Proof using: let-in policy, optional auto-clear, forward closure*

- "Proof using p*" means: use p and any section var about p.
- Simplify the grammar/parser for proof using <expression>.
- Section variables with a body (let-in) are pulled in automatically
  since they are safe to be used (add no extra quantification)
- automatic clear of "unused" section variables made optional:
    Set Proof Using Clear Unused.
  since clearing section hypotheses does not "always work" (e.g. hint
  databases are not really cleaned)
- term_typing: trigger a "suggest proof using" message also for Let
  theorems.

1 files changed, 3 insertions, 12 deletions

diff --git a/proofs/proof_using.mli b/proofs/proof_using.mli
index fb3497f106..dcf8a0fcd2 100644
--- a/proofs/proof_using.mli
+++ b/proofs/proof_using.mli
@@ -6,21 +6,12 @@
 (*         *       GNU Lesser General Public License Version 2.1        *)
 (************************************************************************)
 
-
-(* [minimize_hyps e s1] gives [s2] s.t. [Id.Set.subset s2 s1] is [true]
- * and [keep_hyps e s1] is equal to [keep_hyps e s2].  Inefficient. *)
-val minimize_hyps : Environ.env -> Names.Id.Set.t -> Names.Id.Set.t
-
-(* [minimize_unused_hyps e s1] gives [s2] s.t. [Id.Set.subset s2 s1] is [true]
- * and s.t. calling [clear s1] would do the same as [clear s2].  Inefficient. *)
-val minimize_unused_hyps : Environ.env -> Names.Id.Set.t -> Names.Id.Set.t
-
 val process_expr :
-  Environ.env -> Vernacexpr.section_subset_descr -> Constr.types list ->
+  Environ.env -> Vernacexpr.section_subset_expr -> Constr.types list ->
     Names.Id.t list
 
-val name_set : Names.Id.t -> Vernacexpr.section_subset_descr -> unit
+val name_set : Names.Id.t -> Vernacexpr.section_subset_expr -> unit
 
-val to_string : Vernacexpr.section_subset_descr -> string
+val to_string : Vernacexpr.section_subset_expr -> string
 
 val get_default_proof_using : unit -> string option