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_msp430_interrupt
    6. abi_ptx
    7. abi_riscv_interrupt
    8. abi_unadjusted
    9. abi_vectorcall
    10. abi_x86_interrupt
    11. adt_const_params
    12. alloc_error_handler
    13. allocator_internals
    14. allow_internal_unsafe
    15. allow_internal_unstable
    16. anonymous_lifetime_in_impl_trait
    17. arbitrary_self_types
    18. arbitrary_self_types_pointers
    19. arm_target_feature
    20. asm_experimental_arch
    21. asm_experimental_reg
    22. asm_goto
    23. asm_goto_with_outputs
    24. asm_unwind
    25. associated_const_equality
    26. associated_type_defaults
    27. async_fn_in_dyn_trait
    28. async_fn_track_caller
    29. async_for_loop
    30. async_trait_bounds
    31. auto_traits
    32. avx512_target_feature
    33. box_patterns
    34. bpf_target_feature
    35. builtin_syntax
    36. c_variadic
    37. cfg_boolean_literals
    38. cfg_emscripten_wasm_eh
    39. cfg_overflow_checks
    40. cfg_relocation_model
    41. cfg_sanitize
    42. cfg_sanitizer_cfi
    43. cfg_target_compact
    44. cfg_target_has_atomic
    45. cfg_target_has_atomic_equal_alignment
    46. cfg_target_thread_local
    47. cfg_ub_checks
    48. cfg_version
    49. cfi_encoding
    50. closure_lifetime_binder
    51. closure_track_caller
    52. cmse_nonsecure_entry
    53. compiler_builtins
    54. const_async_blocks
    55. const_closures
    56. const_destruct
    57. const_for
    58. const_precise_live_drops
    59. const_trait_impl
    60. const_try
    61. coroutine_clone
    62. coroutines
    63. coverage_attribute
    64. csky_target_feature
    65. custom_inner_attributes
    66. custom_mir
    67. custom_test_frameworks
    68. decl_macro
    69. default_field_values
    70. deprecated_safe
    71. deprecated_suggestion
    72. deref_patterns
    73. doc_auto_cfg
    74. doc_cfg
    75. doc_cfg_hide
    76. doc_masked
    77. doc_notable_trait
    78. dropck_eyepatch
    79. dyn_compatible_for_dispatch
    80. dyn_star
    81. ermsb_target_feature
    82. exhaustive_patterns
    83. explicit_tail_calls
    84. extern_types
    85. f128
    86. f16
    87. ffi_const
    88. ffi_pure
    89. fmt_debug
    90. fn_align
    91. fn_delegation
    92. freeze_impls
    93. fundamental
    94. gen_blocks
    95. generic_arg_infer
    96. generic_assert
    97. generic_const_exprs
    98. generic_const_items
    99. global_registration
    100. guard_patterns
    101. half_open_range_patterns_in_slices
    102. hexagon_target_feature
    103. if_let_guard
    104. impl_trait_in_assoc_type
    105. impl_trait_in_bindings
    106. impl_trait_in_fn_trait_return
    107. inherent_associated_types
    108. inline_const_pat
    109. intra_doc_pointers
    110. intrinsics
    111. lahfsahf_target_feature
    112. lang_items
    113. large_assignments
    114. lazy_type_alias
    115. let_chains
    116. lifetime_capture_rules_2024
    117. link_arg_attribute
    118. link_cfg
    119. link_llvm_intrinsics
    120. linkage
    121. loongarch_target_feature
    122. m68k_target_feature
    123. macro_metavar_expr
    124. macro_metavar_expr_concat
    125. marker_trait_attr
    126. min_generic_const_args
    127. min_specialization
    128. mips_target_feature
    129. more_maybe_bounds
    130. more_qualified_paths
    131. multiple_supertrait_upcastable
    132. must_not_suspend
    133. mut_ref
    134. naked_functions
    135. native_link_modifiers_as_needed
    136. needs_panic_runtime
    137. negative_bounds
    138. negative_impls
    139. never_patterns
    140. never_type
    141. never_type_fallback
    142. no_core
    143. no_sanitize
    144. non_exhaustive_omitted_patterns_lint
    145. non_lifetime_binders
    146. offset_of_enum
    147. offset_of_slice
    148. omit_gdb_pretty_printer_section
    149. optimize_attribute
