Merge pull request #123 from AeneasVerif/son/clean

Cleanup the code in preparation of the nested loops

8 files changed, 188 insertions, 203 deletions

diff --git a/tests/fstar/misc/Bitwise.fst b/tests/fstar/misc/Bitwise.fst
index 7330f07a..11ef6861 100644
--- a/tests/fstar/misc/Bitwise.fst
+++ b/tests/fstar/misc/Bitwise.fst
@@ -18,15 +18,15 @@ let shift_i32 (a : i32) : result i32 =
 (** [bitwise::xor_u32]:
     Source: 'src/bitwise.rs', lines 17:0-17:37 *)
 let xor_u32 (a : u32) (b : u32) : result u32 =
-  Return (u32_xor a b)
+  Ok (u32_xor a b)
 
 (** [bitwise::or_u32]:
     Source: 'src/bitwise.rs', lines 21:0-21:36 *)
 let or_u32 (a : u32) (b : u32) : result u32 =
-  Return (u32_or a b)
+  Ok (u32_or a b)
 
 (** [bitwise::and_u32]:
     Source: 'src/bitwise.rs', lines 25:0-25:37 *)
 let and_u32 (a : u32) (b : u32) : result u32 =
-  Return (u32_and a b)
+  Ok (u32_and a b)
 
diff --git a/tests/fstar/misc/Constants.fst b/tests/fstar/misc/Constants.fst
index 8d1cf3ce..4fbafb83 100644
--- a/tests/fstar/misc/Constants.fst
+++ b/tests/fstar/misc/Constants.fst
@@ -7,17 +7,17 @@ open Primitives
 
 (** [constants::X0]
     Source: 'src/constants.rs', lines 5:0-5:17 *)
-let x0_body : result u32 = Return 0
+let x0_body : result u32 = Ok 0
 let x0 : u32 = eval_global x0_body
 
 (** [constants::X1]
     Source: 'src/constants.rs', lines 7:0-7:17 *)
-let x1_body : result u32 = Return core_u32_max
+let x1_body : result u32 = Ok core_u32_max
 let x1 : u32 = eval_global x1_body
 
 (** [constants::X2]
     Source: 'src/constants.rs', lines 10:0-10:17 *)
-let x2_body : result u32 = Return 3
+let x2_body : result u32 = Ok 3
 let x2 : u32 = eval_global x2_body
 
 (** [constants::incr]:
@@ -33,7 +33,7 @@ let x3 : u32 = eval_global x3_body
 (** [constants::mk_pair0]:
     Source: 'src/constants.rs', lines 23:0-23:51 *)
 let mk_pair0 (x : u32) (y1 : u32) : result (u32 & u32) =
-  Return (x, y1)
+  Ok (x, y1)
 
 (** [constants::Pair]
     Source: 'src/constants.rs', lines 36:0-36:23 *)
@@ -42,7 +42,7 @@ type pair_t (t1 t2 : Type0) = { x : t1; y : t2; }
 (** [constants::mk_pair1]:
     Source: 'src/constants.rs', lines 27:0-27:55 *)
 let mk_pair1 (x : u32) (y1 : u32) : result (pair_t u32 u32) =
-  Return { x = x; y = y1 }
+  Ok { x = x; y = y1 }
 
 (** [constants::P0]
     Source: 'src/constants.rs', lines 31:0-31:24 *)
@@ -56,12 +56,12 @@ let p1 : pair_t u32 u32 = eval_global p1_body
 
 (** [constants::P2]
     Source: 'src/constants.rs', lines 33:0-33:24 *)
-let p2_body : result (u32 & u32) = Return (0, 1)
+let p2_body : result (u32 & u32) = Ok (0, 1)
 let p2 : (u32 & u32) = eval_global p2_body
 
 (** [constants::P3]
     Source: 'src/constants.rs', lines 34:0-34:28 *)
-let p3_body : result (pair_t u32 u32) = Return { x = 0; y = 1 }
+let p3_body : result (pair_t u32 u32) = Ok { x = 0; y = 1 }
 let p3 : pair_t u32 u32 = eval_global p3_body
 
 (** [constants::Wrap]
@@ -71,7 +71,7 @@ type wrap_t (t : Type0) = { value : t; }
 (** [constants::{constants::Wrap<T>}::new]:
     Source: 'src/constants.rs', lines 54:4-54:41 *)
 let wrap_new (t : Type0) (value : t) : result (wrap_t t) =
-  Return { value = value }
+  Ok { value = value }
 
 (** [constants::Y]
     Source: 'src/constants.rs', lines 41:0-41:22 *)
@@ -81,7 +81,7 @@ let y : wrap_t i32 = eval_global y_body
 (** [constants::unwrap_y]:
     Source: 'src/constants.rs', lines 43:0-43:30 *)
 let unwrap_y : result i32 =
-  Return y.value
+  Ok y.value
 
 (** [constants::YVAL]
     Source: 'src/constants.rs', lines 47:0-47:19 *)
@@ -90,13 +90,13 @@ let yval : i32 = eval_global yval_body
 
 (** [constants::get_z1::Z1]
     Source: 'src/constants.rs', lines 62:4-62:17 *)
-let get_z1_z1_body : result i32 = Return 3
+let get_z1_z1_body : result i32 = Ok 3
 let get_z1_z1 : i32 = eval_global get_z1_z1_body
 
 (** [constants::get_z1]:
     Source: 'src/constants.rs', lines 61:0-61:28 *)
 let get_z1 : result i32 =
-  Return get_z1_z1
+  Ok get_z1_z1
 
 (** [constants::add]:
     Source: 'src/constants.rs', lines 66:0-66:39 *)
@@ -105,12 +105,12 @@ let add (a : i32) (b : i32) : result i32 =
 
 (** [constants::Q1]
     Source: 'src/constants.rs', lines 74:0-74:17 *)
-let q1_body : result i32 = Return 5
+let q1_body : result i32 = Ok 5
 let q1 : i32 = eval_global q1_body
 
 (** [constants::Q2]
     Source: 'src/constants.rs', lines 75:0-75:17 *)
-let q2_body : result i32 = Return q1
+let q2_body : result i32 = Ok q1
 let q2 : i32 = eval_global q2_body
 
 (** [constants::Q3]
@@ -125,7 +125,7 @@ let get_z2 : result i32 =
 
 (** [constants::S1]
     Source: 'src/constants.rs', lines 80:0-80:18 *)
-let s1_body : result u32 = Return 6
+let s1_body : result u32 = Ok 6
 let s1 : u32 = eval_global s1_body
 
 (** [constants::S2]
@@ -135,7 +135,7 @@ let s2 : u32 = eval_global s2_body
 
 (** [constants::S3]
     Source: 'src/constants.rs', lines 82:0-82:29 *)
-let s3_body : result (pair_t u32 u32) = Return p3
+let s3_body : result (pair_t u32 u32) = Ok p3
 let s3 : pair_t u32 u32 = eval_global s3_body
 
 (** [constants::S4]
@@ -149,11 +149,11 @@ type v_t (t : Type0) (n : usize) = { x : array t n; }
 
 (** [constants::{constants::V<T, N>#1}::LEN]
     Source: 'src/constants.rs', lines 91:4-91:24 *)
-let v_len_body (t : Type0) (n : usize) : result usize = Return n
+let v_len_body (t : Type0) (n : usize) : result usize = Ok n
 let v_len (t : Type0) (n : usize) : usize = eval_global (v_len_body t n)
 
