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_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. c_variadic_naked_functions
    42. cfg_contract_checks
    43. cfg_emscripten_wasm_eh
    44. cfg_overflow_checks
    45. cfg_relocation_model
    46. cfg_sanitize
    47. cfg_sanitizer_cfi
    48. cfg_target_compact
    49. cfg_target_has_atomic
    50. cfg_target_has_atomic_equal_alignment
    51. cfg_target_has_reliable_f16_f128
    52. cfg_target_thread_local
    53. cfg_ub_checks
    54. cfg_version
    55. cfi_encoding
    56. closure_lifetime_binder
    57. closure_track_caller
    58. cmse_nonsecure_entry
    59. compiler_builtins
    60. const_async_blocks
    61. const_closures
    62. const_destruct
    63. const_for
    64. const_precise_live_drops
    65. const_trait_impl
    66. const_try
    67. contracts
    68. contracts_internals
    69. coroutine_clone
    70. coroutines
    71. coverage_attribute
    72. csky_target_feature
    73. custom_inner_attributes
    74. custom_mir
    75. custom_test_frameworks
    76. decl_macro
    77. default_field_values
    78. deprecated_safe
    79. deprecated_suggestion
    80. deref_patterns
    81. derive_from
    82. doc_cfg
    83. doc_masked
    84. doc_notable_trait
    85. dropck_eyepatch
    86. effective_target_features
    87. ergonomic_clones
    88. ermsb_target_feature
    89. exhaustive_patterns
    90. explicit_extern_abis
    91. explicit_tail_calls
    92. export_stable
    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. 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_to_uninit
    62. cmp_minmax
    63. coerce_pointee_validated
    64. coerce_unsized
    65. cold_path
    66. concat_bytes
    67. const_alloc_error
    68. const_btree_len
    69. const_carrying_mul_add
    70. const_cell_traits
    71. const_clone
    72. const_cmp
    73. const_control_flow
    74. const_convert
    75. const_default
    76. const_drop_in_place
    77. const_eval_select
    78. const_format_args
    79. const_heap
    80. const_index
    81. const_manually_drop_take
    82. const_mul_add
    83. const_ops
    84. const_option_ops
    85. const_range
    86. const_range_bounds
    87. const_raw_ptr_comparison
    88. const_ref_cell
    89. const_result_trait_fn
    90. const_result_unwrap_unchecked
    91. const_select_unpredictable
    92. const_slice_from_mut_ptr_range
    93. const_slice_from_ptr_range
    94. const_slice_make_iter
    95. const_split_off_first_last
    96. const_swap_with_slice
    97. const_try_residual
    98. const_type_name
    99. container_error_extra
    100. context_ext
    101. control_flow_into_value
    102. control_flow_ok
    103. convert_float_to_int
    104. copied_into_inner
    105. core_float_math
    106. core_intrinsics
    107. core_intrinsics_fallbacks
    108. core_io_borrowed_buf
    109. core_private_bignum
    110. core_private_diy_float
    111. coroutine_trait
    112. cow_is_borrowed
    113. cstr_bytes
    114. cstr_display
    115. cstr_internals
    116. current_thread_id
    117. cursor_split
    118. darwin_objc
    119. deadline_api
    120. debug_closure_helpers
    121. dec2flt
    122. deque_extend_front
    123. deref_pure_trait
    124. derive_clone_copy
    125. derive_coerce_pointee
    126. derive_const
    127. derive_eq
    128. dir_entry_ext2
    129. discriminant_kind
    130. disjoint_bitor
    131. dispatch_from_dyn
    132. downcast_unchecked
    133. drain_keep_rest
    134. drop_guard
    135. duration_constants
    136. duration_constructors
    137. duration_millis_float
    138. duration_units
    139. edition_panic
    140. error_generic_member_access
    141. error_iter
    142. error_reporter
    143. error_type_id
    144. exact_bitshifts
    145. exact_div
    146. exact_size_is_empty
    147. exclusive_wrapper
    148. exit_status_error
    149. exitcode_exit_method
    150. extend_one
    151. extend_one_unchecked
    152. fd
    153. fd_read
    154. file_buffered
    155. float_algebraic
    156. float_erf
    157. float_gamma
    158. float_minimum_maximum
    159. flt2dec
    160. fmt_arguments_from_str