    150. panic_runtime
    151. patchable_function_entry
    152. pattern_complexity
    153. pattern_types
    154. pin_ergonomics
    155. postfix_match
    156. powerpc_target_feature
    157. precise_capturing_in_traits
    158. prelude_import
    159. prfchw_target_feature
    160. proc_macro_hygiene
    161. profiler_runtime
    162. ref_pat_eat_one_layer_2024
    163. ref_pat_eat_one_layer_2024_structural
    164. register_tool
    165. repr_simd
    166. repr128
    167. return_type_notation
    168. riscv_target_feature
    169. rtm_target_feature
    170. rust_cold_cc
    171. rustc_allow_const_fn_unstable
    172. rustc_attrs
    173. rustc_private
    174. rustdoc_internals
    175. rustdoc_missing_doc_code_examples
    176. s390x_target_feature
    177. sha512_sm_x86
    178. simd_ffi
    179. sparc_target_feature
    180. specialization
    181. sse4a_target_feature
    182. staged_api
    183. start
    184. stmt_expr_attributes
    185. strict_provenance_lints
    186. string_deref_patterns
    187. structural_match
    188. target_feature_11
    189. tbm_target_feature
    190. test_unstable_lint
    191. thread_local
    192. trait_alias
    193. trait_upcasting
    194. transmute_generic_consts
    195. transparent_unions
    196. trivial_bounds
    197. try_blocks
    198. type_alias_impl_trait
    199. type_changing_struct_update
    200. unboxed_closures
    201. unqualified_local_imports
    202. unsafe_binders
    203. unsafe_fields
    204. unsized_const_params
    205. unsized_fn_params
    206. unsized_locals
    207. unsized_tuple_coercion
    208. used_with_arg
    209. wasm_target_feature
    210. with_negative_coherence
    211. x86_amx_intrinsics
    212. x87_target_feature
    213. xop_target_feature
    214. 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. btree_cursors
    39. btree_entry_insert
    40. btree_extract_if
    41. btree_set_entry
    42. btreemap_alloc
    43. buf_read_has_data_left
    44. bufreader_peek
    45. c_size_t
    46. c_str_module
    47. c_void_variant
    48. can_vector
    49. cell_leak
    50. cell_update
    51. cfg_accessible
    52. cfg_eval
    53. cfg_match
    54. char_internals
    55. clone_to_uninit
    56. cmp_minmax
    57. coerce_unsized
    58. concat_bytes
    59. concat_idents
    60. const_alloc_error
    61. const_array_as_mut_slice
    62. const_array_each_ref
    63. const_black_box
    64. const_box
    65. const_btree_len
    66. const_carrying_mul_add
    67. const_cell
    68. const_char_classify
    69. const_copy_from_slice
    70. const_eq_ignore_ascii_case
    71. const_eval_select
    72. const_format_args
    73. const_heap
    74. const_is_char_boundary
    75. const_mut_cursor
    76. const_ptr_sub_ptr
    77. const_range_bounds
    78. const_raw_ptr_comparison
    79. const_slice_flatten
    80. const_slice_from_mut_ptr_range
    81. const_slice_from_ptr_range
    82. const_slice_reverse
    83. const_sockaddr_setters
    84. const_str_from_utf8
    85. const_str_split_at
    86. const_swap_nonoverlapping
    87. const_type_id
    88. const_type_name
    89. const_vec_string_slice
    90. container_error_extra
    91. context_ext
    92. convert_float_to_int
    93. core_intrinsics
    94. core_intrinsics_fallbacks
    95. core_io_borrowed_buf
    96. core_private_bignum
    97. core_private_diy_float
    98. coroutine_trait
    99. cow_is_borrowed
    100. cstr_bytes
    101. cstr_internals
    102. cursor_split
    103. deadline_api
    104. debug_closure_helpers
    105. dec2flt
    106. deref_pure_trait
    107. derive_clone_copy
    108. derive_coerce_pointee
    109. derive_const
    110. derive_eq
    111. dir_entry_ext2
    112. discriminant_kind
    113. dispatch_from_dyn
    114. downcast_unchecked
    115. drain_keep_rest
    116. duration_constants
    117. duration_constructors
    118. duration_millis_float