 (** [constants::use_v]:
     Source: 'src/constants.rs', lines 94:0-94:42 *)
 let use_v (t : Type0) (n : usize) : result usize =
-  Return (v_len t n)
+  Ok (v_len t n)
 
diff --git a/tests/fstar/misc/External.Funs.fst b/tests/fstar/misc/External.Funs.fst
index 78960404..d4247b8f 100644
--- a/tests/fstar/misc/External.Funs.fst
+++ b/tests/fstar/misc/External.Funs.fst
@@ -22,10 +22,10 @@ let test_new_non_zero_u32
 (** [external::test_vec]:
     Source: 'src/external.rs', lines 17:0-17:17 *)
 let test_vec : result unit =
-  let* _ = alloc_vec_Vec_push u32 (alloc_vec_Vec_new u32) 0 in Return ()
+  let* _ = alloc_vec_Vec_push u32 (alloc_vec_Vec_new u32) 0 in Ok ()
 
 (** Unit test for [external::test_vec] *)
-let _ = assert_norm (test_vec = Return ())
+let _ = assert_norm (test_vec = Ok ())
 
 (** [external::custom_swap]:
     Source: 'src/external.rs', lines 24:0-24:66 *)
@@ -34,8 +34,8 @@ let custom_swap
   result (state & (t & (t -> state -> result (state & (t & t)))))
   =
   let* (st1, (x1, y1)) = core_mem_swap t x y st in
-  let back = fun ret st2 -> Return (st2, (ret, y1)) in
-  Return (st1, (x1, back))
+  let back = fun ret st2 -> Ok (st2, (ret, y1)) in
+  Ok (st1, (x1, back))
 
 (** [external::test_custom_swap]:
     Source: 'src/external.rs', lines 29:0-29:59 *)
@@ -43,12 +43,12 @@ let test_custom_swap
   (x : u32) (y : u32) (st : state) : result (state & (u32 & u32)) =
   let* (st1, (_, custom_swap_back)) = custom_swap u32 x y st in
   let* (_, (x1, y1)) = custom_swap_back 1 st1 in
-  Return (st1, (x1, y1))
+  Ok (st1, (x1, y1))
 
 (** [external::test_swap_non_zero]:
     Source: 'src/external.rs', lines 35:0-35:44 *)
 let test_swap_non_zero (x : u32) (st : state) : result (state & u32) =
   let* (st1, p) = swap u32 x 0 st in
   let (x1, _) = p in
-  if x1 = 0 then Fail Failure else Return (st1, x1)
+  if x1 = 0 then Fail Failure else Ok (st1, x1)
 
diff --git a/tests/fstar/misc/Loops.Funs.fst b/tests/fstar/misc/Loops.Funs.fst
index 93683deb..26cb91d2 100644
--- a/tests/fstar/misc/Loops.Funs.fst
+++ b/tests/fstar/misc/Loops.Funs.fst
@@ -70,7 +70,7 @@ let rec sum_array_loop
     let* s1 = u32_add s i1 in
     let* i2 = usize_add i 1 in
     sum_array_loop n a i2 s1
-  else Return s
+  else Ok s
 
 (** [loops::sum_array]:
     Source: 'src/loops.rs', lines 50:0-50:52 *)
@@ -92,7 +92,7 @@ let rec clear_loop
     let* i2 = usize_add i 1 in
     let* v1 = index_mut_back 0 in
     clear_loop v1 i2
-  else Return v
+  else Ok v
 
 (** [loops::clear]:
     Source: 'src/loops.rs', lines 62:0-62:30 *)
@@ -106,8 +106,8 @@ let rec list_mem_loop
   Tot (result bool) (decreases (list_mem_loop_decreases x ls))
   =
   begin match ls with
-  | List_Cons y tl -> if y = x then Return true else list_mem_loop x tl
-  | List_Nil -> Return false
+  | List_Cons y tl -> if y = x then Ok true else list_mem_loop x tl
+  | List_Nil -> Ok false
   end
 
 (** [loops::list_mem]:
@@ -125,12 +125,12 @@ let rec list_nth_mut_loop_loop
   begin match ls with
   | List_Cons x tl ->
     if i = 0
-    then let back = fun ret -> Return (List_Cons ret tl) in Return (x, back)
+    then let back = fun ret -> Ok (List_Cons ret tl) in Ok (x, back)
     else
       let* i1 = u32_sub i 1 in
       let* (x1, back) = list_nth_mut_loop_loop t tl i1 in
-      let back1 = fun ret -> let* tl1 = back ret in Return (List_Cons x tl1) in
-      Return (x1, back1)
+      let back1 = fun ret -> let* tl1 = back ret in Ok (List_Cons x tl1) in
+      Ok (x1, back1)
   | List_Nil -> Fail Failure
   end
 
@@ -151,7 +151,7 @@ let rec list_nth_shared_loop_loop
   begin match ls with
   | List_Cons x tl ->
     if i = 0
-    then Return x
+    then Ok x
     else let* i1 = u32_sub i 1 in list_nth_shared_loop_loop t tl i1
   | List_Nil -> Fail Failure
   end
@@ -171,11 +171,11 @@ let rec get_elem_mut_loop
   begin match ls with
   | List_Cons y tl ->
     if y = x
-    then let back = fun ret -> Return (List_Cons ret tl) in Return (y, back)
+    then let back = fun ret -> Ok (List_Cons ret tl) in Ok (y, back)
     else
       let* (i, back) = get_elem_mut_loop x tl in
-      let back1 = fun ret -> let* tl1 = back ret in Return (List_Cons y tl1) in
-      Return (i, back1)
+      let back1 = fun ret -> let* tl1 = back ret in Ok (List_Cons y tl1) in
+      Ok (i, back1)
   | List_Nil -> Fail Failure
   end
 
@@ -190,7 +190,7 @@ let get_elem_mut
       (core_slice_index_SliceIndexUsizeSliceTInst (list_t usize)) slots 0 in
   let* (i, back) = get_elem_mut_loop x ls in
   let back1 = fun ret -> let* l = back ret in index_mut_back l in
-  Return (i, back1)
+  Ok (i, back1)
 
 (** [loops::get_elem_shared]: loop 0:
     Source: 'src/loops.rs', lines 129:0-143:1 *)
@@ -199,7 +199,7 @@ let rec get_elem_shared_loop
   Tot (result usize) (decreases (get_elem_shared_loop_decreases x ls))
   =
   begin match ls with
-  | List_Cons y tl -> if y = x then Return y else get_elem_shared_loop x tl
+  | List_Cons y tl -> if y = x then Ok y else get_elem_shared_loop x tl
   | List_Nil -> Fail Failure
   end
 
@@ -218,12 +218,12 @@ let id_mut
   (t : Type0) (ls : list_t t) :
   result ((list_t t) & (list_t t -> result (list_t t)))
   =
-  Return (ls, Return)
+  Ok (ls, Ok)
 
 (** [loops::id_shared]:
     Source: 'src/loops.rs', lines 149:0-149:45 *)
 let id_shared (t : Type0) (ls : list_t t) : result (list_t t) =
-  Return ls
+  Ok ls
 
