Merge pull request #64 from AeneasVerif/son/merge_back

Merge the forward/backward functions

1 files changed, 734 insertions, 0 deletions

diff --git a/tests/fstar-split/misc/Loops.Funs.fst b/tests/fstar-split/misc/Loops.Funs.fst
new file mode 100644
index 00000000..3168fddb
--- /dev/null
+++ b/tests/fstar-split/misc/Loops.Funs.fst
@@ -0,0 +1,734 @@
+(** THIS FILE WAS AUTOMATICALLY GENERATED BY AENEAS *)
+(** [loops]: function definitions *)
+module Loops.Funs
+open Primitives
+include Loops.Types
+include Loops.Clauses
+
+#set-options "--z3rlimit 50 --fuel 1 --ifuel 1"
+
+(** [loops::sum]: loop 0: forward function
+    Source: 'src/loops.rs', lines 4:0-14:1 *)
+let rec sum_loop
+  (max : u32) (i : u32) (s : u32) :
+  Tot (result u32) (decreases (sum_loop_decreases max i s))
+  =
+  if i < max
+  then let* s1 = u32_add s i in let* i1 = u32_add i 1 in sum_loop max i1 s1
+  else u32_mul s 2
+
+(** [loops::sum]: forward function
+    Source: 'src/loops.rs', lines 4:0-4:27 *)
+let sum (max : u32) : result u32 =
+  sum_loop max 0 0
+
+(** [loops::sum_with_mut_borrows]: loop 0: forward function
+    Source: 'src/loops.rs', lines 19:0-31:1 *)
+let rec sum_with_mut_borrows_loop
+  (max : u32) (mi : u32) (ms : u32) :
+  Tot (result u32) (decreases (sum_with_mut_borrows_loop_decreases max mi ms))
+  =
+  if mi < max
+  then
+    let* ms1 = u32_add ms mi in
+    let* mi1 = u32_add mi 1 in
+    sum_with_mut_borrows_loop max mi1 ms1
+  else u32_mul ms 2
+
+(** [loops::sum_with_mut_borrows]: forward function
+    Source: 'src/loops.rs', lines 19:0-19:44 *)
+let sum_with_mut_borrows (max : u32) : result u32 =
+  sum_with_mut_borrows_loop max 0 0
+
+(** [loops::sum_with_shared_borrows]: loop 0: forward function
+    Source: 'src/loops.rs', lines 34:0-48:1 *)
+let rec sum_with_shared_borrows_loop
+  (max : u32) (i : u32) (s : u32) :
+  Tot (result u32) (decreases (sum_with_shared_borrows_loop_decreases max i s))
+  =
+  if i < max
+  then
+    let* i1 = u32_add i 1 in
+    let* s1 = u32_add s i1 in
+    sum_with_shared_borrows_loop max i1 s1
+  else u32_mul s 2
+
+(** [loops::sum_with_shared_borrows]: forward function
+    Source: 'src/loops.rs', lines 34:0-34:47 *)
+let sum_with_shared_borrows (max : u32) : result u32 =
+  sum_with_shared_borrows_loop max 0 0
+
+(** [loops::clear]: loop 0: merged forward/backward function
+    (there is a single backward function, and the forward function returns ())
+    Source: 'src/loops.rs', lines 52:0-58:1 *)
+let rec clear_loop
+  (v : alloc_vec_Vec u32) (i : usize) :
+  Tot (result (alloc_vec_Vec u32)) (decreases (clear_loop_decreases v i))
+  =
+  let i1 = alloc_vec_Vec_len u32 v in
+  if i < i1
+  then
+    let* i2 = usize_add i 1 in
+    let* v1 =
+      alloc_vec_Vec_index_mut_back u32 usize
+        (core_slice_index_SliceIndexUsizeSliceTInst u32) v i 0 in
+    clear_loop v1 i2
+  else Return v
+
+(** [loops::clear]: merged forward/backward function
+    (there is a single backward function, and the forward function returns ())
+    Source: 'src/loops.rs', lines 52:0-52:30 *)
+let clear (v : alloc_vec_Vec u32) : result (alloc_vec_Vec u32) =
+  clear_loop v 0
+
+(** [loops::list_mem]: loop 0: forward function
+    Source: 'src/loops.rs', lines 66:0-75:1 *)
