1. The Unstable Book
  2. 1. Compiler flags
    1. 1.1. branch_protection
    2. 1.2. cf_protection
    3. 1.3. check_cfg
    4. 1.4. codegen_backend
    5. 1.5. control_flow_guard
    6. 1.6. debug_info_for_profiling
    7. 1.7. emit_stack_sizes
    8. 1.8. location_detail
    9. 1.9. move_size_limit
    10. 1.10. no_unique_section_names
    11. 1.11. profile
    12. 1.12. profile_sample_use
    13. 1.13. remap_cwd_prefix
    14. 1.14. report_time
    15. 1.15. sanitizer
    16. 1.16. self_profile
    17. 1.17. self_profile_events
    18. 1.18. src_hash_algorithm
    19. 1.19. temps_dir
    20. 1.20. tls_model
    21. 1.21. unsound_mir_opts
  3. 2. Language features
    1. 2.1. aarch64_ver_target_feature
    2. 2.2. abi_amdgpu_kernel
    3. 2.3. abi_avr_interrupt
    4. 2.4. abi_c_cmse_nonsecure_call
    5. 2.5. abi_efiapi
    6. 2.6. abi_msp430_interrupt
    7. 2.7. abi_ptx
    8. 2.8. abi_thiscall
    9. 2.9. abi_unadjusted
    10. 2.10. abi_vectorcall
    11. 2.11. abi_x86_interrupt
    12. 2.12. adt_const_params
    13. 2.13. alloc_error_handler
    14. 2.14. allocator_internals
    15. 2.15. allow_internal_unsafe
    16. 2.16. allow_internal_unstable
    17. 2.17. arbitrary_enum_discriminant
    18. 2.18. arbitrary_self_types
    19. 2.19. arm_target_feature
    20. 2.20. asm_const
    21. 2.21. asm_experimental_arch
    22. 2.22. asm_sym
    23. 2.23. asm_unwind
    24. 2.24. associated_const_equality
    25. 2.25. associated_type_bounds
    26. 2.26. associated_type_defaults
    27. 2.27. async_closure
    28. 2.28. auto_traits
    29. 2.29. avx512_target_feature
    30. 2.30. box_patterns
    31. 2.31. box_syntax
    32. 2.32. bpf_target_feature
    33. 2.33. c_unwind
    34. 2.34. c_variadic
    35. 2.35. capture_disjoint_fields
    36. 2.36. cfg_sanitize
    37. 2.37. cfg_target_abi
    38. 2.38. cfg_target_compact
    39. 2.39. cfg_target_has_atomic
    40. 2.40. cfg_target_has_atomic_equal_alignment
    41. 2.41. cfg_target_thread_local
    42. 2.42. cfg_version
    43. 2.43. closure_track_caller
    44. 2.44. cmpxchg16b_target_feature
    45. 2.45. cmse_nonsecure_entry
    46. 2.46. compiler_builtins
    47. 2.47. const_async_blocks
    48. 2.48. const_eval_limit
    49. 2.49. const_extern_fn
    50. 2.50. const_fn_floating_point_arithmetic
    51. 2.51. const_for
    52. 2.52. const_mut_refs
    53. 2.53. const_precise_live_drops
    54. 2.54. const_refs_to_cell
    55. 2.55. const_trait_impl
    56. 2.56. const_try
    57. 2.57. custom_inner_attributes
    58. 2.58. custom_test_frameworks
    59. 2.59. debugger_visualizer
    60. 2.60. decl_macro
    61. 2.61. default_alloc_error_handler
    62. 2.62. default_type_parameter_fallback
    63. 2.63. deprecated_safe
    64. 2.64. deprecated_suggestion
    65. 2.65. doc_auto_cfg
    66. 2.66. doc_cfg
    67. 2.67. doc_cfg_hide
    68. 2.68. doc_masked
    69. 2.69. doc_notable_trait
    70. 2.70. dropck_eyepatch
    71. 2.71. ermsb_target_feature
    72. 2.72. exclusive_range_pattern
    73. 2.73. exhaustive_patterns
    74. 2.74. explicit_generic_args_with_impl_trait
    75. 2.75. extern_types
    76. 2.76. f16c_target_feature
    77. 2.77. ffi_const
    78. 2.78. ffi_pure
    79. 2.79. ffi_returns_twice
    80. 2.80. fn_align
    81. 2.81. fundamental