    119. duration_units
    120. edition_panic
    121. error_generic_member_access
    122. error_iter
    123. error_reporter
    124. error_type_id
    125. exact_size_is_empty
    126. exclusive_wrapper
    127. exit_status_error
    128. exitcode_exit_method
    129. extend_one
    130. extend_one_unchecked
    131. extract_if
    132. fd
    133. fd_read
    134. file_buffered
    135. file_lock
    136. float_gamma
    137. float_minimum_maximum
    138. float_next_up_down
    139. flt2dec
    140. fmt_helpers_for_derive
    141. fmt_internals
    142. fn_ptr_trait
    143. fn_traits
    144. forget_unsized
    145. format_args_nl
    146. formatting_options
    147. freeze
    148. future_join
    149. gen_future
    150. generic_assert_internals
    151. get_many_mut
    152. get_many_mut_helpers
    153. get_mut_unchecked
    154. hash_extract_if
    155. hash_raw_entry
    156. hash_set_entry
    157. hasher_prefixfree_extras
    158. hashmap_internals
    159. hint_must_use
    160. inplace_iteration
    161. int_roundings
    162. integer_atomics
    163. integer_sign_cast
    164. internal_impls_macro
    165. internal_output_capture
    166. io_const_error
    167. io_const_error_internals
    168. io_error_inprogress
    169. io_error_more
    170. io_error_uncategorized
    171. io_slice_as_bytes
    172. ip
    173. ip_from
    174. is_ascii_octdigit
    175. is_loongarch_feature_detected
    176. is_riscv_feature_detected
    177. iter_advance_by
    178. iter_array_chunks
    179. iter_chain
    180. iter_collect_into
    181. iter_from_coroutine
    182. iter_intersperse
    183. iter_is_partitioned
    184. iter_map_windows
    185. iter_next_chunk
    186. iter_order_by
    187. iter_partition_in_place
    188. iterator_try_collect
    189. iterator_try_reduce
    190. junction_point
    191. layout_for_ptr
    192. lazy_cell_into_inner
    193. lazy_get
    194. legacy_receiver_trait
    195. liballoc_internals
    196. libstd_sys_internals
    197. linked_list_cursors
    198. linked_list_remove
    199. linked_list_retain
    200. linux_pidfd
    201. local_waker
    202. lock_value_accessors
    203. log_syntax
    204. map_many_mut
    205. map_try_insert
    206. mapped_lock_guards
    207. maybe_uninit_array_assume_init
    208. maybe_uninit_as_bytes
    209. maybe_uninit_fill
    210. maybe_uninit_slice
    211. maybe_uninit_uninit_array
    212. maybe_uninit_uninit_array_transpose
    213. maybe_uninit_write_slice
    214. mem_copy_fn
    215. mixed_integer_ops_unsigned_sub
    216. more_float_constants
    217. mpmc_channel
    218. new_range_api
    219. new_zeroed_alloc
    220. non_null_from_ref
    221. non_zero_count_ones
    222. nonnull_provenance
    223. nonzero_bitwise
    224. nonzero_from_mut
    225. nonzero_internals
    226. nonzero_ops
    227. num_midpoint_signed
    228. numfmt
    229. once_cell_get_mut
    230. once_cell_try
    231. once_cell_try_insert
    232. once_wait
    233. one_sided_range
    234. option_array_transpose
    235. option_zip
    236. os_str_display
    237. os_str_slice
    238. os_string_pathbuf_leak
    239. os_string_truncate
    240. panic_abort
    241. panic_always_abort
    242. panic_backtrace_config
    243. panic_can_unwind
    244. panic_internals
    245. panic_payload_as_str
    246. panic_unwind
    247. panic_update_hook
    248. path_add_extension
    249. path_file_prefix
    250. pattern
    251. pattern_type_macro
    252. peer_credentials_unix_socket
    253. pin_coerce_unsized_trait
    254. pointer_is_aligned_to
    255. pointer_like_trait
    256. portable_simd
    257. print_internals
    258. proc_macro_def_site
    259. proc_macro_diagnostic
    260. proc_macro_expand
    261. proc_macro_internals
    262. proc_macro_quote
    263. proc_macro_span
    264. proc_macro_totokens
    265. proc_macro_tracked_env