+let rec list_mem_loop
+  (x : u32) (ls : list_t u32) :
+  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
+  end
+
+(** [loops::list_mem]: forward function
+    Source: 'src/loops.rs', lines 66:0-66:52 *)
+let list_mem (x : u32) (ls : list_t u32) : result bool =
+  list_mem_loop x ls
+
+(** [loops::list_nth_mut_loop]: loop 0: forward function
+    Source: 'src/loops.rs', lines 78:0-88:1 *)
+let rec list_nth_mut_loop_loop
+  (t : Type0) (ls : list_t t) (i : u32) :
+  Tot (result t) (decreases (list_nth_mut_loop_loop_decreases t ls i))
+  =
+  begin match ls with
+  | List_Cons x tl ->
+    if i = 0
+    then Return x
+    else let* i1 = u32_sub i 1 in list_nth_mut_loop_loop t tl i1
+  | List_Nil -> Fail Failure
+  end
+
+(** [loops::list_nth_mut_loop]: forward function
+    Source: 'src/loops.rs', lines 78:0-78:71 *)
+let list_nth_mut_loop (t : Type0) (ls : list_t t) (i : u32) : result t =
+  list_nth_mut_loop_loop t ls i
+
+(** [loops::list_nth_mut_loop]: loop 0: backward function 0
+    Source: 'src/loops.rs', lines 78:0-88:1 *)
+let rec list_nth_mut_loop_loop_back
+  (t : Type0) (ls : list_t t) (i : u32) (ret : t) :
+  Tot (result (list_t t)) (decreases (list_nth_mut_loop_loop_decreases t ls i))
+  =
+  begin match ls with
+  | List_Cons x tl ->
+    if i = 0
+    then Return (List_Cons ret tl)
+    else
+      let* i1 = u32_sub i 1 in
+      let* tl1 = list_nth_mut_loop_loop_back t tl i1 ret in
+      Return (List_Cons x tl1)
+  | List_Nil -> Fail Failure
+  end
+
+(** [loops::list_nth_mut_loop]: backward function 0
+    Source: 'src/loops.rs', lines 78:0-78:71 *)
+let list_nth_mut_loop_back
+  (t : Type0) (ls : list_t t) (i : u32) (ret : t) : result (list_t t) =
+  list_nth_mut_loop_loop_back t ls i ret
+
+(** [loops::list_nth_shared_loop]: loop 0: forward function
+    Source: 'src/loops.rs', lines 91:0-101:1 *)
+let rec list_nth_shared_loop_loop
+  (t : Type0) (ls : list_t t) (i : u32) :
+  Tot (result t) (decreases (list_nth_shared_loop_loop_decreases t ls i))
+  =
+  begin match ls with
+  | List_Cons x tl ->
+    if i = 0
+    then Return x
+    else let* i1 = u32_sub i 1 in list_nth_shared_loop_loop t tl i1
+  | List_Nil -> Fail Failure
+  end
+
+(** [loops::list_nth_shared_loop]: forward function
+    Source: 'src/loops.rs', lines 91:0-91:66 *)
+let list_nth_shared_loop (t : Type0) (ls : list_t t) (i : u32) : result t =
+  list_nth_shared_loop_loop t ls i
+
+(** [loops::get_elem_mut]: loop 0: forward function
+    Source: 'src/loops.rs', lines 103:0-117:1 *)
+let rec get_elem_mut_loop
+  (x : usize) (ls : list_t usize) :
+  Tot (result usize) (decreases (get_elem_mut_loop_decreases x ls))
+  =
+  begin match ls with
+  | List_Cons y tl -> if y = x then Return y else get_elem_mut_loop x tl
+  | List_Nil -> Fail Failure
+  end
+
+(** [loops::get_elem_mut]: forward function
+    Source: 'src/loops.rs', lines 103:0-103:73 *)
+let get_elem_mut
+  (slots : alloc_vec_Vec (list_t usize)) (x : usize) : result usize =
+  let* l =
+    alloc_vec_Vec_index_mut (list_t usize) usize
+      (core_slice_index_SliceIndexUsizeSliceTInst (list_t usize)) slots 0 in
+  get_elem_mut_loop x l
+
+(** [loops::get_elem_mut]: loop 0: backward function 0
+    Source: 'src/loops.rs', lines 103:0-117:1 *)
