1. The Unstable Book
  2. Compiler flags
    1. allow_features
    2. autodiff
    3. branch_protection
    4. cf_protection
    5. codegen_backend
    6. codegen_options
    7. control_flow_guard
    8. coverage_options
    9. crate_attr
    10. debug_info_for_profiling
    11. debug_info_type_line_numbers
    12. default_visibility
    13. direct_access_external_data
    14. dump_mono_stats
    15. dump_mono_stats_format
    16. dylib_lto
    17. embed_metadata
    18. embed_source
    19. emit_stack_sizes
    20. emscripten_wasm_eh
    21. env_set
    22. export_executable_symbols
    23. extern_options
    24. external_clangrt
    25. fixed_x18
    26. fmt_debug
    27. function_return
    28. instrument_xray
    29. link_native_libraries
    30. linker_features
    31. lint_llvm_ir
    32. llvm_module_flag
    33. location_detail
    34. min_function_alignment
    35. move_size_limit
    36. no_jump_tables
    37. no_parallel_llvm
    38. no_unique_section_names
    39. on_broken_pipe
    40. patchable_function_entry
    41. print_check_cfg
    42. print_crate_root_lint_levels
    43. print_supported_crate_types
    44. profile_sample_use
    45. randomize_layout
    46. reg_struct_return
    47. regparm
    48. remap_cwd_prefix
    49. remap_path_scope
    50. report_time
    51. rustc_bootstrap
    52. rustc_override_version_string
    53. sanitizer
    54. self_profile
    55. self_profile_events
    56. shell_argfiles
    57. small_data_threshold
    58. src_hash_algorithm
    59. temps_dir
    60. tiny_const_eval_limit
    61. tls_model
    62. ub_checks
    63. unsound_mir_opts
    64. verbose_asm
    65. virtual_function_elimination
    66. 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_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_contract_checks
    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. contracts
    62. contracts_internals
    63. coroutine_clone
    64. coroutines
    65. coverage_attribute
    66. csky_target_feature
    67. custom_inner_attributes
    68. custom_mir
    69. custom_test_frameworks
    70. decl_macro
    71. default_field_values
    72. deprecated_safe
    73. deprecated_suggestion
    74. deref_patterns
    75. doc_auto_cfg
    76. doc_cfg
    77. doc_cfg_hide
    78. doc_masked
    79. doc_notable_trait
    80. dropck_eyepatch
    81. dyn_star
    82. ergonomic_clones
    83. ermsb_target_feature
    84. exhaustive_patterns
    85. explicit_extern_abis
    86. explicit_tail_calls
    87. extended_varargs_abi_support
    88. extern_system_varargs
    89. extern_types
    90. f128
    91. f16
    92. ffi_const
    93. ffi_pure
    94. fmt_debug
    95. fn_align
    96. fn_delegation
    97. freeze_impls
    98. fundamental
    99. gen_blocks
    100. generic_arg_infer
    101. generic_assert
    102. generic_const_exprs
    103. generic_const_items
    104. generic_const_parameter_types
    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. intra_doc_pointers
    117. intrinsics
    118. keylocker_x86
    119. lahfsahf_target_feature
    120. lang_items
    121. large_assignments
    122. lazy_type_alias
    123. let_chains
    124. link_arg_attribute
    125. link_cfg
    126. link_llvm_intrinsics
    127. linkage
    128. loongarch_target_feature
    129. m68k_target_feature
    130. macro_metavar_expr
    131. macro_metavar_expr_concat
    132. marker_trait_attr
    133. min_generic_const_args
    134. min_specialization
    135. mips_target_feature
    136. more_maybe_bounds
    137. more_qualified_paths
    138. movrs_target_feature
    139. multiple_supertrait_upcastable
    140. must_not_suspend
    141. mut_ref
    142. naked_functions_rustic_abi
    143. naked_functions_target_feature
    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. prelude_import
    168. prfchw_target_feature
    169. proc_macro_hygiene
    170. profiler_runtime
    171. raw_dylib_elf
    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. super_let
    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. align_to_uninit_mut
    5. alloc_error_hook
    6. alloc_internals
    7. alloc_layout_extra
    8. allocator_api
    9. alloctests
    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. cfg_accessible
    56. cfg_eval
    57. cfg_match
    58. char_internals
    59. char_max_len
    60. clone_to_uninit
    61. cmp_minmax
    62. coerce_pointee_validated
    63. coerce_unsized
    64. cold_path
    65. concat_bytes
    66. concat_idents
    67. const_alloc_error
    68. const_array_as_mut_slice
    69. const_array_each_ref
    70. const_btree_len
    71. const_carrying_mul_add
    72. const_deref
    73. const_eq_ignore_ascii_case
    74. const_eval_select
    75. const_format_args
    76. const_heap
    77. const_ops
    78. const_range_bounds
    79. const_raw_ptr_comparison
    80. const_slice_from_mut_ptr_range
    81. const_slice_from_ptr_range
    82. const_slice_make_iter
    83. const_slice_reverse
    84. const_split_off_first_last
    85. const_swap_nonoverlapping
    86. const_type_id
    87. const_type_name
    88. container_error_extra
    89. context_ext
    90. control_flow_into_value
    91. convert_float_to_int
    92. core_intrinsics
    93. core_intrinsics_fallbacks
    94. core_io_borrowed_buf
    95. core_private_bignum
    96. core_private_diy_float
    97. coroutine_trait
    98. cow_is_borrowed
    99. cstr_bytes
    100. cstr_internals
    101. cursor_split
