diff options
Diffstat (limited to 'tests/fstar/hashmap')
| -rw-r--r-- | tests/fstar/hashmap/Hashmap.Funs.fst | 540 | ||||
| -rw-r--r-- | tests/fstar/hashmap/Primitives.fst | 4 |
2 files changed, 157 insertions, 387 deletions
diff --git a/tests/fstar/hashmap/Hashmap.Funs.fst b/tests/fstar/hashmap/Hashmap.Funs.fst index 68bda221..0140aadc 100644 --- a/tests/fstar/hashmap/Hashmap.Funs.fst +++ b/tests/fstar/hashmap/Hashmap.Funs.fst @@ -17,15 +17,10 @@ let rec hash_map_allocate_slots_loop_fwd (decreases (hash_map_allocate_slots_loop_decreases t slots n)) = if n > 0 - then - begin match vec_push_back (list_t t) slots ListNil with - | Fail e -> Fail e - | Return slots0 -> - begin match usize_sub n 1 with - | Fail e -> Fail e - | Return n0 -> hash_map_allocate_slots_loop_fwd t slots0 n0 - end - end + then begin + let* slots0 = vec_push_back (list_t t) slots ListNil in + let* n0 = usize_sub n 1 in + hash_map_allocate_slots_loop_fwd t slots0 n0 end else Return slots (** [hashmap::HashMap::{0}::allocate_slots] *) @@ -40,19 +35,10 @@ let hash_map_new_with_capacity_fwd result (hash_map_t t) = let v = vec_new (list_t t) in - begin match hash_map_allocate_slots_fwd t v capacity with - | Fail e -> Fail e - | Return slots -> - begin match usize_mul capacity max_load_dividend with - | Fail e -> Fail e - | Return i -> - begin match usize_div i max_load_divisor with - | Fail e -> Fail e - | Return i0 -> - Return (Mkhash_map_t 0 (max_load_dividend, max_load_divisor) i0 slots) - end - end - end + let* slots = hash_map_allocate_slots_fwd t v capacity in + let* i = usize_mul capacity max_load_dividend in + let* i0 = usize_div i max_load_divisor in + Return (Mkhash_map_t 0 (max_load_dividend, max_load_divisor) i0 slots) (** [hashmap::HashMap::{0}::new] *) let hash_map_new_fwd (t : Type0) : result (hash_map_t t) = @@ -66,26 +52,18 @@ let rec hash_map_clear_loop_fwd_back = let i0 = vec_len (list_t t) slots in if i < i0 - then - begin match usize_add i 1 with - | Fail e -> Fail e - | Return i1 -> - begin match vec_index_mut_back (list_t t) slots i ListNil with - | Fail e -> Fail e - | Return slots0 -> hash_map_clear_loop_fwd_back t slots0 i1 - end - end + then begin + let* i1 = usize_add i 1 in + let* slots0 = vec_index_mut_back (list_t t) slots i ListNil in + hash_map_clear_loop_fwd_back t slots0 i1 end else Return slots (** [hashmap::HashMap::{0}::clear] *) let hash_map_clear_fwd_back (t : Type0) (self : hash_map_t t) : result (hash_map_t t) = - begin match hash_map_clear_loop_fwd_back t self.hash_map_slots 0 with - | Fail e -> Fail e - | Return v -> - Return (Mkhash_map_t 0 self.hash_map_max_load_factor self.hash_map_max_load - v) - end + let* v = hash_map_clear_loop_fwd_back t self.hash_map_slots 0 in + Return (Mkhash_map_t 0 self.hash_map_max_load_factor self.hash_map_max_load + v) (** [hashmap::HashMap::{0}::len] *) let hash_map_len_fwd (t : Type0) (self : hash_map_t t) : result usize = @@ -120,11 +98,9 @@ let rec hash_map_insert_in_list_loop_back | ListCons ckey cvalue tl -> if ckey = key then Return (ListCons ckey value tl) - else - begin match hash_map_insert_in_list_loop_back t key value tl with - | Fail e -> Fail e - | Return tl0 -> Return (ListCons ckey cvalue tl0) - end + else begin + let* tl0 = hash_map_insert_in_list_loop_back t key value tl in + Return (ListCons ckey cvalue tl0) end | ListNil -> let l = ListNil in Return (ListCons key value l) end @@ -138,55 +114,23 @@ let hash_map_insert_no_resize_fwd_back (t : Type0) (self : hash_map_t t) (key : usize) (value : t) : result (hash_map_t t) = - begin match hash_key_fwd