Implement two phases of loops join + collapse

2 files changed, 16 insertions, 453 deletions

diff --git a/tests/fstar/misc/Loops.Clauses.Template.fst b/tests/fstar/misc/Loops.Clauses.Template.fst
index 77f9c3e4..21c128bb 100644
--- a/tests/fstar/misc/Loops.Clauses.Template.fst
+++ b/tests/fstar/misc/Loops.Clauses.Template.fst
@@ -30,111 +30,6 @@ let sum_array_loop_decreases (n : usize) (a : array u32 n) (i : usize)
   (s : u32) : nat =
   admit ()
 
-(** [loops::clear]: decreases clause
-    Source: 'tests/src/loops.rs', lines 62:0-68:1 *)
-unfold
-let clear_loop_decreases (v : alloc_vec_Vec u32) (i : usize) : nat = admit ()
-
-(** [loops::list_mem]: decreases clause
-    Source: 'tests/src/loops.rs', lines 76:0-85:1 *)
-unfold let list_mem_loop_decreases (x : u32) (ls : list_t u32) : nat = admit ()
-
-(** [loops::list_nth_mut_loop]: decreases clause
-    Source: 'tests/src/loops.rs', lines 88:0-98:1 *)
-unfold
-let list_nth_mut_loop_loop_decreases (t : Type0) (ls : list_t t) (i : u32) :
-  nat =
-  admit ()
-
-(** [loops::list_nth_shared_loop]: decreases clause
-    Source: 'tests/src/loops.rs', lines 101:0-111:1 *)
-unfold
-let list_nth_shared_loop_loop_decreases (t : Type0) (ls : list_t t) (i : u32) :
-  nat =
-  admit ()
-
-(** [loops::get_elem_mut]: decreases clause
-    Source: 'tests/src/loops.rs', lines 113:0-127:1 *)
-unfold
-let get_elem_mut_loop_decreases (x : usize) (ls : list_t usize) : nat =
-  admit ()
-
-(** [loops::get_elem_shared]: decreases clause
-    Source: 'tests/src/loops.rs', lines 129:0-143:1 *)
-unfold
-let get_elem_shared_loop_decreases (x : usize) (ls : list_t usize) : nat =
-  admit ()
-
-(** [loops::list_nth_mut_loop_with_id]: decreases clause
-    Source: 'tests/src/loops.rs', lines 154:0-165:1 *)
-unfold
-let list_nth_mut_loop_with_id_loop_decreases (t : Type0) (i : u32)
-  (ls : list_t t) : nat =
-  admit ()
-
-(** [loops::list_nth_shared_loop_with_id]: decreases clause
-    Source: 'tests/src/loops.rs', lines 168:0-179:1 *)
-unfold
-let list_nth_shared_loop_with_id_loop_decreases (t : Type0) (i : u32)
-  (ls : list_t t) : nat =
-  admit ()
-
-(** [loops::list_nth_mut_loop_pair]: decreases clause
-    Source: 'tests/src/loops.rs', lines 184:0-205:1 *)
-unfold
-let list_nth_mut_loop_pair_loop_decreases (t : Type0) (ls0 : list_t t)
-  (ls1 : list_t t) (i : u32) : nat =
-  admit ()
-
-(** [loops::list_nth_shared_loop_pair]: decreases clause
-    Source: 'tests/src/loops.rs', lines 208:0-229:1 *)
-unfold
-let list_nth_shared_loop_pair_loop_decreases (t : Type0) (ls0 : list_t t)
-  (ls1 : list_t t) (i : u32) : nat =
-  admit ()
-
-(** [loops::list_nth_mut_loop_pair_merge]: decreases clause
-    Source: 'tests/src/loops.rs', lines 233:0-248:1 *)
-unfold
-let list_nth_mut_loop_pair_merge_loop_decreases (t : Type0) (ls0 : list_t t)
-  (ls1 : list_t t) (i : u32) : nat =
-  admit ()
-
-(** [loops::list_nth_shared_loop_pair_merge]: decreases clause
-    Source: 'tests/src/loops.rs', lines 251:0-266:1 *)
-unfold
-let list_nth_shared_loop_pair_merge_loop_decreases (t : Type0) (ls0 : list_t t)
-  (ls1 : list_t t) (i : u32) : nat =
-  admit ()
-
-(** [loops::list_nth_mut_shared_loop_pair]: decreases clause
-    Source: 'tests/src/loops.rs', lines 269:0-284:1 *)
-unfold
-let list_nth_mut_shared_loop_pair_loop_decreases (t : Type0) (ls0 : list_t t)
-  (ls1 : list_t t) (i : u32) : nat =
-  admit ()
-
-(** [loops::list_nth_mut_shared_loop_pair_merge]: decreases clause
-    Source: 'tests/src/loops.rs', lines 288:0-303:1 *)
-unfold
-let list_nth_mut_shared_loop_pair_merge_loop_decreases (t : Type0)
-  (ls0 : list_t t) (ls1 : list_t t) (i : u32) : nat =
-  admit ()
-
-(** [loops::list_nth_shared_mut_loop_pair]: decreases clause
-    Source: 'tests/src/loops.rs', lines 307:0-322:1 *)
-unfold
-let list_nth_shared_mut_loop_pair_loop_decreases (t : Type0) (ls0 : list_t t)
-  (ls1 : list_t t) (i : u32) : nat =
-  admit ()
-
-(** [loops::list_nth_shared_mut_loop_pair_merge]: decreases clause
-    Source: 'tests/src/loops.rs', lines 326:0-341:1 *)
-unfold
-let list_nth_shared_mut_loop_pair_merge_loop_decreases (t : Type0)
-  (ls0 : list_t t) (ls1 : list_t t) (i : u32) : nat =
-  admit ()
-
 (** [loops::ignore_input_mut_borrow]: decreases clause
     Source: 'tests/src/loops.rs', lines 345:0-349:1 *)
 unfold let ignore_input_mut_borrow_loop_decreases (i : u32) : nat = admit ()
diff --git a/tests/fstar/misc/Loops.Funs.fst b/tests/fstar/misc/Loops.Funs.fst
index 0eafeebb..dc53a04b 100644
--- a/tests/fstar/misc/Loops.Funs.fst
+++ b/tests/fstar/misc/Loops.Funs.fst
@@ -77,62 +77,15 @@ let rec sum_array_loop
 let sum_array (n : usize) (a : array u32 n) : result u32 =
   sum_array_loop n a 0 0
 