+let rec get_elem_mut_loop_back
+  (x : usize) (ls : list_t usize) (ret : usize) :
+  Tot (result (list_t usize)) (decreases (get_elem_mut_loop_decreases x ls))
+  =
+  begin match ls with
+  | List_Cons y tl ->
+    if y = x
+    then Return (List_Cons ret tl)
+    else let* tl1 = get_elem_mut_loop_back x tl ret in Return (List_Cons y tl1)
+  | List_Nil -> Fail Failure
+  end
+
+(** [loops::get_elem_mut]: backward function 0
+    Source: 'src/loops.rs', lines 103:0-103:73 *)
+let get_elem_mut_back
+  (slots : alloc_vec_Vec (list_t usize)) (x : usize) (ret : usize) :
+  result (alloc_vec_Vec (list_t usize))
+  =
+  let* l =
+    alloc_vec_Vec_index_mut (list_t usize) usize
+      (core_slice_index_SliceIndexUsizeSliceTInst (list_t usize)) slots 0 in
+  let* l1 = get_elem_mut_loop_back x l ret in
+  alloc_vec_Vec_index_mut_back (list_t usize) usize
+    (core_slice_index_SliceIndexUsizeSliceTInst (list_t usize)) slots 0 l1
+
+(** [loops::get_elem_shared]: loop 0: forward function
+    Source: 'src/loops.rs', lines 119:0-133:1 *)
+let rec get_elem_shared_loop
+  (x : usize) (ls : list_t usize) :
+  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_Nil -> Fail Failure
+  end
+
+(** [loops::get_elem_shared]: forward function
+    Source: 'src/loops.rs', lines 119:0-119:68 *)
+let get_elem_shared
+  (slots : alloc_vec_Vec (list_t usize)) (x : usize) : result usize =
+  let* l =
+    alloc_vec_Vec_index (list_t usize) usize
+      (core_slice_index_SliceIndexUsizeSliceTInst (list_t usize)) slots 0 in
+  get_elem_shared_loop x l
+
+(** [loops::id_mut]: forward function
+    Source: 'src/loops.rs', lines 135:0-135:50 *)
+let id_mut (t : Type0) (ls : list_t t) : result (list_t t) =
+  Return ls
+
+(** [loops::id_mut]: backward function 0
+    Source: 'src/loops.rs', lines 135:0-135:50 *)
+let id_mut_back
+  (t : Type0) (ls : list_t t) (ret : list_t t) : result (list_t t) =
+  Return ret
+
+(** [loops::id_shared]: forward function
+    Source: 'src/loops.rs', lines 139:0-139:45 *)
+let id_shared (t : Type0) (ls : list_t t) : result (list_t t) =
+  Return ls
+
+(** [loops::list_nth_mut_loop_with_id]: loop 0: forward function
+    Source: 'src/loops.rs', lines 144:0-155:1 *)
+let rec list_nth_mut_loop_with_id_loop
+  (t : Type0) (i : u32) (ls : list_t t) :
+  Tot (result t) (decreases (list_nth_mut_loop_with_id_loop_decreases t i ls))
+  =
+  begin match ls with
+  | List_Cons x tl ->
+    if i = 0
+    then Return x
+    else let* i1 = u32_sub i 1 in list_nth_mut_loop_with_id_loop t i1 tl
+  | List_Nil -> Fail Failure
+  end
+
+(** [loops::list_nth_mut_loop_with_id]: forward function
+    Source: 'src/loops.rs', lines 144:0-144:75 *)
+let list_nth_mut_loop_with_id
+  (t : Type0) (ls : list_t t) (i : u32) : result t =
+  let* ls1 = id_mut t ls in list_nth_mut_loop_with_id_loop t i ls1
+
+(** [loops::list_nth_mut_loop_with_id]: loop 0: backward function 0
+    Source: 'src/loops.rs', lines 144:0-155:1 *)
+let rec list_nth_mut_loop_with_id_loop_back
+  (t : Type0) (i : u32) (ls : list_t t) (ret : t) :
+  Tot (result (list_t t))
+  (decreases (list_nth_mut_loop_with_id_loop_decreases t i ls))
+  =
+  begin match ls with
+  | List_Cons x tl ->
+    if i = 0
+    then Return (List_Cons ret tl)