    161. fmt_helpers_for_derive
    162. fmt_internals
    163. fn_ptr_trait
    164. fn_traits
    165. forget_unsized
    166. format_args_nl
    167. formatting_options
    168. freeze
    169. fs_set_times
    170. funnel_shifts
    171. future_join
    172. gen_future
    173. generic_assert_internals
    174. generic_atomic
    175. get_disjoint_mut_helpers
    176. get_mut_unchecked
    177. gethostname
    178. hash_set_entry
    179. hasher_prefixfree_extras
    180. hashmap_internals
    181. hint_must_use
    182. inplace_iteration
    183. int_format_into
    184. int_from_ascii
    185. int_lowest_highest_one
    186. int_roundings
    187. integer_atomics
    188. internal_impls_macro
    189. internal_output_capture
    190. io_const_error
    191. io_const_error_internals
    192. io_error_inprogress
    193. io_error_more
    194. io_error_uncategorized
    195. io_slice_as_bytes
    196. ip
    197. ip_as_octets
    198. is_ascii_octdigit
    199. is_loongarch_feature_detected
    200. is_riscv_feature_detected
    201. isolate_most_least_significant_one
    202. iter_advance_by
    203. iter_array_chunks
    204. iter_collect_into
    205. iter_from_coroutine
    206. iter_intersperse
    207. iter_is_partitioned
    208. iter_macro
    209. iter_map_windows
    210. iter_next_chunk
    211. iter_order_by
    212. iter_partition_in_place
    213. iterator_try_collect
    214. iterator_try_reduce
    215. junction_point
    216. layout_for_ptr
    217. lazy_cell_into_inner
    218. lazy_get
    219. legacy_receiver_trait
    220. liballoc_internals
    221. libstd_sys_internals
    222. likely_unlikely
    223. linked_list_cursors
    224. linked_list_remove
    225. linked_list_retain
    226. linux_pidfd
    227. local_key_cell_update
    228. local_waker
    229. lock_value_accessors
    230. log_syntax
    231. map_try_insert
    232. mapped_lock_guards
    233. maybe_uninit_array_assume_init
    234. maybe_uninit_as_bytes
    235. maybe_uninit_fill
    236. maybe_uninit_slice
    237. maybe_uninit_uninit_array_transpose
    238. maybe_uninit_write_slice
    239. mem_conjure_zst
    240. mem_copy_fn
    241. min_const_control_flow
    242. more_float_constants
    243. motor_ext
    244. mpmc_channel
    245. mutex_data_ptr
    246. new_range_api
    247. next_index
    248. nonpoison_condvar
    249. nonpoison_mutex
    250. nonpoison_rwlock
    251. nonzero_bitwise
    252. nonzero_from_mut
    253. nonzero_internals
    254. nonzero_ops
    255. normalize_lexically
    256. numfmt
    257. objc_class_variant
    258. objc_selector_variant
    259. once_cell_get_mut
    260. once_cell_try
    261. once_cell_try_insert
    262. one_sided_range
    263. option_array_transpose
    264. option_reduce
    265. option_zip
    266. os_str_slice
    267. os_string_truncate
    268. panic_abort
    269. panic_always_abort
    270. panic_backtrace_config
    271. panic_can_unwind
    272. panic_internals
    273. panic_unwind
    274. panic_update_hook
    275. partial_ord_chaining_methods
    276. path_is_empty
    277. path_trailing_sep
    278. pattern
    279. pattern_type_macro
    280. pattern_type_range_trait
    281. peekable_next_if_map
    282. peer_credentials_unix_socket
    283. phantom_variance_markers
    284. pin_coerce_unsized_trait
    285. pin_derefmut_internals
    286. pointer_is_aligned_to
    287. pointer_try_cast_aligned
    288. portable_simd
    289. prelude_future
    290. prelude_next
    291. print_internals
    292. proc_macro_def_site
    293. proc_macro_diagnostic
    294. proc_macro_expand
    295. proc_macro_internals
    296. proc_macro_quote
    297. proc_macro_span
    298. proc_macro_totokens
    299. proc_macro_tracked_env
    300. proc_macro_value
    301. process_chroot
    302. process_exitcode_internals
    303. process_internals
    304. process_setsid
    305. profiler_runtime_lib
    306. profiling_marker_api
    307. ptr_alignment_type
    308. ptr_as_ref_unchecked
    309. ptr_as_uninit
    310. ptr_cast_array
    311. ptr_internals
    312. ptr_mask
    313. ptr_metadata
    314. pub_crate_should_not_need_unstable_attr
