1. The Unstable Book
  2. Compiler flags
    1. branch_protection
    2. cf_protection
    3. codegen_backend
    4. codegen_options
    5. control_flow_guard
    6. coverage_options
    7. debug_info_for_profiling
    8. debug_info_type_line_numbers
    9. default_visibility
    10. direct_access_external_data
    11. dump_mono_stats
    12. dump_mono_stats_format
    13. dwarf_version
    14. dylib_lto
    15. embed_source
    16. emit_stack_sizes
    17. emscripten_wasm_eh
    18. env_set
    19. export_executable_symbols
    20. extern_options
    21. external_clangrt
    22. fixed_x18
    23. fmt_debug
    24. function_return
    25. instrument_xray
    26. link_native_libraries
    27. linker_features
    28. lint_llvm_ir
    29. llvm_module_flag
    30. location_detail
    31. min_function_alignment
    32. move_size_limit
    33. no_jump_tables
    34. no_parallel_llvm
    35. no_unique_section_names
    36. on_broken_pipe
    37. patchable_function_entry
    38. print_check_cfg
    39. profile_sample_use
    40. randomize_layout
    41. reg_struct_return
    42. regparm
    43. remap_cwd_prefix
    44. remap_path_scope
    45. report_time
    46. sanitizer
    47. self_profile
    48. self_profile_events
    49. shell_argfiles
    50. small_data_threshold
    51. src_hash_algorithm
    52. temps_dir
    53. tiny_const_eval_limit
    54. tls_model
    55. ub_checks
    56. unsound_mir_opts
    57. verbose_asm
    58. virtual_function_elimination
    59. wasm_c_abi
  3. Language features
    1. aarch64_unstable_target_feature
    2. aarch64_ver_target_feature
    3. abi_avr_interrupt
    4. abi_c_cmse_nonsecure_call
    5. abi_gpu_kernel
    6. abi_msp430_interrupt
    7. abi_ptx
    8. abi_riscv_interrupt
    9. abi_unadjusted
    10. abi_vectorcall
    11. abi_x86_interrupt
    12. adt_const_params
    13. alloc_error_handler
    14. allocator_internals
    15. allow_internal_unsafe
    16. allow_internal_unstable
    17. anonymous_lifetime_in_impl_trait
    18. arbitrary_self_types
    19. arbitrary_self_types_pointers
    20. arm_target_feature
    21. asm_experimental_arch
    22. asm_experimental_reg
    23. asm_goto
    24. asm_goto_with_outputs
    25. asm_unwind
    26. associated_const_equality
    27. associated_type_defaults
    28. async_fn_in_dyn_trait
    29. async_fn_track_caller
    30. async_for_loop
    31. async_trait_bounds
    32. auto_traits
    33. avx512_target_feature
    34. box_patterns
    35. bpf_target_feature
    36. builtin_syntax
    37. c_variadic
    38. cfg_boolean_literals
    39. cfg_emscripten_wasm_eh
    40. cfg_overflow_checks
    41. cfg_relocation_model
    42. cfg_sanitize
    43. cfg_sanitizer_cfi
    44. cfg_target_compact
    45. cfg_target_has_atomic
    46. cfg_target_has_atomic_equal_alignment
    47. cfg_target_thread_local
    48. cfg_ub_checks
    49. cfg_version
    50. cfi_encoding
    51. closure_lifetime_binder
    52. closure_track_caller
    53. cmse_nonsecure_entry
    54. compiler_builtins
    55. const_async_blocks
    56. const_closures
    57. const_destruct
    58. const_for
    59. const_precise_live_drops
    60. const_trait_impl
    61. const_try
    62. coroutine_clone
    63. coroutines
    64. coverage_attribute
    65. csky_target_feature
    66. custom_inner_attributes
    67. custom_mir
    68. custom_test_frameworks
    69. decl_macro
    70. default_field_values
    71. deprecated_safe
    72. deprecated_suggestion
    73. deref_patterns
    74. doc_auto_cfg
    75. doc_cfg
    76. doc_cfg_hide
    77. doc_masked
    78. doc_notable_trait
    79. dropck_eyepatch
    80. dyn_compatible_for_dispatch