    102. deadline_api
    103. debug_closure_helpers
    104. dec2flt
    105. deref_pure_trait
    106. derive_clone_copy
    107. derive_coerce_pointee
    108. derive_const
    109. derive_eq
    110. dir_entry_ext2
    111. discriminant_kind
    112. disjoint_bitor
    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. fd
    132. fd_read
    133. file_buffered
    134. file_lock
    135. float_algebraic
    136. float_erf
    137. float_gamma
    138. float_minimum_maximum
    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_disjoint_mut_helpers
    152. get_mut_unchecked
    153. hash_set_entry
    154. hasher_prefixfree_extras
    155. hashmap_internals
    156. hint_must_use
    157. inplace_iteration
    158. int_from_ascii
    159. int_roundings
    160. integer_atomics
    161. internal_impls_macro
    162. internal_output_capture
    163. io_const_error
    164. io_const_error_internals
    165. io_error_inprogress
    166. io_error_more
    167. io_error_uncategorized
    168. io_slice_as_bytes
    169. ip
    170. ip_as_octets
    171. ip_from
    172. is_ascii_octdigit
    173. is_loongarch_feature_detected
    174. is_riscv_feature_detected
    175. isolate_most_least_significant_one
    176. iter_advance_by
    177. iter_array_chunks
    178. iter_chain
    179. iter_collect_into
    180. iter_from_coroutine
    181. iter_intersperse
    182. iter_is_partitioned
    183. iter_map_windows
    184. iter_next_chunk
    185. iter_order_by
    186. iter_partition_in_place
    187. iterator_try_collect
    188. iterator_try_reduce
    189. junction_point
    190. layout_for_ptr
    191. lazy_cell_into_inner
    192. lazy_get
    193. legacy_receiver_trait
    194. liballoc_internals
    195. libstd_sys_internals
    196. likely_unlikely
    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_try_insert
    205. mapped_lock_guards
    206. maybe_uninit_array_assume_init
    207. maybe_uninit_as_bytes
    208. maybe_uninit_fill
    209. maybe_uninit_slice
    210. maybe_uninit_uninit_array_transpose
    211. maybe_uninit_write_slice
    212. mem_copy_fn
    213. mixed_integer_ops_unsigned_sub
    214. more_float_constants
    215. mpmc_channel
    216. new_range_api
    217. new_zeroed_alloc
    218. next_index
    219. non_null_from_ref
    220. nonnull_provenance
    221. nonzero_bitwise
    222. nonzero_from_mut
    223. nonzero_internals
    224. nonzero_ops
    225. numfmt
    226. once_cell_get_mut
    227. once_cell_try
    228. once_cell_try_insert
    229. one_sided_range
    230. option_array_transpose
    231. option_zip
    232. os_str_slice
    233. os_string_pathbuf_leak
    234. os_string_truncate
    235. panic_abort
    236. panic_always_abort
    237. panic_backtrace_config
    238. panic_can_unwind
    239. panic_internals
    240. panic_payload_as_str
    241. panic_unwind
    242. panic_update_hook
    243. partial_ord_chaining_methods
    244. path_add_extension
    245. path_file_prefix
    246. pattern
    247. pattern_type_macro
    248. pattern_type_range_trait
    249. peer_credentials_unix_socket
    250. phantom_variance_markers
    251. pin_coerce_unsized_trait
    252. pointer_is_aligned_to
    253. pointer_like_trait
    254. portable_simd
    255. prelude_future
    256. prelude_next
    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. proc_macro_value
    267. process_exitcode_internals
    268. process_internals
    269. profiler_runtime_lib
    270. ptr_alignment_type
    271. ptr_as_ref_unchecked
    272. ptr_as_uninit
    273. ptr_internals
    274. ptr_mask
    275. ptr_metadata
    276. pub_crate_should_not_need_unstable_attr
    277. random
    278. range_bounds_is_empty
    279. range_into_bounds
    280. raw_os_error_ty
    281. raw_slice_split
    282. raw_vec_internals
    283. read_buf
    284. reentrant_lock
    285. restricted_std
    286. result_flattening
    287. round_char_boundary
    288. rt
    289. rwlock_downgrade
    290. sealed
    291. seek_stream_len
    292. select_unpredictable
    293. set_ptr_value
    294. setgroups
    295. sgx_platform
    296. sized_type_properties
    297. slice_as_array
    298. slice_as_chunks
    299. slice_concat_ext
    300. slice_concat_trait
    301. slice_from_ptr_range
    302. slice_index_methods
    303. slice_internals
    304. slice_iter_mut_as_mut_slice
    305. slice_partition_dedup
    306. slice_pattern
    307. slice_ptr_get
    308. slice_range
    309. slice_split_once
    310. slice_swap_unchecked
    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. stdarch_s390x_feature_detection
    320. stdio_makes_pipe
    321. step_trait
    322. str_as_str
    323. str_from_raw_parts
    324. str_from_utf16_endian
    325. str_internals
    326. str_lines_remainder
    327. str_split_inclusive_remainder
    328. str_split_remainder
    329. str_split_whitespace_remainder
    330. strict_overflow_ops
    331. strict_provenance_atomic_ptr
    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. unchecked_neg
    369. unchecked_shifts
    370. unicode_internals
    371. unique_rc_arc
    372. unix_file_vectored_at
    373. unix_mkfifo
    374. unix_set_mark
    375. unix_socket_ancillary_data
    376. unix_socket_peek
    377. unsafe_cell_access
    378. unsafe_pinned
    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_deque_pop_if
    388. vec_into_raw_parts
    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