1. The Unstable Book
  2. Compiler flags
    1. autodiff
    2. branch_protection
    3. cf_protection
    4. codegen_backend
    5. codegen_options
    6. control_flow_guard
    7. coverage_options
    8. crate_attr
    9. debug_info_for_profiling
    10. debug_info_type_line_numbers
    11. default_visibility
    12. direct_access_external_data
    13. dump_mono_stats
    14. dump_mono_stats_format
    15. dwarf_version
    16. dylib_lto
    17. embed_source
    18. emit_stack_sizes
    19. emscripten_wasm_eh
    20. env_set
    21. export_executable_symbols
    22. extern_options
    23. external_clangrt
    24. fixed_x18
    25. fmt_debug
    26. function_return
    27. instrument_xray
    28. link_native_libraries
    29. linker_features
    30. lint_llvm_ir
    31. llvm_module_flag
    32. location_detail
    33. min_function_alignment
    34. move_size_limit
    35. no_jump_tables
    36. no_parallel_llvm
    37. no_unique_section_names
    38. on_broken_pipe
    39. patchable_function_entry
    40. print_check_cfg
    41. profile_sample_use
    42. randomize_layout
    43. reg_struct_return
    44. regparm
    45. remap_cwd_prefix
    46. remap_path_scope
    47. report_time
    48. sanitizer
    49. self_profile
    50. self_profile_events
    51. shell_argfiles
    52. small_data_threshold
    53. src_hash_algorithm
    54. temps_dir
    55. tiny_const_eval_limit
    56. tls_model
    57. ub_checks
    58. unsound_mir_opts
    59. verbose_asm
    60. virtual_function_elimination
    61. 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_contract_checks
    40. cfg_emscripten_wasm_eh
    41. cfg_overflow_checks
    42. cfg_relocation_model
    43. cfg_sanitize
    44. cfg_sanitizer_cfi
    45. cfg_target_compact
    46. cfg_target_has_atomic
    47. cfg_target_has_atomic_equal_alignment
    48. cfg_target_thread_local
    49. cfg_ub_checks
    50. cfg_version
    51. cfi_encoding
    52. closure_lifetime_binder
    53. closure_track_caller
    54. cmse_nonsecure_entry
    55. compiler_builtins
    56. const_async_blocks
    57. const_closures
    58. const_destruct
    59. const_for
    60. const_precise_live_drops
    61. const_trait_impl
    62. const_try
    63. contracts
    64. contracts_internals
    65. coroutine_clone
    66. coroutines
    67. coverage_attribute
    68. csky_target_feature
    69. custom_inner_attributes
    70. custom_mir
    71. custom_test_frameworks
    72. decl_macro
    73. default_field_values
    74. deprecated_safe
    75. deprecated_suggestion
    76. deref_patterns
    77. doc_auto_cfg
    78. doc_cfg
    79. doc_cfg_hide
    80. doc_masked
    81. doc_notable_trait
    82. dropck_eyepatch
    83. dyn_star
    84. ergonomic_clones
    85. ermsb_target_feature
    86. exhaustive_patterns
    87. explicit_tail_calls
    88. extended_varargs_abi_support
    89. extern_system_varargs
    90. extern_types
    91. f128
    92. f16
    93. ffi_const
    94. ffi_pure
    95. fmt_debug
    96. fn_align
    97. fn_delegation
    98. freeze_impls
    99. fundamental
    100. gen_blocks
    101. generic_arg_infer
    102. generic_assert
    103. generic_const_exprs
    104. generic_const_items
    105. generic_const_parameter_types
    106. generic_pattern_types
    107. global_registration
    108. guard_patterns
    109. half_open_range_patterns_in_slices
    110. hexagon_target_feature
    111. if_let_guard
    112. impl_trait_in_assoc_type
    113. impl_trait_in_bindings
    114. impl_trait_in_fn_trait_return
    115. import_trait_associated_functions
    116. inherent_associated_types
    117. inline_const_pat
    118. intra_doc_pointers
    119. intrinsics
    120. keylocker_x86
    121. lahfsahf_target_feature
    122. lang_items
    123. large_assignments
    124. lazy_type_alias
    125. let_chains
    126. link_arg_attribute
    127. link_cfg
    128. link_llvm_intrinsics
    129. linkage
    130. loongarch_target_feature
    131. m68k_target_feature
    132. macro_metavar_expr
    133. macro_metavar_expr_concat
    134. marker_trait_attr
    135. min_generic_const_args
    136. min_specialization
