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. instrument_xray
    32. link_native_libraries
    33. lint_llvm_ir
    34. llvm_module_flag
    35. location_detail
    36. macro_stats
    37. min_function_alignment
    38. move_size_limit
    39. no_jump_tables
    40. no_parallel_llvm
    41. no_steal_thir
    42. no_unique_section_names
    43. offload
    44. on_broken_pipe
    45. patchable_function_entry
    46. print_check_cfg
    47. print_crate_root_lint_levels
    48. print_supported_crate_types
    49. profile_sample_use
    50. randomize_layout
    51. reg_struct_return
    52. regparm
    53. remap_cwd_prefix
    54. remap_path_scope
    55. report_time
    56. sanitizer
    57. self_profile
    58. self_profile_events
    59. shell_argfiles
    60. small_data_threshold
    61. src_hash_algorithm
    62. temps_dir
    63. terminal_urls
    64. tiny_const_eval_limit
    65. tls_model
    66. track_diagnostics
    67. treat_err_as_bug
    68. ub_checks
    69. unsound_mir_opts
    70. verbose_asm
    71. virtual_function_elimination
    72. 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. doc_auto_cfg
    81. doc_cfg
    82. doc_cfg_hide
    83. doc_masked
    84. doc_notable_trait
    85. dropck_eyepatch
    86. ergonomic_clones
    87. ermsb_target_feature
    88. exhaustive_patterns
    89. explicit_extern_abis
    90. explicit_tail_calls
    91. export_stable
    92. extended_varargs_abi_support
    93. extern_system_varargs
    94. extern_types
    95. f128
    96. f16
    97. ffi_const
    98. ffi_pure
    99. fmt_debug
    100. fn_align
    101. fn_delegation
    102. freeze_impls
    103. frontmatter
    104. fundamental
    105. gen_blocks
    106. generic_assert
    107. generic_const_exprs
    108. generic_const_items
    109. generic_const_parameter_types
    110. generic_pattern_types
    111. global_registration
    112. guard_patterns
    113. half_open_range_patterns_in_slices
    114. hexagon_target_feature
    115. if_let_guard
    116. impl_trait_in_assoc_type
    117. impl_trait_in_bindings
    118. impl_trait_in_fn_trait_return
    119. import_trait_associated_functions
    120. inherent_associated_types
    121. intra_doc_pointers
    122. intrinsics
    123. lahfsahf_target_feature
    124. lang_items
    125. large_assignments
    126. lazy_type_alias
    127. link_arg_attribute
    128. link_cfg
    129. link_llvm_intrinsics
    130. linkage
    131. loongarch_target_feature
    132. loop_match
    133. m68k_target_feature
    134. macro_attr
    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. no_sanitize
    159. non_exhaustive_omitted_patterns_lint
    160. non_lifetime_binders
    161. nvptx_target_feature
    162. offset_of_enum
    163. offset_of_slice
    164. optimize_attribute
    165. panic_runtime
    166. patchable_function_entry
    167. pattern_complexity_limit
    168. pattern_types
    169. pin_ergonomics
    170. postfix_match
    171. powerpc_target_feature
    172. prelude_import
    173. prfchw_target_feature
    174. proc_macro_hygiene
    175. profiler_runtime
    176. raw_dylib_elf
    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. simd_ffi
    192. sized_hierarchy
    193. sparc_target_feature
    194. specialization
    195. sse4a_target_feature
    196. staged_api
    197. stmt_expr_attributes
    198. strict_provenance_lints
    199. string_deref_patterns
    200. structural_match
    201. super_let
    202. supertrait_item_shadowing
    203. tbm_target_feature
    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. as_array_of_cells
    18. ascii_char
    19. ascii_char_variants
    20. assert_matches
    21. async_fn_traits
    22. async_gen_internals
    23. async_iter_from_iter
    24. async_iterator
    25. atomic_from_mut
    26. atomic_internals
    27. atomic_try_update
    28. autodiff
    29. backtrace_frames
    30. bigint_helper_methods
    31. bikeshed_guaranteed_no_drop
    32. binary_heap_drain_sorted
    33. binary_heap_into_iter_sorted
    34. binary_heap_peek_mut_refresh
    35. bool_to_result
    36. bound_as_ref
    37. box_as_ptr
    38. box_into_boxed_slice
    39. box_into_inner
    40. box_vec_non_null
    41. breakpoint
    42. bstr
    43. bstr_internals
    44. btree_cursors
    45. btree_entry_insert
    46. btree_extract_if
    47. btree_set_entry
    48. btreemap_alloc
    49. buf_read_has_data_left
    50. bufreader_peek
    51. c_size_t
    52. c_void_variant
    53. can_vector
    54. cast_maybe_uninit
    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_array_each_ref
    69. const_btree_len
    70. const_carrying_mul_add
    71. const_clone
    72. const_cmp
    73. const_default
    74. const_deref
    75. const_eval_select
    76. const_exposed_provenance
    77. const_format_args