    82. 2.82. generators
    83. 2.83. generic_arg_infer
    84. 2.84. generic_associated_types
    85. 2.85. generic_associated_types_extended
    86. 2.86. generic_const_exprs
    87. 2.87. half_open_range_patterns
    88. 2.88. hexagon_target_feature
    89. 2.89. if_let_guard
    90. 2.90. imported_main
    91. 2.91. infer_static_outlives_requirements
    92. 2.92. inherent_associated_types
    93. 2.93. inline_const
    94. 2.94. inline_const_pat
    95. 2.95. intra_doc_pointers
    96. 2.96. intrinsics
    97. 2.97. isa_attribute
    98. 2.98. label_break_value
    99. 2.99. lang_items
    100. 2.100. large_assignments
    101. 2.101. let_chains
    102. 2.102. let_else
    103. 2.103. link_cfg
    104. 2.104. link_llvm_intrinsics
    105. 2.105. linkage
    106. 2.106. lint_reasons
    107. 2.107. macro_metavar_expr
    108. 2.108. marker_trait_attr
    109. 2.109. min_specialization
    110. 2.110. mips_target_feature
    111. 2.111. more_qualified_paths
    112. 2.112. movbe_target_feature
    113. 2.113. must_not_suspend
    114. 2.114. naked_functions
    115. 2.115. native_link_modifiers_as_needed
    116. 2.116. native_link_modifiers_bundle
    117. 2.117. native_link_modifiers_verbatim
    118. 2.118. needs_panic_runtime
    119. 2.119. negative_impls
    120. 2.120. never_type
    121. 2.121. never_type_fallback
    122. 2.122. nll
    123. 2.123. no_core
    124. 2.124. no_coverage
    125. 2.125. no_niche
    126. 2.126. no_sanitize
    127. 2.127. non_exhaustive_omitted_patterns_lint
    128. 2.128. object_safe_for_dispatch
    129. 2.129. omit_gdb_pretty_printer_section
    130. 2.130. optimize_attribute
    131. 2.131. panic_runtime
    132. 2.132. platform_intrinsics
    133. 2.133. plugin
    134. 2.134. powerpc_target_feature
    135. 2.135. precise_pointer_size_matching
    136. 2.136. prelude_import
    137. 2.137. proc_macro_hygiene
    138. 2.138. profiler_runtime
    139. 2.139. raw_dylib
    140. 2.140. raw_ref_op
    141. 2.141. register_attr
    142. 2.142. register_tool
    143. 2.143. repr_simd
    144. 2.144. repr128
    145. 2.145. riscv_target_feature
    146. 2.146. rtm_target_feature
    147. 2.147. rustc_allow_const_fn_unstable
    148. 2.148. rustc_attrs
    149. 2.149. rustc_private
    150. 2.150. rustdoc_internals
    151. 2.151. simd_ffi
    152. 2.152. specialization
    153. 2.153. sse4a_target_feature
    154. 2.154. staged_api
    155. 2.155. start
    156. 2.156. static_nobundle
    157. 2.157. stmt_expr_attributes
    158. 2.158. strict_provenance
    159. 2.159. structural_match
    160. 2.160. target_feature_11
    161. 2.161. tbm_target_feature
    162. 2.162. test_2018_feature
    163. 2.163. test_unstable_lint
    164. 2.164. thread_local
    165. 2.165. trait_alias
    166. 2.166. trait_upcasting
    167. 2.167. transparent_unions
    168. 2.168. trivial_bounds
    169. 2.169. try_blocks
    170. 2.170. type_alias_impl_trait
    171. 2.171. type_ascription
    172. 2.172. type_changing_struct_update
    173. 2.173. unboxed_closures
    174. 2.174. unsafe_pin_internals
    175. 2.175. unsized_fn_params
    176. 2.176. unsized_locals
    177. 2.177. unsized_tuple_coercion
    178. 2.178. untagged_unions
    179. 2.179. used_with_arg