    81. dyn_star
    82. ermsb_target_feature
    83. exhaustive_patterns
    84. explicit_tail_calls
    85. extern_types
    86. f128
    87. f16
    88. ffi_const
    89. ffi_pure
    90. fmt_debug
    91. fn_align
    92. fn_delegation
    93. freeze_impls
    94. fundamental
    95. gen_blocks
    96. generic_arg_infer
    97. generic_assert
    98. generic_const_exprs
    99. generic_const_items
    100. global_registration
    101. guard_patterns
    102. half_open_range_patterns_in_slices
    103. hexagon_target_feature
    104. if_let_guard
    105. impl_trait_in_assoc_type
    106. impl_trait_in_bindings
    107. impl_trait_in_fn_trait_return
    108. import_trait_associated_functions
    109. inherent_associated_types
    110. inline_const_pat
    111. intra_doc_pointers
    112. intrinsics
    113. lahfsahf_target_feature
    114. lang_items
    115. large_assignments
    116. lazy_type_alias
    117. let_chains
    118. lifetime_capture_rules_2024
    119. link_arg_attribute
    120. link_cfg
    121. link_llvm_intrinsics
    122. linkage
    123. loongarch_target_feature
    124. m68k_target_feature
    125. macro_metavar_expr
    126. macro_metavar_expr_concat
    127. marker_trait_attr
    128. min_generic_const_args
    129. min_specialization
    130. mips_target_feature
    131. more_maybe_bounds
    132. more_qualified_paths
    133. multiple_supertrait_upcastable
    134. must_not_suspend
    135. mut_ref
    136. naked_functions
    137. native_link_modifiers_as_needed
    138. needs_panic_runtime
    139. negative_bounds
    140. negative_impls
    141. never_patterns
    142. never_type
    143. never_type_fallback
    144. no_core
    145. no_sanitize
    146. non_exhaustive_omitted_patterns_lint
    147. non_lifetime_binders
    148. offset_of_enum
    149. offset_of_slice
    150. omit_gdb_pretty_printer_section
    151. optimize_attribute
    152. panic_runtime
    153. patchable_function_entry
    154. pattern_complexity
    155. pattern_types
    156. pin_ergonomics
    157. postfix_match
    158. powerpc_target_feature
    159. precise_capturing_in_traits
    160. prelude_import
    161. prfchw_target_feature
    162. proc_macro_hygiene
    163. profiler_runtime
    164. ref_pat_eat_one_layer_2024
    165. ref_pat_eat_one_layer_2024_structural
    166. register_tool
    167. repr_simd
    168. repr128
    169. return_type_notation
    170. riscv_target_feature
    171. rtm_target_feature
    172. rust_cold_cc
    173. rustc_allow_const_fn_unstable
    174. rustc_attrs
    175. rustc_private
    176. rustdoc_internals
    177. rustdoc_missing_doc_code_examples
    178. s390x_target_feature
    179. sha512_sm_x86
    180. simd_ffi
    181. sparc_target_feature
    182. specialization
    183. sse4a_target_feature
    184. staged_api
    185. stmt_expr_attributes
    186. strict_provenance_lints
    187. string_deref_patterns
    188. structural_match
    189. target_feature_11
    190. tbm_target_feature
    191. test_unstable_lint
    192. thread_local
    193. trait_alias
    194. trait_upcasting
    195. transmute_generic_consts
    196. transparent_unions
    197. trivial_bounds
    198. try_blocks
    199. type_alias_impl_trait
    200. type_changing_struct_update
    201. unboxed_closures
    202. unqualified_local_imports
    203. unsafe_binders
    204. unsafe_fields
    205. unsized_const_params
    206. unsized_fn_params
    207. unsized_locals
    208. unsized_tuple_coercion
    209. used_with_arg
    210. wasm_target_feature
    211. with_negative_coherence
    212. x86_amx_intrinsics
    213. x87_target_feature
    214. xop_target_feature
