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