Avoid type checking private_constants (side_eff) again during Qed (#4357).

Side effects are now an opaque data type, called private_constant, you can
only obtain from safe_typing.  When add_constant is called on a
definition_entry that contains private constants, they are either
- inlined in the main proof term but not re-checked
- declared globally without re-checking them
As a safety measure, the opaque data type contains a pointer to the
revstruct (an internal field of safe_env that changes every time a new
constant is added), and such pointer is compared with the current value
store in safe_env when the private_constant is inlined.  Only when the
comparison is successful the private_constant is not re-checked.  Otherwise
else it is.  In short, we accept into the kernel private constant only
when they arrive in the very same order and on top of the very same env
they arrived when we fist checked them.

Note: private_constants produced by workers never pass the safety
measure (the revstruct pointer is an Ephemeron).  Sending back the
entire revstruct is possible but: 1. we lack a way to quickly compare
two revstructs, 2. it can be large.

1 files changed, 10 insertions, 10 deletions

diff --git a/tactics/elimschemes.ml b/tactics/elimschemes.ml
index e6a8cbe3a..8a6d93cf7 100644
--- a/tactics/elimschemes.ml
+++ b/tactics/elimschemes.ml
@@ -52,7 +52,7 @@ let optimize_non_type_induction_scheme kind dep sort _ ind =
     let ctxset = Univ.ContextSet.of_context ctx in
     let ectx = Evd.evar_universe_context_of ctxset in
     let sigma, c = build_induction_scheme env (Evd.from_ctx ectx) (ind,u) dep sort in
-      (c, Evd.evar_universe_context sigma), Declareops.no_seff
+      (c, Evd.evar_universe_context sigma), Safe_typing.empty_private_constants
 
 let build_induction_scheme_in_type dep sort ind =
   let env = Global.env () in
@@ -68,15 +68,15 @@ let build_induction_scheme_in_type dep sort ind =
  
 let rect_scheme_kind_from_type =
   declare_individual_scheme_object "_rect_nodep"
-    (fun _ x -> build_induction_scheme_in_type false InType x, Declareops.no_seff)
+    (fun _ x -> build_induction_scheme_in_type false InType x, Safe_typing.empty_private_constants)
 
 let rect_scheme_kind_from_prop =
   declare_individual_scheme_object "_rect" ~aux:"_rect_from_prop"
-    (fun _ x -> build_induction_scheme_in_type false InType x, Declareops.no_seff)
+    (fun _ x -> build_induction_scheme_in_type false InType x, Safe_typing.empty_private_constants)
 
 let rect_dep_scheme_kind_from_type =
   declare_individual_scheme_object "_rect" ~aux:"_rect_from_type"
-    (fun _ x -> build_induction_scheme_in_type true InType x, Declareops.no_seff)
+    (fun _ x -> build_induction_scheme_in_type true InType x, Safe_typing.empty_private_constants)
 
 let ind_scheme_kind_from_type =
   declare_individual_scheme_object "_ind_nodep"
@@ -109,24 +109,24 @@ let build_case_analysis_scheme_in_type dep sort ind =
 
 let case_scheme_kind_from_type =
   declare_individual_scheme_object "_case_nodep"
-  (fun _ x -> build_case_analysis_scheme_in_type false InType x, Declareops.no_seff)
+  (fun _ x -> build_case_analysis_scheme_in_type false InType x, Safe_typing.empty_private_constants)
 
 let case_scheme_kind_from_prop =
   declare_individual_scheme_object "_case" ~aux:"_case_from_prop"
-  (fun _ x -> build_case_analysis_scheme_in_type false InType x, Declareops.no_seff)
+  (fun _ x -> build_case_analysis_scheme_in_type false InType x, Safe_typing.empty_private_constants)
 
 let case_dep_scheme_kind_from_type =
   declare_individual_scheme_object "_case" ~aux:"_case_from_type"
-  (fun _ x -> build_case_analysis_scheme_in_type true InType x, Declareops.no_seff)
+  (fun _ x -> build_case_analysis_scheme_in_type true InType x, Safe_typing.empty_private_constants)
 
 let case_dep_scheme_kind_from_type_in_prop =
   declare_individual_scheme_object "_casep_dep"
-  (fun _ x -> build_case_analysis_scheme_in_type true InProp x, Declareops.no_seff)
+  (fun _ x -> build_case_analysis_scheme_in_type true InProp x, Safe_typing.empty_private_constants)
 
 let case_dep_scheme_kind_from_prop =
   declare_individual_scheme_object "_case_dep"
-  (fun _ x -> build_case_analysis_scheme_in_type true InType x, Declareops.no_seff)
+  (fun _ x -> build_case_analysis_scheme_in_type true InType x, Safe_typing.empty_private_constants)
 
 let case_dep_scheme_kind_from_prop_in_prop =
   declare_individual_scheme_object "_casep"
-  (fun _ x -> build_case_analysis_scheme_in_type true InProp x, Declareops.no_seff)
+  (fun _ x -> build_case_analysis_scheme_in_type true InProp x, Safe_typing.empty_private_constants)