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. ergonomic_clones
    88. ermsb_target_feature
    89. exhaustive_patterns
    90. explicit_extern_abis
    91. explicit_tail_calls
    92. export_stable
    93. extended_varargs_abi_support
    94. extern_system_varargs
    95. extern_types
    96. f128
    97. f16
    98. ffi_const
    99. ffi_pure
    100. fmt_debug
    101. fn_align
    102. fn_delegation
    103. freeze_impls
    104. frontmatter
    105. fundamental
    106. gen_blocks
    107. generic_assert
    108. generic_const_exprs
    109. generic_const_items
    110. generic_const_parameter_types
    111. generic_pattern_types
    112. global_registration
    113. guard_patterns
    114. half_open_range_patterns_in_slices
    115. hexagon_target_feature
    116. if_let_guard
    117. impl_trait_in_assoc_type
    118. impl_trait_in_bindings
    119. impl_trait_in_fn_trait_return
    120. import_trait_associated_functions
    121. inherent_associated_types
    122. intra_doc_pointers
    123. intrinsics
    124. lahfsahf_target_feature
    125. lang_items
    126. large_assignments
    127. lazy_type_alias
    128. link_arg_attribute
    129. link_cfg
    130. link_llvm_intrinsics
    131. linkage
    132. loongarch_target_feature
    133. loop_match
    134. m68k_target_feature
    135. macro_attr
    136. macro_derive
    137. macro_metavar_expr
    138. macro_metavar_expr_concat
    139. marker_trait_attr
    140. min_generic_const_args
    141. min_specialization
    142. mips_target_feature
    143. more_maybe_bounds
    144. more_qualified_paths
    145. movrs_target_feature
    146. multiple_supertrait_upcastable
    147. must_not_suspend
    148. mut_ref
    149. naked_functions_rustic_abi
    150. naked_functions_target_feature
    151. native_link_modifiers_as_needed
    152. needs_panic_runtime
    153. negative_bounds
    154. negative_impls
    155. never_patterns
    156. never_type
    157. never_type_fallback
    158. new_range
    159. no_core
    160. non_exhaustive_omitted_patterns_lint
    161. non_lifetime_binders
    162. nvptx_target_feature
    163. offset_of_enum
    164. offset_of_slice
    165. optimize_attribute
    166. panic_runtime
    167. patchable_function_entry
    168. pattern_complexity_limit
    169. pattern_types
    170. pin_ergonomics
    171. postfix_match
    172. powerpc_target_feature
    173. prelude_import
    174. prfchw_target_feature
    175. proc_macro_hygiene
    176. profiler_runtime
    177. raw_dylib_elf
    178. ref_pat_eat_one_layer_2024
    179. ref_pat_eat_one_layer_2024_structural
    180. register_tool
    181. repr_simd
    182. return_type_notation
    183. riscv_target_feature
    184. rtm_target_feature
    185. rust_cold_cc
    186. rustc_allow_const_fn_unstable
    187. rustc_attrs
    188. rustc_private
    189. rustdoc_internals
    190. rustdoc_missing_doc_code_examples
    191. s390x_target_feature
    192. sanitize
    193. simd_ffi
    194. sized_hierarchy
    195. sparc_target_feature
    196. specialization
    197. staged_api
    198. stmt_expr_attributes
    199. strict_provenance_lints
    200. string_deref_patterns
    201. structural_match
    202. super_let
    203. supertrait_item_shadowing
    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. 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_array_each_ref
    68. const_btree_len
    69. const_carrying_mul_add
    70. const_clone
    71. const_cmp
    72. const_default
    73. const_deref
    74. const_eval_select
    75. const_format_args
    76. const_from
    77. const_heap
    78. const_index
    79. const_ops
    80. const_option_ops
    81. const_range_bounds
    82. const_raw_ptr_comparison
    83. const_ref_cell
    84. const_result_trait_fn
    85. const_slice_from_mut_ptr_range
    86. const_slice_from_ptr_range
    87. const_slice_make_iter
    88. const_slice_rotate
    89. const_split_off_first_last
    90. const_swap_with_slice
    91. const_system_time
    92. const_type_name
    93. container_error_extra
    94. context_ext
    95. control_flow_into_value
    96. control_flow_ok
    97. convert_float_to_int
    98. core_float_math
    99. core_intrinsics
    100. core_intrinsics_fallbacks
    101. core_io_borrowed_buf
    102. core_private_bignum
    103. core_private_diy_float
    104. coroutine_trait
    105. cow_is_borrowed
