1. The Unstable Book
  2. Compiler environment variables
    1. COLORTERM
    2. QNX_TARGET
    3. RUSTC_BLESS
    4. RUSTC_BOOTSTRAP
    5. RUSTC_BREAK_ON_ICE
    6. RUSTC_CTFE_BACKTRACE
    7. RUSTC_FORCE_RUSTC_VERSION
    8. RUSTC_GRAPHVIZ_FONT
    9. RUSTC_ICE
    10. RUSTC_LOG
    11. RUSTC_OVERRIDE_VERSION_STRING
    12. RUSTC_TRANSLATION_NO_DEBUG_ASSERT
    13. RUST_BACKTRACE
    14. RUST_DEP_GRAPH
    15. RUST_DEP_GRAPH_FILTER
    16. RUST_FORBID_DEP_GRAPH_EDGE
    17. RUST_MIN_STACK
    18. RUST_TARGET_PATH
    19. SDKROOT
    20. TERM
    21. UNSTABLE_RUSTDOC_TEST_LINE
    22. UNSTABLE_RUSTDOC_TEST_PATH
  3. Compiler flags
    1. allow_features
    2. autodiff
    3. branch_protection
    4. cf_protection
    5. codegen_backend
    6. codegen_options
    7. codegen_source_order
    8. control_flow_guard
    9. coverage_options
    10. crate_attr
    11. debug_info_for_profiling
    12. debug_info_type_line_numbers
    13. default_visibility
    14. direct_access_external_data
    15. dump_mono_stats
    16. dump_mono_stats_format
    17. dylib_lto
    18. eagerly_emit_delayed_bugs
    19. embed_metadata
    20. embed_source
    21. emit_stack_sizes
    22. emscripten_wasm_eh
    23. env_set
    24. export_executable_symbols
    25. extern_options
    26. external_clangrt
    27. fixed_x18
    28. fmt_debug
    29. function_return
    30. hint_mostly_unused
    31. indirect_branch_cs_prefix
    32. instrument_xray
    33. link_native_libraries
    34. lint_llvm_ir
    35. llvm_module_flag
    36. location_detail
    37. macro_stats
    38. min_function_alignment
    39. move_size_limit
    40. no_jump_tables
    41. no_parallel_llvm
    42. no_steal_thir
    43. no_unique_section_names
    44. offload
    45. on_broken_pipe
    46. patchable_function_entry
    47. print_check_cfg
    48. print_crate_root_lint_levels
    49. print_supported_crate_types
    50. profile_sample_use
    51. randomize_layout
    52. reg_struct_return
    53. regparm
    54. remap_cwd_prefix
    55. remap_path_scope
    56. report_time
    57. sanitizer
    58. self_profile
    59. self_profile_events
    60. shell_argfiles
    61. small_data_threshold
    62. src_hash_algorithm
    63. temps_dir
    64. terminal_urls
    65. tiny_const_eval_limit
    66. tls_model
    67. track_diagnostics
    68. treat_err_as_bug
    69. ub_checks
    70. unsound_mir_opts
    71. verbose_asm
    72. virtual_function_elimination
    73. wasm_c_abi
  4. Language features
    1. aarch64_unstable_target_feature
    2. aarch64_ver_target_feature
    3. abi_avr_interrupt
    4. abi_cmse_nonsecure_call
    5. abi_custom
    6. abi_gpu_kernel
    7. abi_msp430_interrupt
    8. abi_ptx
    9. abi_riscv_interrupt
    10. abi_unadjusted
    11. abi_vectorcall
    12. abi_x86_interrupt
    13. adt_const_params
    14. alloc_error_handler
    15. allocator_internals
    16. allow_internal_unsafe
    17. allow_internal_unstable
    18. anonymous_lifetime_in_impl_trait
    19. apx_target_feature
    20. arbitrary_self_types
    21. arbitrary_self_types_pointers
    22. arm_target_feature
    23. asm_cfg
    24. asm_experimental_arch
    25. asm_experimental_reg
    26. asm_goto_with_outputs
    27. asm_unwind
    28. associated_const_equality
    29. associated_type_defaults
    30. async_drop
    31. async_fn_in_dyn_trait
    32. async_fn_track_caller
    33. async_for_loop
    34. async_trait_bounds
    35. auto_traits
    36. avx10_target_feature
    37. box_patterns
    38. bpf_target_feature
    39. builtin_syntax
    40. c_variadic
    41. cfg_contract_checks
    42. cfg_emscripten_wasm_eh
    43. cfg_overflow_checks
    44. cfg_relocation_model
    45. cfg_sanitize
    46. cfg_sanitizer_cfi
    47. cfg_target_compact
    48. cfg_target_has_atomic
    49. cfg_target_has_atomic_equal_alignment
    50. cfg_target_has_reliable_f16_f128