    180. 2.180. wasm_abi
    181. 2.181. wasm_target_feature
    182. 2.182. with_negative_coherence
    183. 2.183. yeet_expr
  4. 3. Library Features
    1. 3.1. absolute_path
    2. 3.2. alloc_c_string
    3. 3.3. alloc_error_hook
    4. 3.4. alloc_ffi
    5. 3.5. alloc_internals
    6. 3.6. alloc_layout_extra
    7. 3.7. allocator_api
    8. 3.8. arc_unwrap_or_clone
    9. 3.9. array_chunks
    10. 3.10. array_error_internals
    11. 3.11. array_into_iter_constructors
    12. 3.12. array_methods
    13. 3.13. array_try_from_fn
    14. 3.14. array_try_map
    15. 3.15. array_windows
    16. 3.16. array_zip
    17. 3.17. as_array_of_cells
    18. 3.18. assert_matches
    19. 3.19. async_iter_from_iter
    20. 3.20. async_iterator
    21. 3.21. atomic_from_mut
    22. 3.22. atomic_mut_ptr
    23. 3.23. backtrace
    24. 3.24. backtrace_frames
    25. 3.25. bench_black_box
    26. 3.26. bigint_helper_methods
    27. 3.27. binary_heap_as_slice
    28. 3.28. binary_heap_drain_sorted
    29. 3.29. binary_heap_into_iter_sorted
    30. 3.30. binary_heap_retain
    31. 3.31. bound_as_ref
    32. 3.32. bound_map
    33. 3.33. box_into_boxed_slice
    34. 3.34. box_into_inner
    35. 3.35. box_into_pin
    36. 3.36. btree_drain_filter
    37. 3.37. buf_read_has_data_left
    38. 3.38. build_hasher_simple_hash_one
    39. 3.39. byte_slice_trim_ascii
    40. 3.40. c_size_t
    41. 3.41. c_void_variant
    42. 3.42. can_vector
    43. 3.43. cell_leak
    44. 3.44. cell_update
    45. 3.45. cfg_accessible
    46. 3.46. cfg_eval
    47. 3.47. char_error_internals
    48. 3.48. char_indices_offset
    49. 3.49. char_internals
    50. 3.50. coerce_unsized
    51. 3.51. concat_bytes
    52. 3.52. concat_idents
    53. 3.53. const_align_of_val
    54. 3.54. const_align_of_val_raw
    55. 3.55. const_align_offset
    56. 3.56. const_alloc_error
    57. 3.57. const_alloc_layout
    58. 3.58. const_arguments_as_str
    59. 3.59. const_array_from_ref
    60. 3.60. const_array_into_iter_constructors
    61. 3.61. const_assert_type2
    62. 3.62. const_assume
    63. 3.63. const_bigint_helper_methods
    64. 3.64. const_black_box
    65. 3.65. const_bool_to_option
    66. 3.66. const_borrow
    67. 3.67. const_box
    68. 3.68. const_btree_new
    69. 3.69. const_caller_location
    70. 3.70. const_cell_into_inner
    71. 3.71. const_char_convert
    72. 3.72. const_clone
    73. 3.73. const_convert
    74. 3.74. const_cow_is_borrowed
    75. 3.75. const_default_impls
    76. 3.76. const_deref
    77. 3.77. const_discriminant
    78. 3.78. const_eval_select
    79. 3.79. const_float_bits_conv
    80. 3.80. const_float_classify
    81. 3.81. const_fmt_arguments_new
    82. 3.82. const_format_args
    83. 3.83. const_heap
    84. 3.84. const_inherent_unchecked_arith
    85. 3.85. const_int_unchecked_arith
    86. 3.86. const_intoiterator_identity
    87. 3.87. const_intrinsic_copy
    88. 3.88. const_intrinsic_forget
    89. 3.89. const_intrinsic_raw_eq
    90. 3.90. const_io_structs
    91. 3.91. const_ip
    92. 3.92. const_ipv4
    93. 3.93. const_ipv6
    94. 3.94. const_is_char_boundary
    95. 3.95. const_likely
    96. 3.96. const_maybe_uninit_array_assume_init
    97. 3.97. const_maybe_uninit_as_mut_ptr
    98. 3.98. const_maybe_uninit_assume_init