    106. cstr_bytes
    107. cstr_display
    108. cstr_internals
    109. cursor_split
    110. deadline_api
    111. debug_closure_helpers
    112. dec2flt
    113. deref_pure_trait
    114. derive_clone_copy
    115. derive_coerce_pointee
    116. derive_const
    117. derive_eq
    118. dir_entry_ext2
    119. discriminant_kind
    120. disjoint_bitor
    121. dispatch_from_dyn
    122. downcast_unchecked
    123. drain_keep_rest
    124. drop_guard
    125. duration_constants
    126. duration_constructors
    127. duration_millis_float
    128. duration_units
    129. edition_panic
    130. error_generic_member_access
    131. error_iter
    132. error_reporter
    133. error_type_id
    134. exact_div
    135. exact_size_is_empty
    136. exclusive_wrapper
    137. exit_status_error
    138. exitcode_exit_method
    139. extend_one
    140. extend_one_unchecked
    141. fd
    142. fd_read
    143. file_buffered
    144. file_with_nul
    145. float_algebraic
    146. float_erf
    147. float_gamma
    148. float_minimum_maximum
    149. flt2dec
    150. fmt_helpers_for_derive
    151. fmt_internals
    152. fn_ptr_trait
    153. fn_traits
    154. forget_unsized
    155. format_args_nl
    156. formatting_options
    157. freeze
    158. future_join
    159. gen_future
    160. generic_assert_internals
    161. generic_atomic
    162. get_disjoint_mut_helpers
    163. get_mut_unchecked
    164. hash_map_internals
    165. hash_map_macro
    166. hash_set_entry
    167. hasher_prefixfree_extras
    168. hashmap_internals
    169. hint_must_use
    170. inplace_iteration
    171. int_format_into
    172. int_from_ascii
    173. int_lowest_highest_one
    174. int_roundings
    175. integer_atomics
    176. internal_impls_macro
    177. internal_output_capture
    178. io_const_error
    179. io_const_error_internals
    180. io_error_inprogress
    181. io_error_more
    182. io_error_uncategorized
    183. io_slice_as_bytes
    184. ip
    185. ip_as_octets
    186. is_ascii_octdigit
    187. is_loongarch_feature_detected
    188. is_riscv_feature_detected
    189. isolate_most_least_significant_one
    190. iter_advance_by
    191. iter_array_chunks
    192. iter_collect_into
    193. iter_from_coroutine
    194. iter_intersperse
    195. iter_is_partitioned
    196. iter_macro
    197. iter_map_windows
    198. iter_next_chunk
    199. iter_order_by
    200. iter_partition_in_place
    201. iterator_try_collect
    202. iterator_try_reduce
    203. junction_point
    204. layout_for_ptr
    205. lazy_cell_into_inner
    206. lazy_get
    207. legacy_receiver_trait
    208. liballoc_internals
    209. libstd_sys_internals
    210. likely_unlikely
    211. linked_list_cursors
    212. linked_list_remove
    213. linked_list_retain
    214. linux_pidfd
    215. local_key_cell_update
    216. local_waker
    217. lock_value_accessors
    218. log_syntax
    219. map_try_insert
    220. mapped_lock_guards
    221. maybe_uninit_array_assume_init
    222. maybe_uninit_as_bytes
    223. maybe_uninit_fill
    224. maybe_uninit_slice
    225. maybe_uninit_uninit_array_transpose
    226. maybe_uninit_write_slice
    227. mem_copy_fn
    228. more_float_constants
    229. mpmc_channel
    230. mutex_data_ptr
    231. new_range_api
    232. new_zeroed_alloc
    233. next_index
    234. nonpoison_mutex
    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_zip
    247. os_str_slice
    248. os_string_truncate
    249. panic_abort
    250. panic_always_abort
    251. panic_backtrace_config
    252. panic_can_unwind
    253. panic_internals
    254. panic_unwind
    255. panic_update_hook
    256. partial_ord_chaining_methods
    257. path_add_extension
    258. pattern
    259. pattern_type_macro
    260. pattern_type_range_trait
    261. peer_credentials_unix_socket
    262. phantom_variance_markers
    263. pin_coerce_unsized_trait
    264. pointer_is_aligned_to
    265. pointer_try_cast_aligned
    266. portable_simd
    267. prelude_future
    268. prelude_next
    269. print_internals
    270. proc_macro_def_site
    271. proc_macro_diagnostic
    272. proc_macro_expand
    273. proc_macro_internals
    274. proc_macro_quote
    275. proc_macro_span
    276. proc_macro_totokens
    277. proc_macro_tracked_env
    278. proc_macro_value
    279. process_chroot
