Remove the Sigma (monotonous state) API.

Reminder of (some of) the reasons for removal:

- Despite the claim in sigma.mli, it does *not* prevent evar
  leaks, something like:

  fun env evd ->
  let (evd',ev) = new_evar env evd in
  (evd,ev)

  will typecheck even with Sigma-like type annotations (with a proof of
  reflexivity)

- The API stayed embryonic. Even typing functions were not ported to
  Sigma.

- Some unsafe combinators (Unsafe.tclEVARS) were replaced with slightly
  less unsafe ones (e.g. s_enter), but those ones were not marked unsafe
  at all (despite still being so).

- There was no good story for higher order functions manipulating evar
  maps. Without higher order, one can most of the time get away with
  reusing the same name for the updated evar map.

- Most of the code doing complex things with evar maps was using unsafe
  casts to sigma. This code should be fixed, but this is an orthogonal
  issue.

Of course, this was showing a nice and elegant use of GADTs, but the
cost/benefit ratio in practice did not seem good.

1 files changed, 5 insertions, 5 deletions

diff --git a/tactics/tacticals.mli b/tactics/tacticals.mli
index 96270f748..9603212de 100644
--- a/tactics/tacticals.mli
+++ b/tactics/tacticals.mli
@@ -225,7 +225,7 @@ module New : sig
   val tclTIMEOUT : int -> unit tactic -> unit tactic
   val tclTIME : string option -> 'a tactic -> 'a tactic
 
-  val nLastDecls  : ('a, 'r) Proofview.Goal.t -> int -> named_context
+  val nLastDecls  : 'a Proofview.Goal.t -> int -> named_context
 
   val ifOnHyp     : (identifier * types -> bool) ->
     (identifier -> unit Proofview.tactic) -> (identifier -> unit Proofview.tactic) ->
@@ -236,7 +236,7 @@ module New : sig
   val onLastHyp        : (constr -> unit tactic) -> unit tactic
   val onLastDecl       : (named_declaration -> unit tactic) -> unit tactic
 
-  val onHyps      : ([ `LZ ], named_context) Proofview.Goal.enter ->
+  val onHyps      : ([ `LZ ] Proofview.Goal.t -> named_context) ->
                     (named_context -> unit tactic) -> unit tactic
   val afterHyp    : Id.t -> (named_context -> unit tactic) -> unit tactic
 
@@ -244,9 +244,9 @@ module New : sig
   val tryAllHypsAndConcl  : (identifier option -> unit tactic) -> unit tactic
   val onClause   : (identifier option -> unit tactic) -> clause -> unit tactic
 
-  val elimination_sort_of_goal : ('a, 'r) Proofview.Goal.t -> sorts_family
-  val elimination_sort_of_hyp  : Id.t -> ('a, 'r) Proofview.Goal.t -> sorts_family
-  val elimination_sort_of_clause : Id.t option -> ('a, 'r) Proofview.Goal.t -> sorts_family
+  val elimination_sort_of_goal : 'a Proofview.Goal.t -> sorts_family
+  val elimination_sort_of_hyp  : Id.t -> 'a Proofview.Goal.t -> sorts_family
+  val elimination_sort_of_clause : Id.t option -> 'a Proofview.Goal.t -> sorts_family
 
   val elimination_then :
     (branch_args -> unit Proofview.tactic) ->