 (** [loops::list_nth_mut_loop_with_id]: loop 0:
     Source: 'src/loops.rs', lines 154:0-165:1 *)
@@ -235,12 +235,12 @@ let rec list_nth_mut_loop_with_id_loop
   begin match ls with
   | List_Cons x tl ->
     if i = 0
-    then let back = fun ret -> Return (List_Cons ret tl) in Return (x, back)
+    then let back = fun ret -> Ok (List_Cons ret tl) in Ok (x, back)
     else
       let* i1 = u32_sub i 1 in
       let* (x1, back) = list_nth_mut_loop_with_id_loop t i1 tl in
-      let back1 = fun ret -> let* tl1 = back ret in Return (List_Cons x tl1) in
-      Return (x1, back1)
+      let back1 = fun ret -> let* tl1 = back ret in Ok (List_Cons x tl1) in
+      Ok (x1, back1)
   | List_Nil -> Fail Failure
   end
 
@@ -253,7 +253,7 @@ let list_nth_mut_loop_with_id
   let* (ls1, id_mut_back) = id_mut t ls in
   let* (x, back) = list_nth_mut_loop_with_id_loop t i ls1 in
   let back1 = fun ret -> let* l = back ret in id_mut_back l in
-  Return (x, back1)
+  Ok (x, back1)
 
 (** [loops::list_nth_shared_loop_with_id]: loop 0:
     Source: 'src/loops.rs', lines 168:0-179:1 *)
@@ -265,7 +265,7 @@ let rec list_nth_shared_loop_with_id_loop
   begin match ls with
   | List_Cons x tl ->
     if i = 0
-    then Return x
+    then Ok x
     else let* i1 = u32_sub i 1 in list_nth_shared_loop_with_id_loop t i1 tl
   | List_Nil -> Fail Failure
   end
@@ -289,17 +289,17 @@ let rec list_nth_mut_loop_pair_loop
     | List_Cons x1 tl1 ->
       if i = 0
       then
-        let back'a = fun ret -> Return (List_Cons ret tl0) in
-        let back'b = fun ret -> Return (List_Cons ret tl1) in
-        Return ((x0, x1), back'a, back'b)
+        let back'a = fun ret -> Ok (List_Cons ret tl0) in
+        let back'b = fun ret -> Ok (List_Cons ret tl1) in
+        Ok ((x0, x1), back'a, back'b)
       else
         let* i1 = u32_sub i 1 in
         let* (p, back'a, back'b) = list_nth_mut_loop_pair_loop t tl0 tl1 i1 in
         let back'a1 =
-          fun ret -> let* tl01 = back'a ret in Return (List_Cons x0 tl01) in
+          fun ret -> let* tl01 = back'a ret in Ok (List_Cons x0 tl01) in
         let back'b1 =
-          fun ret -> let* tl11 = back'b ret in Return (List_Cons x1 tl11) in
-        Return (p, back'a1, back'b1)
+          fun ret -> let* tl11 = back'b ret in Ok (List_Cons x1 tl11) in
+        Ok (p, back'a1, back'b1)
     | List_Nil -> Fail Failure
     end
   | List_Nil -> Fail Failure
@@ -325,7 +325,7 @@ let rec list_nth_shared_loop_pair_loop
     begin match ls1 with
     | List_Cons x1 tl1 ->
       if i = 0
-      then Return (x0, x1)
+      then Ok (x0, x1)
       else let* i1 = u32_sub i 1 in list_nth_shared_loop_pair_loop t tl0 tl1 i1
     | List_Nil -> Fail Failure
     end
@@ -353,16 +353,16 @@ let rec list_nth_mut_loop_pair_merge_loop
       then
         let back =
           fun ret ->
-            let (x, x2) = ret in Return (List_Cons x tl0, List_Cons x2 tl1) in
-        Return ((x0, x1), back)
+            let (x, x2) = ret in Ok (List_Cons x tl0, List_Cons x2 tl1) in
+        Ok ((x0, x1), back)
       else
         let* i1 = u32_sub i 1 in
         let* (p, back) = list_nth_mut_loop_pair_merge_loop t tl0 tl1 i1 in
         let back1 =
           fun ret ->
             let* (tl01, tl11) = back ret in
-            Return (List_Cons x0 tl01, List_Cons x1 tl11) in
-        Return (p, back1)
+            Ok (List_Cons x0 tl01, List_Cons x1 tl11) in
+        Ok (p, back1)
     | List_Nil -> Fail Failure
     end
   | List_Nil -> Fail Failure
@@ -388,7 +388,7 @@ let rec list_nth_shared_loop_pair_merge_loop
     begin match ls1 with
     | List_Cons x1 tl1 ->
       if i = 0
-      then Return (x0, x1)
+      then Ok (x0, x1)
       else
         let* i1 = u32_sub i 1 in
         list_nth_shared_loop_pair_merge_loop t tl0 tl1 i1
@@ -415,15 +415,13 @@ let rec list_nth_mut_shared_loop_pair_loop
     begin match ls1 with
     | List_Cons x1 tl1 ->
       if i = 0
-      then
-        let back = fun ret -> Return (List_Cons ret tl0) in
-        Return ((x0, x1), back)
+      then let back = fun ret -> Ok (List_Cons ret tl0) in Ok ((x0, x1), back)
       else
         let* i1 = u32_sub i 1 in
         let* (p, back) = list_nth_mut_shared_loop_pair_loop t tl0 tl1 i1 in
-        let back1 =
-          fun ret -> let* tl01 = back ret in Return (List_Cons x0 tl01) in
-        Return (p, back1)
+        let back1 = fun ret -> let* tl01 = back ret in Ok (List_Cons x0 tl01)
+          in
+        Ok (p, back1)
     | List_Nil -> Fail Failure
     end
   | List_Nil -> Fail Failure
@@ -449,16 +447,14 @@ let rec list_nth_mut_shared_loop_pair_merge_loop
     begin match ls1 with
     | List_Cons x1 tl1 ->
       if i = 0
-      then
-        let back = fun ret -> Return (List_Cons ret tl0) in
-        Return ((x0, x1), back)
+      then let back = fun ret -> Ok (List_Cons ret tl0) in Ok ((x0, x1), back)
       else
         let* i1 = u32_sub i 1 in
         let* (p, back) = list_nth_mut_shared_loop_pair_merge_loop t tl0 tl1 i1
           in
-        let back1 =
-          fun ret -> let* tl01 = back ret in Return (List_Cons x0 tl01) in
-        Return (p, back1)
+        let back1 = fun ret -> let* tl01 = back ret in Ok (List_Cons x0 tl01)
+          in
+        Ok (p, back1)
     | List_Nil -> Fail Failure
     end
   | List_Nil -> Fail Failure
@@ -484,15 +480,13 @@ let rec list_nth_shared_mut_loop_pair_loop
     begin match ls1 with
     | List_Cons x1 tl1 ->
       if i = 0
-      then
-        let back = fun ret -> Return (List_Cons ret tl1) in
-        Return ((x0, x1), back)
+      then let back = fun ret -> Ok (List_Cons ret tl1) in Ok ((x0, x1), back)
       else
         let* i1 = u32_sub i 1 in
         let* (p, back) = list_nth_shared_mut_loop_pair_loop t tl0 tl1 i1 in
-        let back1 =
-          fun ret -> let* tl11 = back ret in Return (List_Cons x1 tl11) in
-        Return (p, back1)
+        let back1 = fun ret -> let* tl11 = back ret in Ok (List_Cons x1 tl11)
+          in
+        Ok (p, back1)
     | List_Nil -> Fail Failure
     end
   | List_Nil -> Fail Failure
@@ -518,16 +512,14 @@ let rec list_nth_shared_mut_loop_pair_merge_loop
     begin match ls1 with
     | List_Cons x1 tl1 ->
       if i = 0
-      then
-        let back = fun ret -> Return (List_Cons ret tl1) in
-        Return ((x0, x1), back)
+      then let back = fun ret -> Ok (List_Cons ret tl1) in Ok ((x0, x1), back)
       else
         let* i1 = u32_sub i 1 in
         let* (p, back) = list_nth_shared_mut_loop_pair_merge_loop t tl0 tl1 i1
           in
-        let back1 =
-          fun ret -> let* tl11 = back ret in Return (List_Cons x1 tl11) in
-        Return (p, back1)
+        let back1 = fun ret -> let* tl11 = back ret in Ok (List_Cons x1 tl11)
+          in
+        Ok (p, back1)
     | List_Nil -> Fail Failure
     end
   | List_Nil -> Fail Failure
@@ -549,12 +541,12 @@ let rec ignore_input_mut_borrow_loop
   =
   if i > 0
   then let* i1 = u32_sub i 1 in ignore_input_mut_borrow_loop i1
-  else Return ()
+  else Ok ()
 
