mli
+++ b/engine/proofview.mli
@@ -326,6 +326,9 @@ val unifiable : Evd.evar_map -> Evar.t -> Evar.t list -> bool
     considered). *)
 val shelve_unifiable : unit tactic
 
+(** Idem but also returns the list of shelved variables *)
+val shelve_unifiable_informative : Evar.t list tactic
+
 (** [guard_no_unifiable] returns the list of unifiable goals if some
     goals are unifiable (see {!shelve_unifiable}) in the current focus. *)
 val guard_no_unifiable : Names.Name.t list option tactic
@@ -466,6 +469,12 @@ module Unsafe : sig
       solved. *)
   val advance : Evd.evar_map -> Evar.t -> Evar.t option
 
+  (** [undefined sigma l] applies [advance] to the goals of [l], then
+      returns the subset of resulting goals which have not yet been
+      defined *)
+  val undefined : Evd.evar_map -> Proofview_monad.goal_with_state list ->
+    Proofview_monad.goal_with_state list
+
   val typeclass_resolvable : unit Evd.Store.field
 
 end