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
    143. naked_functions_rustic_abi
    144. naked_functions_target_feature
    145. native_link_modifiers_as_needed
    146. needs_panic_runtime
    147. negative_bounds
    148. negative_impls
    149. never_patterns
    150. never_type
    151. never_type_fallback
    152. new_range
    153. no_core
    154. no_sanitize
    155. non_exhaustive_omitted_patterns_lint
    156. non_lifetime_binders
    157. offset_of_enum
    158. offset_of_slice
    159. omit_gdb_pretty_printer_section
    160. optimize_attribute
    161. panic_runtime
    162. patchable_function_entry
    163. pattern_complexity_limit
    164. pattern_types
    165. pin_ergonomics
    166. postfix_match
    167. powerpc_target_feature
    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. super_let
    199. supertrait_item_shadowing
    200. tbm_target_feature
    201. test_unstable_lint
    202. thread_local
    203. trait_alias
    204. transmute_generic_consts
    205. transparent_unions
    206. trivial_bounds
    207. try_blocks
    208. type_alias_impl_trait
    209. type_changing_struct_update
    210. unboxed_closures
    211. unqualified_local_imports
    212. unsafe_binders
    213. unsafe_fields
    214. unsized_const_params
    215. unsized_fn_params
    216. unsized_locals
    217. used_with_arg
    218. wasm_target_feature
    219. where_clause_attrs
    220. with_negative_coherence
    221. x86_amx_intrinsics
    222. x87_target_feature
    223. xop_target_feature
    224. yeet_expr
    225. 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. 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_btree_len
    72. const_carrying_mul_add
    73. const_deref
    74. const_eq_ignore_ascii_case
    75. const_eval_select
    76. const_format_args
    77. const_heap
    78. const_ops
    79. const_range_bounds
    80. const_raw_ptr_comparison
    81. const_slice_from_mut_ptr_range
    82. const_slice_from_ptr_range
    83. const_slice_make_iter
    84. const_slice_reverse
    85. const_split_off_first_last
    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. file_lock
    136. float_algebraic
    137. float_erf
    138. float_gamma
    139. float_minimum_maximum
    140. flt2dec
    141. fmt_helpers_for_derive
    142. fmt_internals
    143. fn_ptr_trait
    144. fn_traits
    145. forget_unsized
    146. format_args_nl
    147. formatting_options
    148. freeze
    149. future_join
    150. gen_future
    151. generic_assert_internals
    152. get_disjoint_mut_helpers
    153. get_mut_unchecked
    154. hash_set_entry
    155. hasher_prefixfree_extras
    156. hashmap_internals
    157. hint_must_use
    158. inplace_iteration
    159. int_from_ascii
    160. int_roundings
    161. integer_atomics
    162. internal_impls_macro
    163. internal_output_capture
    164. io_const_error
    165. io_const_error_internals
    166. io_error_inprogress
    167. io_error_more
    168. io_error_uncategorized
    169. io_slice_as_bytes
    170. ip
    171. ip_as_octets
    172. ip_from
    173. is_ascii_octdigit
    174. is_loongarch_feature_detected
    175. is_riscv_feature_detected
    176. isolate_most_least_significant_one
    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. likely_unlikely
    198. linked_list_cursors
    199. linked_list_remove
    200. linked_list_retain
    201. linux_pidfd
    202. local_waker
    203. lock_value_accessors
    204. log_syntax
    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_transpose
    212. maybe_uninit_write_slice
    213. mem_copy_fn
    214. mixed_integer_ops_unsigned_sub
    215. more_float_constants
    216. mpmc_channel
    217. new_range_api
    218. new_zeroed_alloc
    219. next_index
    220. non_null_from_ref
    221. nonnull_provenance
    222. nonzero_bitwise
    223. nonzero_from_mut
    224. nonzero_internals
    225. nonzero_ops
    226. numfmt
    227. once_cell_get_mut
    228. once_cell_try
    229. once_cell_try_insert
    230. one_sided_range
    231. option_array_transpose
    232. option_zip
    233. os_str_slice
    234. os_string_pathbuf_leak
    235. os_string_truncate
    236. panic_abort
    237. panic_always_abort
    238. panic_backtrace_config
    239. panic_can_unwind
    240. panic_internals
    241. panic_payload_as_str
    242. panic_unwind
    243. panic_update_hook
    244. partial_ord_chaining_methods
    245. path_add_extension
    246. path_file_prefix
    247. pattern
    248. pattern_type_macro
    249. pattern_type_range_trait
    250. peer_credentials_unix_socket
    251. phantom_variance_markers
    252. pin_coerce_unsized_trait
    253. pointer_is_aligned_to
    254. pointer_like_trait
    255. portable_simd
    256. prelude_future
    257. prelude_next
    258. print_internals
    259. proc_macro_def_site
    260. proc_macro_diagnostic
    261. proc_macro_expand
    262. proc_macro_internals
    263. proc_macro_quote
    264. proc_macro_span
    265. proc_macro_totokens
    266. proc_macro_tracked_env
    267. proc_macro_value
    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. pub_crate_should_not_need_unstable_attr
    278. random
    279. range_bounds_is_empty
    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. solid_ext
    313. sort_floats
    314. split_array
    315. split_as_slice
    316. std_internals
    317. stdarch_arm_feature_detection
    318. stdarch_mips_feature_detection
    319. stdarch_powerpc_feature_detection
    320. stdarch_s390x_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_from_utf8_lossy_owned
    334. string_into_chars
    335. string_remove_matches
    336. substr_range
    337. sync_poison_mod
    338. sync_unsafe_cell
    339. tcp_deferaccept
    340. tcp_linger
    341. tcp_quickack
    342. tcplistener_into_incoming
    343. temporary_niche_types
    344. test
    345. thin_box
    346. thread_id_value
    347. thread_local_internals
    348. thread_raw
    349. thread_sleep_until
    350. thread_spawn_hook
    351. trace_macros
    352. track_path
    353. transmutability
    354. trusted_fused
    355. trusted_len
    356. trusted_len_next_unchecked
    357. trusted_random_access
    358. trusted_step
    359. try_find
    360. try_reserve_kind
    361. try_trait_v2
    362. try_trait_v2_residual
    363. try_trait_v2_yeet
    364. try_with_capacity
    365. tuple_trait
    366. type_ascription
    367. ub_checks
    368. uefi_std
    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_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