 (** [loops::ignore_input_mut_borrow]:
     Source: 'src/loops.rs', lines 345:0-345:56 *)
 let ignore_input_mut_borrow (_a : u32) (i : u32) : result u32 =
-  let* _ = ignore_input_mut_borrow_loop i in Return _a
+  let* _ = ignore_input_mut_borrow_loop i in Ok _a
 
 (** [loops::incr_ignore_input_mut_borrow]: loop 0:
     Source: 'src/loops.rs', lines 353:0-358:1 *)
@@ -564,14 +556,14 @@ let rec incr_ignore_input_mut_borrow_loop
   =
   if i > 0
   then let* i1 = u32_sub i 1 in incr_ignore_input_mut_borrow_loop i1
-  else Return ()
+  else Ok ()
 
 (** [loops::incr_ignore_input_mut_borrow]:
     Source: 'src/loops.rs', lines 353:0-353:60 *)
 let incr_ignore_input_mut_borrow (a : u32) (i : u32) : result u32 =
   let* a1 = u32_add a 1 in
   let* _ = incr_ignore_input_mut_borrow_loop i in
-  Return a1
+  Ok a1
 
 (** [loops::ignore_input_shared_borrow]: loop 0:
     Source: 'src/loops.rs', lines 362:0-366:1 *)
@@ -581,10 +573,10 @@ let rec ignore_input_shared_borrow_loop
   =
   if i > 0
   then let* i1 = u32_sub i 1 in ignore_input_shared_borrow_loop i1
-  else Return ()
+  else Ok ()
 
 (** [loops::ignore_input_shared_borrow]:
     Source: 'src/loops.rs', lines 362:0-362:59 *)
 let ignore_input_shared_borrow (_a : u32) (i : u32) : result u32 =
-  let* _ = ignore_input_shared_borrow_loop i in Return _a
+  let* _ = ignore_input_shared_borrow_loop i in Ok _a
 
diff --git a/tests/fstar/misc/NoNestedBorrows.fst b/tests/fstar/misc/NoNestedBorrows.fst
index 1a93beaa..ac443a99 100644
--- a/tests/fstar/misc/NoNestedBorrows.fst
+++ b/tests/fstar/misc/NoNestedBorrows.fst
@@ -151,20 +151,20 @@ let cast_bool_to_i32 (x : bool) : result i32 =
 (** [no_nested_borrows::cast_bool_to_bool]:
     Source: 'src/no_nested_borrows.rs', lines 137:0-137:41 *)
 let cast_bool_to_bool (x : bool) : result bool =
-  Return x
+  Ok x
 
 (** [no_nested_borrows::test2]:
     Source: 'src/no_nested_borrows.rs', lines 142:0-142:14 *)
 let test2 : result unit =
-  let* _ = u32_add 23 44 in Return ()
+  let* _ = u32_add 23 44 in Ok ()
 
 (** Unit test for [no_nested_borrows::test2] *)
-let _ = assert_norm (test2 = Return ())
+let _ = assert_norm (test2 = Ok ())
 
 (** [no_nested_borrows::get_max]:
     Source: 'src/no_nested_borrows.rs', lines 154:0-154:37 *)
 let get_max (x : u32) (y : u32) : result u32 =
-  if x >= y then Return x else Return y
+  if x >= y then Ok x else Ok y
 
 (** [no_nested_borrows::test3]:
     Source: 'src/no_nested_borrows.rs', lines 162:0-162:14 *)
@@ -172,26 +172,26 @@ let test3 : result unit =
   let* x = get_max 4 3 in
   let* y = get_max 10 11 in
   let* z = u32_add x y in
-  if not (z = 15) then Fail Failure else Return ()
+  if not (z = 15) then Fail Failure else Ok ()
 
 (** Unit test for [no_nested_borrows::test3] *)
-let _ = assert_norm (test3 = Return ())
+let _ = assert_norm (test3 = Ok ())
 
 (** [no_nested_borrows::test_neg1]:
     Source: 'src/no_nested_borrows.rs', lines 169:0-169:18 *)
 let test_neg1 : result unit =
-  let* y = i32_neg 3 in if not (y = -3) then Fail Failure else Return ()
+  let* y = i32_neg 3 in if not (y = -3) then Fail Failure else Ok ()
 
 (** Unit test for [no_nested_borrows::test_neg1] *)
-let _ = assert_norm (test_neg1 = Return ())
+let _ = assert_norm (test_neg1 = Ok ())
 
 (** [no_nested_borrows::refs_test1]:
     Source: 'src/no_nested_borrows.rs', lines 176:0-176:19 *)
 let refs_test1 : result unit =
-  if not (1 = 1) then Fail Failure else Return ()
+  if not (1 = 1) then Fail Failure else Ok ()
 
 (** Unit test for [no_nested_borrows::refs_test1] *)
-let _ = assert_norm (refs_test1 = Return ())
+let _ = assert_norm (refs_test1 = Ok ())
 
 (** [no_nested_borrows::refs_test2]:
     Source: 'src/no_nested_borrows.rs', lines 187:0-187:19 *)
@@ -204,18 +204,18 @@ let refs_test2 : result unit =
     else
       if not (2 = 2)
       then Fail Failure
-      else if not (2 = 2) then Fail Failure else Return ()
+      else if not (2 = 2) then Fail Failure else Ok ()
 
 (** Unit test for [no_nested_borrows::refs_test2] *)
-let _ = assert_norm (refs_test2 = Return ())
+let _ = assert_norm (refs_test2 = Ok ())
 
 (** [no_nested_borrows::test_list1]:
     Source: 'src/no_nested_borrows.rs', lines 203:0-203:19 *)
 let test_list1 : result unit =
-  Return ()
+  Ok ()
 
 (** Unit test for [no_nested_borrows::test_list1] *)
-let _ = assert_norm (test_list1 = Return ())
+let _ = assert_norm (test_list1 = Ok ())
 
 (** [no_nested_borrows::test_box1]:
     Source: 'src/no_nested_borrows.rs', lines 208:0-208:18 *)
@@ -223,56 +223,53 @@ let test_box1 : result unit =
   let* (_, deref_mut_back) = alloc_boxed_Box_deref_mut i32 0 in
   let* b = deref_mut_back 1 in
   let* x = alloc_boxed_Box_deref i32 b in
-  if not (x = 1) then Fail Failure else Return ()
+  if not (x = 1) then Fail Failure else Ok ()
 
