Regenerate the test files and add the fstar-split tests

1 files changed, 185 insertions, 204 deletions

diff --git a/tests/fstar/array/Array.Funs.fst b/tests/fstar/array/Array.Funs.fst
index 935bd9c9..da4164bc 100644
--- a/tests/fstar/array/Array.Funs.fst
+++ b/tests/fstar/array/Array.Funs.fst
@@ -7,86 +7,82 @@ include Array.Clauses
 
 #set-options "--z3rlimit 50 --fuel 1 --ifuel 1"
 
-(** [array::incr]: merged forward/backward function
-    (there is a single backward function, and the forward function returns ())
+(** [array::incr]:
     Source: 'src/array.rs', lines 8:0-8:24 *)
 let incr (x : u32) : result u32 =
   u32_add x 1
 
-(** [array::array_to_shared_slice_]: forward function
+(** [array::array_to_shared_slice_]:
     Source: 'src/array.rs', lines 16:0-16:53 *)
 let array_to_shared_slice_ (t : Type0) (s : array t 32) : result (slice t) =
   array_to_slice t 32 s
 
-(** [array::array_to_mut_slice_]: forward function
+(** [array::array_to_mut_slice_]:
     Source: 'src/array.rs', lines 21:0-21:58 *)
-let array_to_mut_slice_ (t : Type0) (s : array t 32) : result (slice t) =
-  array_to_slice t 32 s
-
-(** [array::array_to_mut_slice_]: backward function 0
-    Source: 'src/array.rs', lines 21:0-21:58 *)
-let array_to_mut_slice__back
-  (t : Type0) (s : array t 32) (ret : slice t) : result (array t 32) =
-  array_from_slice t 32 s ret
+let array_to_mut_slice_
+  (t : Type0) (s : array t 32) :
+  result ((slice t) & (slice t -> result (array t 32)))
+  =
+  let* (s1, to_slice_mut_back) = array_to_slice_mut t 32 s in
+  let back = fun ret -> to_slice_mut_back ret in
+  Return (s1, back)
 
-(** [array::array_len]: forward function
+(** [array::array_len]:
     Source: 'src/array.rs', lines 25:0-25:40 *)
 let array_len (t : Type0) (s : array t 32) : result usize =
-  let* s0 = array_to_slice t 32 s in let i = slice_len t s0 in Return i
+  let* s1 = array_to_slice t 32 s in let i = slice_len t s1 in Return i
 
-(** [array::shared_array_len]: forward function
+(** [array::shared_array_len]:
     Source: 'src/array.rs', lines 29:0-29:48 *)
 let shared_array_len (t : Type0) (s : array t 32) : result usize =
-  let* s0 = array_to_slice t 32 s in let i = slice_len t s0 in Return i
+  let* s1 = array_to_slice t 32 s in let i = slice_len t s1 in Return i
 
-(** [array::shared_slice_len]: forward function
+(** [array::shared_slice_len]:
     Source: 'src/array.rs', lines 33:0-33:44 *)
 let shared_slice_len (t : Type0) (s : slice t) : result usize =
   let i = slice_len t s in Return i
 
-(** [array::index_array_shared]: forward function
+(** [array::index_array_shared]:
     Source: 'src/array.rs', lines 37:0-37:57 *)
 let index_array_shared (t : Type0) (s : array t 32) (i : usize) : result t =
   array_index_usize t 32 s i
 
-(** [array::index_array_u32]: forward function
+(** [array::index_array_u32]:
     Source: 'src/array.rs', lines 44:0-44:53 *)
 let index_array_u32 (s : array u32 32) (i : usize) : result u32 =
   array_index_usize u32 32 s i
 
-(** [array::index_array_copy]: forward function
+(** [array::index_array_copy]:
     Source: 'src/array.rs', lines 48:0-48:45 *)
 let index_array_copy (x : array u32 32) : result u32 =
   array_index_usize u32 32 x 0
 