-(** [loops::clear]: loop 0:
-    Source: 'tests/src/loops.rs', lines 62:0-68:1 *)
-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* (_, index_mut_back) =
-      alloc_vec_Vec_index_mut u32 usize
-        (core_slice_index_SliceIndexUsizeSliceTInst u32) v i in
-    let* i2 = usize_add i 1 in
-    let* v1 = index_mut_back 0 in
-    clear_loop v1 i2
-  else Ok v
-
 (** [loops::clear]:
     Source: 'tests/src/loops.rs', lines 62:0-62:30 *)
 let clear (v : alloc_vec_Vec u32) : result (alloc_vec_Vec u32) =
-  clear_loop v 0
-
-(** [loops::list_mem]: loop 0:
-    Source: 'tests/src/loops.rs', lines 76:0-85:1 *)
-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 Ok true else list_mem_loop x tl
-  | List_Nil -> Ok false
-  end
+  admit
 
 (** [loops::list_mem]:
     Source: 'tests/src/loops.rs', lines 76:0-76:52 *)
 let list_mem (x : u32) (ls : list_t u32) : result bool =
-  list_mem_loop x ls
-
-(** [loops::list_nth_mut_loop]: loop 0:
-    Source: 'tests/src/loops.rs', lines 88:0-98:1 *)
-let rec list_nth_mut_loop_loop
-  (t : Type0) (ls : list_t t) (i : u32) :
-  Tot (result (t & (t -> 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 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 Ok (List_Cons x tl1) in
-      Ok (x1, back1)
-  | List_Nil -> Fail Failure
-  end
+  admit
 
 (** [loops::list_nth_mut_loop]:
     Source: 'tests/src/loops.rs', lines 88:0-88:71 *)
@@ -140,44 +93,12 @@ let list_nth_mut_loop
   (t : Type0) (ls : list_t t) (i : u32) :
   result (t & (t -> result (list_t t)))
   =
-  list_nth_mut_loop_loop t ls i
-
-(** [loops::list_nth_shared_loop]: loop 0:
-    Source: 'tests/src/loops.rs', lines 101:0-111:1 *)
-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 Ok x
-    else let* i1 = u32_sub i 1 in list_nth_shared_loop_loop t tl i1
-  | List_Nil -> Fail Failure
-  end
+  admit
 
 (** [loops::list_nth_shared_loop]:
     Source: 'tests/src/loops.rs', lines 101:0-101:66 *)
 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:
-    Source: 'tests/src/loops.rs', lines 113:0-127:1 *)
-let rec get_elem_mut_loop
-  (x : usize) (ls : list_t usize) :
-  Tot (result (usize & (usize -> result (list_t usize))))
-  (decreases (get_elem_mut_loop_decreases x ls))
-  =
-  begin match ls with
-  | List_Cons y tl ->
-    if y = x
-    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 Ok (List_Cons y tl1) in
-      Ok (i, back1)
-  | List_Nil -> Fail Failure
-  end
+  admit
 