    51. cfg_target_thread_local
    52. cfg_ub_checks
    53. cfg_version
    54. cfi_encoding
    55. closure_lifetime_binder
    56. closure_track_caller
    57. cmse_nonsecure_entry
    58. compiler_builtins
    59. const_async_blocks
    60. const_closures
    61. const_destruct
    62. const_for
    63. const_precise_live_drops
    64. const_trait_impl
    65. const_try
    66. contracts
    67. contracts_internals
    68. coroutine_clone
    69. coroutines
    70. coverage_attribute
    71. csky_target_feature
    72. custom_inner_attributes
    73. custom_mir
    74. custom_test_frameworks
    75. decl_macro
    76. default_field_values
    77. deprecated_safe
    78. deprecated_suggestion
    79. deref_patterns
    80. derive_from
    81. doc_auto_cfg
    82. doc_cfg
    83. doc_cfg_hide
    84. doc_masked
    85. doc_notable_trait
    86. dropck_eyepatch
    87. effective_target_features
    88. ergonomic_clones
    89. ermsb_target_feature
    90. exhaustive_patterns
    91. explicit_extern_abis
    92. explicit_tail_calls
    93. export_stable
    94. extended_varargs_abi_support
    95. extern_system_varargs
    96. extern_types
    97. f128
    98. f16
    99. ffi_const
    100. ffi_pure
    101. fmt_debug
    102. fn_align
    103. fn_delegation
    104. freeze_impls
    105. frontmatter
    106. fundamental
    107. gen_blocks
    108. generic_assert
    109. generic_const_exprs
    110. generic_const_items
    111. generic_const_parameter_types
    112. generic_pattern_types
    113. global_registration
    114. guard_patterns
    115. half_open_range_patterns_in_slices
    116. hexagon_target_feature
    117. if_let_guard
    118. impl_trait_in_assoc_type
    119. impl_trait_in_bindings
    120. impl_trait_in_fn_trait_return
    121. import_trait_associated_functions
    122. inherent_associated_types
    123. intra_doc_pointers
    124. intrinsics
    125. lahfsahf_target_feature
    126. lang_items
    127. large_assignments
    128. lazy_type_alias
    129. link_arg_attribute
    130. link_cfg
    131. link_llvm_intrinsics
    132. linkage
    133. loongarch_target_feature
    134. loop_match
    135. m68k_target_feature
    136. macro_attr
    137. macro_derive
    138. macro_metavar_expr
    139. macro_metavar_expr_concat
    140. marker_trait_attr
    141. min_generic_const_args
    142. min_specialization
    143. mips_target_feature
    144. more_maybe_bounds
    145. more_qualified_paths
    146. movrs_target_feature
    147. multiple_supertrait_upcastable
    148. must_not_suspend
    149. mut_ref
    150. naked_functions_rustic_abi
    151. naked_functions_target_feature
    152. native_link_modifiers_as_needed
    153. needs_panic_runtime
    154. negative_bounds
    155. negative_impls
    156. never_patterns
    157. never_type
    158. never_type_fallback
    159. new_range
    160. no_core
    161. non_exhaustive_omitted_patterns_lint
    162. non_lifetime_binders
    163. nvptx_target_feature
    164. offset_of_enum
    165. offset_of_slice
    166. optimize_attribute
    167. panic_runtime
    168. patchable_function_entry
    169. pattern_complexity_limit
    170. pattern_types
    171. pin_ergonomics
    172. postfix_match
    173. powerpc_target_feature
    174. prelude_import
    175. prfchw_target_feature
    176. proc_macro_hygiene
    177. profiler_runtime
    178. raw_dylib_elf
    179. reborrow
    180. ref_pat_eat_one_layer_2024
    181. ref_pat_eat_one_layer_2024_structural
    182. register_tool
    183. repr_simd
    184. return_type_notation
    185. riscv_target_feature
    186. rtm_target_feature
    187. rust_cold_cc
    188. rustc_allow_const_fn_unstable
    189. rustc_attrs
    190. rustc_private
    191. rustdoc_internals
    192. rustdoc_missing_doc_code_examples
    193. s390x_target_feature
    194. sanitize
    195. simd_ffi
    196. sized_hierarchy
