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. debug_info_for_profiling
    9. debug_info_type_line_numbers
    10. default_visibility
    11. direct_access_external_data
    12. dump_mono_stats
    13. dump_mono_stats_format
    14. dwarf_version
    15. dylib_lto
    16. embed_source
    17. emit_stack_sizes
    18. emscripten_wasm_eh
    19. env_set
    20. export_executable_symbols
    21. extern_options
    22. external_clangrt
    23. fixed_x18
    24. fmt_debug
    25. function_return
    26. instrument_xray
    27. link_native_libraries
    28. linker_features
    29. lint_llvm_ir
    30. llvm_module_flag
    31. location_detail
    32. min_function_alignment
    33. move_size_limit
    34. no_jump_tables
    35. no_parallel_llvm
    36. no_unique_section_names
    37. on_broken_pipe
    38. patchable_function_entry
    39. print_check_cfg
    40. profile_sample_use
    41. randomize_layout
    42. reg_struct_return
    43. regparm
    44. remap_cwd_prefix
    45. remap_path_scope
    46. report_time
    47. sanitizer
    48. self_profile
    49. self_profile_events
    50. shell_argfiles
    51. small_data_threshold
    52. src_hash_algorithm
    53. temps_dir
    54. tiny_const_eval_limit
    55. tls_model
    56. ub_checks
    57. unsound_mir_opts
    58. verbose_asm
    59. virtual_function_elimination
    60. 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_compatible_for_dispatch
    84. dyn_star
    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_pattern_types
    106. global_registration
    107. guard_patterns
    108. half_open_range_patterns_in_slices
    109. hexagon_target_feature
    110. if_let_guard
    111. impl_trait_in_assoc_type
    112. impl_trait_in_bindings
    113. impl_trait_in_fn_trait_return
    114. import_trait_associated_functions
    115. inherent_associated_types
    116. inline_const_pat
    117. intra_doc_pointers
    118. intrinsics
    119. keylocker_x86
    120. lahfsahf_target_feature
    121. lang_items
    122. large_assignments
    123. lazy_type_alias
    124. let_chains
    125. lifetime_capture_rules_2024
    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. ref_pat_eat_one_layer_2024
    173. ref_pat_eat_one_layer_2024_structural
    174. register_tool
    175. repr_simd
    176. repr128
    177. return_type_notation
    178. riscv_target_feature
    179. rtm_target_feature
    180. rust_cold_cc
    181. rustc_allow_const_fn_unstable
    182. rustc_attrs
    183. rustc_private
    184. rustdoc_internals
    185. rustdoc_missing_doc_code_examples
    186. s390x_target_feature
    187. sha512_sm_x86
    188. simd_ffi
    189. sparc_target_feature
    190. specialization
    191. sse4a_target_feature
    192. staged_api
    193. stmt_expr_attributes
    194. strict_provenance_lints
    195. string_deref_patterns
    196. structural_match
    197. supertrait_item_shadowing
    198. tbm_target_feature
    199. test_unstable_lint
    200. thread_local
    201. trait_alias
    202. transmute_generic_consts
    203. transparent_unions
    204. trivial_bounds
    205. try_blocks
    206. type_alias_impl_trait
    207. type_changing_struct_update
    208. unboxed_closures
    209. unqualified_local_imports
    210. unsafe_binders
    211. unsafe_fields
    212. unsized_const_params
    213. unsized_fn_params
    214. unsized_locals
    215. unsized_tuple_coercion
    216. used_with_arg
    217. wasm_target_feature
    218. with_negative_coherence
    219. x86_amx_intrinsics
    220. x87_target_feature
    221. xop_target_feature
    222. 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. atomic_try_update
    27. autodiff
    28. backtrace_frames
    29. bigint_helper_methods
    30. bikeshed_guaranteed_no_drop
    31. binary_heap_drain_sorted
    32. binary_heap_into_iter_sorted
    33. bound_as_ref
    34. box_as_ptr
    35. box_into_boxed_slice
    36. box_into_inner
    37. box_uninit_write
    38. box_vec_non_null
    39. breakpoint
    40. bstr
    41. bstr_internals
    42. btree_cursors
    43. btree_entry_insert
    44. btree_extract_if
    45. btree_set_entry
    46. btreemap_alloc
    47. buf_read_has_data_left
    48. bufreader_peek
    49. c_size_t
    50. c_str_module
    51. c_void_variant
    52. can_vector
    53. cell_leak
    54. cell_update
    55. cfg_accessible
    56. cfg_eval
    57. cfg_match
    58. char_internals
    59. clone_to_uninit
    60. cmp_minmax
    61. coerce_pointee_validated
    62. coerce_unsized
    63. cold_path
    64. concat_bytes
    65. concat_idents
    66. const_alloc_error