 (** Unit test for [no_nested_borrows::test_box1] *)
-let _ = assert_norm (test_box1 = Return ())
+let _ = assert_norm (test_box1 = Ok ())
 
 (** [no_nested_borrows::copy_int]:
     Source: 'src/no_nested_borrows.rs', lines 218:0-218:30 *)
 let copy_int (x : i32) : result i32 =
-  Return x
+  Ok x
 
 (** [no_nested_borrows::test_unreachable]:
     Source: 'src/no_nested_borrows.rs', lines 224:0-224:32 *)
 let test_unreachable (b : bool) : result unit =
-  if b then Fail Failure else Return ()
+  if b then Fail Failure else Ok ()
 
 (** [no_nested_borrows::test_panic]:
     Source: 'src/no_nested_borrows.rs', lines 232:0-232:26 *)
 let test_panic (b : bool) : result unit =
-  if b then Fail Failure else Return ()
+  if b then Fail Failure else Ok ()
 
 (** [no_nested_borrows::test_copy_int]:
     Source: 'src/no_nested_borrows.rs', lines 239:0-239:22 *)
 let test_copy_int : result unit =
-  let* y = copy_int 0 in if not (0 = y) then Fail Failure else Return ()
+  let* y = copy_int 0 in if not (0 = y) then Fail Failure else Ok ()
 
 (** Unit test for [no_nested_borrows::test_copy_int] *)
-let _ = assert_norm (test_copy_int = Return ())
+let _ = assert_norm (test_copy_int = Ok ())
 
 (** [no_nested_borrows::is_cons]:
     Source: 'src/no_nested_borrows.rs', lines 246:0-246:38 *)
 let is_cons (t : Type0) (l : list_t t) : result bool =
-  begin match l with
-  | List_Cons _ _ -> Return true
-  | List_Nil -> Return false
-  end
+  begin match l with | List_Cons _ _ -> Ok true | List_Nil -> Ok false end
 
 (** [no_nested_borrows::test_is_cons]:
     Source: 'src/no_nested_borrows.rs', lines 253:0-253:21 *)
 let test_is_cons : result unit =
   let* b = is_cons i32 (List_Cons 0 List_Nil) in
-  if not b then Fail Failure else Return ()
+  if not b then Fail Failure else Ok ()
 
 (** Unit test for [no_nested_borrows::test_is_cons] *)
-let _ = assert_norm (test_is_cons = Return ())
+let _ = assert_norm (test_is_cons = Ok ())
 
 (** [no_nested_borrows::split_list]:
     Source: 'src/no_nested_borrows.rs', lines 259:0-259:48 *)
 let split_list (t : Type0) (l : list_t t) : result (t & (list_t t)) =
   begin match l with
-  | List_Cons hd tl -> Return (hd, tl)
+  | List_Cons hd tl -> Ok (hd, tl)
   | List_Nil -> Fail Failure
   end
 
@@ -281,18 +278,18 @@ let split_list (t : Type0) (l : list_t t) : result (t & (list_t t)) =
 let test_split_list : result unit =
   let* p = split_list i32 (List_Cons 0 List_Nil) in
   let (hd, _) = p in
-  if not (hd = 0) then Fail Failure else Return ()
+  if not (hd = 0) then Fail Failure else Ok ()
 
 (** Unit test for [no_nested_borrows::test_split_list] *)
-let _ = assert_norm (test_split_list = Return ())
+let _ = assert_norm (test_split_list = Ok ())
 
 (** [no_nested_borrows::choose]:
     Source: 'src/no_nested_borrows.rs', lines 274:0-274:70 *)
 let choose
   (t : Type0) (b : bool) (x : t) (y : t) : result (t & (t -> result (t & t))) =
   if b
-  then let back = fun ret -> Return (ret, y) in Return (x, back)
-  else let back = fun ret -> Return (x, ret) in Return (y, back)
+  then let back = fun ret -> Ok (ret, y) in Ok (x, back)
+  else let back = fun ret -> Ok (x, ret) in Ok (y, back)
 
 (** [no_nested_borrows::choose_test]:
     Source: 'src/no_nested_borrows.rs', lines 282:0-282:20 *)
@@ -305,15 +302,15 @@ let choose_test : result unit =
     let* (x, y) = choose_back z1 in
     if not (x = 1)
     then Fail Failure
-    else if not (y = 0) then Fail Failure else Return ()
+    else if not (y = 0) then Fail Failure else Ok ()
 
 (** Unit test for [no_nested_borrows::choose_test] *)
-let _ = assert_norm (choose_test = Return ())
+let _ = assert_norm (choose_test = Ok ())
 
 (** [no_nested_borrows::test_char]:
     Source: 'src/no_nested_borrows.rs', lines 294:0-294:26 *)
 let test_char : result char =
-  Return 'a'
+  Ok 'a'
 
 (** [no_nested_borrows::Tree]
     Source: 'src/no_nested_borrows.rs', lines 299:0-299:16 *)
@@ -332,7 +329,7 @@ and nodeElem_t (t : Type0) =
 let rec list_length (t : Type0) (l : list_t t) : result u32 =
   begin match l with
   | List_Cons _ l1 -> let* i = list_length t l1 in u32_add 1 i
-  | List_Nil -> Return 0
+  | List_Nil -> Ok 0
   end
 
 (** [no_nested_borrows::list_nth_shared]:
@@ -340,9 +337,7 @@ let rec list_length (t : Type0) (l : list_t t) : result u32 =
 let rec list_nth_shared (t : Type0) (l : list_t t) (i : u32) : result t =
   begin match l with
   | List_Cons x tl ->
-    if i = 0
-    then Return x
-    else let* i1 = u32_sub i 1 in list_nth_shared t tl i1
+    if i = 0 then Ok x else let* i1 = u32_sub i 1 in list_nth_shared t tl i1
   | List_Nil -> Fail Failure
   end
 
@@ -355,14 +350,13 @@ let rec list_nth_mut
   begin match l with
   | List_Cons x tl ->
     if i = 0
-    then let back = fun ret -> Return (List_Cons ret tl) in Return (x, back)
+    then let back = fun ret -> Ok (List_Cons ret tl) in Ok (x, back)
     else
       let* i1 = u32_sub i 1 in
       let* (x1, list_nth_mut_back) = list_nth_mut t tl i1 in
       let back =
-        fun ret -> let* tl1 = list_nth_mut_back ret in Return (List_Cons x tl1)
-        in
-      Return (x1, back)
+        fun ret -> let* tl1 = list_nth_mut_back ret in Ok (List_Cons x tl1) in
+      Ok (x1, back)
   | List_Nil -> Fail Failure
   end
 
@@ -372,7 +366,7 @@ let rec list_rev_aux
   (t : Type0) (li : list_t t) (lo : list_t t) : result (list_t t) =
   begin match li with
   | List_Cons hd tl -> list_rev_aux t tl (List_Cons hd lo)
-  | List_Nil -> Return lo
+  | List_Nil -> Ok lo
   end
 
 (** [no_nested_borrows::list_rev]:
@@ -413,10 +407,10 @@ let test_list_functions : result unit =
             then Fail Failure
             else
               let* i6 = list_nth_shared i32 ls 2 in
-              if not (i6 = 2) then Fail Failure else Return ()
+              if not (i6 = 2) then Fail Failure else Ok ()
 