-(** [array::index_mut_array]: forward function
-    Source: 'src/array.rs', lines 52:0-52:62 *)
-let index_mut_array (t : Type0) (s : array t 32) (i : usize) : result t =
-  array_index_usize t 32 s i
-
-(** [array::index_mut_array]: backward function 0
+(** [array::index_mut_array]:
     Source: 'src/array.rs', lines 52:0-52:62 *)
-let index_mut_array_back
-  (t : Type0) (s : array t 32) (i : usize) (ret : t) : result (array t 32) =
-  array_update_usize t 32 s i ret
+let index_mut_array
+  (t : Type0) (s : array t 32) (i : usize) :
+  result (t & (t -> result (array t 32)))
+  =
+  let* (x, index_mut_back) = array_index_mut_usize t 32 s i in
+  let back = fun ret -> index_mut_back ret in
+  Return (x, back)
 
-(** [array::index_slice]: forward function
+(** [array::index_slice]:
     Source: 'src/array.rs', lines 56:0-56:46 *)
 let index_slice (t : Type0) (s : slice t) (i : usize) : result t =
   slice_index_usize t s i
 
-(** [array::index_mut_slice]: forward function
-    Source: 'src/array.rs', lines 60:0-60:58 *)
-let index_mut_slice (t : Type0) (s : slice t) (i : usize) : result t =
-  slice_index_usize t s i
-
-(** [array::index_mut_slice]: backward function 0
+(** [array::index_mut_slice]:
     Source: 'src/array.rs', lines 60:0-60:58 *)
-let index_mut_slice_back
-  (t : Type0) (s : slice t) (i : usize) (ret : t) : result (slice t) =
-  slice_update_usize t s i ret
+let index_mut_slice
+  (t : Type0) (s : slice t) (i : usize) :
+  result (t & (t -> result (slice t)))
+  =
+  let* (x, index_mut_back) = slice_index_mut_usize t s i in
+  let back = fun ret -> index_mut_back ret in
+  Return (x, back)
 
-(** [array::slice_subslice_shared_]: forward function
+(** [array::slice_subslice_shared_]:
     Source: 'src/array.rs', lines 64:0-64:70 *)
 let slice_subslice_shared_
   (x : slice u32) (y : usize) (z : usize) : result (slice u32) =
@@ -94,41 +90,35 @@ let slice_subslice_shared_
     (core_slice_index_SliceIndexRangeUsizeSliceTInst u32) x
     { start = y; end_ = z }
 
-(** [array::slice_subslice_mut_]: forward function
+(** [array::slice_subslice_mut_]:
     Source: 'src/array.rs', lines 68:0-68:75 *)
 let slice_subslice_mut_
-  (x : slice u32) (y : usize) (z : usize) : result (slice u32) =
-  core_slice_index_Slice_index_mut u32 (core_ops_range_Range usize)
-    (core_slice_index_SliceIndexRangeUsizeSliceTInst u32) x
-    { start = y; end_ = z }
-
-(** [array::slice_subslice_mut_]: backward function 0
-    Source: 'src/array.rs', lines 68:0-68:75 *)
-let slice_subslice_mut__back
-  (x : slice u32) (y : usize) (z : usize) (ret : slice u32) :
-  result (slice u32)
+  (x : slice u32) (y : usize) (z : usize) :
+  result ((slice u32) & (slice u32 -> result (slice u32)))
   =
-  core_slice_index_Slice_index_mut_back u32 (core_ops_range_Range usize)
-    (core_slice_index_SliceIndexRangeUsizeSliceTInst u32) x
-    { start = y; end_ = z } ret
-
-(** [array::array_to_slice_shared_]: forward function
+  let* (s, index_mut_back) =
+    core_slice_index_Slice_index_mut u32 (core_ops_range_Range usize)
+      (core_slice_index_SliceIndexRangeUsizeSliceTInst u32) x
+      { start = y; end_ = z } in
+  let back = fun ret -> index_mut_back ret in
+  Return (s, back)
+
+(** [array::array_to_slice_shared_]:
     Source: 'src/array.rs', lines 72:0-72:54 *)
 let array_to_slice_shared_ (x : array u32 32) : result (slice u32) =
   array_to_slice u32 32 x
 