    99. 3.99. const_maybe_uninit_assume_init_read
    100. 3.100. const_maybe_uninit_uninit_array
    101. 3.101. const_maybe_uninit_write
    102. 3.102. const_maybe_uninit_zeroed
    103. 3.103. const_nonnull_new
    104. 3.104. const_nonnull_slice_from_raw_parts
    105. 3.105. const_num_from_num
    106. 3.106. const_ops
    107. 3.107. const_option
    108. 3.108. const_option_cloned
    109. 3.109. const_option_ext
    110. 3.110. const_pin
    111. 3.111. const_pointer_byte_offsets
    112. 3.112. const_pref_align_of
    113. 3.113. const_ptr_as_ref
    114. 3.114. const_ptr_is_null
    115. 3.115. const_ptr_offset_from
    116. 3.116. const_ptr_read
    117. 3.117. const_ptr_sub_ptr
    118. 3.118. const_ptr_write
    119. 3.119. const_raw_ptr_comparison
    120. 3.120. const_replace
    121. 3.121. const_result
    122. 3.122. const_result_drop
    123. 3.123. const_size_of_val
    124. 3.124. const_size_of_val_raw
    125. 3.125. const_slice_first_last
    126. 3.126. const_slice_from_raw_parts
    127. 3.127. const_slice_from_ref
    128. 3.128. const_slice_index
    129. 3.129. const_slice_ptr_len
    130. 3.130. const_socketaddr
    131. 3.131. const_str_from_utf8
    132. 3.132. const_str_from_utf8_unchecked_mut
    133. 3.133. const_swap
    134. 3.134. const_transmute_copy
    135. 3.135. const_type_id
    136. 3.136. const_type_name
    137. 3.137. const_unsafecell_get_mut
    138. 3.138. const_weak_new
    139. 3.139. container_error_extra
    140. 3.140. control_flow_enum
    141. 3.141. convert_float_to_int
    142. 3.142. core_c_str
    143. 3.143. core_ffi_c
    144. 3.144. core_intrinsics
    145. 3.145. core_panic
    146. 3.146. core_private_bignum
    147. 3.147. core_private_diy_float
    148. 3.148. cow_is_borrowed
    149. 3.149. cstr_from_bytes_until_nul
    150. 3.150. cstr_internals
    151. 3.151. cursor_remaining
    152. 3.152. deadline_api
    153. 3.153. dec2flt
    154. 3.154. default_free_fn
    155. 3.155. derive_clone_copy
    156. 3.156. derive_eq
    157. 3.157. dir_entry_ext2
    158. 3.158. discriminant_kind
    159. 3.159. dispatch_from_dyn
    160. 3.160. div_duration
    161. 3.161. downcast_unchecked
    162. 3.162. drain_filter
    163. 3.163. duration_checked_float
    164. 3.164. duration_constants
    165. 3.165. duration_consts_float
    166. 3.166. edition_panic
    167. 3.167. entry_insert
    168. 3.168. error_iter
    169. 3.169. error_reporter
    170. 3.170. error_type_id
    171. 3.171. exact_size_is_empty
    172. 3.172. exit_status_error
    173. 3.173. exitcode_exit_method
    174. 3.174. extend_one
    175. 3.175. fd
    176. 3.176. fd_read
    177. 3.177. float_minimum_maximum
    178. 3.178. flt2dec
    179. 3.179. fmt_internals
    180. 3.180. fn_traits
    181. 3.181. forget_unsized
    182. 3.182. format_args_nl
    183. 3.183. future_join
    184. 3.184. future_poll_fn
    185. 3.185. gen_future
    186. 3.186. generator_trait
    187. 3.187. generic_assert_internals
    188. 3.188. get_mut_unchecked
    189. 3.189. hash_drain_filter
    190. 3.190. hash_raw_entry
    191. 3.191. hash_set_entry
    192. 3.192. hasher_prefixfree_extras
    193. 3.193. hashmap_internals
    194. 3.194. hint_must_use
    195. 3.195. inplace_iteration