    197. sparc_target_feature
    198. specialization
    199. staged_api
    200. stmt_expr_attributes
    201. strict_provenance_lints
    202. string_deref_patterns
    203. structural_match
    204. super_let
    205. supertrait_item_shadowing
    206. test_unstable_lint
    207. thread_local
    208. trait_alias
    209. transmute_generic_consts
    210. transparent_unions
    211. trivial_bounds
    212. try_blocks
    213. type_alias_impl_trait
    214. type_changing_struct_update
    215. unboxed_closures
    216. unqualified_local_imports
    217. unsafe_binders
    218. unsafe_fields
    219. unsized_const_params
    220. unsized_fn_params
    221. used_with_arg
    222. wasm_target_feature
    223. where_clause_attrs
    224. with_negative_coherence
    225. x86_amx_intrinsics
    226. x87_target_feature
    227. xop_target_feature
    228. yeet_expr
    229. yield_expr
  5. 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. arc_is_unique
    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. ascii_char
    18. ascii_char_variants
    19. assert_matches
    20. async_fn_traits
    21. async_gen_internals
    22. async_iter_from_iter
    23. async_iterator
    24. atomic_from_mut
    25. atomic_internals
    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. bool_to_result
    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_void_variant
    52. can_vector
    53. cast_maybe_uninit
    54. cell_leak
    55. cfg_accessible
    56. cfg_eval
    57. cfg_select
    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. const_alloc_error
    67. const_btree_len
    68. const_carrying_mul_add
    69. const_clone
    70. const_cmp
    71. const_default
    72. const_deref
    73. const_eval_select
    74. const_format_args
    75. const_from
    76. const_heap
    77. const_index
    78. const_ops
    79. const_option_ops
    80. const_range_bounds
    81. const_raw_ptr_comparison
    82. const_ref_cell
    83. const_result_trait_fn
    84. const_slice_from_mut_ptr_range
    85. const_slice_from_ptr_range
    86. const_slice_make_iter
    87. const_slice_rotate
    88. const_split_off_first_last
    89. const_swap_with_slice
    90. const_system_time
    91. const_type_name
    92. container_error_extra
    93. context_ext
    94. control_flow_into_value
    95. control_flow_ok
    96. convert_float_to_int
    97. core_float_math
    98. core_intrinsics
    99. core_intrinsics_fallbacks
    100. core_io_borrowed_buf
    101. core_private_bignum
    102. core_private_diy_float
    103. coroutine_trait
    104. cow_is_borrowed
    105. cstr_bytes
    106. cstr_display
    107. cstr_internals
    108. cursor_split
    109. deadline_api
    110. debug_closure_helpers
    111. dec2flt
    112. deref_pure_trait
    113. derive_clone_copy
    114. derive_coerce_pointee
    115. derive_const
    116. derive_eq
    117. dir_entry_ext2
    118. discriminant_kind
    119. disjoint_bitor
    120. dispatch_from_dyn
    121. downcast_unchecked
    122. drain_keep_rest
    123. drop_guard
    124. duration_constants
    125. duration_constructors
    126. duration_millis_float
    127. duration_units
    128. edition_panic
    129. error_generic_member_access
    130. error_iter
    131. error_reporter
    132. error_type_id
    133. exact_div
    134. exact_size_is_empty
    135. exclusive_wrapper
    136. exit_status_error
    137. exitcode_exit_method
    138. extend_one
    139. extend_one_unchecked
    140. fd
    141. fd_read
    142. file_buffered
    143. file_with_nul
    144. float_algebraic
    145. float_erf
    146. float_gamma
    147. float_minimum_maximum
    148. flt2dec
    149. fmt_helpers_for_derive
    150. fmt_internals
    151. fn_ptr_trait
    152. fn_traits
    153. forget_unsized
    154. format_args_nl
    155. formatting_options
    156. freeze
    157. future_join
