val pts_to_not_null (#a:Type)
                    (#opened:inames)
                    (#p:perm)
                    (#v:a)
                    (r:ref a)
  : STGhost unit opened
      (pts_to r p v)
      (fun _ -> pts_to r p v)
      (requires True)
      (ensures fun _ -> r =!= null)
let pts_to_not_null #a #opened #p #v r
  = extract_fact #opened (pts_to r p v) (r =!= null) (R.pts_to_not_null r p v);
    ()
val pts_to_not_null (#a:Type)
                    (#opened:inames)
                    (#p:perm)
                    (#v:a)
                    (r:ref a)
  : STGhost unit opened
      (pts_to r p v)
      (fun _ -> pts_to r p v)
      (requires True)
      (ensures fun _ -> r =!= null)
let pts_to_not_null #a #opened #p #v r =
extract_fact #opened (pts_to r p v) (r =!= null) (R.pts_to_not_null r p v);
()
Steel.ST.Reference.fst.checked
Steel.ST.Util.fsti.checked Steel.ST.Coercions.fsti.checked Steel.Reference.fsti.checked prims.fst.checked FStar.Pervasives.fsti.checked FStar.Ghost.fsti.checked
Steel.ST.Reference.fst
Steel.Memory.inames Steel.FractionalPermission.perm Steel.ST.Reference.ref Prims.unit Steel.ST.Effect.Ghost.extract_fact Steel.ST.Reference.pts_to Prims.l_not Prims.eq2 Steel.ST.Reference.null Steel.Reference.pts_to_not_null
(*
   Copyright 2020 Microsoft Research

   Licensed under the Apache License, Version 2.0 (the "License");
   you may not use this file except in compliance with the License.
   You may obtain a copy of the License at

       http://www.apache.org/licenses/LICENSE-2.0

   Unless required by applicable law or agreed to in writing, software
   distributed under the License is distributed on an "AS IS" BASIS,
   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   See the License for the specific language governing permissions and
   limitations under the License.
*)

module Steel.ST.Reference
open FStar.Ghost
open Steel.ST.Util
open Steel.ST.Coercions
module R = Steel.Reference

let ref (a:Type0)
  : Type0
  = R.ref a

let null (#a:Type0)
  : ref a
  = R.null #a

let is_null (#a:Type0) (r:ref a)
  : b:bool{b <==> r == null}
  = R.is_null r

let pts_to (#a:Type0)
           (r:ref a)
           ([@@@smt_fallback] p:perm)
           ([@@@smt_fallback] v:a)
  : vprop
  = R.pts_to r p v

let pts_to_injective_eq
      (#a: Type)
      (#opened:inames)
      (#p0 #p1:perm)
      (#v0 #v1:a)
      (r: ref a)
  : STGhost unit opened
      (pts_to r p0 v0 `star` pts_to r p1 v1)
      (fun _ -> pts_to r p0 v0 `star` pts_to r p1 v0)
      (requires True)
      (ensures fun _ -> v0 == v1)
  = coerce_ghost
    (fun _ -> R.pts_to_injective_eq #a #opened #p0 #p1 #(hide v0) #(hide v1) r)
val pts_to_not_null (#a:Type)
                    (#opened:inames)
                    (#p:perm)
                    (#v:a)
                    (r:ref a)
  : STGhost unit opened
      (pts_to r p v)
      (fun _ -> pts_to r p v)
      (requires True)
      (ensures fun _ -> r =!= null)
r: Steel.ST.Reference.ref a -> Steel.ST.Effect.Ghost.STGhost Prims.unit