-(** [array::array_to_slice_mut_]: forward function
+(** [array::array_to_slice_mut_]:
     Source: 'src/array.rs', lines 76:0-76:59 *)
-let array_to_slice_mut_ (x : array u32 32) : result (slice u32) =
-  array_to_slice u32 32 x
-
-(** [array::array_to_slice_mut_]: backward function 0
-    Source: 'src/array.rs', lines 76:0-76:59 *)
-let array_to_slice_mut__back
-  (x : array u32 32) (ret : slice u32) : result (array u32 32) =
-  array_from_slice u32 32 x ret
+let array_to_slice_mut_
+  (x : array u32 32) :
+  result ((slice u32) & (slice u32 -> result (array u32 32)))
+  =
+  let* (s, to_slice_mut_back) = array_to_slice_mut u32 32 x in
+  let back = fun ret -> to_slice_mut_back ret in
+  Return (s, back)
 
-(** [array::array_subslice_shared_]: forward function
+(** [array::array_subslice_shared_]:
     Source: 'src/array.rs', lines 80:0-80:74 *)
 let array_subslice_shared_
   (x : array u32 32) (y : usize) (z : usize) : result (slice u32) =
@@ -137,274 +127,263 @@ let array_subslice_shared_
     (core_slice_index_SliceIndexRangeUsizeSliceTInst u32)) x
     { start = y; end_ = z }
 
-(** [array::array_subslice_mut_]: forward function
+(** [array::array_subslice_mut_]:
     Source: 'src/array.rs', lines 84:0-84:79 *)
 let array_subslice_mut_
-  (x : array u32 32) (y : usize) (z : usize) : result (slice u32) =
-  core_array_Array_index_mut u32 (core_ops_range_Range usize) 32
-    (core_ops_index_IndexMutSliceTIInst u32 (core_ops_range_Range usize)
-    (core_slice_index_SliceIndexRangeUsizeSliceTInst u32)) x
-    { start = y; end_ = z }
-
-(** [array::array_subslice_mut_]: backward function 0
-    Source: 'src/array.rs', lines 84:0-84:79 *)
-let array_subslice_mut__back
-  (x : array u32 32) (y : usize) (z : usize) (ret : slice u32) :
-  result (array u32 32)
+  (x : array u32 32) (y : usize) (z : usize) :
+  result ((slice u32) & (slice u32 -> result (array u32 32)))
   =
-  core_array_Array_index_mut_back u32 (core_ops_range_Range usize) 32
-    (core_ops_index_IndexMutSliceTIInst u32 (core_ops_range_Range usize)
-    (core_slice_index_SliceIndexRangeUsizeSliceTInst u32)) x
-    { start = y; end_ = z } ret
+  let* (s, index_mut_back) =
+    core_array_Array_index_mut u32 (core_ops_range_Range usize) 32
+      (core_ops_index_IndexMutSliceTIInst u32 (core_ops_range_Range usize)
+      (core_slice_index_SliceIndexRangeUsizeSliceTInst u32)) x
+      { start = y; end_ = z } in
+  let back = fun ret -> index_mut_back ret in
+  Return (s, back)
 
-(** [array::index_slice_0]: forward function
+(** [array::index_slice_0]:
     Source: 'src/array.rs', lines 88:0-88:38 *)
 let index_slice_0 (t : Type0) (s : slice t) : result t =
   slice_index_usize t s 0
 
-(** [array::index_array_0]: forward function
+(** [array::index_array_0]:
     Source: 'src/array.rs', lines 92:0-92:42 *)
 let index_array_0 (t : Type0) (s : array t 32) : result t =
   array_index_usize t 32 s 0
 
