[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.

1 files changed, 4 insertions, 3 deletions

diff --git a/engine/termops.mli b/engine/termops.mli
index a3559a693b..5aa6235f5c 100644
--- a/engine/termops.mli
+++ b/engine/termops.mli
@@ -76,9 +76,10 @@ val fold_constr_with_full_binders : Evd.evar_map ->
   (Context.Rel.Declaration.t -> 'a -> 'a) -> ('a -> 'b -> constr -> 'b) ->
     'a -> 'b -> constr -> 'b
 
-val iter_constr_with_full_binders :
-  (Context.Rel.Declaration.t -> 'a -> 'a) -> ('a -> Constr.constr -> unit) -> 'a ->
-    Constr.constr -> unit
+val iter_constr_with_full_binders : Evd.evar_map ->
+  (rel_declaration -> 'a -> 'a) ->
+  ('a -> constr -> unit) -> 'a ->
+  constr -> unit
 
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