 (** Unit test for [no_nested_borrows::test_list_functions] *)
-let _ = assert_norm (test_list_functions = Return ())
+let _ = assert_norm (test_list_functions = Ok ())
 
 (** [no_nested_borrows::id_mut_pair1]:
     Source: 'src/no_nested_borrows.rs', lines 414:0-414:89 *)
@@ -424,7 +418,7 @@ let id_mut_pair1
   (t1 t2 : Type0) (x : t1) (y : t2) :
   result ((t1 & t2) & ((t1 & t2) -> result (t1 & t2)))
   =
-  Return ((x, y), Return)
+  Ok ((x, y), Ok)
 
 (** [no_nested_borrows::id_mut_pair2]:
     Source: 'src/no_nested_borrows.rs', lines 418:0-418:88 *)
@@ -432,7 +426,7 @@ let id_mut_pair2
   (t1 t2 : Type0) (p : (t1 & t2)) :
   result ((t1 & t2) & ((t1 & t2) -> result (t1 & t2)))
   =
-  let (x, x1) = p in Return ((x, x1), Return)
+  let (x, x1) = p in Ok ((x, x1), Ok)
 
 (** [no_nested_borrows::id_mut_pair3]:
     Source: 'src/no_nested_borrows.rs', lines 422:0-422:93 *)
@@ -440,7 +434,7 @@ let id_mut_pair3
   (t1 t2 : Type0) (x : t1) (y : t2) :
   result ((t1 & t2) & (t1 -> result t1) & (t2 -> result t2))
   =
-  Return ((x, y), Return, Return)
+  Ok ((x, y), Ok, Ok)
 
 (** [no_nested_borrows::id_mut_pair4]:
     Source: 'src/no_nested_borrows.rs', lines 426:0-426:92 *)
@@ -448,7 +442,7 @@ let id_mut_pair4
   (t1 t2 : Type0) (p : (t1 & t2)) :
   result ((t1 & t2) & (t1 -> result t1) & (t2 -> result t2))
   =
-  let (x, x1) = p in Return ((x, x1), Return, Return)
+  let (x, x1) = p in Ok ((x, x1), Ok, Ok)
 
 (** [no_nested_borrows::StructWithTuple]
     Source: 'src/no_nested_borrows.rs', lines 433:0-433:34 *)
@@ -457,17 +451,17 @@ type structWithTuple_t (t1 t2 : Type0) = { p : (t1 & t2); }
 (** [no_nested_borrows::new_tuple1]:
     Source: 'src/no_nested_borrows.rs', lines 437:0-437:48 *)
 let new_tuple1 : result (structWithTuple_t u32 u32) =
-  Return { p = (1, 2) }
+  Ok { p = (1, 2) }
 
 (** [no_nested_borrows::new_tuple2]:
     Source: 'src/no_nested_borrows.rs', lines 441:0-441:48 *)
 let new_tuple2 : result (structWithTuple_t i16 i16) =
-  Return { p = (1, 2) }
+  Ok { p = (1, 2) }
 
 (** [no_nested_borrows::new_tuple3]:
     Source: 'src/no_nested_borrows.rs', lines 445:0-445:48 *)
 let new_tuple3 : result (structWithTuple_t u64 i64) =
-  Return { p = (1, 2) }
+  Ok { p = (1, 2) }
 
 (** [no_nested_borrows::StructWithPair]
     Source: 'src/no_nested_borrows.rs', lines 450:0-450:33 *)
@@ -476,7 +470,7 @@ type structWithPair_t (t1 t2 : Type0) = { p : pair_t t1 t2; }
 (** [no_nested_borrows::new_pair1]:
     Source: 'src/no_nested_borrows.rs', lines 454:0-454:46 *)
 let new_pair1 : result (structWithPair_t u32 u32) =
-  Return { p = { x = 1; y = 2 } }
+  Ok { p = { x = 1; y = 2 } }
 
 (** [no_nested_borrows::test_constants]:
     Source: 'src/no_nested_borrows.rs', lines 462:0-462:23 *)
@@ -497,44 +491,44 @@ let test_constants : result unit =
       then Fail Failure
       else
         let* swp = new_pair1 in
-        if not (swp.p.x = 1) then Fail Failure else Return ()
+        if not (swp.p.x = 1) then Fail Failure else Ok ()
 
 (** Unit test for [no_nested_borrows::test_constants] *)
-let _ = assert_norm (test_constants = Return ())
+let _ = assert_norm (test_constants = Ok ())
 
 (** [no_nested_borrows::test_weird_borrows1]:
     Source: 'src/no_nested_borrows.rs', lines 471:0-471:28 *)
 let test_weird_borrows1 : result unit =
-  Return ()
+  Ok ()
 
 (** Unit test for [no_nested_borrows::test_weird_borrows1] *)
-let _ = assert_norm (test_weird_borrows1 = Return ())
+let _ = assert_norm (test_weird_borrows1 = Ok ())
 
 (** [no_nested_borrows::test_mem_replace]:
     Source: 'src/no_nested_borrows.rs', lines 481:0-481:37 *)
 let test_mem_replace (px : u32) : result u32 =
   let (y, _) = core_mem_replace u32 px 1 in
-  if not (y = 0) then Fail Failure else Return 2
+  if not (y = 0) then Fail Failure else Ok 2
 
 (** [no_nested_borrows::test_shared_borrow_bool1]:
     Source: 'src/no_nested_borrows.rs', lines 488:0-488:47 *)
 let test_shared_borrow_bool1 (b : bool) : result u32 =
-  if b then Return 0 else Return 1
+  if b then Ok 0 else Ok 1
 
 (** [no_nested_borrows::test_shared_borrow_bool2]:
     Source: 'src/no_nested_borrows.rs', lines 501:0-501:40 *)
 let test_shared_borrow_bool2 : result u32 =
-  Return 0
+  Ok 0
 
 (** [no_nested_borrows::test_shared_borrow_enum1]:
     Source: 'src/no_nested_borrows.rs', lines 516:0-516:52 *)
 let test_shared_borrow_enum1 (l : list_t u32) : result u32 =
-  begin match l with | List_Cons _ _ -> Return 1 | List_Nil -> Return 0 end
+  begin match l with | List_Cons _ _ -> Ok 1 | List_Nil -> Ok 0 end
 
 (** [no_nested_borrows::test_shared_borrow_enum2]:
     Source: 'src/no_nested_borrows.rs', lines 528:0-528:40 *)
 let test_shared_borrow_enum2 : result u32 =
-  Return 0
+  Ok 0
 
 (** [no_nested_borrows::incr]:
     Source: 'src/no_nested_borrows.rs', lines 539:0-539:24 *)
@@ -549,7 +543,7 @@ let call_incr (x : u32) : result u32 =
 (** [no_nested_borrows::read_then_incr]:
     Source: 'src/no_nested_borrows.rs', lines 548:0-548:41 *)
 let read_then_incr (x : u32) : result (u32 & u32) =
-  let* x1 = u32_add x 1 in Return (x, x1)
+  let* x1 = u32_add x 1 in Ok (x, x1)
 
 (** [no_nested_borrows::Tuple]
     Source: 'src/no_nested_borrows.rs', lines 554:0-554:24 *)
@@ -558,12 +552,12 @@ type tuple_t (t1 t2 : Type0) = t1 * t2
 (** [no_nested_borrows::use_tuple_struct]:
     Source: 'src/no_nested_borrows.rs', lines 556:0-556:48 *)
 let use_tuple_struct (x : tuple_t u32 u32) : result (tuple_t u32 u32) =
-  let (_, i) = x in Return (1, i)
+  let (_, i) = x in Ok (1, i)
 
