[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, 1 insertions, 1 deletions

diff --git a/pretyping/inductiveops.mli b/pretyping/inductiveops.mli
index 55149552a..8efa087a7 100644
--- a/pretyping/inductiveops.mli
+++ b/pretyping/inductiveops.mli
@@ -198,4 +198,4 @@ val type_of_inductive_knowing_conclusion :
   env -> evar_map -> Inductive.mind_specif Univ.puniverses -> EConstr.types -> evar_map * EConstr.types
 
 (********************)
-val control_only_guard : env -> types -> unit
+val control_only_guard : env -> Evd.evar_map -> EConstr.types -> unit