+    else
+      let* i1 = u32_sub i 1 in
+      let* tl1 = list_nth_mut_loop_with_id_loop_back t i1 tl ret in
+      Return (List_Cons x tl1)
+  | List_Nil -> Fail Failure
+  end
+
+(** [loops::list_nth_mut_loop_with_id]: backward function 0
+    Source: 'src/loops.rs', lines 144:0-144:75 *)
+let list_nth_mut_loop_with_id_back
+  (t : Type0) (ls : list_t t) (i : u32) (ret : t) : result (list_t t) =
+  let* ls1 = id_mut t ls in
+  let* l = list_nth_mut_loop_with_id_loop_back t i ls1 ret in
+  id_mut_back t ls l
+
+(** [loops::list_nth_shared_loop_with_id]: loop 0: forward function
+    Source: 'src/loops.rs', lines 158:0-169:1 *)
+let rec list_nth_shared_loop_with_id_loop
+  (t : Type0) (i : u32) (ls : list_t t) :
+  Tot (result t)
+  (decreases (list_nth_shared_loop_with_id_loop_decreases t i ls))
+  =
+  begin match ls with
+  | List_Cons x tl ->
+    if i = 0
+    then Return x
+    else let* i1 = u32_sub i 1 in list_nth_shared_loop_with_id_loop t i1 tl
+  | List_Nil -> Fail Failure
+  end
+
+(** [loops::list_nth_shared_loop_with_id]: forward function
+    Source: 'src/loops.rs', lines 158:0-158:70 *)
+let list_nth_shared_loop_with_id
+  (t : Type0) (ls : list_t t) (i : u32) : result t =
+  let* ls1 = id_shared t ls in list_nth_shared_loop_with_id_loop t i ls1
+
+(** [loops::list_nth_mut_loop_pair]: loop 0: forward function
+    Source: 'src/loops.rs', lines 174:0-195:1 *)
+let rec list_nth_mut_loop_pair_loop
+  (t : Type0) (ls0 : list_t t) (ls1 : list_t t) (i : u32) :
+  Tot (result (t & t))
+  (decreases (list_nth_mut_loop_pair_loop_decreases t ls0 ls1 i))
+  =
+  begin match ls0 with
+  | List_Cons x0 tl0 ->
+    begin match ls1 with
+    | List_Cons x1 tl1 ->
+      if i = 0
+      then Return (x0, x1)
+      else let* i1 = u32_sub i 1 in list_nth_mut_loop_pair_loop t tl0 tl1 i1
+    | List_Nil -> Fail Failure
+    end
+  | List_Nil -> Fail Failure
+  end
+
+(** [loops::list_nth_mut_loop_pair]: forward function
+    Source: 'src/loops.rs', lines 174:0-178:27 *)
+let list_nth_mut_loop_pair
+  (t : Type0) (ls0 : list_t t) (ls1 : list_t t) (i : u32) : result (t & t) =
+  list_nth_mut_loop_pair_loop t ls0 ls1 i
+
+(** [loops::list_nth_mut_loop_pair]: loop 0: backward function 0
+    Source: 'src/loops.rs', lines 174:0-195:1 *)
+let rec list_nth_mut_loop_pair_loop_back'a
+  (t : Type0) (ls0 : list_t t) (ls1 : list_t t) (i : u32) (ret : t) :
+  Tot (result (list_t t))
+  (decreases (list_nth_mut_loop_pair_loop_decreases t ls0 ls1 i))
+  =
+  begin match ls0 with
+  | List_Cons x0 tl0 ->
+    begin match ls1 with
+    | List_Cons _ tl1 ->
+      if i = 0
+      then Return (List_Cons ret tl0)
+      else
+        let* i1 = u32_sub i 1 in
+        let* tl01 = list_nth_mut_loop_pair_loop_back'a t tl0 tl1 i1 ret in
+        Return (List_Cons x0 tl01)
+    | List_Nil -> Fail Failure
+    end
+  | List_Nil -> Fail Failure
+  end
+
+(** [loops::list_nth_mut_loop_pair]: backward function 0
+    Source: 'src/loops.rs', lines 174:0-178:27 *)
+let list_nth_mut_loop_pair_back'a
+  (t : Type0) (ls0 : list_t t) (ls1 : list_t t) (i : u32) (ret : t) :
+  result (list_t t)
+  =
+  list_nth_mut_loop_pair_loop_back'a t ls0 ls1 i ret
+
+(** [loops::list_nth_mut_loop_pair]: loop 0: backward function 1