    315. push_mut
    316. random
    317. range_bounds_is_empty
    318. range_into_bounds
    319. raw_os_error_ty
    320. raw_slice_split
    321. raw_vec_internals
    322. read_array
    323. read_buf
    324. read_buf_at
    325. reentrant_lock
    326. reentrant_lock_data_ptr
    327. refcell_try_map
    328. restricted_std
    329. result_option_map_or_default
    330. rev_into_inner
    331. rt
    332. rwlock_data_ptr
    333. sealed
    334. seek_io_take_position
    335. seek_stream_len
    336. set_permissions_nofollow
    337. set_ptr_value
    338. setgroups
    339. sgx_platform
    340. sized_type_properties
    341. slice_concat_ext
    342. slice_concat_trait
    343. slice_from_ptr_range
    344. slice_index_methods
    345. slice_internals
    346. slice_iter_mut_as_mut_slice
    347. slice_partition_dedup
    348. slice_pattern
    349. slice_ptr_get
    350. slice_range
    351. slice_split_once
    352. slice_swap_unchecked
    353. sliceindex_wrappers
    354. smart_pointer_try_map
    355. solid_ext
    356. sort_floats
    357. split_array
    358. split_as_slice
    359. std_internals
    360. stdarch_aarch64_feature_detection
    361. stdarch_arm_feature_detection
    362. stdarch_internal
    363. stdarch_loongarch_feature_detection
    364. stdarch_mips_feature_detection
    365. stdarch_powerpc_feature_detection
    366. stdarch_riscv_feature_detection
    367. stdio_makes_pipe
    368. step_trait
    369. str_as_str
    370. str_from_raw_parts
    371. str_from_utf16_endian
    372. str_internals
    373. str_lines_remainder
    374. str_split_inclusive_remainder
    375. str_split_remainder
    376. str_split_whitespace_remainder
    377. string_from_utf8_lossy_owned
    378. string_into_chars
    379. string_remove_matches
    380. string_replace_in_place
    381. strip_circumfix
    382. substr_range
    383. sync_nonpoison
    384. sync_poison_mod
    385. sync_unsafe_cell
    386. tcp_deferaccept
    387. tcp_linger
    388. tcplistener_into_incoming
    389. temporary_niche_types
    390. test
    391. thin_box
    392. thread_id_value
    393. thread_local_internals
    394. thread_raw
    395. thread_sleep_until
    396. thread_spawn_hook
    397. trace_macros
    398. track_path
    399. transmutability
    400. trim_prefix_suffix
    401. trivial_clone
    402. trusted_fused
    403. trusted_len
    404. trusted_len_next_unchecked
    405. trusted_random_access
    406. trusted_step
    407. try_find
    408. try_reserve_kind
    409. try_trait_v2
    410. try_trait_v2_residual
    411. try_trait_v2_yeet
    412. try_with_capacity
    413. tuple_trait
    414. type_ascription
    415. ub_checks
    416. uefi_std
    417. uint_bit_width
    418. unchecked_neg
    419. unchecked_shifts
    420. unicode_internals
    421. unique_rc_arc
    422. unix_file_vectored_at
    423. unix_mkfifo
    424. unix_send_signal
    425. unix_set_mark
    426. unix_socket_ancillary_data
    427. unix_socket_exclbind
    428. unix_socket_peek
    429. unsafe_cell_access
    430. unsafe_pinned
    431. unsize
    432. unwrap_infallible
    433. update_panic_count
    434. utf16_extra
    435. variant_count
    436. vec_deque_extract_if
    437. vec_deque_iter_as_slices
    438. vec_deque_truncate_front
    439. vec_into_chunks
    440. vec_peek_mut
    441. vec_push_within_capacity
    442. vec_recycle
    443. vec_split_at_spare
    444. vec_try_remove
    445. waker_from_fn_ptr
    446. wasi_ext
    447. windows_by_handle
    448. windows_c
    449. windows_change_time
    450. windows_handle
    451. windows_net
    452. windows_process_exit_code_from
    453. windows_process_extensions_async_pipes
    454. windows_process_extensions_force_quotes
    455. windows_process_extensions_inherit_handles
    456. windows_process_extensions_main_thread_handle
    457. windows_process_extensions_raw_attribute
    458. windows_process_extensions_show_window
    459. windows_process_extensions_startupinfo
    460. windows_stdio
    461. wrapping_int_impl
    462. wrapping_next_power_of_two
    463. write_all_vectored
    464. wtf8_internals
    465. yeet_desugar_details