 (** [no_nested_borrows::create_tuple_struct]:
     Source: 'src/no_nested_borrows.rs', lines 560:0-560:61 *)
 let create_tuple_struct (x : u32) (y : u64) : result (tuple_t u32 u64) =
-  Return (x, y)
+  Ok (x, y)
 
 (** [no_nested_borrows::IdType]
     Source: 'src/no_nested_borrows.rs', lines 565:0-565:20 *)
@@ -572,10 +566,10 @@ type idType_t (t : Type0) = t
 (** [no_nested_borrows::use_id_type]:
     Source: 'src/no_nested_borrows.rs', lines 567:0-567:40 *)
 let use_id_type (t : Type0) (x : idType_t t) : result t =
-  Return x
+  Ok x
 
 (** [no_nested_borrows::create_id_type]:
     Source: 'src/no_nested_borrows.rs', lines 571:0-571:43 *)
 let create_id_type (t : Type0) (x : t) : result (idType_t t) =
-  Return x
+  Ok x
 
diff --git a/tests/fstar/misc/Paper.fst b/tests/fstar/misc/Paper.fst
index c2f47ad1..e6b4eb25 100644
--- a/tests/fstar/misc/Paper.fst
+++ b/tests/fstar/misc/Paper.fst
@@ -13,18 +13,18 @@ let ref_incr (x : i32) : result i32 =
 (** [paper::test_incr]:
     Source: 'src/paper.rs', lines 8:0-8:18 *)
 let test_incr : result unit =
-  let* x = ref_incr 0 in if not (x = 1) then Fail Failure else Return ()
+  let* x = ref_incr 0 in if not (x = 1) then Fail Failure else Ok ()
 
 (** Unit test for [paper::test_incr] *)
-let _ = assert_norm (test_incr = Return ())
+let _ = assert_norm (test_incr = Ok ())
 
 (** [paper::choose]:
     Source: 'src/paper.rs', lines 15:0-15:70 *)
 let choose
   (t : Type0) (b : bool) (x : t) (y : t) : result (t & (t -> result (t & t))) =
   if b
-  then let back = fun ret -> Return (ret, y) in Return (x, back)
-  else let back = fun ret -> Return (x, ret) in Return (y, back)
+  then let back = fun ret -> Ok (ret, y) in Ok (x, back)
+  else let back = fun ret -> Ok (x, ret) in Ok (y, back)
 
 (** [paper::test_choose]:
     Source: 'src/paper.rs', lines 23:0-23:20 *)
@@ -37,10 +37,10 @@ let test_choose : result unit =
     let* (x, y) = choose_back z1 in
     if not (x = 1)
     then Fail Failure
-    else if not (y = 0) then Fail Failure else Return ()
+    else if not (y = 0) then Fail Failure else Ok ()
 
 (** Unit test for [paper::test_choose] *)
-let _ = assert_norm (test_choose = Return ())
+let _ = assert_norm (test_choose = Ok ())
 
 (** [paper::List]
     Source: 'src/paper.rs', lines 35:0-35:16 *)
@@ -57,14 +57,13 @@ let rec list_nth_mut
   begin match l with
   | List_Cons x tl ->
     if i = 0
-    then let back = fun ret -> Return (List_Cons ret tl) in Return (x, back)
+    then let back = fun ret -> Ok (List_Cons ret tl) in Ok (x, back)
     else
       let* i1 = u32_sub i 1 in
       let* (x1, list_nth_mut_back) = list_nth_mut t tl i1 in
       let back =
-        fun ret -> let* tl1 = list_nth_mut_back ret in Return (List_Cons x tl1)
-        in
-      Return (x1, back)
+        fun ret -> let* tl1 = list_nth_mut_back ret in Ok (List_Cons x tl1) in
+      Ok (x1, back)
   | List_Nil -> Fail Failure
   end
 
@@ -73,7 +72,7 @@ let rec list_nth_mut
 let rec sum (l : list_t i32) : result i32 =
   begin match l with
   | List_Cons x tl -> let* i = sum tl in i32_add x i
-  | List_Nil -> Return 0
+  | List_Nil -> Ok 0
   end
 
 (** [paper::test_nth]:
@@ -85,10 +84,10 @@ let test_nth : result unit =
   let* x1 = i32_add x 1 in
   let* l2 = list_nth_mut_back x1 in
   let* i = sum l2 in
-  if not (i = 7) then Fail Failure else Return ()
+  if not (i = 7) then Fail Failure else Ok ()
 
 (** Unit test for [paper::test_nth] *)
-let _ = assert_norm (test_nth = Return ())
+let _ = assert_norm (test_nth = Ok ())
 
 (** [paper::call_choose]:
     Source: 'src/paper.rs', lines 76:0-76:44 *)
@@ -97,5 +96,5 @@ let call_choose (p : (u32 & u32)) : result u32 =
   let* (pz, choose_back) = choose u32 true px py in
   let* pz1 = u32_add pz 1 in
   let* (px1, _) = choose_back pz1 in
-  Return px1
+  Ok px1
 
diff --git a/tests/fstar/misc/PoloniusList.fst b/tests/fstar/misc/PoloniusList.fst
index 4203247e..c0bc592e 100644
--- a/tests/fstar/misc/PoloniusList.fst
+++ b/tests/fstar/misc/PoloniusList.fst
@@ -20,13 +20,13 @@ let rec get_list_at_x
   begin match ls with
   | List_Cons hd tl ->
     if hd = x
-    then Return (List_Cons hd tl, Return)
+    then Ok (List_Cons hd tl, Ok)
     else
       let* (l, get_list_at_x_back) = get_list_at_x tl x in
       let back =
-        fun ret ->
-          let* tl1 = get_list_at_x_back ret in Return (List_Cons hd tl1) in
-      Return (l, back)
-  | List_Nil -> Return (List_Nil, Return)
+        fun ret -> let* tl1 = get_list_at_x_back ret in Ok (List_Cons hd tl1)
+        in
+      Ok (l, back)
+  | List_Nil -> Ok (List_Nil, Ok)
   end
 
diff --git a/tests/fstar/misc/Primitives.fst b/tests/fstar/misc/Primitives.fst
index fca80829..acdb09dc 100644
--- a/tests/fstar/misc/Primitives.fst
+++ b/tests/fstar/misc/Primitives.fst
@@ -23,11 +23,11 @@ type error : Type0 =
 | OutOfFuel
 
 type result (a : Type0) : Type0 =
-| Return : v:a -> result a
+| Ok : v:a -> result a
 | Fail : e:error -> result a
 
 // Monadic return operator
-unfold let return (#a : Type0) (x : a) : result a = Return x
+unfold let return (#a : Type0) (x : a) : result a = Ok x
 
 // Monadic bind operator.
 // Allows to use the notation:
@@ -36,17 +36,17 @@ unfold let return (#a : Type0) (x : a) : result a = Return x
 // ...
 // ```
 unfold let (let*) (#a #b : Type0) (m: result a)
-  (f: (x:a) -> Pure (result b) (requires (m == Return x)) (ensures fun _ -> True)) :
+  (f: (x:a) -> Pure (result b) (requires (m == Ok x)) (ensures fun _ -> True)) :
   result b =
   match m with
-  | Return x -> f x
+  | Ok x -> f x
   | Fail e   -> Fail e
 