    137. mips_target_feature
    138. more_maybe_bounds
    139. more_qualified_paths
    140. multiple_supertrait_upcastable
    141. must_not_suspend
    142. mut_ref
    143. naked_functions
    144. native_link_modifiers_as_needed
    145. needs_panic_runtime
    146. negative_bounds
    147. negative_impls
    148. never_patterns
    149. never_type
    150. never_type_fallback
    151. new_range
    152. no_core
    153. no_sanitize
    154. non_exhaustive_omitted_patterns_lint
    155. non_lifetime_binders
    156. offset_of_enum
    157. offset_of_slice
    158. omit_gdb_pretty_printer_section
    159. optimize_attribute
    160. panic_runtime
    161. patchable_function_entry
    162. pattern_complexity_limit
    163. pattern_types
    164. pin_ergonomics
    165. postfix_match
    166. powerpc_target_feature
    167. precise_capturing_in_traits
    168. prelude_import
    169. prfchw_target_feature
    170. proc_macro_hygiene
    171. profiler_runtime
    172. raw_dylib_elf
    173. ref_pat_eat_one_layer_2024
    174. ref_pat_eat_one_layer_2024_structural
    175. register_tool
    176. repr_simd
    177. repr128
    178. return_type_notation
    179. riscv_target_feature
    180. rtm_target_feature
    181. rust_cold_cc
    182. rustc_allow_const_fn_unstable
    183. rustc_attrs
    184. rustc_private
    185. rustdoc_internals
    186. rustdoc_missing_doc_code_examples
    187. s390x_target_feature
    188. sha512_sm_x86
    189. simd_ffi
    190. sparc_target_feature
    191. specialization
    192. sse4a_target_feature
    193. staged_api
    194. stmt_expr_attributes
    195. strict_provenance_lints
    196. string_deref_patterns
    197. structural_match
    198. supertrait_item_shadowing
    199. tbm_target_feature
    200. test_unstable_lint
    201. thread_local
    202. trait_alias
    203. transmute_generic_consts
    204. transparent_unions
    205. trivial_bounds
    206. try_blocks
    207. type_alias_impl_trait
    208. type_changing_struct_update
    209. unboxed_closures
    210. unqualified_local_imports
    211. unsafe_binders
    212. unsafe_fields
    213. unsized_const_params
    214. unsized_fn_params
    215. unsized_locals
    216. used_with_arg
    217. wasm_target_feature
    218. where_clause_attrs
    219. with_negative_coherence
    220. x86_amx_intrinsics
    221. x87_target_feature
    222. xop_target_feature
    223. yeet_expr
    224. yield_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. alloctests
    9. anonymous_pipe
    10. array_chunks
    11. array_into_iter_constructors
    12. array_ptr_get
    13. array_repeat
    14. array_try_from_fn
    15. array_try_map
    16. array_windows
    17. as_array_of_cells
    18. ascii_char
    19. ascii_char_variants
    20. assert_matches
    21. async_drop
    22. async_fn_traits
    23. async_gen_internals
    24. async_iter_from_iter
    25. async_iterator
    26. atomic_from_mut
    27. atomic_try_update
    28. autodiff
    29. backtrace_frames
    30. bigint_helper_methods
    31. bikeshed_guaranteed_no_drop
    32. binary_heap_drain_sorted
    33. binary_heap_into_iter_sorted
    34. binary_heap_peek_mut_refresh
    35. bound_as_ref
    36. box_as_ptr
    37. box_into_boxed_slice
    38. box_into_inner
    39. box_vec_non_null
    40. breakpoint
    41. bstr
    42. bstr_internals
    43. btree_cursors
    44. btree_entry_insert
    45. btree_extract_if
    46. btree_set_entry
    47. btreemap_alloc
    48. buf_read_has_data_left
    49. bufreader_peek
    50. c_size_t
    51. c_str_module
    52. c_void_variant
    53. can_vector
    54. cell_leak
    55. cell_update
    56. cfg_accessible
    57. cfg_eval
    58. cfg_match
    59. char_internals
    60. char_max_len
    61. clone_to_uninit
    62. cmp_minmax
    63. coerce_pointee_validated
    64. coerce_unsized
    65. cold_path
    66. concat_bytes
    67. concat_idents
    68. const_alloc_error
    69. const_array_as_mut_slice
    70. const_array_each_ref
    71. const_box
    72. const_btree_len
    73. const_carrying_mul_add
    74. const_cell
    75. const_deref
    76. const_eq_ignore_ascii_case