    215. yeet_expr
  4. Library Features
    1. abort_unwind
    2. acceptfilter
    3. addr_parse_ascii
    4. alloc_error_hook
    5. alloc_internals
    6. alloc_layout_extra
    7. allocator_api
    8. anonymous_pipe
    9. array_chunks
    10. array_into_iter_constructors
    11. array_ptr_get
    12. array_repeat
    13. array_try_from_fn
    14. array_try_map
    15. array_windows
    16. as_array_of_cells
    17. ascii_char
    18. ascii_char_variants
    19. assert_matches
    20. async_drop
    21. async_fn_traits
    22. async_gen_internals
    23. async_iter_from_iter
    24. async_iterator
    25. atomic_from_mut
    26. autodiff
    27. backtrace_frames
    28. bigint_helper_methods
    29. binary_heap_drain_sorted
    30. binary_heap_into_iter_sorted
    31. bound_as_ref
    32. box_as_ptr
    33. box_into_boxed_slice
    34. box_into_inner
    35. box_uninit_write
    36. box_vec_non_null
    37. breakpoint
    38. bstr
    39. bstr_internals
    40. btree_cursors
    41. btree_entry_insert
    42. btree_extract_if
    43. btree_set_entry
    44. btreemap_alloc
    45. buf_read_has_data_left
    46. bufreader_peek
    47. c_size_t
    48. c_str_module
    49. c_void_variant
    50. can_vector
    51. cell_leak
    52. cell_update
    53. cfg_accessible
    54. cfg_eval
    55. cfg_match
    56. char_internals
    57. clone_to_uninit
    58. cmp_minmax
    59. coerce_unsized
    60. cold_path
    61. concat_bytes
    62. concat_idents
    63. const_alloc_error
    64. const_array_as_mut_slice
    65. const_array_each_ref
    66. const_black_box
    67. const_box
    68. const_btree_len
    69. const_carrying_mul_add
    70. const_cell
    71. const_char_classify
    72. const_copy_from_slice
    73. const_deref
    74. const_eq_ignore_ascii_case
    75. const_eval_select
    76. const_format_args
    77. const_heap
    78. const_is_char_boundary
    79. const_mut_cursor
    80. const_ops
    81. const_ptr_sub_ptr
    82. const_range_bounds
    83. const_raw_ptr_comparison
    84. const_slice_flatten
    85. const_slice_from_mut_ptr_range
    86. const_slice_from_ptr_range
    87. const_slice_reverse
    88. const_sockaddr_setters
    89. const_str_from_utf8
    90. const_str_split_at
    91. const_swap_nonoverlapping
    92. const_type_id
    93. const_type_name
    94. const_vec_string_slice
    95. container_error_extra
    96. context_ext
    97. convert_float_to_int
    98. core_intrinsics
    99. core_intrinsics_fallbacks
    100. core_io_borrowed_buf
    101. core_private_bignum
    102. core_private_diy_float
    103. coroutine_trait
    104. cow_is_borrowed
    105. cstr_bytes
    106. cstr_internals
    107. cursor_split
    108. deadline_api
    109. debug_closure_helpers
    110. dec2flt
    111. deref_pure_trait
    112. derive_clone_copy
    113. derive_coerce_pointee
    114. derive_const
    115. derive_eq
    116. dir_entry_ext2
    117. discriminant_kind
    118. dispatch_from_dyn
    119. downcast_unchecked
    120. drain_keep_rest
    121. duration_constants
    122. duration_constructors
    123. duration_millis_float
    124. duration_units
    125. edition_panic
    126. error_generic_member_access
    127. error_iter
    128. error_reporter
    129. error_type_id
    130. exact_size_is_empty
    131. exclusive_wrapper
    132. exit_status_error
    133. exitcode_exit_method
    134. extend_one
    135. extend_one_unchecked
    136. extract_if
    137. fd
    138. fd_read
    139. file_buffered
    140. file_lock
    141. float_gamma
    142. float_minimum_maximum
    143. flt2dec
    144. fmt_helpers_for_derive
    145. fmt_internals