+    Source: 'src/loops.rs', lines 174:0-195:1 *)
+let rec list_nth_mut_loop_pair_loop_back'b
+  (t : Type0) (ls0 : list_t t) (ls1 : list_t t) (i : u32) (ret : t) :
+  Tot (result (list_t t))
+  (decreases (list_nth_mut_loop_pair_loop_decreases t ls0 ls1 i))
+  =
+  begin match ls0 with
+  | List_Cons _ tl0 ->
+    begin match ls1 with
+    | List_Cons x1 tl1 ->
+      if i = 0
+      then Return (List_Cons ret tl1)
+      else
+        let* i1 = u32_sub i 1 in
+        let* tl11 = list_nth_mut_loop_pair_loop_back'b t tl0 tl1 i1 ret in
+        Return (List_Cons x1 tl11)
+    | List_Nil -> Fail Failure
+    end
+  | List_Nil -> Fail Failure
+  end
+
+(** [loops::list_nth_mut_loop_pair]: backward function 1
+    Source: 'src/loops.rs', lines 174:0-178:27 *)
+let list_nth_mut_loop_pair_back'b
+  (t : Type0) (ls0 : list_t t) (ls1 : list_t t) (i : u32) (ret : t) :
+  result (list_t t)
+  =
+  list_nth_mut_loop_pair_loop_back'b t ls0 ls1 i ret
+
+(** [loops::list_nth_shared_loop_pair]: loop 0: forward function
+    Source: 'src/loops.rs', lines 198:0-219:1 *)
+let rec list_nth_shared_loop_pair_loop
+  (t : Type0) (ls0 : list_t t) (ls1 : list_t t) (i : u32) :
+  Tot (result (t & t))
+  (decreases (list_nth_shared_loop_pair_loop_decreases t ls0 ls1 i))
+  =
+  begin match ls0 with
+  | List_Cons x0 tl0 ->
+    begin match ls1 with
+    | List_Cons x1 tl1 ->
+      if i = 0
+      then Return (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
+  | List_Nil -> Fail Failure
+  end
+
+(** [loops::list_nth_shared_loop_pair]: forward function
+    Source: 'src/loops.rs', lines 198:0-202:19 *)
+let list_nth_shared_loop_pair
+  (t : Type0) (ls0 : list_t t) (ls1 : list_t t) (i : u32) : result (t & t) =
+  list_nth_shared_loop_pair_loop t ls0 ls1 i
+
+(** [loops::list_nth_mut_loop_pair_merge]: loop 0: forward function
+    Source: 'src/loops.rs', lines 223:0-238:1 *)
+let rec list_nth_mut_loop_pair_merge_loop
+  (t : Type0) (ls0 : list_t t) (ls1 : list_t t) (i : u32) :
+  Tot (result (t & t))
+  (decreases (list_nth_mut_loop_pair_merge_loop_decreases t ls0 ls1 i))
+  =
+  begin match ls0 with
+  | List_Cons x0 tl0 ->
+    begin match ls1 with
+    | List_Cons x1 tl1 ->
+      if i = 0
+      then Return (x0, x1)
+      else
+        let* i1 = u32_sub i 1 in list_nth_mut_loop_pair_merge_loop t tl0 tl1 i1
+    | List_Nil -> Fail Failure
+    end
+  | List_Nil -> Fail Failure
+  end
+
+(** [loops::list_nth_mut_loop_pair_merge]: forward function
+    Source: 'src/loops.rs', lines 223:0-227:27 *)
+let list_nth_mut_loop_pair_merge
+  (t : Type0) (ls0 : list_t t) (ls1 : list_t t) (i : u32) : result (t & t) =
+  list_nth_mut_loop_pair_merge_loop t ls0 ls1 i
+
+(** [loops::list_nth_mut_loop_pair_merge]: loop 0: backward function 0
+    Source: 'src/loops.rs', lines 223:0-238:1 *)
+let rec list_nth_mut_loop_pair_merge_loop_back
+  (t : Type0) (ls0 : list_t t) (ls1 : list_t t) (i : u32) (ret : (t & t)) :
+  Tot (result ((list_t t) & (list_t t)))
+  (decreases (list_nth_mut_loop_pair_merge_loop_decreases t ls0 ls1 i))
+  =
+  begin match ls0 with
+  | List_Cons x0 tl0 ->
+    begin match ls1 with
+    | List_Cons x1 tl1 ->
+      if i = 0
+      then let (x, x2) = ret in Return (List_Cons x tl0, List_Cons x2 tl1)