    158. gen_future
    159. generic_assert_internals
    160. generic_atomic
    161. get_disjoint_mut_helpers
    162. get_mut_unchecked
    163. hash_map_internals
    164. hash_map_macro
    165. hash_set_entry
    166. hasher_prefixfree_extras
    167. hashmap_internals
    168. hint_must_use
    169. inplace_iteration
    170. int_format_into
    171. int_from_ascii
    172. int_lowest_highest_one
    173. int_roundings
    174. integer_atomics
    175. internal_impls_macro
    176. internal_output_capture
    177. io_const_error
    178. io_const_error_internals
    179. io_error_inprogress
    180. io_error_more
    181. io_error_uncategorized
    182. io_slice_as_bytes
    183. ip
    184. ip_as_octets
    185. is_ascii_octdigit
    186. is_loongarch_feature_detected
    187. is_riscv_feature_detected
    188. isolate_most_least_significant_one
    189. iter_advance_by
    190. iter_array_chunks
    191. iter_collect_into
    192. iter_from_coroutine
    193. iter_intersperse
    194. iter_is_partitioned
    195. iter_macro
    196. iter_map_windows
    197. iter_next_chunk
    198. iter_order_by
    199. iter_partition_in_place
    200. iterator_try_collect
    201. iterator_try_reduce
    202. junction_point
    203. layout_for_ptr
    204. lazy_cell_into_inner
    205. lazy_get
    206. legacy_receiver_trait
    207. liballoc_internals
    208. libstd_sys_internals
    209. likely_unlikely
    210. linked_list_cursors
    211. linked_list_remove
    212. linked_list_retain
    213. linux_pidfd
    214. local_key_cell_update
    215. local_waker
    216. lock_value_accessors
    217. log_syntax
    218. map_try_insert
    219. mapped_lock_guards
    220. maybe_uninit_array_assume_init
    221. maybe_uninit_as_bytes
    222. maybe_uninit_fill
    223. maybe_uninit_slice
    224. maybe_uninit_uninit_array_transpose
    225. maybe_uninit_write_slice
    226. mem_copy_fn
    227. more_float_constants
    228. mpmc_channel
    229. mutex_data_ptr
    230. new_range_api
    231. new_zeroed_alloc
    232. next_index
    233. nonpoison_mutex
    234. nonpoison_rwlock
    235. nonzero_bitwise
    236. nonzero_from_mut
    237. nonzero_internals
    238. nonzero_ops
    239. normalize_lexically
    240. numfmt
    241. once_cell_get_mut
    242. once_cell_try
    243. once_cell_try_insert
    244. one_sided_range
    245. option_array_transpose
    246. option_reduce
    247. option_zip
    248. os_str_slice
    249. os_string_truncate
    250. panic_abort
    251. panic_always_abort
    252. panic_backtrace_config
    253. panic_can_unwind
    254. panic_internals
    255. panic_unwind
    256. panic_update_hook
    257. partial_ord_chaining_methods
    258. path_add_extension
    259. pattern
    260. pattern_type_macro
    261. pattern_type_range_trait
    262. peer_credentials_unix_socket
    263. phantom_variance_markers
    264. pin_coerce_unsized_trait
    265. pointer_is_aligned_to
    266. pointer_try_cast_aligned
    267. portable_simd
    268. prelude_future
    269. prelude_next
    270. print_internals
    271. proc_macro_def_site
    272. proc_macro_diagnostic
    273. proc_macro_expand
    274. proc_macro_internals
    275. proc_macro_quote
    276. proc_macro_span
    277. proc_macro_totokens
    278. proc_macro_tracked_env
    279. proc_macro_value
    280. process_chroot
    281. process_exitcode_internals
    282. process_internals
    283. process_setsid
    284. profiler_runtime_lib
    285. ptr_alignment_type
    286. ptr_as_ref_unchecked
    287. ptr_as_uninit
    288. ptr_cast_array
    289. ptr_internals
    290. ptr_mask
    291. ptr_metadata
    292. pub_crate_should_not_need_unstable_attr
    293. push_mut
    294. random
    295. range_bounds_is_empty
    296. range_into_bounds
    297. raw_os_error_ty
    298. raw_slice_split
    299. raw_vec_internals
    300. read_buf