-(** [array::index_index_array]: forward function
+(** [array::index_index_array]:
     Source: 'src/array.rs', lines 103:0-103:71 *)
 let index_index_array
   (s : array (array u32 32) 32) (i : usize) (j : usize) : result u32 =
   let* a = array_index_usize (array u32 32) 32 s i in
   array_index_usize u32 32 a j
 
-(** [array::update_update_array]: forward function
+(** [array::update_update_array]:
     Source: 'src/array.rs', lines 114:0-114:70 *)
 let update_update_array
   (s : array (array u32 32) 32) (i : usize) (j : usize) : result unit =
-  let* a = array_index_usize (array u32 32) 32 s i in
-  let* a0 = array_update_usize u32 32 a j 0 in
-  let* _ = array_update_usize (array u32 32) 32 s i a0 in
+  let* (a, index_mut_back) = array_index_mut_usize (array u32 32) 32 s i in
+  let* (_, index_mut_back1) = array_index_mut_usize u32 32 a j in
+  let* a1 = index_mut_back1 0 in
+  let* _ = index_mut_back a1 in
   Return ()
 
-(** [array::array_local_deep_copy]: forward function
+(** [array::array_local_deep_copy]:
     Source: 'src/array.rs', lines 118:0-118:43 *)
 let array_local_deep_copy (x : array u32 32) : result unit =
   Return ()
 
-(** [array::take_array]: forward function
+(** [array::take_array]:
     Source: 'src/array.rs', lines 122:0-122:30 *)
 let take_array (a : array u32 2) : result unit =
   Return ()
 
-(** [array::take_array_borrow]: forward function
+(** [array::take_array_borrow]:
     Source: 'src/array.rs', lines 123:0-123:38 *)
 let take_array_borrow (a : array u32 2) : result unit =
   Return ()
 
-(** [array::take_slice]: forward function
+(** [array::take_slice]:
     Source: 'src/array.rs', lines 124:0-124:28 *)
 let take_slice (s : slice u32) : result unit =
   Return ()
 
-(** [array::take_mut_slice]: merged forward/backward function
-    (there is a single backward function, and the forward function returns ())
+(** [array::take_mut_slice]:
     Source: 'src/array.rs', lines 125:0-125:36 *)
 let take_mut_slice (s : slice u32) : result (slice u32) =
   Return s
 
-(** [array::const_array]: forward function
+(** [array::const_array]:
     Source: 'src/array.rs', lines 127:0-127:32 *)
 let const_array : result (array u32 2) =
   Return (mk_array u32 2 [ 0; 0 ])
 
-(** [array::const_slice]: forward function
+(** [array::const_slice]:
     Source: 'src/array.rs', lines 131:0-131:20 *)
 let const_slice : result unit =
   let* _ = array_to_slice u32 2 (mk_array u32 2 [ 0; 0 ]) in Return ()
 
-(** [array::take_all]: forward function
+(** [array::take_all]:
     Source: 'src/array.rs', lines 141:0-141:17 *)
 let take_all : result unit =
   let* _ = take_array (mk_array u32 2 [ 0; 0 ]) in
+  let* _ = take_array (mk_array u32 2 [ 0; 0 ]) in
   let* _ = take_array_borrow (mk_array u32 2 [ 0; 0 ]) in
   let* s = array_to_slice u32 2 (mk_array u32 2 [ 0; 0 ]) in
   let* _ = take_slice s in
-  let* s0 = array_to_slice u32 2 (mk_array u32 2 [ 0; 0 ]) in
-  let* s1 = take_mut_slice s0 in
-  let* _ = array_from_slice u32 2 (mk_array u32 2 [ 0; 0 ]) s1 in
+  let* (s1, to_slice_mut_back) =
+    array_to_slice_mut u32 2 (mk_array u32 2 [ 0; 0 ]) in
+  let* s2 = take_mut_slice s1 in
+  let* _ = to_slice_mut_back s2 in
   Return ()
 
