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. 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. 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_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_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_system_varargs
    93. extern_types
    94. f128
    95. f16
    96. ffi_const
    97. ffi_pure
    98. fmt_debug
    99. fn_align
    100. fn_delegation
    101. freeze_impls
    102. frontmatter
    103. fundamental
    104. gen_blocks
    105. generic_assert
    106. generic_const_exprs
    107. generic_const_items
    108. generic_const_parameter_types
    109. generic_pattern_types
    110. global_registration
    111. guard_patterns
    112. half_open_range_patterns_in_slices
    113. hexagon_target_feature
    114. if_let_guard
    115. impl_trait_in_assoc_type
    116. impl_trait_in_bindings
    117. impl_trait_in_fn_trait_return
    118. import_trait_associated_functions
    119. inherent_associated_types
    120. intra_doc_pointers
    121. intrinsics
    122. lahfsahf_target_feature
    123. lang_items
    124. large_assignments
    125. lazy_type_alias
    126. link_arg_attribute
    127. link_cfg
    128. link_llvm_intrinsics
    129. linkage
    130. loongarch_target_feature
    131. loop_match
    132. m68k_target_feature
    133. macro_attr
    134. macro_derive
    135. macro_metavar_expr
    136. macro_metavar_expr_concat
    137. marker_trait_attr
    138. min_generic_const_args
    139. min_specialization
    140. mips_target_feature
    141. more_maybe_bounds
    142. more_qualified_paths
    143. movrs_target_feature
    144. multiple_supertrait_upcastable
    145. must_not_suspend
    146. mut_ref
    147. naked_functions_rustic_abi
    148. naked_functions_target_feature
    149. native_link_modifiers_as_needed
    150. needs_panic_runtime
    151. negative_bounds
    152. negative_impls
    153. never_patterns
    154. never_type
    155. never_type_fallback
    156. new_range
    157. no_core
    158. non_exhaustive_omitted_patterns_lint
    159. non_lifetime_binders
    160. nvptx_target_feature
    161. offset_of_enum
    162. offset_of_slice
    163. optimize_attribute
    164. panic_runtime
    165. patchable_function_entry
    166. pattern_complexity_limit
    167. pattern_types
    168. pin_ergonomics
    169. postfix_match
    170. powerpc_target_feature
    171. prelude_import
    172. prfchw_target_feature
    173. proc_macro_hygiene
    174. profiler_runtime
    175. raw_dylib_elf
    176. reborrow
    177. ref_pat_eat_one_layer_2024
    178. ref_pat_eat_one_layer_2024_structural
    179. register_tool
    180. repr_simd
    181. return_type_notation
    182. riscv_target_feature
    183. rtm_target_feature
    184. rust_cold_cc
    185. rustc_allow_const_fn_unstable
    186. rustc_attrs
    187. rustc_private
    188. rustdoc_internals
    189. rustdoc_missing_doc_code_examples
    190. s390x_target_feature
    191. sanitize
    192. simd_ffi
    193. sized_hierarchy
    194. sparc_target_feature
    195. specialization
    196. staged_api
    197. static_align
    198. stmt_expr_attributes
    199. strict_provenance_lints
    200. string_deref_patterns
    201. structural_match
    202. super_let
    203. supertrait_item_shadowing
    204. target_feature_inline_always
    205. test_unstable_lint
    206. thread_local
    207. trait_alias
    208. transmute_generic_consts
    209. transparent_unions
    210. trivial_bounds
    211. try_blocks
    212. type_alias_impl_trait
    213. type_changing_struct_update
    214. unboxed_closures
    215. unqualified_local_imports
    216. unsafe_binders
    217. unsafe_fields
    218. unsized_const_params
    219. unsized_fn_params
