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_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. sanitizer
    52. self_profile
    53. self_profile_events
    54. shell_argfiles
    55. small_data_threshold
    56. src_hash_algorithm
    57. temps_dir
    58. tiny_const_eval_limit
    59. tls_model
    60. ub_checks
    61. unsound_mir_opts
    62. verbose_asm
    63. virtual_function_elimination
    64. 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_boolean_literals
    38. cfg_contract_checks
    39. cfg_emscripten_wasm_eh
    40. cfg_overflow_checks
    41. cfg_relocation_model
    42. cfg_sanitize
    43. cfg_sanitizer_cfi
    44. cfg_target_compact
    45. cfg_target_has_atomic
    46. cfg_target_has_atomic_equal_alignment
    47. cfg_target_thread_local
    48. cfg_ub_checks
    49. cfg_version
    50. cfi_encoding
    51. closure_lifetime_binder
    52. closure_track_caller
    53. cmse_nonsecure_entry
    54. compiler_builtins
    55. const_async_blocks
    56. const_closures
    57. const_destruct
    58. const_for
    59. const_precise_live_drops
    60. const_trait_impl
    61. const_try
    62. contracts
    63. contracts_internals
    64. coroutine_clone
    65. coroutines
    66. coverage_attribute
    67. csky_target_feature
    68. custom_inner_attributes
    69. custom_mir
    70. custom_test_frameworks
    71. decl_macro
    72. default_field_values
    73. deprecated_safe
    74. deprecated_suggestion
    75. deref_patterns
    76. doc_auto_cfg
    77. doc_cfg
    78. doc_cfg_hide
    79. doc_masked
    80. doc_notable_trait
    81. dropck_eyepatch
    82. dyn_star
    83. ergonomic_clones
    84. ermsb_target_feature
    85. exhaustive_patterns
    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_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. 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. used_with_arg
    216. wasm_target_feature
    217. where_clause_attrs
    218. with_negative_coherence
    219. x86_amx_intrinsics
    220. x87_target_feature
    221. xop_target_feature
    222. yeet_expr
    223. 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. 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. binary_heap_peek_mut_refresh
    34. bound_as_ref
    35. box_as_ptr
    36. box_into_boxed_slice
    37. box_into_inner
    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. 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_reverse
    83. const_split_off_first_last
    84. const_swap_nonoverlapping
    85. const_type_id
    86. const_type_name
    87. container_error_extra
    88. context_ext
    89. control_flow_into_value
    90. convert_float_to_int
    91. core_intrinsics
    92. core_intrinsics_fallbacks
    93. core_io_borrowed_buf
    94. core_private_bignum
    95. core_private_diy_float
    96. coroutine_trait
    97. cow_is_borrowed
    98. cstr_bytes
    99. cstr_internals
    100. cursor_split
    101. deadline_api
    102. debug_closure_helpers
    103. dec2flt
    104. deref_pure_trait
    105. derive_clone_copy
    106. derive_coerce_pointee
    107. derive_const
    108. derive_eq
    109. dir_entry_ext2
    110. discriminant_kind
    111. disjoint_bitor
    112. dispatch_from_dyn
    113. downcast_unchecked
    114. drain_keep_rest
    115. duration_constants
    116. duration_constructors
    117. duration_millis_float
    118. duration_units
    119. edition_panic
    120. error_generic_member_access
    121. error_iter
    122. error_reporter
    123. error_type_id
    124. exact_size_is_empty
    125. exclusive_wrapper
    126. exit_status_error
    127. exitcode_exit_method
    128. extend_one
    129. extend_one_unchecked
    130. fd
    131. fd_read
    132. file_buffered
    133. file_lock
    134. float_erf
    135. float_gamma
    136. float_minimum_maximum
    137. flt2dec
    138. fmt_helpers_for_derive
    139. fmt_internals
    140. fn_ptr_trait
    141. fn_traits
    142. forget_unsized
    143. format_args_nl
    144. formatting_options
    145. freeze
    146. future_join
    147. gen_future
    148. generic_assert_internals
    149. get_disjoint_mut_helpers
    150. get_mut_unchecked
    151. hash_set_entry
    152. hasher_prefixfree_extras
    153. hashmap_internals
    154. hint_must_use
    155. inplace_iteration
    156. int_from_ascii
    157. int_roundings
    158. integer_atomics
    159. internal_impls_macro
    160. internal_output_capture
    161. io_const_error
    162. io_const_error_internals
    163. io_error_inprogress
    164. io_error_more
    165. io_error_uncategorized