    67. const_array_as_mut_slice
    68. const_array_each_ref
    69. const_box
    70. const_btree_len
    71. const_carrying_mul_add
    72. const_cell
    73. const_char_classify
    74. const_copy_from_slice
    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_ptr_sub_ptr
    82. const_range_bounds
    83. const_raw_ptr_comparison
    84. const_slice_from_mut_ptr_range
    85. const_slice_from_ptr_range
    86. const_slice_reverse
    87. const_sockaddr_setters
    88. const_str_from_utf8
    89. const_swap_nonoverlapping
    90. const_type_id
    91. const_type_name
    92. const_vec_string_slice
    93. container_error_extra
    94. context_ext
    95. convert_float_to_int
    96. core_intrinsics
    97. core_intrinsics_fallbacks
    98. core_io_borrowed_buf
    99. core_private_bignum
    100. core_private_diy_float
    101. coroutine_trait
    102. cow_is_borrowed
    103. cstr_bytes
    104. cstr_internals
    105. cursor_split
    106. deadline_api
    107. debug_closure_helpers
    108. dec2flt
    109. deref_pure_trait
    110. derive_clone_copy
    111. derive_coerce_pointee
    112. derive_const
    113. derive_eq
    114. dir_entry_ext2
    115. discriminant_kind
    116. disjoint_bitor
    117. dispatch_from_dyn
    118. downcast_unchecked
    119. drain_keep_rest
    120. duration_constants
    121. duration_constructors
    122. duration_millis_float
    123. duration_units
    124. edition_panic
    125. error_generic_member_access
    126. error_iter
    127. error_reporter
    128. error_type_id
    129. exact_size_is_empty
    130. exclusive_wrapper
    131. exit_status_error
    132. exitcode_exit_method
    133. extend_one
    134. extend_one_unchecked
    135. extract_if
    136. fd
    137. fd_read
    138. file_buffered
    139. float_erf
    140. float_gamma
    141. float_minimum_maximum
    142. flt2dec
    143. fmt_helpers_for_derive
    144. fmt_internals
    145. fn_ptr_trait
    146. fn_traits
    147. forget_unsized
    148. format_args_nl
    149. formatting_options
    150. freeze
    151. future_join
    152. gen_future
    153. generic_assert_internals
    154. get_disjoint_mut_helpers
    155. get_mut_unchecked
    156. hash_extract_if
    157. hash_raw_entry
    158. hash_set_entry
    159. hasher_prefixfree_extras
    160. hashmap_internals
    161. hint_must_use
    162. inherent_str_constructors
    163. inplace_iteration
    164. int_from_ascii
    165. int_roundings
    166. integer_atomics
    167. internal_impls_macro
    168. internal_output_capture
    169. io_const_error
    170. io_const_error_internals
    171. io_error_inprogress
    172. io_error_more
    173. io_error_uncategorized
    174. io_slice_as_bytes
    175. ip
    176. ip_from
    177. is_ascii_octdigit
    178. is_loongarch_feature_detected
    179. is_riscv_feature_detected
    180. iter_advance_by
    181. iter_array_chunks
    182. iter_chain
    183. iter_collect_into
    184. iter_from_coroutine
    185. iter_intersperse
    186. iter_is_partitioned
    187. iter_map_windows
    188. iter_next_chunk
    189. iter_order_by
    190. iter_partition_in_place
    191. iterator_try_collect
    192. iterator_try_reduce
    193. junction_point
    194. layout_for_ptr
    195. lazy_cell_into_inner
    196. lazy_get
    197. legacy_receiver_trait
    198. liballoc_internals
    199. libstd_sys_internals
    200. likely_unlikely
    201. linked_list_cursors
    202. linked_list_remove
    203. linked_list_retain
    204. linux_pidfd
    205. local_waker
    206. lock_value_accessors
    207. log_syntax
    208. map_try_insert
    209. mapped_lock_guards
    210. maybe_uninit_array_assume_init
    211. maybe_uninit_as_bytes
    212. maybe_uninit_fill
    213. maybe_uninit_slice
    214. maybe_uninit_uninit_array
    215. maybe_uninit_uninit_array_transpose
    216. maybe_uninit_write_slice
    217. mem_copy_fn
    218. mixed_integer_ops_unsigned_sub
    219. more_float_constants
    220. mpmc_channel
    221. new_range_api
    222. new_zeroed_alloc
    223. non_null_from_ref
    224. nonnull_provenance
    225. nonzero_bitwise
    226. nonzero_from_mut
    227. nonzero_internals
    228. nonzero_ops
    229. num_midpoint_signed
    230. numfmt
    231. once_cell_get_mut
    232. once_cell_try
    233. once_cell_try_insert
    234. one_sided_range
    235. option_array_transpose
    236. option_zip
    237. os_str_display
    238. os_str_slice
    239. os_string_pathbuf_leak
    240. os_string_truncate
    241. panic_abort
    242. panic_always_abort
    243. panic_backtrace_config