    220. used_with_arg
    221. wasm_target_feature
    222. where_clause_attrs
    223. with_negative_coherence
    224. x86_amx_intrinsics
    225. x87_target_feature
    226. xop_target_feature
    227. yeet_expr
    228. 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_try_from_fn
    14. array_try_map
    15. array_windows
    16. ascii_char
    17. ascii_char_variants
    18. assert_matches
    19. async_fn_traits
    20. async_gen_internals
    21. async_iter_from_iter
    22. async_iterator
    23. atomic_from_mut
    24. atomic_internals
    25. atomic_try_update
    26. autodiff
    27. backtrace_frames
    28. bigint_helper_methods
    29. bikeshed_guaranteed_no_drop
    30. binary_heap_drain_sorted
    31. binary_heap_into_iter_sorted
    32. binary_heap_peek_mut_refresh
    33. bool_to_result
    34. bound_as_ref
    35. bound_copied
    36. box_as_ptr
    37. box_into_boxed_slice
    38. box_into_inner
    39. box_take
    40. box_vec_non_null
    41. breakpoint
    42. bstr
    43. bstr_internals
    44. btree_cursors
    45. btree_set_entry
    46. btreemap_alloc
    47. buf_read_has_data_left
    48. bufreader_peek
    49. c_size_t
    50. c_void_variant
    51. can_vector
    52. cast_maybe_uninit
    53. cell_get_cloned
    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_cell_traits
    70. const_clone
    71. const_cmp
    72. const_convert
    73. const_default
    74. const_drop_in_place
    75. const_eval_select
    76. const_format_args
    77. const_heap
    78. const_index
    79. const_mul_add
    80. const_ops
    81. const_option_ops
    82. const_range_bounds
    83. const_raw_ptr_comparison
    84. const_ref_cell
    85. const_result_trait_fn
    86. const_slice_from_mut_ptr_range
    87. const_slice_from_ptr_range
    88. const_slice_make_iter
    89. const_split_off_first_last
    90. const_swap_with_slice
    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. current_thread_id
    109. cursor_split
    110. darwin_objc
    111. deadline_api
    112. debug_closure_helpers
    113. dec2flt
    114. deref_pure_trait
    115. derive_clone_copy
    116. derive_coerce_pointee
    117. derive_const
    118. derive_eq
    119. dir_entry_ext2
    120. discriminant_kind
    121. disjoint_bitor
    122. dispatch_from_dyn
    123. downcast_unchecked
    124. drain_keep_rest
    125. drop_guard
    126. duration_constants
    127. duration_constructors
    128. duration_from_nanos_u128
    129. duration_millis_float
    130. duration_units
    131. edition_panic
    132. error_generic_member_access
    133. error_iter
    134. error_reporter
    135. error_type_id
    136. exact_bitshifts
    137. exact_div
    138. exact_size_is_empty
    139. exclusive_wrapper
    140. exit_status_error
    141. exitcode_exit_method
    142. extend_one
    143. extend_one_unchecked
    144. fd
    145. fd_read
    146. file_buffered
    147. float_algebraic
    148. float_erf
    149. float_gamma
    150. float_minimum_maximum
    151. flt2dec
    152. fmt_helpers_for_derive
    153. fmt_internals
    154. fn_ptr_trait
    155. fn_traits
    156. forget_unsized
    157. format_args_nl
    158. formatting_options
    159. freeze
    160. fs_set_times
    161. funnel_shifts
    162. future_join
    163. gen_future
    164. generic_assert_internals
    165. generic_atomic
    166. get_disjoint_mut_helpers
    167. get_mut_unchecked
    168. gethostname
    169. hash_map_internals
    170. hash_map_macro
    171. hash_set_entry
    172. hasher_prefixfree_extras
    173. hashmap_internals
    174. hint_must_use
    175. inplace_iteration
    176. int_format_into
    177. int_from_ascii
    178. int_lowest_highest_one
    179. int_roundings
    180. integer_atomics
