From 775b2473976075aa6458a51682f3beeee75dc17a Mon Sep 17 00:00:00 2001
From: Son Ho
Date: Wed, 29 Jun 2022 08:50:17 +0200
Subject: Make minor modifications

---
 src/InterpreterExpressions.ml | 25 ++++++++++++++++++++++++-
 1 file changed, 24 insertions(+), 1 deletion(-)

(limited to 'src/InterpreterExpressions.ml')

diff --git a/src/InterpreterExpressions.ml b/src/InterpreterExpressions.ml
index bdcadf3a..6bb2baf0 100644
--- a/src/InterpreterExpressions.ml
+++ b/src/InterpreterExpressions.ml
@@ -48,11 +48,20 @@ let expand_primitively_copyable_at_place (config : C.config)
   (* Apply *)
   expand cf ctx
 
-(** Read a place (CPS-style function *)
+(** Read a place (CPS-style function).
+
+    We also check that the value *doesn't contain bottoms or inactivated
+    borrows.
+ *)
 let read_place (config : C.config) (access : access_kind) (p : E.place)
     (cf : V.typed_value -> m_fun) : m_fun =
  fun ctx ->
   let v = read_place_unwrap config access p ctx in
+  (* Check that there are no bottoms in the value *)
+  assert (not (bottom_in_value ctx.ended_regions v));
+  (* Check that there are no inactivated borrows in the value *)
+  assert (not (inactivated_in_value v));
+  (* Call the continuation *)
   cf v ctx
 
 (** Small utility.
@@ -60,6 +69,14 @@ let read_place (config : C.config) (access : access_kind) (p : E.place)
     Prepare the access to a place in a right-value (typically an operand) by
     reorganizing the environment.
 
+    We reorganize the environment so that:
+    - we can access the place (we prepare *along* the path)
+    - the value at the place itself doesn't contain loans (the `access_kind`
+      controls whether we only end mutable loans, or also shared loans).
+
+    We also check, after the reorganization, that the value at the place
+    *doesn't contain any bottom nor inactivated borrows*.
+
     [expand_prim_copy]: if true, expand the symbolic values which are primitively
     copyable and contain borrows.
  *)
@@ -67,14 +84,20 @@ let access_rplace_reorganize_and_read (config : C.config)
     (expand_prim_copy : bool) (access : access_kind) (p : E.place)
     (cf : V.typed_value -> m_fun) : m_fun =
  fun ctx ->
+  (* Make sure we can evaluate the path *)
   let cc = update_ctx_along_read_place config access p in
+  (* End the proper loans at the place itself *)
   let cc = comp cc (end_loans_at_place config access p) in
+  (* Expand the copyable values which contain borrows (which are necessarily shared
+   * borrows) *)
   let cc =
     if expand_prim_copy then
       comp cc (expand_primitively_copyable_at_place config access p)
     else cc
   in
+  (* Read the place - note that this checks that the value doesn't contain bottoms *)
   let read_place = read_place config access p in
+  (* Compose *)
   comp cc read_place cf ctx
 
 let access_rplace_reorganize (config : C.config) (expand_prim_copy : bool)
-- 
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