-(** [array::index_array]: forward function
+(** [array::index_array]:
     Source: 'src/array.rs', lines 155:0-155:38 *)
 let index_array (x : array u32 2) : result u32 =
   array_index_usize u32 2 x 0
 
-(** [array::index_array_borrow]: forward function
+(** [array::index_array_borrow]:
     Source: 'src/array.rs', lines 158:0-158:46 *)
 let index_array_borrow (x : array u32 2) : result u32 =
   array_index_usize u32 2 x 0
 
-(** [array::index_slice_u32_0]: forward function
+(** [array::index_slice_u32_0]:
     Source: 'src/array.rs', lines 162:0-162:42 *)
 let index_slice_u32_0 (x : slice u32) : result u32 =
   slice_index_usize u32 x 0
 
-(** [array::index_mut_slice_u32_0]: forward function
-    Source: 'src/array.rs', lines 166:0-166:50 *)
-let index_mut_slice_u32_0 (x : slice u32) : result u32 =
-  slice_index_usize u32 x 0
-
-(** [array::index_mut_slice_u32_0]: backward function 0
+(** [array::index_mut_slice_u32_0]:
     Source: 'src/array.rs', lines 166:0-166:50 *)
-let index_mut_slice_u32_0_back (x : slice u32) : result (slice u32) =
-  let* _ = slice_index_usize u32 x 0 in Return x
+let index_mut_slice_u32_0 (x : slice u32) : result (u32 & (slice u32)) =
+  let* i = slice_index_usize u32 x 0 in Return (i, x)
 
-(** [array::index_all]: forward function
+(** [array::index_all]:
     Source: 'src/array.rs', lines 170:0-170:25 *)
 let index_all : result u32 =
   let* i = index_array (mk_array u32 2 [ 0; 0 ]) in
-  let* i0 = index_array (mk_array u32 2 [ 0; 0 ]) in
-  let* i1 = u32_add i i0 in
-  let* i2 = index_array_borrow (mk_array u32 2 [ 0; 0 ]) in
-  let* i3 = u32_add i1 i2 in
+  let* i1 = index_array (mk_array u32 2 [ 0; 0 ]) in
+  let* i2 = u32_add i i1 in
+  let* i3 = index_array_borrow (mk_array u32 2 [ 0; 0 ]) in
+  let* i4 = u32_add i2 i3 in
   let* s = array_to_slice u32 2 (mk_array u32 2 [ 0; 0 ]) in
-  let* i4 = index_slice_u32_0 s in
-  let* i5 = u32_add i3 i4 in
-  let* s0 = array_to_slice u32 2 (mk_array u32 2 [ 0; 0 ]) in
-  let* i6 = index_mut_slice_u32_0 s0 in
-  let* i7 = u32_add i5 i6 in
-  let* s1 = index_mut_slice_u32_0_back s0 in
-  let* _ = array_from_slice u32 2 (mk_array u32 2 [ 0; 0 ]) s1 in
-  Return i7
-
-(** [array::update_array]: forward function
+  let* i5 = index_slice_u32_0 s in
+  let* i6 = u32_add i4 i5 in
+  let* (s1, to_slice_mut_back) =
+    array_to_slice_mut u32 2 (mk_array u32 2 [ 0; 0 ]) in
+  let* (i7, s2) = index_mut_slice_u32_0 s1 in
+  let* i8 = u32_add i6 i7 in
+  let* _ = to_slice_mut_back s2 in
+  Return i8
+
+(** [array::update_array]:
     Source: 'src/array.rs', lines 184:0-184:36 *)
 let update_array (x : array u32 2) : result unit =
-  let* _ = array_update_usize u32 2 x 0 1 in Return ()
+  let* (_, index_mut_back) = array_index_mut_usize u32 2 x 0 in
+  let* _ = index_mut_back 1 in
+  Return ()
 