 // Monadic assert(...)
-let massert (b:bool) : result unit = if b then Return () else Fail Failure
+let massert (b:bool) : result unit = if b then Ok () else Fail Failure
 
 // Normalize and unwrap a successful result (used for globals).
-let eval_global (#a : Type0) (x : result a{Return? (normalize_term x)}) : a = Return?.v x
+let eval_global (#a : Type0) (x : result a{Ok? (normalize_term x)}) : a = Ok?.v x
 
 (*** Misc *)
 type char = FStar.Char.char
@@ -144,7 +144,7 @@ let scalar_max (ty : scalar_ty) : int =
 type scalar (ty : scalar_ty) : eqtype = x:int{scalar_min ty <= x && x <= scalar_max ty}
 
 let mk_scalar (ty : scalar_ty) (x : int) : result (scalar ty) =
-  if scalar_min ty <= x && scalar_max ty >= x then Return x else Fail Failure
+  if scalar_min ty <= x && scalar_max ty >= x then Ok x else Fail Failure
 
 let scalar_neg (#ty : scalar_ty) (x : scalar ty) : result (scalar ty) = mk_scalar ty (-x)
 
@@ -498,9 +498,9 @@ type core_ops_range_Range (a : Type0) = {
 
 (*** [alloc] *)
 
-let alloc_boxed_Box_deref (t : Type0) (x : t) : result t = Return x
+let alloc_boxed_Box_deref (t : Type0) (x : t) : result t = Ok x
 let alloc_boxed_Box_deref_mut (t : Type0) (x : t) : result (t & (t -> result t)) =
-  Return (x, (fun x -> Return x))
+  Ok (x, (fun x -> Ok x))
 
 // Trait instance
 let alloc_boxed_Box_coreopsDerefInst (self : Type0) : core_ops_deref_Deref self = {
@@ -528,20 +528,20 @@ let mk_array (a : Type0) (n : usize)
   l
 
 let array_index_usize (a : Type0) (n : usize) (x : array a n) (i : usize) : result a =
-  if i < length x then Return (index x i)
+  if i < length x then Ok (index x i)
   else Fail Failure
 
 let array_update_usize (a : Type0) (n : usize) (x : array a n) (i : usize) (nx : a) :
   result (array a n) =
-  if i < length x then Return (list_update x i nx)
+  if i < length x then Ok (list_update x i nx)
   else Fail Failure
 
 let array_index_mut_usize (a : Type0) (n : usize) (x : array a n) (i : usize) :
   result (a & (a -> result (array a n))) =
   match array_index_usize a n x i with
   | Fail e -> Fail e
-  | Return v ->
-    Return (v, array_update_usize a n x i)
+  | Ok v ->
+    Ok (v, array_update_usize a n x i)
 
 (*** Slice *)
 type slice (a : Type0) = s:list a{length s <= usize_max}
@@ -549,30 +549,30 @@ type slice (a : Type0) = s:list a{length s <= usize_max}
 let slice_len (a : Type0) (s : slice a) : usize = length s
 
 let slice_index_usize (a : Type0) (x : slice a) (i : usize) : result a =
-  if i < length x then Return (index x i)
+  if i < length x then Ok (index x i)
   else Fail Failure
 
 let slice_update_usize (a : Type0) (x : slice a) (i : usize) (nx : a) : result (slice a) =
-  if i < length x then Return (list_update x i nx)
+  if i < length x then Ok (list_update x i nx)
   else Fail Failure
 
 let slice_index_mut_usize (a : Type0) (s : slice a) (i : usize) :
   result (a & (a -> result (slice a))) =
   match slice_index_usize a s i with
   | Fail e -> Fail e
-  | Return x ->
-    Return (x, slice_update_usize a s i)
+  | Ok x ->
+    Ok (x, slice_update_usize a s i)
 
 (*** Subslices *)
 
-let array_to_slice (a : Type0) (n : usize) (x : array a n) : result (slice a) = Return x
+let array_to_slice (a : Type0) (n : usize) (x : array a n) : result (slice a) = Ok x
 let array_from_slice (a : Type0) (n : usize) (x : array a n) (s : slice a) : result (array a n) =
-  if length s = n then Return s
+  if length s = n then Ok s
   else Fail Failure
 
 let array_to_slice_mut (a : Type0) (n : usize) (x : array a n) :
   result (slice a & (slice a -> result (array a n))) =
-  Return (x, array_from_slice a n x)
+  Ok (x, array_from_slice a n x)
 
 // TODO: finish the definitions below (there lacks [List.drop] and [List.take] in the standard library *)
 let array_subslice (a : Type0) (n : usize) (x : array a n) (r : core_ops_range_Range usize) : result (slice a) =
@@ -598,16 +598,16 @@ let alloc_vec_Vec_len (a : Type0) (v : alloc_vec_Vec a) : usize = length v
 
 // Helper
 let alloc_vec_Vec_index_usize (#a : Type0) (v : alloc_vec_Vec a) (i : usize) : result a =
-  if i < length v then Return (index v i) else Fail Failure
+  if i < length v then Ok (index v i) else Fail Failure
 // Helper
 let alloc_vec_Vec_update_usize (#a : Type0) (v : alloc_vec_Vec a) (i : usize) (x : a) : result (alloc_vec_Vec a) =
-  if i < length v then Return (list_update v i x) else Fail Failure
+  if i < length v then Ok (list_update v i x) else Fail Failure
 
 let alloc_vec_Vec_index_mut_usize (#a : Type0) (v: alloc_vec_Vec a) (i: usize) :
   result (a & (a → result (alloc_vec_Vec a))) =
   match alloc_vec_Vec_index_usize v i with
-  | Return x ->
-    Return (x, alloc_vec_Vec_update_usize v i)
+  | Ok x ->
+    Ok (x, alloc_vec_Vec_update_usize v i)
   | Fail e -> Fail e
 
 let alloc_vec_Vec_push (a  : Type0) (v : alloc_vec_Vec a) (x : a) :
@@ -616,17 +616,17 @@ let alloc_vec_Vec_push (a  : Type0) (v : alloc_vec_Vec a) (x : a) :
   (ensures (fun res ->
     match res with
     | Fail e -> e == Failure
-    | Return v' -> length v' = length v + 1)) =
+    | Ok v' -> length v' = length v + 1)) =
   if length v < usize_max then begin
     (**) assert_norm(length [x] == 1);
     (**) append_length v [x];
     (**) assert(length (append v [x]) = length v + 1);
-    Return (append v [x])
+    Ok (append v [x])
     end
   else Fail Failure
 
 let alloc_vec_Vec_insert (a : Type0) (v : alloc_vec_Vec a) (i : usize) (x : a) : result (alloc_vec_Vec a) =
-  if i < length v then Return (list_update v i x) else Fail Failure
+  if i < length v then Ok (list_update v i x) else Fail Failure
 
 // Trait declaration: [core::slice::index::private_slice_index::Sealed]
 type core_slice_index_private_slice_index_Sealed (self : Type0) = unit
@@ -650,7 +650,7 @@ let core_slice_index_Slice_index
   let* x = inst.get i s in
   match x with
   | None -> Fail Failure
-  | Some x -> Return x
+  | Some x -> Ok x
 
 // [core::slice::index::Range:::get]: forward function
 let core_slice_index_RangeUsize_get (t : Type0) (i : core_ops_range_Range usize) (s : slice t) :