+      else
+        let* i1 = u32_sub i 1 in
+        let* (tl01, tl11) =
+          list_nth_mut_loop_pair_merge_loop_back t tl0 tl1 i1 ret in
+        Return (List_Cons x0 tl01, List_Cons x1 tl11)
+    | List_Nil -> Fail Failure
+    end
+  | List_Nil -> Fail Failure
+  end
+
+(** [loops::list_nth_mut_loop_pair_merge]: backward function 0
+    Source: 'src/loops.rs', lines 223:0-227:27 *)
+let list_nth_mut_loop_pair_merge_back
+  (t : Type0) (ls0 : list_t t) (ls1 : list_t t) (i : u32) (ret : (t & t)) :
+  result ((list_t t) & (list_t t))
+  =
+  list_nth_mut_loop_pair_merge_loop_back t ls0 ls1 i ret
+
+(** [loops::list_nth_shared_loop_pair_merge]: loop 0: forward function
+    Source: 'src/loops.rs', lines 241:0-256:1 *)
+let rec list_nth_shared_loop_pair_merge_loop
+  (t : Type0) (ls0 : list_t t) (ls1 : list_t t) (i : u32) :
+  Tot (result (t & t))
+  (decreases (list_nth_shared_loop_pair_merge_loop_decreases t ls0 ls1 i))
+  =
+  begin match ls0 with
+  | List_Cons x0 tl0 ->
+    begin match ls1 with
+    | List_Cons x1 tl1 ->
+      if i = 0
+      then Return (x0, x1)
+      else
+        let* i1 = u32_sub i 1 in
+        list_nth_shared_loop_pair_merge_loop t tl0 tl1 i1
+    | List_Nil -> Fail Failure
+    end
+  | List_Nil -> Fail Failure
+  end
+
+(** [loops::list_nth_shared_loop_pair_merge]: forward function
+    Source: 'src/loops.rs', lines 241:0-245:19 *)
+let list_nth_shared_loop_pair_merge
+  (t : Type0) (ls0 : list_t t) (ls1 : list_t t) (i : u32) : result (t & t) =
+  list_nth_shared_loop_pair_merge_loop t ls0 ls1 i
+
+(** [loops::list_nth_mut_shared_loop_pair]: loop 0: forward function
+    Source: 'src/loops.rs', lines 259:0-274:1 *)
+let rec list_nth_mut_shared_loop_pair_loop
+  (t : Type0) (ls0 : list_t t) (ls1 : list_t t) (i : u32) :
+  Tot (result (t & t))
+  (decreases (list_nth_mut_shared_loop_pair_loop_decreases t ls0 ls1 i))
+  =
+  begin match ls0 with
+  | List_Cons x0 tl0 ->
+    begin match ls1 with
+    | List_Cons x1 tl1 ->
+      if i = 0
+      then Return (x0, x1)
+      else
+        let* i1 = u32_sub i 1 in
+        list_nth_mut_shared_loop_pair_loop t tl0 tl1 i1
+    | List_Nil -> Fail Failure
+    end
+  | List_Nil -> Fail Failure
+  end
+
+(** [loops::list_nth_mut_shared_loop_pair]: forward function
+    Source: 'src/loops.rs', lines 259:0-263:23 *)
+let list_nth_mut_shared_loop_pair
+  (t : Type0) (ls0 : list_t t) (ls1 : list_t t) (i : u32) : result (t & t) =
+  list_nth_mut_shared_loop_pair_loop t ls0 ls1 i
+
+(** [loops::list_nth_mut_shared_loop_pair]: loop 0: backward function 0
+    Source: 'src/loops.rs', lines 259:0-274:1 *)
+let rec list_nth_mut_shared_loop_pair_loop_back
+  (t : Type0) (ls0 : list_t t) (ls1 : list_t t) (i : u32) (ret : t) :
+  Tot (result (list_t t))
+  (decreases (list_nth_mut_shared_loop_pair_loop_decreases t ls0 ls1 i))
+  =
+  begin match ls0 with
+  | List_Cons x0 tl0 ->
+    begin match ls1 with
+    | List_Cons _ tl1 ->
+      if i = 0
+      then Return (List_Cons ret tl0)
+      else
+        let* i1 = u32_sub i 1 in
+        let* tl01 = list_nth_mut_shared_loop_pair_loop_back t tl0 tl1 i1 ret in
+        Return (List_Cons x0 tl01)
+    | List_Nil -> Fail Failure
+    end
+  | List_Nil -> Fail Failure
+  end
+