-(** [array::update_array_mut_borrow]: merged forward/backward function
-    (there is a single backward function, and the forward function returns ())
+(** [array::update_array_mut_borrow]:
     Source: 'src/array.rs', lines 187:0-187:48 *)
 let update_array_mut_borrow (x : array u32 2) : result (array u32 2) =
-  array_update_usize u32 2 x 0 1
+  let* (_, index_mut_back) = array_index_mut_usize u32 2 x 0 in
+  index_mut_back 1
 
-(** [array::update_mut_slice]: merged forward/backward function
-    (there is a single backward function, and the forward function returns ())
+(** [array::update_mut_slice]:
     Source: 'src/array.rs', lines 190:0-190:38 *)
 let update_mut_slice (x : slice u32) : result (slice u32) =
-  slice_update_usize u32 x 0 1
+  let* (_, index_mut_back) = slice_index_mut_usize u32 x 0 in index_mut_back 1
 
-(** [array::update_all]: forward function
+(** [array::update_all]:
     Source: 'src/array.rs', lines 194:0-194:19 *)
 let update_all : result unit =
   let* _ = update_array (mk_array u32 2 [ 0; 0 ]) in
-  let* x = update_array_mut_borrow (mk_array u32 2 [ 0; 0 ]) in
-  let* s = array_to_slice u32 2 x in
-  let* s0 = update_mut_slice s in
-  let* _ = array_from_slice u32 2 x s0 in
+  let* _ = update_array (mk_array u32 2 [ 0; 0 ]) in
+  let* a = update_array_mut_borrow (mk_array u32 2 [ 0; 0 ]) in
+  let* (s, to_slice_mut_back) = array_to_slice_mut u32 2 a in
+  let* s1 = update_mut_slice s in
+  let* _ = to_slice_mut_back s1 in
   Return ()
 
-(** [array::range_all]: forward function
+(** [array::range_all]:
     Source: 'src/array.rs', lines 205:0-205:18 *)
 let range_all : result unit =
-  let* s =
+  let* (s, index_mut_back) =
     core_array_Array_index_mut u32 (core_ops_range_Range usize) 4
       (core_ops_index_IndexMutSliceTIInst u32 (core_ops_range_Range usize)
       (core_slice_index_SliceIndexRangeUsizeSliceTInst u32))
       (mk_array u32 4 [ 0; 0; 0; 0 ]) { start = 1; end_ = 3 } in
-  let* s0 = update_mut_slice s in
-  let* _ =
-    core_array_Array_index_mut_back u32 (core_ops_range_Range usize) 4
-      (core_ops_index_IndexMutSliceTIInst u32 (core_ops_range_Range usize)
-      (core_slice_index_SliceIndexRangeUsizeSliceTInst u32))
-      (mk_array u32 4 [ 0; 0; 0; 0 ]) { start = 1; end_ = 3 } s0 in
+  let* s1 = update_mut_slice s in
+  let* _ = index_mut_back s1 in
   Return ()
 
-(** [array::deref_array_borrow]: forward function
+(** [array::deref_array_borrow]:
     Source: 'src/array.rs', lines 214:0-214:46 *)
 let deref_array_borrow (x : array u32 2) : result u32 =
   array_index_usize u32 2 x 0
 
-(** [array::deref_array_mut_borrow]: forward function
+(** [array::deref_array_mut_borrow]:
     Source: 'src/array.rs', lines 219:0-219:54 *)
-let deref_array_mut_borrow (x : array u32 2) : result u32 =
-  array_index_usize u32 2 x 0
+let deref_array_mut_borrow (x : array u32 2) : result (u32 & (array u32 2)) =
+  let* i = array_index_usize u32 2 x 0 in Return (i, x)
 
-(** [array::deref_array_mut_borrow]: backward function 0
-    Source: 'src/array.rs', lines 219:0-219:54 *)
-let deref_array_mut_borrow_back (x : array u32 2) : result (array u32 2) =
-  let* _ = array_index_usize u32 2 x 0 in Return x
-
-(** [array::take_array_t]: forward function
+(** [array::take_array_t]:
     Source: 'src/array.rs', lines 227:0-227:31 *)
 let take_array_t (a : array aB_t 2) : result unit =
   Return ()
 
