Remove the hacks relying on hardwired libobject tags.

The patch is done in a minimal way. The hacks are turned into a new kind of
safer hacks, but hacks nonetheless. They should go away at some point, but
the current patch is focussed on the removal of Libobject cruft, not making
the dirty code of its upper-layer callers any cleaner.

2 files changed, 20 insertions, 5 deletions

diff --git a/tactics/declare.ml b/tactics/declare.ml
index da4de3df77..133b26a99d 100644
--- a/tactics/declare.ml
+++ b/tactics/declare.ml
@@ -130,8 +130,8 @@ let dummy_constant cst = {
 
 let classify_constant cst = Substitute (dummy_constant cst)
 
-let (inConstant : constant_obj -> obj) =
-  declare_object { (default_object "CONSTANT") with
+let (objConstant : constant_obj Libobject.Dyn.tag) =
+  declare_object_full { (default_object "CONSTANT") with
     cache_function = cache_constant;
     load_function = load_constant;
     open_function = open_constant;
@@ -139,6 +139,8 @@ let (inConstant : constant_obj -> obj) =
     subst_function = ident_subst_function;
     discharge_function = discharge_constant }
 
+let inConstant v = Libobject.Dyn.Easy.inj v objConstant
+
 let update_tables c =
   Impargs.declare_constant_implicits c;
   Notation.declare_ref_arguments_scope Evd.empty (GlobRef.ConstRef c)
@@ -357,10 +359,12 @@ type variable_declaration =
 
 (* This object is only for things which iterate over objects to find
    variables (only Prettyp.print_context AFAICT) *)
-let inVariable : unit -> obj =
-  declare_object { (default_object "VARIABLE") with
+let objVariable : unit Libobject.Dyn.tag =
+  declare_object_full { (default_object "VARIABLE") with
     classify_function = (fun () -> Dispose)}
 
+let inVariable v = Libobject.Dyn.Easy.inj v objVariable
+
 let declare_variable ~name ~kind d =
   (* Constr raisonne sur les noms courts *)
   if Decls.variable_exists name then
@@ -497,4 +501,9 @@ module Internal = struct
     ; proof_entry_type = Some typ
     }, args
 
+  type nonrec constant_obj = constant_obj
+
+  let objVariable = objVariable
+  let objConstant = objConstant
+
 end
diff --git a/tactics/declare.mli b/tactics/declare.mli
index c646d2f85b..00c1e31717 100644
--- a/tactics/declare.mli
+++ b/tactics/declare.mli
@@ -131,7 +131,8 @@ val check_exists : Id.t -> unit
 (* Used outside this module only in indschemes *)
 exception AlreadyDeclared of (string option * Id.t)
 
-(* For legacy support, do not use *)
+(** {6 For legacy support, do not use}  *)
+
 module Internal : sig
 
   val map_entry_body : f:('a Entries.proof_output -> 'b Entries.proof_output) -> 'a proof_entry -> 'b proof_entry
@@ -145,4 +146,9 @@ module Internal : sig
 
   val shrink_entry : EConstr.named_context -> 'a proof_entry -> 'a proof_entry * Constr.constr list
 
+  type constant_obj
+
+  val objConstant : constant_obj Libobject.Dyn.tag
+  val objVariable : unit Libobject.Dyn.tag
+
 end