    280. process_exitcode_internals
    281. process_internals
    282. process_setsid
    283. profiler_runtime_lib
    284. ptr_alignment_type
    285. ptr_as_ref_unchecked
    286. ptr_as_uninit
    287. ptr_cast_array
    288. ptr_internals
    289. ptr_mask
    290. ptr_metadata
    291. pub_crate_should_not_need_unstable_attr
    292. push_mut
    293. random
    294. range_bounds_is_empty
    295. range_into_bounds
    296. raw_os_error_ty
    297. raw_slice_split
    298. raw_vec_internals
    299. read_buf
    300. reentrant_lock
    301. reentrant_lock_data_ptr
    302. refcell_try_map
    303. restricted_std
    304. result_option_map_or_default
    305. rev_into_inner
    306. round_char_boundary
    307. rt
    308. rwlock_data_ptr
    309. rwlock_downgrade
    310. sealed
    311. seek_io_take_position
    312. seek_stream_len
    313. set_permissions_nofollow
    314. set_ptr_value
    315. setgroups
    316. sgx_platform
    317. sized_type_properties
    318. slice_as_array
    319. slice_concat_ext
    320. slice_concat_trait
    321. slice_from_ptr_range
    322. slice_index_methods
    323. slice_internals
    324. slice_iter_mut_as_mut_slice
    325. slice_partition_dedup
    326. slice_pattern
    327. slice_ptr_get
    328. slice_range
    329. slice_split_once
    330. slice_swap_unchecked
    331. solid_ext
    332. sort_floats
    333. split_array
    334. split_as_slice
    335. std_internals
    336. stdarch_aarch64_feature_detection
    337. stdarch_arm_feature_detection
    338. stdarch_internal
    339. stdarch_loongarch_feature_detection
    340. stdarch_mips_feature_detection
    341. stdarch_powerpc_feature_detection
    342. stdarch_riscv_feature_detection
    343. stdarch_s390x_feature_detection
    344. stdio_makes_pipe
    345. step_trait
    346. str_as_str
    347. str_from_raw_parts
    348. str_from_utf16_endian
    349. str_internals
    350. str_lines_remainder
    351. str_split_inclusive_remainder
    352. str_split_remainder
    353. str_split_whitespace_remainder
    354. strict_provenance_atomic_ptr
    355. string_from_utf8_lossy_owned
    356. string_into_chars
    357. string_remove_matches
    358. substr_range
    359. sync_nonpoison
    360. sync_poison_mod
    361. sync_unsafe_cell
    362. tcp_deferaccept
    363. tcp_linger
    364. tcplistener_into_incoming
    365. temporary_niche_types
    366. test
    367. thin_box
    368. thread_id_value
    369. thread_local_internals
    370. thread_raw
    371. thread_sleep_until
    372. thread_spawn_hook
    373. trace_macros
    374. track_path
    375. transmutability
    376. trim_prefix_suffix
    377. trusted_fused
    378. trusted_len
    379. trusted_len_next_unchecked
    380. trusted_random_access
    381. trusted_step
    382. try_find
    383. try_reserve_kind
    384. try_trait_v2
    385. try_trait_v2_residual
    386. try_trait_v2_yeet
    387. try_with_capacity
    388. tuple_trait
    389. type_ascription
    390. ub_checks
    391. uefi_std
    392. uint_bit_width
    393. unchecked_neg
    394. unchecked_shifts
    395. unicode_internals
    396. unique_rc_arc
    397. unix_file_vectored_at
    398. unix_mkfifo
    399. unix_send_signal
    400. unix_set_mark
    401. unix_socket_ancillary_data
    402. unix_socket_exclbind
    403. unix_socket_peek
    404. unsafe_cell_access
    405. unsafe_pinned
    406. unsigned_nonzero_div_ceil
    407. unsize
    408. unwrap_infallible
    409. update_panic_count
    410. utf16_extra
    411. variant_count
    412. vec_deque_iter_as_slices
    413. vec_deque_pop_if
    414. vec_deque_truncate_front
    415. vec_into_chunks
    416. vec_into_raw_parts
    417. vec_peek_mut
    418. vec_push_within_capacity
    419. vec_split_at_spare
    420. wasi_ext
    421. windows_by_handle
    422. windows_c
    423. windows_change_time
    424. windows_handle
    425. windows_net
    426. windows_process_exit_code_from
    427. windows_process_extensions_async_pipes
    428. windows_process_extensions_force_quotes
    429. windows_process_extensions_main_thread_handle
    430. windows_process_extensions_raw_attribute
    431. windows_process_extensions_show_window
    432. windows_process_extensions_startupinfo
    433. windows_stdio
    434. wrapping_int_impl
    435. wrapping_next_power_of_two
    436. write_all_vectored
    437. yeet_desugar_details