-(** [array::non_copyable_array]: forward function
+(** [array::non_copyable_array]:
     Source: 'src/array.rs', lines 229:0-229:27 *)
 let non_copyable_array : result unit =
   let* _ = take_array_t (mk_array aB_t 2 [ AB_A; AB_B ]) in Return ()
 
-(** [array::sum]: loop 0: forward function
+(** [array::sum]: loop 0:
     Source: 'src/array.rs', lines 242:0-250:1 *)
 let rec sum_loop
-  (s : slice u32) (sum0 : u32) (i : usize) :
-  Tot (result u32) (decreases (sum_loop_decreases s sum0 i))
+  (s : slice u32) (sum1 : u32) (i : usize) :
+  Tot (result u32) (decreases (sum_loop_decreases s sum1 i))
   =
-  let i0 = slice_len u32 s in
-  if i < i0
+  let i1 = slice_len u32 s in
+  if i < i1
   then
-    let* i1 = slice_index_usize u32 s i in
-    let* sum1 = u32_add sum0 i1 in
-    let* i2 = usize_add i 1 in
-    sum_loop s sum1 i2
-  else Return sum0
+    let* i2 = slice_index_usize u32 s i in
+    let* sum3 = u32_add sum1 i2 in
+    let* i3 = usize_add i 1 in
+    sum_loop s sum3 i3
+  else Return sum1
 
-(** [array::sum]: forward function
+(** [array::sum]:
     Source: 'src/array.rs', lines 242:0-242:28 *)
 let sum (s : slice u32) : result u32 =
   sum_loop s 0 0
 
-(** [array::sum2]: loop 0: forward function
+(** [array::sum2]: loop 0:
     Source: 'src/array.rs', lines 252:0-261:1 *)
 let rec sum2_loop
-  (s : slice u32) (s2 : slice u32) (sum0 : u32) (i : usize) :
-  Tot (result u32) (decreases (sum2_loop_decreases s s2 sum0 i))
+  (s : slice u32) (s2 : slice u32) (sum1 : u32) (i : usize) :
+  Tot (result u32) (decreases (sum2_loop_decreases s s2 sum1 i))
   =
-  let i0 = slice_len u32 s in
-  if i < i0
+  let i1 = slice_len u32 s in
+  if i < i1
   then
-    let* i1 = slice_index_usize u32 s i in
-    let* i2 = slice_index_usize u32 s2 i in
-    let* i3 = u32_add i1 i2 in
-    let* sum1 = u32_add sum0 i3 in
-    let* i4 = usize_add i 1 in
-    sum2_loop s s2 sum1 i4
-  else Return sum0
-
-(** [array::sum2]: forward function
+    let* i2 = slice_index_usize u32 s i in
+    let* i3 = slice_index_usize u32 s2 i in
+    let* i4 = u32_add i2 i3 in
+    let* sum3 = u32_add sum1 i4 in
+    let* i5 = usize_add i 1 in
+    sum2_loop s s2 sum3 i5
+  else Return sum1
+
+(** [array::sum2]:
     Source: 'src/array.rs', lines 252:0-252:41 *)
 let sum2 (s : slice u32) (s2 : slice u32) : result u32 =
   let i = slice_len u32 s in
-  let i0 = slice_len u32 s2 in
-  if not (i = i0) then Fail Failure else sum2_loop s s2 0 0
+  let i1 = slice_len u32 s2 in
+  if not (i = i1) then Fail Failure else sum2_loop s s2 0 0
 