 (** [loops::get_elem_mut]:
     Source: 'tests/src/loops.rs', lines 113:0-113:73 *)
@@ -185,32 +106,13 @@ let get_elem_mut
   (slots : alloc_vec_Vec (list_t usize)) (x : usize) :
   result (usize & (usize -> result (alloc_vec_Vec (list_t usize))))
   =
-  let* (ls, index_mut_back) =
-    alloc_vec_Vec_index_mut (list_t usize) usize
-      (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
-  Ok (i, back1)
-
-(** [loops::get_elem_shared]: loop 0:
-    Source: 'tests/src/loops.rs', lines 129:0-143:1 *)
-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 Ok y else get_elem_shared_loop x tl
-  | List_Nil -> Fail Failure
-  end
+  admit
 
 (** [loops::get_elem_shared]:
     Source: 'tests/src/loops.rs', lines 129:0-129:68 *)
 let get_elem_shared
   (slots : alloc_vec_Vec (list_t usize)) (x : usize) : result usize =
-  let* ls =
-    alloc_vec_Vec_index (list_t usize) usize
-      (core_slice_index_SliceIndexUsizeSliceTInst (list_t usize)) slots 0 in
-  get_elem_shared_loop x ls
+  admit
 
 (** [loops::id_mut]:
     Source: 'tests/src/loops.rs', lines 145:0-145:50 *)
@@ -225,85 +127,19 @@ let id_mut
 let id_shared (t : Type0) (ls : list_t t) : result (list_t t) =
   Ok ls
 
-(** [loops::list_nth_mut_loop_with_id]: loop 0:
-    Source: 'tests/src/loops.rs', lines 154:0-165:1 *)
-let rec list_nth_mut_loop_with_id_loop
-  (t : Type0) (i : u32) (ls : list_t t) :
-  Tot (result (t & (t -> 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 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 Ok (List_Cons x tl1) in
-      Ok (x1, back1)
-  | List_Nil -> Fail Failure
-  end
-
 (** [loops::list_nth_mut_loop_with_id]:
     Source: 'tests/src/loops.rs', lines 154:0-154:75 *)
 let list_nth_mut_loop_with_id
   (t : Type0) (ls : list_t t) (i : u32) :
   result (t & (t -> result (list_t t)))
   =
-  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
-  Ok (x, back1)
-
-(** [loops::list_nth_shared_loop_with_id]: loop 0:
-    Source: 'tests/src/loops.rs', lines 168:0-179:1 *)
-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 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
+  admit
 
 (** [loops::list_nth_shared_loop_with_id]:
     Source: 'tests/src/loops.rs', lines 168:0-168:70 *)
 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:
-    Source: 'tests/src/loops.rs', lines 184:0-205:1 *)
-let rec list_nth_mut_loop_pair_loop
-  (t : Type0) (ls0 : list_t t) (ls1 : list_t t) (i : u32) :
-  Tot (result ((t & t) & (t -> result (list_t t)) & (t -> 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 x1 tl1 ->
-      if i = 0
-      then
-        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 Ok (List_Cons x0 tl01) in
-        let 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
-  end
+  admit
 
 (** [loops::list_nth_mut_loop_pair]:
     Source: 'tests/src/loops.rs', lines 184:0-188:27 *)
@@ -311,62 +147,13 @@ let list_nth_mut_loop_pair
   (t : Type0) (ls0 : list_t t) (ls1 : list_t t) (i : u32) :
   result ((t & t) & (t -> result (list_t t)) & (t -> result (list_t t)))
   =
-  list_nth_mut_loop_pair_loop t ls0 ls1 i
-
-(** [loops::list_nth_shared_loop_pair]: loop 0:
-    Source: 'tests/src/loops.rs', lines 208:0-229:1 *)
-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 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
-  | List_Nil -> Fail Failure
-  end
+  admit
 
 (** [loops::list_nth_shared_loop_pair]:
     Source: 'tests/src/loops.rs', lines 208:0-212:19 *)
 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:
-    Source: 'tests/src/loops.rs', lines 233:0-248:1 *)
-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) & ((t & t) -> 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 back =
-          fun ret ->
-            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
-            Ok (List_Cons x0 tl01, List_Cons x1 tl11) in
-        Ok (p, back1)
-    | List_Nil -> Fail Failure
-    end
-  | List_Nil -> Fail Failure
-  end
+  admit
 