    77. const_eval_select
    78. const_format_args
    79. const_heap
    80. const_ops
    81. const_range_bounds
    82. const_raw_ptr_comparison
    83. const_slice_from_mut_ptr_range
    84. const_slice_from_ptr_range
    85. const_slice_reverse
    86. const_swap_nonoverlapping
    87. const_type_id
    88. const_type_name
    89. container_error_extra
    90. context_ext
    91. control_flow_into_value
    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. disjoint_bitor
    114. dispatch_from_dyn
    115. downcast_unchecked
    116. drain_keep_rest
    117. duration_constants
    118. duration_constructors
    119. duration_millis_float
    120. duration_units
    121. edition_panic
    122. error_generic_member_access
    123. error_iter
    124. error_reporter
    125. error_type_id
    126. exact_size_is_empty
    127. exclusive_wrapper
    128. exit_status_error
    129. exitcode_exit_method
    130. extend_one
    131. extend_one_unchecked
    132. fd
    133. fd_read
    134. file_buffered
    135. float_erf
    136. float_gamma
    137. float_minimum_maximum
    138. flt2dec
    139. fmt_helpers_for_derive
    140. fmt_internals
    141. fn_ptr_trait
    142. fn_traits
    143. forget_unsized
    144. format_args_nl
    145. formatting_options
    146. freeze
    147. future_join
    148. gen_future
    149. generic_assert_internals
    150. get_disjoint_mut_helpers
    151. get_mut_unchecked
    152. hash_set_entry
    153. hasher_prefixfree_extras
    154. hashmap_internals
    155. hint_must_use
    156. inplace_iteration
    157. int_from_ascii
    158. int_roundings
    159. integer_atomics
    160. internal_impls_macro
    161. internal_output_capture
    162. io_const_error
    163. io_const_error_internals
    164. io_error_inprogress
    165. io_error_more
    166. io_error_uncategorized
    167. io_slice_as_bytes
    168. ip
    169. ip_as_octets
    170. ip_from
    171. is_ascii_octdigit
    172. is_loongarch_feature_detected
    173. is_riscv_feature_detected
    174. isolate_most_least_significant_one
    175. iter_advance_by
    176. iter_array_chunks
    177. iter_chain
    178. iter_collect_into
    179. iter_from_coroutine
    180. iter_intersperse
    181. iter_is_partitioned
    182. iter_map_windows
    183. iter_next_chunk
    184. iter_order_by
    185. iter_partition_in_place
    186. iterator_try_collect
    187. iterator_try_reduce
    188. junction_point
    189. layout_for_ptr
    190. lazy_cell_into_inner
    191. lazy_get
    192. legacy_receiver_trait
    193. liballoc_internals
    194. libstd_sys_internals
    195. likely_unlikely
    196. linked_list_cursors
    197. linked_list_remove
    198. linked_list_retain
    199. linux_pidfd
    200. local_waker
    201. lock_value_accessors
    202. log_syntax
    203. map_try_insert
    204. mapped_lock_guards
    205. maybe_uninit_array_assume_init
    206. maybe_uninit_as_bytes
    207. maybe_uninit_fill
    208. maybe_uninit_slice
    209. maybe_uninit_uninit_array_transpose
    210. maybe_uninit_write_slice
    211. mem_copy_fn
    212. mixed_integer_ops_unsigned_sub
    213. more_float_constants
    214. mpmc_channel
    215. new_range_api
    216. new_zeroed_alloc
    217. non_null_from_ref
    218. nonnull_provenance
    219. nonzero_bitwise
    220. nonzero_from_mut
    221. nonzero_internals
    222. nonzero_ops
    223. numfmt
    224. once_cell_get_mut
    225. once_cell_try
    226. once_cell_try_insert
    227. one_sided_range
    228. option_array_transpose
    229. option_zip
    230. os_str_slice
    231. os_string_pathbuf_leak
    232. os_string_truncate
    233. panic_abort
    234. panic_always_abort
    235. panic_backtrace_config
    236. panic_can_unwind
    237. panic_internals
    238. panic_payload_as_str
    239. panic_unwind
    240. panic_update_hook
    241. path_add_extension
    242. path_file_prefix
    243. pattern
    244. pattern_type_macro
    245. pattern_type_range_trait
    246. peer_credentials_unix_socket
    247. phantom_variance_markers
    248. pin_coerce_unsized_trait
    249. pointer_is_aligned_to
    250. pointer_like_trait