-(** [array::f0]: forward function
+(** [array::f0]:
     Source: 'src/array.rs', lines 263:0-263:11 *)
 let f0 : result unit =
-  let* s = array_to_slice u32 2 (mk_array u32 2 [ 1; 2 ]) in
-  let* s0 = slice_update_usize u32 s 0 1 in
-  let* _ = array_from_slice u32 2 (mk_array u32 2 [ 1; 2 ]) s0 in
+  let* (s, to_slice_mut_back) =
+    array_to_slice_mut u32 2 (mk_array u32 2 [ 1; 2 ]) in
+  let* (_, index_mut_back) = slice_index_mut_usize u32 s 0 in
+  let* s1 = index_mut_back 1 in
+  let* _ = to_slice_mut_back s1 in
   Return ()
 
-(** [array::f1]: forward function
+(** [array::f1]:
     Source: 'src/array.rs', lines 268:0-268:11 *)
 let f1 : result unit =
-  let* _ = array_update_usize u32 2 (mk_array u32 2 [ 1; 2 ]) 0 1 in Return ()
+  let* (_, index_mut_back) =
+    array_index_mut_usize u32 2 (mk_array u32 2 [ 1; 2 ]) 0 in
+  let* _ = index_mut_back 1 in
+  Return ()
 
-(** [array::f2]: forward function
+(** [array::f2]:
     Source: 'src/array.rs', lines 273:0-273:17 *)
 let f2 (i : u32) : result unit =
   Return ()
 
-(** [array::f4]: forward function
+(** [array::f4]:
     Source: 'src/array.rs', lines 282:0-282:54 *)
 let f4 (x : array u32 32) (y : usize) (z : usize) : result (slice u32) =
   core_array_Array_index u32 (core_ops_range_Range usize) 32
@@ -412,34 +391,36 @@ let f4 (x : array u32 32) (y : usize) (z : usize) : result (slice u32) =
     (core_slice_index_SliceIndexRangeUsizeSliceTInst u32)) x
     { start = y; end_ = z }
 
-(** [array::f3]: forward function
+(** [array::f3]:
     Source: 'src/array.rs', lines 275:0-275:18 *)
 let f3 : result u32 =
   let* i = array_index_usize u32 2 (mk_array u32 2 [ 1; 2 ]) 0 in
   let* _ = f2 i in
   let b = array_repeat u32 32 0 in
   let* s = array_to_slice u32 2 (mk_array u32 2 [ 1; 2 ]) in
-  let* s0 = f4 b 16 18 in
-  sum2 s s0
+  let* s1 = f4 b 16 18 in
+  sum2 s s1
 
 (** [array::SZ]
     Source: 'src/array.rs', lines 286:0-286:19 *)
 let sz_body : result usize = Return 32
 let sz_c : usize = eval_global sz_body
 
-(** [array::f5]: forward function
+(** [array::f5]:
     Source: 'src/array.rs', lines 289:0-289:31 *)
 let f5 (x : array u32 32) : result u32 =
   array_index_usize u32 32 x 0
 
-(** [array::ite]: forward function
+(** [array::ite]:
     Source: 'src/array.rs', lines 294:0-294:12 *)
 let ite : result unit =
-  let* s = array_to_slice u32 2 (mk_array u32 2 [ 0; 0 ]) in
-  let* s0 = array_to_slice u32 2 (mk_array u32 2 [ 0; 0 ]) in
-  let* s1 = index_mut_slice_u32_0_back s0 in
-  let* _ = array_from_slice u32 2 (mk_array u32 2 [ 0; 0 ]) s1 in
-  let* s2 = index_mut_slice_u32_0_back s in
-  let* _ = array_from_slice u32 2 (mk_array u32 2 [ 0; 0 ]) s2 in
+  let* (s, to_slice_mut_back) =
+    array_to_slice_mut u32 2 (mk_array u32 2 [ 0; 0 ]) in
+  let* (_, s1) = index_mut_slice_u32_0 s in
+  let* (s2, to_slice_mut_back1) =
+    array_to_slice_mut u32 2 (mk_array u32 2 [ 0; 0 ]) in
+  let* (_, s3) = index_mut_slice_u32_0 s2 in
+  let* _ = to_slice_mut_back1 s3 in
+  let* _ = to_slice_mut_back s1 in
   Return ()