    78. const_from
    79. const_heap
    80. const_index
    81. const_ops
    82. const_option_ops
    83. const_pathbuf_osstring_new
    84. const_range_bounds
    85. const_raw_ptr_comparison
    86. const_ref_cell
    87. const_result_trait_fn
    88. const_slice_from_mut_ptr_range
    89. const_slice_from_ptr_range
    90. const_slice_make_iter
    91. const_slice_rotate
    92. const_split_off_first_last
    93. const_swap_with_slice
    94. const_system_time
    95. const_type_name
    96. container_error_extra
    97. context_ext
    98. control_flow_into_value
    99. control_flow_ok
    100. convert_float_to_int
    101. core_float_math
    102. core_intrinsics
    103. core_intrinsics_fallbacks
    104. core_io_borrowed_buf
    105. core_private_bignum
    106. core_private_diy_float
    107. coroutine_trait
    108. cow_is_borrowed
    109. cstr_bytes
    110. cstr_display
    111. cstr_internals
    112. cursor_split
    113. deadline_api
    114. debug_closure_helpers
    115. dec2flt
    116. deref_pure_trait
    117. derive_clone_copy
    118. derive_coerce_pointee
    119. derive_const
    120. derive_eq
    121. dir_entry_ext2
    122. discriminant_kind
    123. disjoint_bitor
    124. dispatch_from_dyn
    125. downcast_unchecked
    126. drain_keep_rest
    127. drop_guard
    128. duration_constants
    129. duration_constructors
    130. duration_millis_float
    131. duration_units
    132. edition_panic
    133. error_generic_member_access
    134. error_iter
    135. error_reporter
    136. error_type_id
    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. file_with_nul
    148. float_algebraic
    149. float_erf
    150. float_gamma
    151. float_minimum_maximum
    152. flt2dec
    153. fmt_helpers_for_derive
    154. fmt_internals
    155. fn_ptr_trait
    156. fn_traits
    157. forget_unsized
    158. format_args_nl
    159. formatting_options
    160. freeze
    161. future_join
    162. gen_future
    163. generic_assert_internals
    164. generic_atomic
    165. get_disjoint_mut_helpers
    166. get_mut_unchecked
    167. hash_map_internals
    168. hash_map_macro
    169. hash_set_entry
    170. hasher_prefixfree_extras
    171. hashmap_internals
    172. hint_must_use
    173. inplace_iteration
    174. int_format_into
    175. int_from_ascii
    176. int_roundings
    177. integer_atomics
    178. internal_impls_macro
    179. internal_output_capture
    180. io_const_error
    181. io_const_error_internals
    182. io_error_inprogress
    183. io_error_more
    184. io_error_uncategorized
    185. io_slice_as_bytes
    186. ip
    187. ip_as_octets
    188. ip_from
    189. is_ascii_octdigit
    190. is_loongarch_feature_detected
    191. is_riscv_feature_detected
    192. isolate_most_least_significant_one
    193. iter_advance_by
    194. iter_array_chunks
    195. iter_chain
    196. iter_collect_into
    197. iter_from_coroutine
    198. iter_intersperse
    199. iter_is_partitioned
    200. iter_macro
    201. iter_map_windows
    202. iter_next_chunk
    203. iter_order_by
    204. iter_partition_in_place
    205. iterator_try_collect
    206. iterator_try_reduce
    207. junction_point
    208. layout_for_ptr
    209. lazy_cell_into_inner
    210. lazy_get
    211. legacy_receiver_trait
    212. liballoc_internals
    213. libstd_sys_internals
    214. likely_unlikely
    215. linked_list_cursors
    216. linked_list_remove
    217. linked_list_retain
    218. linux_pidfd
    219. local_key_cell_update
    220. local_waker
    221. lock_value_accessors
    222. log_syntax
    223. map_try_insert
    224. mapped_lock_guards
    225. maybe_uninit_array_assume_init
    226. maybe_uninit_as_bytes
    227. maybe_uninit_fill
    228. maybe_uninit_slice
    229. maybe_uninit_uninit_array_transpose
    230. maybe_uninit_write_slice
    231. mem_copy_fn
    232. more_float_constants
    233. mpmc_channel
    234. mutex_data_ptr
    235. new_range_api
    236. new_zeroed_alloc
    237. next_index
    238. nonpoison_mutex
    239. nonzero_bitwise
    240. nonzero_from_mut
    241. nonzero_internals
    242. nonzero_ops
    243. normalize_lexically
    244. numfmt
    245. once_cell_get_mut
    246. once_cell_try
    247. once_cell_try_insert
    248. one_sided_range
    249. option_array_transpose
    250. option_zip
    251. os_str_slice
    252. os_string_truncate
    253. panic_abort
    254. panic_always_abort
    255. panic_backtrace_config
    256. panic_can_unwind
    257. panic_internals
    258. panic_unwind
    259. panic_update_hook
    260. partial_ord_chaining_methods
    261. path_add_extension
    262. pattern
    263. pattern_type_macro
    264. pattern_type_range_trait
    265. peer_credentials_unix_socket
    266. phantom_variance_markers