    196. 3.196. int_error_internals
    197. 3.197. int_log
    198. 3.198. int_roundings
    199. 3.199. integer_atomics
    200. 3.200. internal_output_capture
    201. 3.201. into_future
    202. 3.202. io_error_more
    203. 3.203. io_error_other
    204. 3.204. io_error_uncategorized
    205. 3.205. io_read_to_string
    206. 3.206. io_safety
    207. 3.207. io_slice_advance
    208. 3.208. ip
    209. 3.209. is_some_with
    210. 3.210. is_sorted
    211. 3.211. iter_advance_by
    212. 3.212. iter_collect_into
    213. 3.213. iter_from_generator
    214. 3.214. iter_intersperse
    215. 3.215. iter_is_partitioned
    216. 3.216. iter_order_by
    217. 3.217. iter_partition_in_place
    218. 3.218. iterator_try_collect
    219. 3.219. iterator_try_reduce
    220. 3.220. layout_for_ptr
    221. 3.221. liballoc_internals
    222. 3.222. libstd_sys_internals
    223. 3.223. libstd_thread_internals
    224. 3.224. linked_list_cursors
    225. 3.225. linked_list_remove
    226. 3.226. linux_pidfd
    227. 3.227. local_key_cell_methods
    228. 3.228. log_syntax
    229. 3.229. main_separator_str
    230. 3.230. map_entry_replace
    231. 3.231. map_first_last
    232. 3.232. map_try_insert
    233. 3.233. maybe_uninit_array_assume_init
    234. 3.234. maybe_uninit_as_bytes
    235. 3.235. maybe_uninit_slice
    236. 3.236. maybe_uninit_uninit_array
    237. 3.237. maybe_uninit_write_slice
    238. 3.238. mixed_integer_ops
    239. 3.239. mutex_unlock
    240. 3.240. mutex_unpoison
    241. 3.241. new_uninit
    242. 3.242. nonnull_slice_from_raw_parts
    243. 3.243. nonzero_bits
    244. 3.244. nonzero_min_max
    245. 3.245. nonzero_ops
    246. 3.246. numfmt
    247. 3.247. once_cell
    248. 3.248. one_sided_range
    249. 3.249. option_get_or_insert_default
    250. 3.250. option_result_contains
    251. 3.251. option_zip
    252. 3.252. panic_abort
    253. 3.253. panic_always_abort
    254. 3.254. panic_backtrace_config
    255. 3.255. panic_can_unwind
    256. 3.256. panic_info_message
    257. 3.257. panic_internals
    258. 3.258. panic_unwind
    259. 3.259. panic_update_hook
    260. 3.260. path_file_prefix
    261. 3.261. path_try_exists
    262. 3.262. pattern
    263. 3.263. peer_credentials_unix_socket
    264. 3.264. pin_deref_mut
    265. 3.265. pin_macro
    266. 3.266. pointer_byte_offsets
    267. 3.267. pointer_is_aligned
    268. 3.268. poll_ready
    269. 3.269. portable_simd
    270. 3.270. prelude_2024
    271. 3.271. print_internals
    272. 3.272. proc_macro_def_site
    273. 3.273. proc_macro_diagnostic
    274. 3.274. proc_macro_expand
    275. 3.275. proc_macro_internals
    276. 3.276. proc_macro_quote
    277. 3.277. proc_macro_span
    278. 3.278. proc_macro_span_shrink
    279. 3.279. proc_macro_tracked_env
    280. 3.280. process_exitcode_internals
    281. 3.281. process_internals
    282. 3.282. process_set_process_group
    283. 3.283. profiler_runtime_lib
    284. 3.284. ptr_as_uninit
    285. 3.285. ptr_const_cast
    286. 3.286. ptr_internals
    287. 3.287. ptr_metadata
    288. 3.288. ptr_sub_ptr
    289. 3.289. ptr_to_from_bits
    290. 3.290. pub_crate_should_not_need_unstable_attr
    291. 3.291. raw_os_nonzero
    292. 3.292. raw_vec_internals