    181. internal_impls_macro
    182. internal_output_capture
    183. io_const_error
    184. io_const_error_internals
    185. io_error_inprogress
    186. io_error_more
    187. io_error_uncategorized
    188. io_slice_as_bytes
    189. ip
    190. ip_as_octets
    191. is_ascii_octdigit
    192. is_loongarch_feature_detected
    193. is_riscv_feature_detected
    194. isolate_most_least_significant_one
    195. iter_advance_by
    196. iter_array_chunks
    197. iter_collect_into
    198. iter_from_coroutine
    199. iter_intersperse
    200. iter_is_partitioned
    201. iter_macro
    202. iter_map_windows
    203. iter_next_chunk
    204. iter_order_by
    205. iter_partition_in_place
    206. iterator_try_collect
    207. iterator_try_reduce
    208. junction_point
    209. layout_for_ptr
    210. lazy_cell_into_inner
    211. lazy_get
    212. legacy_receiver_trait
    213. liballoc_internals
    214. libstd_sys_internals
    215. likely_unlikely
    216. linked_list_cursors
    217. linked_list_remove
    218. linked_list_retain
    219. linux_pidfd
    220. local_key_cell_update
    221. local_waker
    222. lock_value_accessors
    223. log_syntax
    224. map_try_insert
    225. mapped_lock_guards
    226. maybe_uninit_array_assume_init
    227. maybe_uninit_as_bytes
    228. maybe_uninit_fill
    229. maybe_uninit_slice
    230. maybe_uninit_uninit_array_transpose
    231. maybe_uninit_write_slice
    232. mem_conjure_zst
    233. mem_copy_fn
    234. more_float_constants
    235. motor_ext
    236. mpmc_channel
    237. mutex_data_ptr
    238. new_range_api
    239. next_index
    240. nonpoison_condvar
    241. nonpoison_mutex
    242. nonpoison_rwlock
    243. nonzero_bitwise
    244. nonzero_from_mut
    245. nonzero_internals
    246. nonzero_ops
    247. normalize_lexically
    248. numfmt
    249. objc_class_variant
    250. objc_selector_variant
    251. once_cell_get_mut
    252. once_cell_try
    253. once_cell_try_insert
    254. one_sided_range
    255. option_array_transpose
    256. option_reduce
    257. option_zip
    258. os_str_slice
    259. os_string_truncate
    260. panic_abort
    261. panic_always_abort
    262. panic_backtrace_config
    263. panic_can_unwind
    264. panic_internals
    265. panic_unwind
    266. panic_update_hook
    267. partial_ord_chaining_methods
    268. path_trailing_sep
    269. pattern
    270. pattern_type_macro
    271. pattern_type_range_trait
    272. peekable_next_if_map
    273. peer_credentials_unix_socket
    274. phantom_variance_markers
    275. pin_coerce_unsized_trait
    276. pin_derefmut_internals
    277. pointer_is_aligned_to
    278. pointer_try_cast_aligned
    279. portable_simd
    280. prelude_future
    281. prelude_next
    282. print_internals
    283. proc_macro_def_site
    284. proc_macro_diagnostic
    285. proc_macro_expand
    286. proc_macro_internals
    287. proc_macro_quote
    288. proc_macro_span
    289. proc_macro_totokens
    290. proc_macro_tracked_env
    291. proc_macro_value
    292. process_chroot
    293. process_exitcode_internals
    294. process_internals
    295. process_setsid
    296. profiler_runtime_lib
    297. ptr_alignment_type
    298. ptr_as_ref_unchecked
    299. ptr_as_uninit
    300. ptr_cast_array
    301. ptr_internals
    302. ptr_mask
    303. ptr_metadata
    304. pub_crate_should_not_need_unstable_attr
    305. push_mut
    306. random
    307. range_bounds_is_empty
    308. range_into_bounds
    309. raw_os_error_ty
    310. raw_slice_split
    311. raw_vec_internals
    312. read_buf
    313. read_buf_at
    314. reentrant_lock
    315. reentrant_lock_data_ptr
    316. refcell_try_map
    317. restricted_std