+(** [loops::list_nth_mut_shared_loop_pair]: backward function 0
+    Source: 'src/loops.rs', lines 259:0-263:23 *)
+let list_nth_mut_shared_loop_pair_back
+  (t : Type0) (ls0 : list_t t) (ls1 : list_t t) (i : u32) (ret : t) :
+  result (list_t t)
+  =
+  list_nth_mut_shared_loop_pair_loop_back t ls0 ls1 i ret
+
+(** [loops::list_nth_mut_shared_loop_pair_merge]: loop 0: forward function
+    Source: 'src/loops.rs', lines 278:0-293:1 *)
+let rec list_nth_mut_shared_loop_pair_merge_loop
+  (t : Type0) (ls0 : list_t t) (ls1 : list_t t) (i : u32) :
+  Tot (result (t & t))
+  (decreases (list_nth_mut_shared_loop_pair_merge_loop_decreases t ls0 ls1 i))
+  =
+  begin match ls0 with
+  | List_Cons x0 tl0 ->
+    begin match ls1 with
+    | List_Cons x1 tl1 ->
+      if i = 0
+      then Return (x0, x1)
+      else
+        let* i1 = u32_sub i 1 in
+        list_nth_mut_shared_loop_pair_merge_loop t tl0 tl1 i1
+    | List_Nil -> Fail Failure
+    end
+  | List_Nil -> Fail Failure
+  end
+
+(** [loops::list_nth_mut_shared_loop_pair_merge]: forward function
+    Source: 'src/loops.rs', lines 278:0-282:23 *)
+let list_nth_mut_shared_loop_pair_merge
+  (t : Type0) (ls0 : list_t t) (ls1 : list_t t) (i : u32) : result (t & t) =
+  list_nth_mut_shared_loop_pair_merge_loop t ls0 ls1 i
+
+(** [loops::list_nth_mut_shared_loop_pair_merge]: loop 0: backward function 0
+    Source: 'src/loops.rs', lines 278:0-293:1 *)
+let rec list_nth_mut_shared_loop_pair_merge_loop_back
+  (t : Type0) (ls0 : list_t t) (ls1 : list_t t) (i : u32) (ret : t) :
+  Tot (result (list_t t))
+  (decreases (list_nth_mut_shared_loop_pair_merge_loop_decreases t ls0 ls1 i))
+  =
+  begin match ls0 with
+  | List_Cons x0 tl0 ->
+    begin match ls1 with
+    | List_Cons _ tl1 ->
+      if i = 0
+      then Return (List_Cons ret tl0)
+      else
+        let* i1 = u32_sub i 1 in
+        let* tl01 =
+          list_nth_mut_shared_loop_pair_merge_loop_back t tl0 tl1 i1 ret in
+        Return (List_Cons x0 tl01)
+    | List_Nil -> Fail Failure
+    end
+  | List_Nil -> Fail Failure
+  end
+
+(** [loops::list_nth_mut_shared_loop_pair_merge]: backward function 0
+    Source: 'src/loops.rs', lines 278:0-282:23 *)
+let list_nth_mut_shared_loop_pair_merge_back
+  (t : Type0) (ls0 : list_t t) (ls1 : list_t t) (i : u32) (ret : t) :
+  result (list_t t)
+  =
+  list_nth_mut_shared_loop_pair_merge_loop_back t ls0 ls1 i ret
+
+(** [loops::list_nth_shared_mut_loop_pair]: loop 0: forward function
+    Source: 'src/loops.rs', lines 297:0-312:1 *)
+let rec list_nth_shared_mut_loop_pair_loop
+  (t : Type0) (ls0 : list_t t) (ls1 : list_t t) (i : u32) :
+  Tot (result (t & t))
+  (decreases (list_nth_shared_mut_loop_pair_loop_decreases t ls0 ls1 i))
+  =
+  begin match ls0 with
+  | List_Cons x0 tl0 ->
+    begin match ls1 with
+    | List_Cons x1 tl1 ->
+      if i = 0
+      then Return (x0, x1)
+      else
+        let* i1 = u32_sub i 1 in
+        list_nth_shared_mut_loop_pair_loop t tl0 tl1 i1
+    | List_Nil -> Fail Failure
+    end
+  | List_Nil -> Fail Failure
+  end
+
+(** [loops::list_nth_shared_mut_loop_pair]: forward function
+    Source: 'src/loops.rs', lines 297:0-301:23 *)
+let list_nth_shared_mut_loop_pair