 (** [loops::list_nth_mut_loop_pair_merge]:
     Source: 'tests/src/loops.rs', lines 233:0-237:27 *)
@@ -374,58 +161,13 @@ let list_nth_mut_loop_pair_merge
   (t : Type0) (ls0 : list_t t) (ls1 : list_t t) (i : u32) :
   result ((t & t) & ((t & t) -> result ((list_t t) & (list_t t))))
   =
-  list_nth_mut_loop_pair_merge_loop t ls0 ls1 i
-
-(** [loops::list_nth_shared_loop_pair_merge]: loop 0:
-    Source: 'tests/src/loops.rs', lines 251:0-266:1 *)
-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 Ok (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
+  admit
 
 (** [loops::list_nth_shared_loop_pair_merge]:
     Source: 'tests/src/loops.rs', lines 251:0-255:19 *)
 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:
-    Source: 'tests/src/loops.rs', lines 269:0-284:1 *)
-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) & (t -> 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 x1 tl1 ->
-      if i = 0
-      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 Ok (List_Cons x0 tl01)
-          in
-        Ok (p, back1)
-    | List_Nil -> Fail Failure
-    end
-  | List_Nil -> Fail Failure
-  end
+  admit
 
 (** [loops::list_nth_mut_shared_loop_pair]:
     Source: 'tests/src/loops.rs', lines 269:0-273:23 *)
@@ -433,32 +175,7 @@ let list_nth_mut_shared_loop_pair
   (t : Type0) (ls0 : list_t t) (ls1 : list_t t) (i : u32) :
   result ((t & t) & (t -> result (list_t t)))
   =
-  list_nth_mut_shared_loop_pair_loop t ls0 ls1 i
-
-(** [loops::list_nth_mut_shared_loop_pair_merge]: loop 0:
-    Source: 'tests/src/loops.rs', lines 288:0-303:1 *)
-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) & (t -> 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 x1 tl1 ->
-      if i = 0
-      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 Ok (List_Cons x0 tl01)
-          in
-        Ok (p, back1)
-    | List_Nil -> Fail Failure
-    end
-  | List_Nil -> Fail Failure
-  end
+  admit
 
 (** [loops::list_nth_mut_shared_loop_pair_merge]:
     Source: 'tests/src/loops.rs', lines 288:0-292:23 *)
@@ -466,31 +183,7 @@ let list_nth_mut_shared_loop_pair_merge
   (t : Type0) (ls0 : list_t t) (ls1 : list_t t) (i : u32) :
   result ((t & t) & (t -> result (list_t t)))
   =
-  list_nth_mut_shared_loop_pair_merge_loop t ls0 ls1 i
-
-(** [loops::list_nth_shared_mut_loop_pair]: loop 0:
-    Source: 'tests/src/loops.rs', lines 307:0-322:1 *)
-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) & (t -> result (list_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 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 Ok (List_Cons x1 tl11)
-          in
-        Ok (p, back1)
-    | List_Nil -> Fail Failure
-    end
-  | List_Nil -> Fail Failure
-  end
+  admit
 
 (** [loops::list_nth_shared_mut_loop_pair]:
     Source: 'tests/src/loops.rs', lines 307:0-311:23 *)
@@ -498,32 +191,7 @@ let list_nth_shared_mut_loop_pair
   (t : Type0) (ls0 : list_t t) (ls1 : list_t t) (i : u32) :
   result ((t & t) & (t -> result (list_t t)))
   =
-  list_nth_shared_mut_loop_pair_loop t ls0 ls1 i
-
-(** [loops::list_nth_shared_mut_loop_pair_merge]: loop 0:
-    Source: 'tests/src/loops.rs', lines 326:0-341:1 *)
-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) & (t -> result (list_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 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 Ok (List_Cons x1 tl11)
-          in
-        Ok (p, back1)
-    | List_Nil -> Fail Failure
-    end
-  | List_Nil -> Fail Failure
-  end
+  admit
 
 (** [loops::list_nth_shared_mut_loop_pair_merge]:
     Source: 'tests/src/loops.rs', lines 326:0-330:23 *)
@@ -531,7 +199,7 @@ let list_nth_shared_mut_loop_pair_merge
   (t : Type0) (ls0 : list_t t) (ls1 : list_t t) (i : u32) :
   result ((t & t) & (t -> result (list_t t)))
   =
-  list_nth_shared_mut_loop_pair_merge_loop t ls0 ls1 i
+  admit
 
 (** [loops::ignore_input_mut_borrow]: loop 0:
     Source: 'tests/src/loops.rs', lines 345:0-349:1 *)