    318. result_option_map_or_default
    319. rev_into_inner
    320. rt
    321. rwlock_data_ptr
    322. sealed
    323. seek_io_take_position
    324. seek_stream_len
    325. set_permissions_nofollow
    326. set_ptr_value
    327. setgroups
    328. sgx_platform
    329. sized_type_properties
    330. slice_as_array
    331. slice_concat_ext
    332. slice_concat_trait
    333. slice_from_ptr_range
    334. slice_index_methods
    335. slice_internals
    336. slice_iter_mut_as_mut_slice
    337. slice_partition_dedup
    338. slice_pattern
    339. slice_ptr_get
    340. slice_range
    341. slice_split_once
    342. slice_swap_unchecked
    343. solid_ext
    344. sort_floats
    345. split_array
    346. split_as_slice
    347. std_internals
    348. stdarch_aarch64_feature_detection
    349. stdarch_arm_feature_detection
    350. stdarch_internal
    351. stdarch_loongarch_feature_detection
    352. stdarch_mips_feature_detection
    353. stdarch_powerpc_feature_detection
    354. stdarch_riscv_feature_detection
    355. stdarch_s390x_feature_detection
    356. stdio_makes_pipe
    357. step_trait
    358. str_as_str
    359. str_from_raw_parts
    360. str_from_utf16_endian
    361. str_internals
    362. str_lines_remainder
    363. str_split_inclusive_remainder
    364. str_split_remainder
    365. str_split_whitespace_remainder
    366. string_from_utf8_lossy_owned
    367. string_into_chars
    368. string_remove_matches
    369. string_replace_in_place
    370. substr_range
    371. sync_nonpoison
    372. sync_poison_mod
    373. sync_unsafe_cell
    374. tcp_deferaccept
    375. tcp_linger
    376. tcplistener_into_incoming
    377. temporary_niche_types
    378. test
    379. thin_box
    380. thread_id_value
    381. thread_local_internals
    382. thread_raw
    383. thread_sleep_until
    384. thread_spawn_hook
    385. trace_macros
    386. track_path
    387. transmutability
    388. trim_prefix_suffix
    389. trusted_fused
    390. trusted_len
    391. trusted_len_next_unchecked
    392. trusted_random_access
    393. trusted_step
    394. try_find
    395. try_reserve_kind
    396. try_trait_v2
    397. try_trait_v2_residual
    398. try_trait_v2_yeet
    399. try_with_capacity
    400. tuple_trait
    401. type_ascription
    402. ub_checks
    403. uefi_std
    404. uint_bit_width
    405. unchecked_neg
    406. unchecked_shifts
    407. unicode_internals
    408. unique_rc_arc
    409. unix_file_vectored_at
    410. unix_mkfifo
    411. unix_send_signal
    412. unix_set_mark
    413. unix_socket_ancillary_data
    414. unix_socket_exclbind
    415. unix_socket_peek
    416. unsafe_cell_access
    417. unsafe_pinned
    418. unsize
    419. unwrap_infallible
    420. update_panic_count
    421. utf16_extra
    422. variant_count
    423. vec_deque_iter_as_slices
    424. vec_deque_pop_if
    425. vec_deque_truncate_front
    426. vec_into_chunks
    427. vec_into_raw_parts
    428. vec_peek_mut
    429. vec_push_within_capacity
    430. vec_split_at_spare
    431. vec_try_remove
    432. wasi_ext
    433. windows_by_handle
    434. windows_c
    435. windows_change_time
    436. windows_handle
    437. windows_net
    438. windows_process_exit_code_from
    439. windows_process_extensions_async_pipes
    440. windows_process_extensions_force_quotes
    441. windows_process_extensions_inherit_handles
    442. windows_process_extensions_main_thread_handle
    443. windows_process_extensions_raw_attribute
    444. windows_process_extensions_show_window
    445. windows_process_extensions_startupinfo
    446. windows_stdio
    447. wrapping_int_impl
    448. wrapping_next_power_of_two
    449. write_all_vectored
    450. wtf8_internals
    451. yeet_desugar_details