+  (t : Type0) (ls0 : list_t t) (ls1 : list_t t) (i : u32) : result (t & t) =
+  list_nth_shared_mut_loop_pair_loop t ls0 ls1 i
+
+(** [loops::list_nth_shared_mut_loop_pair]: loop 0: backward function 1
+    Source: 'src/loops.rs', lines 297:0-312:1 *)
+let rec list_nth_shared_mut_loop_pair_loop_back
+  (t : Type0) (ls0 : list_t t) (ls1 : list_t t) (i : u32) (ret : t) :
+  Tot (result (list_t t))
+  (decreases (list_nth_shared_mut_loop_pair_loop_decreases t ls0 ls1 i))
+  =
+  begin match ls0 with
+  | List_Cons _ tl0 ->
+    begin match ls1 with
+    | List_Cons x1 tl1 ->
+      if i = 0
+      then Return (List_Cons ret tl1)
+      else
+        let* i1 = u32_sub i 1 in
+        let* tl11 = list_nth_shared_mut_loop_pair_loop_back t tl0 tl1 i1 ret in
+        Return (List_Cons x1 tl11)
+    | List_Nil -> Fail Failure
+    end
+  | List_Nil -> Fail Failure
+  end
+
+(** [loops::list_nth_shared_mut_loop_pair]: backward function 1
+    Source: 'src/loops.rs', lines 297:0-301:23 *)
+let list_nth_shared_mut_loop_pair_back
+  (t : Type0) (ls0 : list_t t) (ls1 : list_t t) (i : u32) (ret : t) :
+  result (list_t t)
+  =
+  list_nth_shared_mut_loop_pair_loop_back t ls0 ls1 i ret
+
+(** [loops::list_nth_shared_mut_loop_pair_merge]: loop 0: forward function
+    Source: 'src/loops.rs', lines 316:0-331:1 *)
+let rec list_nth_shared_mut_loop_pair_merge_loop
+  (t : Type0) (ls0 : list_t t) (ls1 : list_t t) (i : u32) :
+  Tot (result (t & t))
+  (decreases (list_nth_shared_mut_loop_pair_merge_loop_decreases t ls0 ls1 i))
+  =
+  begin match ls0 with
+  | List_Cons x0 tl0 ->
+    begin match ls1 with
+    | List_Cons x1 tl1 ->
+      if i = 0
+      then Return (x0, x1)
+      else
+        let* i1 = u32_sub i 1 in
+        list_nth_shared_mut_loop_pair_merge_loop t tl0 tl1 i1
+    | List_Nil -> Fail Failure
+    end
+  | List_Nil -> Fail Failure
+  end
+
+(** [loops::list_nth_shared_mut_loop_pair_merge]: forward function
+    Source: 'src/loops.rs', lines 316:0-320:23 *)
+let list_nth_shared_mut_loop_pair_merge
+  (t : Type0) (ls0 : list_t t) (ls1 : list_t t) (i : u32) : result (t & t) =
+  list_nth_shared_mut_loop_pair_merge_loop t ls0 ls1 i
+
+(** [loops::list_nth_shared_mut_loop_pair_merge]: loop 0: backward function 0
+    Source: 'src/loops.rs', lines 316:0-331:1 *)
+let rec list_nth_shared_mut_loop_pair_merge_loop_back
+  (t : Type0) (ls0 : list_t t) (ls1 : list_t t) (i : u32) (ret : t) :
+  Tot (result (list_t t))
+  (decreases (list_nth_shared_mut_loop_pair_merge_loop_decreases t ls0 ls1 i))
+  =
+  begin match ls0 with
+  | List_Cons _ tl0 ->
+    begin match ls1 with
+    | List_Cons x1 tl1 ->
+      if i = 0
+      then Return (List_Cons ret tl1)
+      else
+        let* i1 = u32_sub i 1 in
+        let* tl11 =
+          list_nth_shared_mut_loop_pair_merge_loop_back t tl0 tl1 i1 ret in
+        Return (List_Cons x1 tl11)
+    | List_Nil -> Fail Failure
+    end
+  | List_Nil -> Fail Failure
+  end
+
+(** [loops::list_nth_shared_mut_loop_pair_merge]: backward function 0
+    Source: 'src/loops.rs', lines 316:0-320:23 *)
+let list_nth_shared_mut_loop_pair_merge_back
+  (t : Type0) (ls0 : list_t t) (ls1 : list_t t) (i : u32) (ret : t) :
+  result (list_t t)
+  =
+  list_nth_shared_mut_loop_pair_merge_loop_back t ls0 ls1 i ret
+