    251. portable_simd
    252. prelude_future
    253. prelude_next
    254. print_internals
    255. proc_macro_def_site
    256. proc_macro_diagnostic
    257. proc_macro_expand
    258. proc_macro_internals
    259. proc_macro_quote
    260. proc_macro_span
    261. proc_macro_totokens
    262. proc_macro_tracked_env
    263. process_exitcode_internals
    264. process_internals
    265. profiler_runtime_lib
    266. ptr_alignment_type
    267. ptr_as_ref_unchecked
    268. ptr_as_uninit
    269. ptr_internals
    270. ptr_mask
    271. ptr_metadata
    272. pub_crate_should_not_need_unstable_attr
    273. random
    274. range_bounds_is_empty
    275. range_into_bounds
    276. raw_os_error_ty
    277. raw_slice_split
    278. raw_vec_internals
    279. read_buf
    280. reentrant_lock
    281. restricted_std
    282. result_flattening
    283. round_char_boundary
    284. rt
    285. rwlock_downgrade
    286. sealed
    287. seek_stream_len
    288. select_unpredictable
    289. set_ptr_value
    290. setgroups
    291. sgx_platform
    292. sized_type_properties
    293. slice_as_array
    294. slice_as_chunks
    295. slice_concat_ext
    296. slice_concat_trait
    297. slice_from_ptr_range
    298. slice_index_methods
    299. slice_internals
    300. slice_iter_mut_as_mut_slice
    301. slice_partition_dedup
    302. slice_pattern
    303. slice_ptr_get
    304. slice_range
    305. slice_split_once
    306. slice_swap_unchecked
    307. solid_ext
    308. sort_floats
    309. split_array
    310. split_as_slice
    311. std_internals
    312. stdarch_arm_feature_detection
    313. stdarch_mips_feature_detection
    314. stdarch_powerpc_feature_detection
    315. stdio_makes_pipe
    316. step_trait
    317. str_as_str
    318. str_from_raw_parts
    319. str_from_utf16_endian
    320. str_internals
    321. str_lines_remainder
    322. str_split_inclusive_remainder
    323. str_split_remainder
    324. str_split_whitespace_remainder
    325. strict_overflow_ops
    326. strict_provenance_atomic_ptr
    327. string_from_utf8_lossy_owned
    328. string_into_chars
    329. string_remove_matches
    330. substr_range
    331. sync_poison_mod
    332. sync_unsafe_cell
    333. tcp_deferaccept
    334. tcp_linger
    335. tcp_quickack
    336. tcplistener_into_incoming
    337. temporary_niche_types
    338. test
    339. thin_box
    340. thread_id_value
    341. thread_local_internals
    342. thread_raw
    343. thread_sleep_until
    344. thread_spawn_hook
    345. trace_macros
    346. track_path
    347. transmutability
    348. trusted_fused
    349. trusted_len
    350. trusted_len_next_unchecked
    351. trusted_random_access
    352. trusted_step
    353. try_find
    354. try_reserve_kind
    355. try_trait_v2
    356. try_trait_v2_residual
    357. try_trait_v2_yeet
    358. try_with_capacity
    359. tuple_trait
    360. type_ascription
    361. ub_checks
    362. uefi_std
    363. unchecked_neg
    364. unchecked_shifts
    365. unicode_internals
    366. unique_rc_arc
    367. unix_file_vectored_at
    368. unix_set_mark
    369. unix_socket_ancillary_data
    370. unix_socket_peek
    371. unsafe_cell_access
    372. unsafe_pin_internals
    373. unsigned_nonzero_div_ceil
    374. unsigned_signed_diff
    375. unsize
    376. unwrap_infallible
    377. update_panic_count
    378. utf16_extra
    379. variant_count
    380. vec_deque_iter_as_slices
    381. vec_deque_pop_if
    382. vec_into_raw_parts
    383. vec_push_within_capacity
    384. vec_split_at_spare
    385. wasi_ext
    386. windows_by_handle
    387. windows_c
    388. windows_change_time
    389. windows_handle
    390. windows_net
    391. windows_process_exit_code_from
    392. windows_process_extensions_async_pipes
    393. windows_process_extensions_force_quotes
    394. windows_process_extensions_main_thread_handle
    395. windows_process_extensions_raw_attribute
    396. windows_process_extensions_show_window
    397. windows_stdio
    398. wrapping_int_impl
    399. wrapping_next_power_of_two
    400. write_all_vectored
    401. yeet_desugar_details