    146. fn_ptr_trait
    147. fn_traits
    148. forget_unsized
    149. format_args_nl
    150. formatting_options
    151. freeze
    152. future_join
    153. gen_future
    154. generic_assert_internals
    155. get_many_mut
    156. get_many_mut_helpers
    157. get_mut_unchecked
    158. hash_extract_if
    159. hash_raw_entry
    160. hash_set_entry
    161. hasher_prefixfree_extras
    162. hashmap_internals
    163. hint_must_use
    164. inplace_iteration
    165. int_roundings
    166. integer_atomics
    167. integer_sign_cast
    168. internal_impls_macro
    169. internal_output_capture
    170. io_const_error
    171. io_const_error_internals
    172. io_error_inprogress
    173. io_error_more
    174. io_error_uncategorized
    175. io_slice_as_bytes
    176. ip
    177. ip_from
    178. is_ascii_octdigit
    179. is_loongarch_feature_detected
    180. is_riscv_feature_detected
    181. iter_advance_by
    182. iter_array_chunks
    183. iter_chain
    184. iter_collect_into
    185. iter_from_coroutine
    186. iter_intersperse
    187. iter_is_partitioned
    188. iter_map_windows
    189. iter_next_chunk
    190. iter_order_by
    191. iter_partition_in_place
    192. iterator_try_collect
    193. iterator_try_reduce
    194. junction_point
    195. layout_for_ptr
    196. lazy_cell_into_inner
    197. lazy_get
    198. legacy_receiver_trait
    199. liballoc_internals
    200. libstd_sys_internals
    201. likely_unlikely
    202. linked_list_cursors
    203. linked_list_remove
    204. linked_list_retain
    205. linux_pidfd
    206. local_waker
    207. lock_value_accessors
    208. log_syntax
    209. map_many_mut
    210. map_try_insert
    211. mapped_lock_guards
    212. maybe_uninit_array_assume_init
    213. maybe_uninit_as_bytes
    214. maybe_uninit_fill
    215. maybe_uninit_slice
    216. maybe_uninit_uninit_array
    217. maybe_uninit_uninit_array_transpose
    218. maybe_uninit_write_slice
    219. mem_copy_fn
    220. mixed_integer_ops_unsigned_sub
    221. more_float_constants
    222. mpmc_channel
    223. new_range_api
    224. new_zeroed_alloc
    225. non_null_from_ref
    226. non_zero_count_ones
    227. nonnull_provenance
    228. nonzero_bitwise
    229. nonzero_from_mut
    230. nonzero_internals
    231. nonzero_ops
    232. num_midpoint_signed
    233. numfmt
    234. once_cell_get_mut
    235. once_cell_try
    236. once_cell_try_insert
    237. once_wait
    238. one_sided_range
    239. option_array_transpose
    240. option_zip
    241. os_str_display
    242. os_str_slice
    243. os_string_pathbuf_leak
    244. os_string_truncate
    245. panic_abort
    246. panic_always_abort
    247. panic_backtrace_config
    248. panic_can_unwind
    249. panic_internals
    250. panic_payload_as_str
    251. panic_unwind
    252. panic_update_hook
    253. path_add_extension
    254. path_file_prefix
    255. pattern
    256. pattern_type_macro
    257. peer_credentials_unix_socket
    258. phantom_variance_markers
    259. pin_coerce_unsized_trait
    260. pointer_is_aligned_to
    261. pointer_like_trait
    262. portable_simd
    263. print_internals
    264. proc_macro_def_site
    265. proc_macro_diagnostic
    266. proc_macro_expand
    267. proc_macro_internals
    268. proc_macro_quote
    269. proc_macro_span
    270. proc_macro_totokens
    271. proc_macro_tracked_env
    272. process_exitcode_internals
    273. process_internals
    274. profiler_runtime_lib
    275. ptr_alignment_type
    276. ptr_as_ref_unchecked
    277. ptr_as_uninit
    278. ptr_internals
    279. ptr_mask
    280. ptr_metadata
    281. ptr_sub_ptr