    244. panic_can_unwind
    245. panic_internals
    246. panic_payload_as_str
    247. panic_unwind
    248. panic_update_hook
    249. path_add_extension
    250. path_file_prefix
    251. pattern
    252. pattern_type_macro
    253. peer_credentials_unix_socket
    254. phantom_variance_markers
    255. pin_coerce_unsized_trait
    256. pointer_is_aligned_to
    257. pointer_like_trait
    258. portable_simd
    259. print_internals
    260. proc_macro_def_site
    261. proc_macro_diagnostic
    262. proc_macro_expand
    263. proc_macro_internals
    264. proc_macro_quote
    265. proc_macro_span
    266. proc_macro_totokens
    267. proc_macro_tracked_env
    268. process_exitcode_internals
    269. process_internals
    270. profiler_runtime_lib
    271. ptr_alignment_type
    272. ptr_as_ref_unchecked
    273. ptr_as_uninit
    274. ptr_internals
    275. ptr_mask
    276. ptr_metadata
    277. ptr_sub_ptr
    278. pub_crate_should_not_need_unstable_attr
    279. random
    280. range_into_bounds
    281. raw_os_error_ty
    282. raw_slice_split
    283. raw_vec_internals
    284. read_buf
    285. reentrant_lock
    286. restricted_std
    287. result_flattening
    288. round_char_boundary
    289. rt
    290. rwlock_downgrade
    291. sealed
    292. seek_stream_len
    293. select_unpredictable
    294. set_ptr_value
    295. setgroups
    296. sgx_platform
    297. sized_type_properties
    298. slice_as_array
    299. slice_as_chunks
    300. slice_concat_ext
    301. slice_concat_trait
    302. slice_from_ptr_range
    303. slice_index_methods
    304. slice_internals
    305. slice_iter_mut_as_mut_slice
    306. slice_partition_dedup
    307. slice_pattern
    308. slice_ptr_get
    309. slice_range
    310. slice_split_once
    311. slice_swap_unchecked
    312. slice_take
    313. solid_ext
    314. sort_floats
    315. split_array
    316. split_as_slice
    317. std_internals
    318. stdarch_arm_feature_detection
    319. stdarch_mips_feature_detection
    320. stdarch_powerpc_feature_detection
    321. stdio_makes_pipe
    322. step_trait
    323. str_as_str
    324. str_from_raw_parts
    325. str_from_utf16_endian
    326. str_internals
    327. str_lines_remainder
    328. str_split_inclusive_remainder
    329. str_split_remainder
    330. str_split_whitespace_remainder
    331. strict_overflow_ops
    332. strict_provenance_atomic_ptr
    333. string_extend_from_within
    334. string_from_utf8_lossy_owned
    335. string_into_chars
    336. string_remove_matches
    337. substr_range
    338. sync_poison_mod
    339. sync_unsafe_cell
    340. tcp_deferaccept
    341. tcp_linger
    342. tcp_quickack
    343. tcplistener_into_incoming
    344. temporary_niche_types
    345. test
    346. thin_box
    347. thread_id_value
    348. thread_local_internals
    349. thread_raw
    350. thread_sleep_until
    351. thread_spawn_hook
    352. trace_macros
    353. track_path
    354. transmutability
    355. trusted_fused
    356. trusted_len
    357. trusted_len_next_unchecked
    358. trusted_random_access
    359. trusted_step
    360. try_find
    361. try_reserve_kind
    362. try_trait_v2
    363. try_trait_v2_residual
    364. try_trait_v2_yeet
    365. try_with_capacity
    366. tuple_trait
    367. type_ascription
    368. ub_checks
    369. uefi_std
    370. unbounded_shifts
    371. unchecked_neg
    372. unchecked_shifts
    373. unicode_internals
    374. unique_rc_arc
    375. unix_file_vectored_at
    376. unix_set_mark
    377. unix_socket_ancillary_data
    378. unix_socket_peek
    379. unsafe_cell_access
    380. unsafe_pin_internals
    381. unsigned_is_multiple_of
    382. unsigned_nonzero_div_ceil
    383. unsigned_signed_diff
    384. unsize
    385. unwrap_infallible
    386. update_panic_count
    387. utf16_extra
    388. variant_count
    389. vec_deque_iter_as_slices
    390. vec_deque_pop_if
    391. vec_into_raw_parts
    392. vec_push_within_capacity
    393. vec_split_at_spare
    394. wasi_ext
    395. windows_by_handle
    396. windows_c
    397. windows_change_time
    398. windows_handle
    399. windows_net
    400. windows_process_exit_code_from
    401. windows_process_extensions_async_pipes
    402. windows_process_extensions_force_quotes
    403. windows_process_extensions_main_thread_handle
    404. windows_process_extensions_raw_attribute
    405. windows_process_extensions_show_window
    406. windows_stdio
    407. wrapping_int_impl
    408. wrapping_next_power_of_two
    409. write_all_vectored
    410. yeet_desugar_details