    301. reentrant_lock
    302. reentrant_lock_data_ptr
    303. refcell_try_map
    304. restricted_std
    305. result_option_map_or_default
    306. rev_into_inner
    307. round_char_boundary
    308. rt
    309. rwlock_data_ptr
    310. rwlock_downgrade
    311. sealed
    312. seek_io_take_position
    313. seek_stream_len
    314. set_permissions_nofollow
    315. set_ptr_value
    316. setgroups
    317. sgx_platform
    318. sized_type_properties
    319. slice_as_array
    320. slice_concat_ext
    321. slice_concat_trait
    322. slice_from_ptr_range
    323. slice_index_methods
    324. slice_internals
    325. slice_iter_mut_as_mut_slice
    326. slice_partition_dedup
    327. slice_pattern
    328. slice_ptr_get
    329. slice_range
    330. slice_split_once
    331. slice_swap_unchecked
    332. solid_ext
    333. sort_floats
    334. split_array
    335. split_as_slice
    336. std_internals
    337. stdarch_aarch64_feature_detection
    338. stdarch_arm_feature_detection
    339. stdarch_internal
    340. stdarch_loongarch_feature_detection
    341. stdarch_mips_feature_detection
    342. stdarch_powerpc_feature_detection
    343. stdarch_riscv_feature_detection
    344. stdarch_s390x_feature_detection
    345. stdio_makes_pipe
    346. step_trait
    347. str_as_str
    348. str_from_raw_parts
    349. str_from_utf16_endian
    350. str_internals
    351. str_lines_remainder
    352. str_split_inclusive_remainder
    353. str_split_remainder
    354. str_split_whitespace_remainder
    355. strict_provenance_atomic_ptr
    356. string_from_utf8_lossy_owned
    357. string_into_chars
    358. string_remove_matches
    359. substr_range
    360. sync_nonpoison
    361. sync_poison_mod
    362. sync_unsafe_cell
    363. tcp_deferaccept
    364. tcp_linger
    365. tcplistener_into_incoming
    366. temporary_niche_types
    367. test
    368. thin_box
    369. thread_id_value
    370. thread_local_internals
    371. thread_raw
    372. thread_sleep_until
    373. thread_spawn_hook
    374. trace_macros
    375. track_path
    376. transmutability
    377. trim_prefix_suffix
    378. trusted_fused
    379. trusted_len
    380. trusted_len_next_unchecked
    381. trusted_random_access
    382. trusted_step
    383. try_find
    384. try_reserve_kind
    385. try_trait_v2
    386. try_trait_v2_residual
    387. try_trait_v2_yeet
    388. try_with_capacity
    389. tuple_trait
    390. type_ascription
    391. ub_checks
    392. uefi_std
    393. uint_bit_width
    394. unchecked_neg
    395. unchecked_shifts
    396. unicode_internals
    397. unique_rc_arc
    398. unix_file_vectored_at
    399. unix_mkfifo
    400. unix_send_signal
    401. unix_set_mark
    402. unix_socket_ancillary_data
    403. unix_socket_exclbind
    404. unix_socket_peek
    405. unsafe_cell_access
    406. unsafe_pinned
    407. unsigned_nonzero_div_ceil
    408. unsize
    409. unwrap_infallible
    410. update_panic_count
    411. utf16_extra
    412. variant_count
    413. vec_deque_iter_as_slices
    414. vec_deque_pop_if
    415. vec_deque_truncate_front
    416. vec_into_chunks
    417. vec_into_raw_parts
    418. vec_peek_mut
    419. vec_push_within_capacity
    420. vec_split_at_spare
    421. wasi_ext
    422. windows_by_handle
    423. windows_c
    424. windows_change_time
    425. windows_handle
    426. windows_net
    427. windows_process_exit_code_from
    428. windows_process_extensions_async_pipes
    429. windows_process_extensions_force_quotes
    430. windows_process_extensions_main_thread_handle
    431. windows_process_extensions_raw_attribute
    432. windows_process_extensions_show_window
    433. windows_process_extensions_startupinfo
    434. windows_stdio
    435. wrapping_int_impl
    436. wrapping_next_power_of_two
    437. write_all_vectored
    438. wtf8_internals
    439. yeet_desugar_details