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