    293. 3.293. read_buf
    294. 3.294. ready_macro
    295. 3.295. receiver_trait
    296. 3.296. restricted_std
    297. 3.297. result_contains_err
    298. 3.298. result_flattening
    299. 3.299. result_into_ok_or_err
    300. 3.300. result_option_inspect
    301. 3.301. round_char_boundary
    302. 3.302. rt
    303. 3.303. saturating_int_assign_impl
    304. 3.304. saturating_int_impl
    305. 3.305. scoped_threads
    306. 3.306. sealed
    307. 3.307. seek_stream_len
    308. 3.308. set_ptr_value
    309. 3.309. setgroups
    310. 3.310. sgx_platform
    311. 3.311. slice_as_chunks
    312. 3.312. slice_concat_ext
    313. 3.313. slice_concat_trait
    314. 3.314. slice_flatten
    315. 3.315. slice_from_ptr_range
    316. 3.316. slice_group_by
    317. 3.317. slice_index_methods
    318. 3.318. slice_internals
    319. 3.319. slice_partition_dedup
    320. 3.320. slice_pattern
    321. 3.321. slice_ptr_get
    322. 3.322. slice_ptr_len
    323. 3.323. slice_range
    324. 3.324. slice_split_at_unchecked
    325. 3.325. slice_swap_unchecked
    326. 3.326. slice_take
    327. 3.327. solid_ext
    328. 3.328. sort_internals
    329. 3.329. split_array
    330. 3.330. split_as_slice
    331. 3.331. std_internals
    332. 3.332. stdsimd
    333. 3.333. step_trait
    334. 3.334. str_internals
    335. 3.335. str_split_as_str
    336. 3.336. str_split_inclusive_as_str
    337. 3.337. str_split_whitespace_as_str
    338. 3.338. string_extend_from_within
    339. 3.339. string_remove_matches
    340. 3.340. sync_unsafe_cell
    341. 3.341. tcp_linger
    342. 3.342. tcplistener_into_incoming
    343. 3.343. test
    344. 3.344. thin_box
    345. 3.345. thread_id_value
    346. 3.346. thread_local_internals
    347. 3.347. thread_spawn_unchecked
    348. 3.348. toowned_clone_into
    349. 3.349. trace_macros
    350. 3.350. track_path
    351. 3.351. trusted_len
    352. 3.352. trusted_random_access
    353. 3.353. trusted_step
    354. 3.354. try_find
    355. 3.355. try_reserve_2
    356. 3.356. try_reserve_kind
    357. 3.357. try_trait_v2
    358. 3.358. try_trait_v2_residual
    359. 3.359. try_trait_v2_yeet
    360. 3.360. type_name_of_val
    361. 3.361. unchecked_math
    362. 3.362. unicode_internals
    363. 3.363. unix_chown
    364. 3.364. unix_socket_abstract
    365. 3.365. unix_socket_ancillary_data
    366. 3.366. unix_socket_peek
    367. 3.367. unsize
    368. 3.368. unwrap_infallible
    369. 3.369. unzip_option
    370. 3.370. update_panic_count
    371. 3.371. utf16_extra
    372. 3.372. utf16_extra_const
    373. 3.373. variant_count
    374. 3.374. vec_into_raw_parts
    375. 3.375. vec_split_at_spare
    376. 3.376. waker_getters
    377. 3.377. wasi_ext
    378. 3.378. windows_by_handle
    379. 3.379. windows_c
    380. 3.380. windows_file_type_ext
    381. 3.381. windows_handle
    382. 3.382. windows_net
    383. 3.383. windows_process_extensions_force_quotes
    384. 3.384. windows_process_extensions_main_thread_handle
    385. 3.385. windows_stdio
    386. 3.386. wrapping_int_impl
    387. 3.387. wrapping_next_power_of_two
    388. 3.388. write_all_vectored
    389. 3.389. yeet_desugar_details

The Rust Unstable Book

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