key with - | Fail e -> Fail e - | Return hash -> - let i = vec_len (list_t t) self.hash_map_slots in - begin match usize_rem hash i with - | Fail e -> Fail e - | Return hash_mod -> - begin match vec_index_mut_fwd (list_t t) self.hash_map_slots hash_mod - with - | Fail e -> Fail e - | Return l -> - begin match hash_map_insert_in_list_fwd t key value l with - | Fail e -> Fail e - | Return inserted -> - if inserted - then - begin match usize_add self.hash_map_num_entries 1 with - | Fail e -> Fail e - | Return i0 -> - begin match hash_map_insert_in_list_back t key value l with - | Fail e -> Fail e - | Return l0 -> - begin match - vec_index_mut_back (list_t t) self.hash_map_slots hash_mod l0 - with - | Fail e -> Fail e - | Return v -> - Return (Mkhash_map_t i0 self.hash_map_max_load_factor - self.hash_map_max_load v) - end - end - end - else - begin match hash_map_insert_in_list_back t key value l with - | Fail e -> Fail e - | Return l0 -> - begin match - vec_index_mut_back (list_t t) self.hash_map_slots hash_mod l0 - with - | Fail e -> Fail e - | Return v -> - Return (Mkhash_map_t self.hash_map_num_entries - self.hash_map_max_load_factor self.hash_map_max_load v) - end - end - end - end - end - end + let* hash = hash_key_fwd key in + let i = vec_len (list_t t) self.hash_map_slots in + let* hash_mod = usize_rem hash i in + let* l = vec_index_mut_fwd (list_t t) self.hash_map_slots hash_mod in + let* inserted = hash_map_insert_in_list_fwd t key value l in + if inserted + then begin + let* i0 = usize_add self.hash_map_num_entries 1 in + let* l0 = hash_map_insert_in_list_back t key value l in + let* v = vec_index_mut_back (list_t t) self.hash_map_slots hash_mod l0 in + Return (Mkhash_map_t i0 self.hash_map_max_load_factor + self.hash_map_max_load v) end + else begin + let* l0 = hash_map_insert_in_list_back t key value l in + let* v = vec_index_mut_back (list_t t) self.hash_map_slots hash_mod l0 in + Return (Mkhash_map_t self.hash_map_num_entries + self.hash_map_max_load_factor self.hash_map_max_load v) end (** [core::num::u32::{9}::MAX] *) let core_num_u32_max_body : result u32 = Return 4294967295 @@ -200,11 +144,8 @@ let rec hash_map_move_elements_from_list_loop_fwd_back = begin match ls with | ListCons k v tl -> - begin match hash_map_insert_no_resize_fwd_back t ntable k v with - | Fail e -> Fail e - | Return ntable0 -> - hash_map_move_elements_from_list_loop_fwd_back t ntable0 tl - end + let* ntable0 = hash_map_insert_no_resize_fwd_back t ntable k v in + hash_map_move_elements_from_list_loop_fwd_back t ntable0 tl | ListNil -> Return ntable end @@ -221,26 +162,14 @@ let rec hash_map_move_elements_loop_fwd_back = let i0 = vec_len (list_t t) slots in if i < i0 - then - begin match vec_index_mut_fwd (list_t t) slots i with - | Fail e -> Fail e - | Return l -> - let ls = mem_replace_fwd (list_t t) l ListNil in - begin match hash_map_move_elements_from_list_fwd_back t ntable ls with - | Fail e -> Fail e - | Return ntable0 -> - begin match usize_add i 1 with - | Fail e -> Fail e - | Return i1 -> - let l0 = mem_replace_back (list_t t) l ListNil in - begin match vec_index_mut_back (list_t t) slots i l0 with - | Fail e -> Fail e - | Return slots0 -> - hash_map_move_elements_loop_fwd_back t ntable0 slots0 i1 - end - end - end - end + then begin + let* l = vec_index_mut_fwd (list_t t) slots i in + let ls = mem_replace_fwd (list_t t) l ListNil in + let* ntable0 = hash_map_move_elements_from_list_fwd_back t ntable ls in + let* i1 = usize_add i 1 in + let l0 = mem_replace_back (list_t t) l ListNil in + let* slots0 = vec_index_mut_back (list_t t) slots i l0 in + hash_map_move_elements_loop_fwd_back t ntable0 slots0 i1 end else Return (ntable, slots) (** [hashmap::HashMap::{0}::move_elements] *) @@ -253,58 +182,33 @@ let hash_map_move_elements_fwd_back (** [hashmap::HashMap::{0}::try_resize] *) let hash_map_try_resize_fwd_back (t : Type0) (self : hash_map_t t) : result (hash_map_t t) = - begin match scalar_cast U32 Usize core_num_u32_max_c with - | Fail e -> Fail e - | Return max_usize -> - let capacity = vec_len (list_t t) self.hash_map_slots in - begin match usize_div max_usize 2 with - | Fail e -> Fail e - | Return n1 -> - let (i, i0) = self.hash_map_max_load_factor in - begin match usize_div n1 i with - | Fail e -> Fail e - | Return i1 -> - if capacity <= i1 - then - begin match usize_mul capacity 2 with - | Fail e -> Fail e - | Return i2 -> - begin match hash_map_new_with_capacity_fwd t i2 i i0 with - | Fail e -> Fail e - | Return ntable -> - begin match - hash_map_move_elements_fwd_back t ntable self.hash_map_slots 0 - with - | Fail e -> Fail e - | Return (ntable0, _) -> - Return (Mkhash_map_t self.hash_map_num_entries (i, i0) - ntable0.hash_map_max_load ntable0.hash_map_slots) - end - end - end - else - Return (Mkhash_map_t self.hash_map_num_entries (i, i0) - self.hash_map_max_load self.hash_map_slots) - end - end - end + let* max_usize = scalar_cast U32 Usize core_num_u32_max_c in + let capacity = vec_len (list_t t) self.hash_map_slots in + let* n1 = usize_div max_usize 2 in + let (i, i0) = self.hash_map_max_load_factor in + let* i1 = usize_div n1 i in + if capacity <= i1 + then begin + let* i2 = usize_mul capacity 2 in + let* ntable = hash_map_new_with_capacity_fwd t i2 i i0 in + let* (ntable0, _) = + hash_map_move_elements_fwd_back t ntable self.hash_map_slots 0 in + Return (Mkhash_map_t self.hash_map_num_entries (i, i0) + ntable0.hash_map_max_load ntable0.hash_map_slots) end + else + Return (Mkhash_map_t self.hash_map_num_entries (i, i0) + self.hash_map_max_load self.hash_map_slots) (** [hashmap::HashMap::{0}::insert] *) let hash_map_insert_fwd_back (t : Type0) (self : hash_map_t t) (key : usize) (value : t) : result (hash_map_t t) = - begin match hash_map_insert_no_resize_fwd_back t self key value with - | Fail e -> Fail e - | Return self0 -> - begin match hash_map_len_fwd t self0 with - | Fail e -> Fail e - | Return i -> - if i > self0.hash_map_max_load - then hash_map_try_resize_fwd_back t self0 - else Return self0 - end - end + let* self0 = hash_map_insert_no_resize_fwd_back t self key value in + let* i = hash_map_len_fwd t self0 in + if i > self0.hash_map_max_load + then hash_map_try_resize_fwd_back t self0 + else Return self0 (** [hashmap::HashMap::{0}::contains_key_in_list] *) let rec hash_map_contains_key_in_list_loop_fwd @@ -328,19 +232,11 @@ let hash_map_contains_key_in_list_fwd (** [hashmap::HashMap::{0}::contains_key] *) let hash_map_contains_key_fwd (t : Type0) (self : hash_map_t t) (key : usize) : result bool = - begin match hash_key_fwd key with - | Fail e -> Fail e - | Return hash -> - let i = vec_len (list_t t) self.hash_map_slots in - begin match usize_rem hash i with - | Fail e -> Fail e - | Return hash_mod -> - begin match vec_index_fwd (list_t t) self.hash_map_slots hash_mod with - | Fail e -> Fail e - | Return l -> hash_map_contains_key_in_list_fwd t key l - end - end - end + let* hash = hash_key_fwd key in + let i = vec_len (list_t t) self.hash_map_slots in + let* hash_mod = usize_rem hash i in + let* l = vec_index_fwd (list_t t) self.hash_map_slots hash_mod in + hash_map_contains_key_in_list_fwd