[econstr] Continue consolidation of EConstr API under `interp`.

This commit was motivated by true spurious conversions arising in my
`to_constr` debug branch.

The changes here need careful review as the tradeoffs are subtle and
still a lot of clean up remains to be done in `vernac/*`.

We have opted for penalize [minimally] the few users coming from true
`Constr`-land, but I am sure we can tweak code in a much better way.

In particular, it is not clear if internalization should take an
`evar_map` even in the cases where it is not triggered, see the
changes under `plugins` for a good example.

Also, the new return type of `Pretyping.understand` should undergo
careful review.

We don't touch `Impargs` as it is not clear how to proceed, however,
the current type of `compute_implicits_gen` looks very suspicious as
it is called often with free evars.

Some TODOs are:

- impargs was calling whd_all, the Econstr equivalent can be either
  + Reductionops.whd_all [which does refolding and no sharing]
  + Reductionops.clos_whd_flags with all as a flag.

4 files changed, 10 insertions, 8 deletions

diff --git a/plugins/ltac/extratactics.ml4 b/plugins/ltac/extratactics.ml4
index 10be8a842..6a758ed1f 100644
--- a/plugins/ltac/extratactics.ml4
+++ b/plugins/ltac/extratactics.ml4
@@ -253,6 +253,7 @@ let add_rewrite_hint ~poly bases ort t lcsr =
   let sigma = Evd.from_env env in
   let f ce =
     let c, ctx = Constrintern.interp_constr env sigma ce in
+    let c = EConstr.to_constr sigma c in
     let ctx =
       let ctx = UState.context_set ctx in
         if poly then ctx
@@ -554,6 +555,7 @@ let add_transitivity_lemma left lem =
   let env = Global.env () in
   let sigma = Evd.from_env env in
   let lem',ctx (*FIXME*) = Constrintern.interp_constr env sigma lem in
+  let lem' = EConstr.to_constr sigma lem' in
   add_anonymous_leaf (inTransitivity (left,lem'))
 
 (* Vernacular syntax *)
@@ -611,8 +613,10 @@ END
 
 VERNAC COMMAND EXTEND RetroknowledgeRegister CLASSIFIED AS SIDEFF
  | [ "Register" constr(c) "as" retroknowledge_field(f) "by" constr(b)] ->
-           [ let tc,ctx = Constrintern.interp_constr (Global.env ()) Evd.empty c in
-             let tb,ctx(*FIXME*) = Constrintern.interp_constr (Global.env ()) Evd.empty b in
+           [ let tc,_ctx = Constrintern.interp_constr (Global.env ()) Evd.empty c in
+             let tb,_ctx(*FIXME*) = Constrintern.interp_constr (Global.env ()) Evd.empty b in
+             let tc = EConstr.to_constr Evd.empty tc in
+             let tb = EConstr.to_constr Evd.empty tb in
              Global.register f tc tb ]
 END
 
@@ -705,7 +709,6 @@ let hResolve id c occ t =
           resolve_hole (subst_hole_with_term loc_begin c_raw t_hole)
   in
   let t_constr,ctx = resolve_hole (subst_var_with_hole occ id t_raw) in
-  let t_constr = EConstr.of_constr t_constr in
   let sigma = Evd.merge_universe_context sigma ctx in
   let t_constr_type = Retyping.get_type_of env sigma t_constr in
   Proofview.tclTHEN (Proofview.Unsafe.tclEVARS sigma)
diff --git a/plugins/ltac/rewrite.ml b/plugins/ltac/rewrite.ml
index e73a18b79..3433987e3 100644
--- a/plugins/ltac/rewrite.ml
+++ b/plugins/ltac/rewrite.ml
@@ -1896,7 +1896,6 @@ let declare_projection n instance_id r =
 
 let build_morphism_signature env sigma m =
   let m,ctx = Constrintern.interp_constr env sigma m in
-  let m = EConstr.of_constr m in
   let sigma = Evd.from_ctx ctx in
   let t = Typing.unsafe_type_of env sigma m in
   let cstrs =
diff --git a/plugins/ltac/tacintern.ml b/plugins/ltac/tacintern.ml
index 22ec6c5b1..9a10fb805 100644
--- a/plugins/ltac/tacintern.ml
+++ b/plugins/ltac/tacintern.ml
@@ -199,7 +199,7 @@ let intern_constr_gen pattern_mode isarity {ltacvars=lfun; genv=env; extra} c =
     ltac_extra = extra;
   } in
   let c' =
-    warn (Constrintern.intern_gen scope ~pattern_mode ~ltacvars env) c
+    warn (Constrintern.intern_gen scope ~pattern_mode ~ltacvars env Evd.(from_env env)) c
   in
   (c',if !strict_check then None else Some c)
 
@@ -316,7 +316,7 @@ let intern_constr_pattern ist ~as_type ~ltacvars pc =
     ltac_extra = ist.extra;
   } in
   let metas,pat = Constrintern.intern_constr_pattern
-    ist.genv ~as_type ~ltacvars pc
+    ist.genv Evd.(from_env ist.genv) ~as_type ~ltacvars pc
   in
   let (glob,_ as c) = intern_constr_gen true false ist pc in
   let bound_names = Glob_ops.bound_glob_vars glob in
@@ -335,7 +335,7 @@ let intern_typed_pattern ist ~as_type ~ltacvars p =
           ltac_bound = Id.Set.empty;
           ltac_extra = ist.extra;
         } in
-      Constrintern.intern_constr_pattern ist.genv ~as_type ~ltacvars p
+      Constrintern.intern_constr_pattern ist.genv Evd.(from_env ist.genv) ~as_type ~ltacvars p
     else
       [], dummy_pat in
   let (glob,_ as c) = intern_constr_gen true false ist p in
diff --git a/plugins/ltac/tacinterp.ml b/plugins/ltac/tacinterp.ml
index 79b5c1622..6a04badf3 100644
--- a/plugins/ltac/tacinterp.ml
+++ b/plugins/ltac/tacinterp.ml
@@ -584,7 +584,7 @@ let interp_glob_closure ist env sigma ?(kind=WithoutTypeConstraint) ?(pattern_mo
         ltac_bound = Id.Map.domain ist.lfun;
         ltac_extra = Genintern.Store.empty;
       } in
-      { closure ; term = intern_gen kind ~pattern_mode ~ltacvars env term_expr }
+      { closure ; term = intern_gen kind ~pattern_mode ~ltacvars env sigma term_expr }
 
 let interp_uconstr ist env sigma c = interp_glob_closure ist env sigma c