    282. pub_crate_should_not_need_unstable_attr
    283. random
    284. raw_os_error_ty
    285. raw_slice_split
    286. raw_vec_internals
    287. read_buf
    288. reentrant_lock
    289. restricted_std
    290. result_flattening
    291. round_char_boundary
    292. rt
    293. rustc_encodable_decodable
    294. rwlock_downgrade
    295. sealed
    296. seek_stream_len
    297. select_unpredictable
    298. set_ptr_value
    299. setgroups
    300. sgx_platform
    301. sized_type_properties
    302. slice_as_array
    303. slice_as_chunks
    304. slice_concat_ext
    305. slice_concat_trait
    306. slice_from_ptr_range
    307. slice_index_methods
    308. slice_internals
    309. slice_iter_mut_as_mut_slice
    310. slice_partition_dedup
    311. slice_pattern
    312. slice_ptr_get
    313. slice_range
    314. slice_split_once
    315. slice_swap_unchecked
    316. slice_take
    317. solid_ext
    318. sort_floats
    319. split_array
    320. split_as_slice
    321. std_internals
    322. stdarch_arm_feature_detection
    323. stdarch_mips_feature_detection
    324. stdarch_powerpc_feature_detection
    325. stdio_makes_pipe
    326. step_trait
    327. str_as_str
    328. str_from_raw_parts
    329. str_from_utf16_endian
    330. str_internals
    331. str_lines_remainder
    332. str_split_inclusive_remainder
    333. str_split_remainder
    334. str_split_whitespace_remainder
    335. strict_overflow_ops
    336. strict_provenance_atomic_ptr
    337. string_extend_from_within
    338. string_from_utf8_lossy_owned
    339. string_into_chars
    340. string_remove_matches
    341. substr_range
    342. sync_poison_mod
    343. sync_unsafe_cell
    344. tcp_deferaccept
    345. tcp_linger
    346. tcp_quickack
    347. tcplistener_into_incoming
    348. temporary_niche_types
    349. test
    350. thin_box
    351. thread_id_value
    352. thread_local_internals
    353. thread_raw
    354. thread_sleep_until
    355. thread_spawn_hook
    356. trace_macros
    357. track_path
    358. transmutability
    359. trusted_fused
    360. trusted_len
    361. trusted_len_next_unchecked
    362. trusted_random_access
    363. trusted_step
    364. try_find
    365. try_reserve_kind
    366. try_trait_v2
    367. try_trait_v2_residual
    368. try_trait_v2_yeet
    369. try_with_capacity
    370. tuple_trait
    371. type_ascription
    372. ub_checks
    373. uefi_std
    374. unbounded_shifts
    375. unchecked_neg
    376. unchecked_shifts
    377. unicode_internals
    378. unique_rc_arc
    379. unix_file_vectored_at
    380. unix_set_mark
    381. unix_socket_ancillary_data
    382. unix_socket_peek
    383. unsafe_pin_internals
    384. unsigned_is_multiple_of
    385. unsigned_nonzero_div_ceil
    386. unsigned_signed_diff
    387. unsize
    388. unwrap_infallible
    389. update_panic_count
    390. utf16_extra
    391. variant_count
    392. vec_deque_iter_as_slices
    393. vec_deque_pop_if
    394. vec_into_raw_parts
    395. vec_pop_if
    396. vec_push_within_capacity
    397. vec_split_at_spare
    398. wasi_ext
    399. windows_by_handle
    400. windows_c
    401. windows_change_time
    402. windows_handle
    403. windows_net
    404. windows_process_exit_code_from
    405. windows_process_extensions_async_pipes
    406. windows_process_extensions_force_quotes
    407. windows_process_extensions_main_thread_handle
    408. windows_process_extensions_raw_attribute
    409. windows_process_extensions_show_window
    410. windows_stdio
    411. wrapping_int_impl
    412. wrapping_next_power_of_two
    413. write_all_vectored
    414. yeet_desugar_details