    266. process_exitcode_internals
    267. process_internals
    268. profiler_runtime_lib
    269. ptr_alignment_type
    270. ptr_as_ref_unchecked
    271. ptr_as_uninit
    272. ptr_internals
    273. ptr_mask
    274. ptr_metadata
    275. ptr_sub_ptr
    276. pub_crate_should_not_need_unstable_attr
    277. random
    278. raw_os_error_ty
    279. raw_slice_split
    280. raw_vec_internals
    281. read_buf
    282. reentrant_lock
    283. restricted_std
    284. result_flattening
    285. round_char_boundary
    286. rt
    287. rustc_encodable_decodable
    288. rwlock_downgrade
    289. sealed
    290. seek_stream_len
    291. select_unpredictable
    292. set_ptr_value
    293. setgroups
    294. sgx_platform
    295. sized_type_properties
    296. slice_as_array
    297. slice_as_chunks
    298. slice_concat_ext
    299. slice_concat_trait
    300. slice_from_ptr_range
    301. slice_index_methods
    302. slice_internals
    303. slice_iter_mut_as_mut_slice
    304. slice_partition_dedup
    305. slice_pattern
    306. slice_ptr_get
    307. slice_range
    308. slice_split_once
    309. slice_swap_unchecked
    310. slice_take
    311. solid_ext
    312. sort_floats
    313. split_array
    314. split_as_slice
    315. std_internals
    316. stdarch_arm_feature_detection
    317. stdarch_mips_feature_detection
    318. stdarch_powerpc_feature_detection
    319. stdio_makes_pipe
    320. step_trait
    321. str_as_str
    322. str_from_raw_parts
    323. str_from_utf16_endian
    324. str_internals
    325. str_lines_remainder
    326. str_split_inclusive_remainder
    327. str_split_remainder
    328. str_split_whitespace_remainder
    329. strict_overflow_ops
    330. strict_provenance_atomic_ptr
    331. string_extend_from_within
    332. string_from_utf8_lossy_owned
    333. string_into_chars
    334. string_remove_matches
    335. substr_range
    336. sync_poison_mod
    337. sync_unsafe_cell
    338. tcp_deferaccept
    339. tcp_linger
    340. tcp_quickack
    341. tcplistener_into_incoming
    342. temporary_niche_types
    343. test
    344. thin_box
    345. thread_id_value
    346. thread_local_internals
    347. thread_raw
    348. thread_sleep_until
    349. thread_spawn_hook
    350. trace_macros
    351. track_path
    352. transmutability
    353. trusted_fused
    354. trusted_len
    355. trusted_len_next_unchecked
    356. trusted_random_access
    357. trusted_step
    358. try_find
    359. try_reserve_kind
    360. try_trait_v2
    361. try_trait_v2_residual
    362. try_trait_v2_yeet
    363. try_with_capacity
    364. tuple_trait
    365. type_ascription
    366. ub_checks
    367. uefi_std
    368. unbounded_shifts
    369. unchecked_neg
    370. unchecked_shifts
    371. unicode_internals
    372. unique_rc_arc
    373. unix_file_vectored_at
    374. unix_set_mark
    375. unix_socket_ancillary_data
    376. unix_socket_peek
    377. unsafe_pin_internals
    378. unsigned_is_multiple_of
    379. unsigned_nonzero_div_ceil
    380. unsigned_signed_diff
    381. unsize
    382. unwrap_infallible
    383. update_panic_count
    384. utf16_extra
    385. variant_count
    386. vec_deque_iter_as_slices
    387. vec_into_raw_parts
    388. vec_pop_if
    389. vec_push_within_capacity
    390. vec_split_at_spare
    391. wasi_ext
    392. windows_by_handle
    393. windows_c
    394. windows_change_time
    395. windows_handle
    396. windows_net
    397. windows_process_exit_code_from
    398. windows_process_extensions_async_pipes
    399. windows_process_extensions_force_quotes
    400. windows_process_extensions_main_thread_handle
    401. windows_process_extensions_raw_attribute
    402. windows_process_extensions_show_window
    403. windows_stdio
    404. wrapping_int_impl
    405. wrapping_next_power_of_two
    406. write_all_vectored
    407. yeet_desugar_details