    166. io_slice_as_bytes
    167. ip
    168. ip_as_octets
    169. ip_from
    170. is_ascii_octdigit
    171. is_loongarch_feature_detected
    172. is_riscv_feature_detected
    173. isolate_most_least_significant_one
    174. iter_advance_by
    175. iter_array_chunks
    176. iter_chain
    177. iter_collect_into
    178. iter_from_coroutine
    179. iter_intersperse
    180. iter_is_partitioned
    181. iter_map_windows
    182. iter_next_chunk
    183. iter_order_by
    184. iter_partition_in_place
    185. iterator_try_collect
    186. iterator_try_reduce
    187. junction_point
    188. layout_for_ptr
    189. lazy_cell_into_inner
    190. lazy_get
    191. legacy_receiver_trait
    192. liballoc_internals
    193. libstd_sys_internals
    194. likely_unlikely
    195. linked_list_cursors
    196. linked_list_remove
    197. linked_list_retain
    198. linux_pidfd
    199. local_waker
    200. lock_value_accessors
    201. log_syntax
    202. map_try_insert
    203. mapped_lock_guards
    204. maybe_uninit_array_assume_init
    205. maybe_uninit_as_bytes
    206. maybe_uninit_fill
    207. maybe_uninit_slice
    208. maybe_uninit_uninit_array_transpose
    209. maybe_uninit_write_slice
    210. mem_copy_fn
    211. mixed_integer_ops_unsigned_sub
    212. more_float_constants
    213. mpmc_channel
    214. new_range_api
    215. new_zeroed_alloc
    216. non_null_from_ref
    217. nonnull_provenance
    218. nonzero_bitwise
    219. nonzero_from_mut
    220. nonzero_internals
    221. nonzero_ops
    222. numfmt
    223. once_cell_get_mut
    224. once_cell_try
    225. once_cell_try_insert
    226. one_sided_range
    227. option_array_transpose
    228. option_zip
    229. os_str_slice
    230. os_string_pathbuf_leak
    231. os_string_truncate
    232. panic_abort
    233. panic_always_abort
    234. panic_backtrace_config
    235. panic_can_unwind
    236. panic_internals
    237. panic_payload_as_str
    238. panic_unwind
    239. panic_update_hook
    240. partial_ord_chaining_methods
    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. stdarch_s390x_feature_detection
    316. stdio_makes_pipe
    317. step_trait
    318. str_as_str
    319. str_from_raw_parts
    320. str_from_utf16_endian
    321. str_internals
    322. str_lines_remainder
    323. str_split_inclusive_remainder
    324. str_split_remainder
    325. str_split_whitespace_remainder
    326. strict_overflow_ops
    327. strict_provenance_atomic_ptr
    328. string_from_utf8_lossy_owned
    329. string_into_chars
    330. string_remove_matches
    331. substr_range
    332. sync_poison_mod
    333. sync_unsafe_cell
    334. tcp_deferaccept
    335. tcp_linger
    336. tcp_quickack
    337. tcplistener_into_incoming
    338. temporary_niche_types
    339. test
    340. thin_box
    341. thread_id_value
    342. thread_local_internals
    343. thread_raw
    344. thread_sleep_until
    345. thread_spawn_hook
    346. trace_macros
    347. track_path
    348. transmutability
    349. trusted_fused
    350. trusted_len
    351. trusted_len_next_unchecked
    352. trusted_random_access
    353. trusted_step
    354. try_find
    355. try_reserve_kind
    356. try_trait_v2
    357. try_trait_v2_residual
    358. try_trait_v2_yeet
    359. try_with_capacity
    360. tuple_trait
    361. type_ascription
    362. ub_checks
    363. uefi_std
    364. unchecked_neg
    365. unchecked_shifts
    366. unicode_internals
    367. unique_rc_arc
    368. unix_file_vectored_at
    369. unix_set_mark
    370. unix_socket_ancillary_data
    371. unix_socket_peek
    372. unsafe_cell_access
    373. unsafe_pin_internals
    374. unsigned_nonzero_div_ceil
    375. unsigned_signed_diff
    376. unsize
    377. unwrap_infallible
    378. update_panic_count
    379. utf16_extra
    380. variant_count
    381. vec_deque_iter_as_slices
    382. vec_deque_pop_if
    383. vec_into_raw_parts
    384. vec_push_within_capacity
    385. vec_split_at_spare
    386. wasi_ext
    387. windows_by_handle
    388. windows_c
    389. windows_change_time
    390. windows_handle
    391. windows_net
    392. windows_process_exit_code_from
    393. windows_process_extensions_async_pipes
    394. windows_process_extensions_force_quotes
    395. windows_process_extensions_main_thread_handle
    396. windows_process_extensions_raw_attribute
    397. windows_process_extensions_show_window
    398. windows_stdio
    399. wrapping_int_impl
    400. wrapping_next_power_of_two
    401. write_all_vectored
    402. yeet_desugar_details