t key l (** [hashmap::HashMap::{0}::get_in_list] *) let rec hash_map_get_in_list_loop_fwd @@ -363,19 +259,11 @@ let hash_map_get_in_list_fwd (** [hashmap::HashMap::{0}::get] *) let hash_map_get_fwd (t : Type0) (self : hash_map_t t) (key : usize) : result t = - begin match hash_key_fwd key with - | Fail e -> Fail e - | Return hash -> - let i = vec_len (list_t t) self.hash_map_slots in - begin match usize_rem hash i with - | Fail e -> Fail e - | Return hash_mod -> - begin match vec_index_fwd (list_t t) self.hash_map_slots hash_mod with - | Fail e -> Fail e - | Return l -> hash_map_get_in_list_fwd t key l - end - end - end + let* hash = hash_key_fwd key in + let i = vec_len (list_t t) self.hash_map_slots in + let* hash_mod = usize_rem hash i in + let* l = vec_index_fwd (list_t t) self.hash_map_slots hash_mod in + hash_map_get_in_list_fwd t key l (** [hashmap::HashMap::{0}::get_mut_in_list] *) let rec hash_map_get_mut_in_list_loop_fwd @@ -405,11 +293,9 @@ let rec hash_map_get_mut_in_list_loop_back | ListCons ckey cvalue tl -> if ckey = key then Return (ListCons ckey ret tl) - else - begin match hash_map_get_mut_in_list_loop_back t tl key ret with - | Fail e -> Fail e - | Return tl0 -> Return (ListCons ckey cvalue tl0) - end + else begin + let* tl0 = hash_map_get_mut_in_list_loop_back t tl key ret in + Return (ListCons ckey cvalue tl0) end | ListNil -> Fail Failure end @@ -421,51 +307,25 @@ let hash_map_get_mut_in_list_back (** [hashmap::HashMap::{0}::get_mut] *) let hash_map_get_mut_fwd (t : Type0) (self : hash_map_t t) (key : usize) : result t = - begin match hash_key_fwd key with - | Fail e -> Fail e - | Return hash -> - let i = vec_len (list_t t) self.hash_map_slots in - begin match usize_rem hash i with - | Fail e -> Fail e - | Return hash_mod -> - begin match vec_index_mut_fwd (list_t t) self.hash_map_slots hash_mod - with - | Fail e -> Fail e - | Return l -> hash_map_get_mut_in_list_fwd t l key - end - end - end + let* hash = hash_key_fwd key in + let i = vec_len (list_t t) self.hash_map_slots in + let* hash_mod = usize_rem hash i in + let* l = vec_index_mut_fwd (list_t t) self.hash_map_slots hash_mod in + hash_map_get_mut_in_list_fwd t l key (** [hashmap::HashMap::{0}::get_mut] *) let hash_map_get_mut_back (t : Type0) (self : hash_map_t t) (key : usize) (ret : t) : result (hash_map_t t) = - begin match hash_key_fwd key with - | Fail e -> Fail e - | Return hash -> - let i = vec_len (list_t t) self.hash_map_slots in - begin match usize_rem hash i with - | Fail e -> Fail e - | Return hash_mod -> - begin match vec_index_mut_fwd (list_t t) self.hash_map_slots hash_mod - with - | Fail e -> Fail e - | Return l -> - begin match hash_map_get_mut_in_list_back t l key ret with - | Fail e -> Fail e - | Return l0 -> - begin match - vec_index_mut_back (list_t t) self.hash_map_slots hash_mod l0 with - | Fail e -> Fail e - | Return v -> - Return (Mkhash_map_t self.hash_map_num_entries - self.hash_map_max_load_factor self.hash_map_max_load v) - end - end - end - end - end + let* hash = hash_key_fwd key in + let i = vec_len (list_t t) self.hash_map_slots in + let* hash_mod = usize_rem hash i in + let* l = vec_index_mut_fwd (list_t t) self.hash_map_slots hash_mod in + let* l0 = hash_map_get_mut_in_list_back t l key ret in + let* v = vec_index_mut_back (list_t t) self.hash_map_slots hash_mod l0 in + Return (Mkhash_map_t self.hash_map_num_entries self.hash_map_max_load_factor + self.hash_map_max_load v) (** [hashmap::HashMap::{0}::remove_from_list] *) let rec hash_map_remove_from_list_loop_fwd @@ -506,11 +366,9 @@ let rec hash_map_remove_from_list_loop_back | ListCons i cvalue tl0 -> Return tl0 | ListNil -> Fail Failure end - else - begin match hash_map_remove_from_list_loop_back t key tl with - | Fail e -> Fail e - | Return tl0 -> Return (ListCons ckey x tl0) - end + else begin + let* tl0 = hash_map_remove_from_list_loop_back t key tl in + Return (ListCons ckey x tl0) end | ListNil -> Return ListNil end @@ -522,164 +380,74 @@ let hash_map_remove_from_list_back (** [hashmap::HashMap::{0}::remove] *) let hash_map_remove_fwd (t : Type0) (self : hash_map_t t) (key : usize) : result (option t) = - begin match hash_key_fwd key with - | Fail e -> Fail e - | Return hash -> - let i = vec_len (list_t t) self.hash_map_slots in - begin match usize_rem hash i with - | Fail e -> Fail e - | Return hash_mod -> - begin match vec_index_mut_fwd (list_t t) self.hash_map_slots hash_mod - with - | Fail e -> Fail e - | Return l -> - begin match hash_map_remove_from_list_fwd t key l with - | Fail e -> Fail e - | Return x -> - begin match x with - | None -> Return None - | Some x0 -> - begin match usize_sub self.hash_map_num_entries 1 with - | Fail e -> Fail e - | Return _ -> Return (Some x0) - end - end - end - end - end + let* hash = hash_key_fwd key in + let i = vec_len (list_t t) self.hash_map_slots in + let* hash_mod = usize_rem hash i in + let* l = vec_index_mut_fwd (list_t t) self.hash_map_slots hash_mod in + let* x = hash_map_remove_from_list_fwd t key l in + begin match x with + | None -> Return None + | Some x0 -> + let* _ = usize_sub self.hash_map_num_entries 1 in Return (Some x0) end (** [hashmap::HashMap::{0}::remove] *) let hash_map_remove_back (t : Type0) (self : hash_map_t t) (key : usize) : result (hash_map_t t) = - begin match hash_key_fwd key with - | Fail e -> Fail e - | Return hash -> - let i = vec_len (list_t t) self.hash_map_slots in - begin match usize_rem hash i with - | Fail e -> Fail e - | Return hash_mod -> - begin match vec_index_mut_fwd (list_t t) self.hash_map_slots hash_mod - with - | Fail e -> Fail e - | Return l -> - begin match hash_map_remove_from_list_fwd t key l with - | Fail e -> Fail e - | Return x -> - begin match x with - | None -> - begin match hash_map_remove_from_list_back t key l with - | Fail e -> Fail e - | Return l0 -> - begin match - vec_index_mut_back (list_t t) self.hash_map_slots hash_mod l0 - with - | Fail e -> Fail e - | Return v -> - Return (Mkhash_map_t self.hash_map_num_entries - self.hash_map_max_load_factor self.hash_map_max_load v) - end - end - | Some x0 -> - begin match usize_sub self.hash_map_num_entries 1 with - | Fail e -> Fail e - | Return i0 -> - begin match hash_map_remove_from_list_back t key l with - | Fail e -> Fail e - | Return l0 -> - begin match - vec_index_mut_back (list_t t) self.hash_map_slots hash_mod l0 - with - | Fail e -> Fail e - | Return v -> - Return (Mkhash_map_t i0 self.hash_map_max_load_factor - self.hash_map_max_load v) - end - end - end - end - end - end - end + let* hash = hash_key_fwd key in + let i = vec_len (list_t t) self.hash_map_slots in + let* hash_mod = usize_rem hash i in + let* l = vec_index_mut_fwd (list_t t) self.hash_map_slots hash_mod in + let* x = hash_map_remove_from_list_fwd t key l in + begin match x with + | None -> + let* l0 = hash_map_remove_from_list_back t key l in + let* v = vec_index_mut_back (list_t t) self.hash_map_slots hash_mod l0 in + Return (Mkhash_map_t self.hash_map_num_entries + self.hash_map_max_load_factor self.hash_map_max_load v) + | Some x0 -> + let* i0 = usize_sub self.hash_map_num_entries 1 in + let* l0 = hash_map_remove_from_list_back t key l in + let* v = vec_index_mut_back (list_t t) self.hash_map_slots hash_mod l0 in + Return (Mkhash_map_t i0 self.hash_map_max_load_factor + self.hash_map_max_load v) end (** [hashmap::test1] *) let test1_fwd : result unit = - begin match hash_map_new_fwd u64 with - | Fail e -> Fail e - | Return hm -> - begin match hash_map_insert_fwd_back u64 hm 0 42 with - | Fail e -> Fail e - | Return hm0 -> - begin match hash_map_insert_fwd_back u64 hm0 128 18 with - | Fail e -> Fail e - | Return hm1 -> - begin match hash_map_insert_fwd_back u64 hm1 1024 138 with - | Fail e -> Fail e - | Return hm2 -> - begin match hash_map_insert_fwd_back u64 hm2 1056 256 with - | Fail e -> Fail e - | Return hm3 -> - begin match hash_map_get_fwd u64 hm3 128 with - | Fail e -> Fail e - | Return i -> - if not (i = 18) - then Fail Failure - else - begin match hash_map_get_mut_back u64 hm3 1024 56 with - | Fail e -> Fail e - | Return hm4 -> - begin match hash_map_get_fwd u64 hm4 1024 with - | Fail e -> Fail e - | Return i0 -> - if not (i0 = 56) - then Fail Failure - else - begin match hash_map_remove_fwd u64 hm4 1024 with - | Fail e -> Fail e - | Return x -> - begin match x with - | None -> Fail Failure - | Some x0 -> - if not (x0 = 56) - then Fail Failure - else - begin match hash_map_remove_back u64 hm4 1024 with - | Fail e -> Fail e - | Return hm5 -> - begin match hash_map_get_fwd u64 hm5 0 with - | Fail e -> Fail e - | Return i1 -> - if not (i1 = 42) - then Fail Failure - else - begin match hash_map_get_fwd u64 hm5 128 with - | Fail e -> Fail e - | Return i2 -> - if not (i2 = 18) - then Fail Failure - else - begin match hash_map_get_fwd u64 hm5 1056 - with - | Fail e -> Fail e - | Return i3 -> - if not (i3 = 256) - then Fail Failure - else Return () - end - end - end - end - end - end - end - end - end - end - end - end - end - end + let* hm = hash_map_new_fwd u64 in + let* hm0 = hash_map_insert_fwd_back u64 hm 0 42 in + let* hm1 = hash_map_insert_fwd_back u64 hm0 128 18 in + let* hm2 = hash_map_insert_fwd_back u64 hm1 1024 138 in + let* hm3 = hash_map_insert_fwd_back u64 hm2 1056 256 in + let* i = hash_map_get_fwd u64 hm3 128 in + if not (i = 18) + then Fail Failure + else begin + let* hm4 = hash_map_get_mut_back u64 hm3 1024 56 in + let* i0 = hash_map_get_fwd u64 hm4 1024 in + if not (i0 = 56) + then Fail Failure + else begin + let* x = hash_map_remove_fwd u64 hm4 1024 in + begin match x with + | None -> Fail Failure + | Some x0 -> + if not (x0 = 56) + then Fail Failure + else begin + let* hm5 = hash_map_remove_back u64 hm4 1024 in + let* i1 = hash_map_get_fwd u64 hm5 0 in + if not (i1 = 42) + then Fail Failure + else begin + let* i2 = hash_map_get_fwd u64 hm5 128 in + if not (i2 = 18) + then Fail Failure + else begin + let* i3 = hash_map_get_fwd u64 hm5 1056 in + if not (i3 = 256) then Fail Failure else Return () end end end + end end end (** Unit test for [hashmap::test1] *) let _ = assert_norm (test1_fwd = Return ()) diff --git a/tests/fstar/hashmap/Primitives.fst b/tests/fstar/hashmap/Primitives.fst index bf0f9078..98a696b6 100644 --- a/tests/fstar/hashmap/Primitives.fst +++ b/tests/fstar/hashmap/Primitives.fst @@ -35,7 +35,9 @@ unfold let return (#a : Type0) (x : a) : result a = Return x // let* x = y in // ... // ``` -unfold let (let*) (#a #b : Type0) (m: result a) (f: a -> result b) : result b = +unfold let (let*) (#a #b : Type0) (m: result a) + (f: (x:a) -> Pure (result b) (requires (m == Return x)) (ensures fun _ -> True)) : + result b = match m with | Return x -> f x | Fail e -> Fail e |