    267. pin_coerce_unsized_trait
    268. pointer_is_aligned_to
    269. pointer_try_cast_aligned
    270. portable_simd
    271. prelude_future
    272. prelude_next
    273. print_internals
    274. proc_macro_def_site
    275. proc_macro_diagnostic
    276. proc_macro_expand
    277. proc_macro_internals
    278. proc_macro_quote
    279. proc_macro_span
    280. proc_macro_totokens
    281. proc_macro_tracked_env
    282. proc_macro_value
    283. process_chroot
    284. process_exitcode_internals
    285. process_internals
    286. process_setsid
    287. profiler_runtime_lib
    288. ptr_alignment_type
    289. ptr_as_ref_unchecked
    290. ptr_as_uninit
    291. ptr_cast_array
    292. ptr_internals
    293. ptr_mask
    294. ptr_metadata
    295. pub_crate_should_not_need_unstable_attr
    296. push_mut
    297. random
    298. range_bounds_is_empty
    299. range_into_bounds
    300. raw_os_error_ty
    301. raw_slice_split
    302. raw_vec_internals
    303. read_buf
    304. reentrant_lock
    305. reentrant_lock_data_ptr
    306. restricted_std
    307. result_option_map_or_default
    308. rev_into_inner
    309. round_char_boundary
    310. rt
    311. rwlock_data_ptr
    312. rwlock_downgrade
    313. sealed
    314. seek_io_take_position
    315. seek_stream_len
    316. set_ptr_value
    317. setgroups
    318. sgx_platform
    319. sized_type_properties
    320. slice_as_array
    321. slice_concat_ext
    322. slice_concat_trait
    323. slice_from_ptr_range
    324. slice_index_methods
    325. slice_internals
    326. slice_iter_mut_as_mut_slice
    327. slice_partition_dedup
    328. slice_pattern
    329. slice_ptr_get
    330. slice_range
    331. slice_split_once
    332. slice_swap_unchecked
    333. solid_ext
    334. sort_floats
    335. split_array
    336. split_as_slice
    337. std_internals
    338. stdarch_aarch64_feature_detection
    339. stdarch_arm_feature_detection
    340. stdarch_internal
    341. stdarch_loongarch_feature_detection
    342. stdarch_mips_feature_detection
    343. stdarch_powerpc_feature_detection
    344. stdarch_riscv_feature_detection
    345. stdarch_s390x_feature_detection
    346. stdio_makes_pipe
    347. step_trait
    348. str_as_str
    349. str_from_raw_parts
    350. str_from_utf16_endian
    351. str_internals
    352. str_lines_remainder
    353. str_split_inclusive_remainder
    354. str_split_remainder
    355. str_split_whitespace_remainder
    356. strict_provenance_atomic_ptr
    357. string_from_utf8_lossy_owned
    358. string_into_chars
    359. string_remove_matches
    360. substr_range
    361. sync_nonpoison
    362. sync_poison_mod
    363. sync_unsafe_cell
    364. tcp_deferaccept
    365. tcp_linger
    366. tcplistener_into_incoming
    367. temporary_niche_types
    368. test
    369. thin_box
    370. thread_id_value
    371. thread_local_internals
    372. thread_raw
    373. thread_sleep_until
    374. thread_spawn_hook
    375. trace_macros
    376. track_path
    377. transmutability
    378. trim_prefix_suffix
    379. trusted_fused
    380. trusted_len
    381. trusted_len_next_unchecked
    382. trusted_random_access
    383. trusted_step
    384. try_find
    385. try_reserve_kind
    386. try_trait_v2
    387. try_trait_v2_residual
    388. try_trait_v2_yeet
    389. try_with_capacity
    390. tuple_trait
    391. type_ascription
    392. ub_checks
    393. uefi_std
    394. uint_bit_width
    395. unchecked_neg
    396. unchecked_shifts
    397. unicode_internals
    398. unique_rc_arc
    399. unix_file_vectored_at
    400. unix_mkfifo
    401. unix_send_signal
    402. unix_set_mark
    403. unix_socket_ancillary_data
    404. unix_socket_exclbind
    405. unix_socket_peek
    406. unsafe_cell_access
    407. unsafe_pinned
    408. unsigned_nonzero_div_ceil
    409. unsize
    410. unwrap_infallible
    411. update_panic_count
    412. utf16_extra
    413. variant_count
    414. vec_deque_iter_as_slices
    415. vec_deque_pop_if
    416. vec_deque_truncate_front
    417. vec_into_chunks
    418. vec_into_raw_parts
    419. vec_peek_mut
    420. vec_push_within_capacity
    421. vec_split_at_spare
    422. wasi_ext
    423. windows_by_handle
    424. windows_c
    425. windows_change_time
    426. windows_handle
    427. windows_net
    428. windows_process_exit_code_from
    429. windows_process_extensions_async_pipes
    430. windows_process_extensions_force_quotes
    431. windows_process_extensions_main_thread_handle
    432. windows_process_extensions_raw_attribute
    433. windows_process_extensions_show_window
    434. windows_process_extensions_startupinfo
    435. windows_stdio
    436. wrapping_int_impl
    437. wrapping_next_power_of_two
    438. write_all_vectored
    439. yeet_desugar_details