Merge branch 'v8.5'

2 files changed, 38 insertions, 2 deletions

diff --git a/engine/evd.ml b/engine/evd.ml
index f414d71dc1..60b1da7049 100644
--- a/engine/evd.ml
+++ b/engine/evd.ml
@@ -330,9 +330,23 @@ let union_evar_universe_context ctx ctx' =
 
 type 'a in_evar_universe_context = 'a * evar_universe_context
 
-let evar_universe_context_set ctx = ctx.uctx_local
+let evar_universe_context_set diff ctx =
+  let initctx = ctx.uctx_local in
+  let cstrs =
+    Univ.LSet.fold
+      (fun l cstrs ->
+       try
+	 match Univ.LMap.find l ctx.uctx_univ_variables with
+	 | Some u -> Univ.Constraint.add (l, Univ.Eq, Option.get (Univ.Universe.level u)) cstrs
+	 | None -> cstrs
+       with Not_found | Option.IsNone -> cstrs)
+      (Univ.Instance.levels (Univ.UContext.instance diff)) Univ.Constraint.empty
+  in
+    Univ.ContextSet.add_constraints cstrs initctx 
+		      
 let evar_universe_context_constraints ctx = snd ctx.uctx_local
 let evar_context_universe_context ctx = Univ.ContextSet.to_context ctx.uctx_local
+    
 let evar_universe_context_of ctx = { empty_evar_universe_context with uctx_local = ctx }
 let evar_universe_context_subst ctx = ctx.uctx_univ_variables
 
@@ -564,6 +578,7 @@ type evar_map = {
                                              name) of the evar which
                                              will be instantiated with
                                              a term containing [e]. *)
+  extras : Store.t;
 }
 
 (*** Lifting primitive from Evar.Map. ***)
@@ -745,6 +760,7 @@ let empty = {
   evar_names = (EvMap.empty,Idmap.empty); (* id<->key for undefined evars *)
   future_goals = [];
   principal_future_goal = None;
+  extras = Store.empty;
 }
 
 let from_env ?ctx e = 
@@ -1320,6 +1336,7 @@ let set_metas evd metas = {
   evar_names = evd.evar_names;
   future_goals = evd.future_goals;
   principal_future_goal = evd.principal_future_goal;
+  extras = Store.empty;
 }
 
 let meta_list evd = metamap_to_list evd.metas
@@ -1468,6 +1485,12 @@ let dependent_evar_ident ev evd =
   | (_,Evar_kinds.VarInstance id) -> id
   | _ -> anomaly (str "Not an evar resulting of a dependent binding")
 
+(**********************************************************)
+(* Extra data *)
+
+let get_extra_data evd = evd.extras
+let set_extra_data extras evd = { evd with extras }
+
 (*******************************************************************)
 
 type pending = (* before: *) evar_map * (* after: *) evar_map
diff --git a/engine/evd.mli b/engine/evd.mli
index eca6d60ad5..f2d8a83350 100644
--- a/engine/evd.mli
+++ b/engine/evd.mli
@@ -310,6 +310,19 @@ val add_universe_constraints : evar_map -> Universes.universe_constraints -> eva
     @raises UniversesDiffer in case a first-order unification fails.
     @raises UniverseInconsistency
 *)
+
+(** {5 Extra data}
+
+  Evar maps can contain arbitrary data, allowing to use an extensible state.
+  As evar maps are theoretically used in a strict state-passing style, such
+  additional data should be passed along transparently. Some old and bug-prone
+  code tends to drop them nonetheless, so you should keep cautious.
+
+*)
+
+val get_extra_data : evar_map -> Store.t
+val set_extra_data : Store.t -> evar_map -> evar_map
+
 (** {5 Enriching with evar maps} *)
 
 type 'a sigma = {
@@ -462,7 +475,7 @@ val univ_flexible_alg : rigid
 
 type 'a in_evar_universe_context = 'a * evar_universe_context
 
-val evar_universe_context_set : evar_universe_context -> Univ.universe_context_set
+val evar_universe_context_set : Univ.universe_context -> evar_universe_context -> Univ.universe_context_set
 val evar_universe_context_constraints : evar_universe_context -> Univ.constraints
 val evar_context_universe_context : evar_universe_context -> Univ.universe_context
 val evar_universe_context_of : Univ.universe_context_set -> evar_universe_context