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, 3 insertions, 3 deletions

diff --git a/tactics/hipattern.mli b/tactics/hipattern.mli
index 9110830aa..a1d986544 100644
--- a/tactics/hipattern.mli
+++ b/tactics/hipattern.mli
@@ -120,11 +120,11 @@ val match_with_equation:
 
 (** Match terms [eq A t u], [identity A t u] or [JMeq A t A u] 
    Returns associated lemmas and [A,t,u] or fails PatternMatchingFailure *)
-val find_eq_data_decompose : ('a, 'r) Proofview.Goal.t -> constr ->
+val find_eq_data_decompose : 'a Proofview.Goal.t -> constr ->
       coq_eq_data * EInstance.t * (types * constr * constr)
 
 (** Idem but fails with an error message instead of PatternMatchingFailure *)
-val find_this_eq_data_decompose : ('a, 'r) Proofview.Goal.t -> constr ->
+val find_this_eq_data_decompose : 'a Proofview.Goal.t -> constr ->
       coq_eq_data * EInstance.t * (types * constr * constr)
 
 (** A variant that returns more informative structure on the equality found *)
@@ -145,7 +145,7 @@ val is_matching_sigma : evar_map -> constr -> bool
 val match_eqdec : evar_map -> constr -> bool * Globnames.global_reference * constr * constr * constr
 
 (** Match an equality up to conversion; returns [(eq,t1,t2)] in normal form *)
-val dest_nf_eq : ('a, 'r) Proofview.Goal.t -> constr -> (constr * constr * constr)
+val dest_nf_eq : 'a Proofview.Goal.t -> constr -> (constr * constr * constr)
 
 (** Match a negation *)
 val is_matching_not : evar_map -> constr -> bool