1. The Unstable Book
  2. 1. Compiler flags
    1. 1.1. codegen_backend
    2. 1.2. control_flow_guard
    3. 1.3. emit_stack_sizes
    4. 1.4. extern_location
    5. 1.5. profile
    6. 1.6. report_time
    7. 1.7. sanitizer
    8. 1.8. self_profile
    9. 1.9. self_profile_events
    10. 1.10. source_based_code_coverage
    11. 1.11. src_hash_algorithm
    12. 1.12. strip
    13. 1.13. tls_model
    14. 1.14. unsound_mir_opts
  3. 2. Language features
    1. 2.1. aarch64_target_feature
    2. 2.2. abi_amdgpu_kernel
    3. 2.3. abi_avr_interrupt
    4. 2.4. abi_c_cmse_nonsecure_call
    5. 2.5. abi_efiapi
    6. 2.6. abi_msp430_interrupt
    7. 2.7. abi_ptx
    8. 2.8. abi_thiscall
    9. 2.9. abi_unadjusted
    10. 2.10. abi_vectorcall
    11. 2.11. abi_x86_interrupt
    12. 2.12. adx_target_feature
    13. 2.13. alloc_error_handler
    14. 2.14. allocator_internals
    15. 2.15. allow_fail
    16. 2.16. allow_internal_unsafe
    17. 2.17. allow_internal_unstable
    18. 2.18. arbitrary_enum_discriminant
    19. 2.19. arbitrary_self_types
    20. 2.20. arm_target_feature
    21. 2.21. associated_type_bounds
    22. 2.22. associated_type_defaults
    23. 2.23. async_closure
    24. 2.24. auto_traits
    25. 2.25. avx512_target_feature
    26. 2.26. bindings_after_at
    27. 2.27. box_patterns
    28. 2.28. box_syntax
    29. 2.29. c_unwind
    30. 2.30. c_variadic
    31. 2.31. capture_disjoint_fields
    32. 2.32. cfg_panic
    33. 2.33. cfg_sanitize
    34. 2.34. cfg_target_has_atomic
    35. 2.35. cfg_target_thread_local
    36. 2.36. cfg_version
    37. 2.37. cmpxchg16b_target_feature
    38. 2.38. cmse_nonsecure_entry
    39. 2.39. compiler_builtins
    40. 2.40. const_eval_limit
    41. 2.41. const_evaluatable_checked
    42. 2.42. const_extern_fn
    43. 2.43. const_fn
    44. 2.44. const_fn_floating_point_arithmetic
    45. 2.45. const_fn_fn_ptr_basics
    46. 2.46. const_fn_trait_bound
    47. 2.47. const_fn_transmute
    48. 2.48. const_fn_union
    49. 2.49. const_fn_unsize
    50. 2.50. const_generics
    51. 2.51. const_generics_defaults
    52. 2.52. const_impl_trait
    53. 2.53. const_mut_refs
    54. 2.54. const_panic
    55. 2.55. const_precise_live_drops
    56. 2.56. const_raw_ptr_deref
    57. 2.57. const_raw_ptr_to_usize_cast
    58. 2.58. const_refs_to_cell
    59. 2.59. const_trait_bound_opt_out
    60. 2.60. const_trait_impl
    61. 2.61. crate_visibility_modifier
    62. 2.62. custom_inner_attributes
    63. 2.63. custom_test_frameworks
    64. 2.64. decl_macro
    65. 2.65. default_alloc_error_handler
    66. 2.66. default_type_parameter_fallback
    67. 2.67. destructuring_assignment
    68. 2.68. doc_cfg
    69. 2.69. doc_keyword
    70. 2.70. doc_masked
    71. 2.71. doc_notable_trait
    72. 2.72. dropck_eyepatch
    73. 2.73. ermsb_target_feature
    74. 2.74. exclusive_range_pattern
    75. 2.75. exhaustive_patterns
    76. 2.76. extended_key_value_attributes
    77. 2.77. extern_types
    78. 2.78. external_doc
    79. 2.79. f16c_target_feature
    80. 2.80. ffi_const
    81. 2.81. ffi_pure
    82. 2.82. ffi_returns_twice
    83. 2.83. format_args_capture
    84. 2.84. fundamental
    85. 2.85. generators
    86. 2.86. generic_associated_types
    87. 2.87. half_open_range_patterns
    88. 2.88. hexagon_target_feature
    89. 2.89. if_let_guard
    90. 2.90. impl_trait_in_bindings
    91. 2.91. imported_main
    92. 2.92. in_band_lifetimes
    93. 2.93. infer_static_outlives_requirements
    94. 2.94. inherent_associated_types
    95. 2.95. inline_const
    96. 2.96. intra_doc_pointers
    97. 2.97. intrinsics
    98. 2.98. isa_attribute
    99. 2.99. label_break_value
    100. 2.100. lang_items
    101. 2.101. large_assignments
    102. 2.102. lazy_normalization_consts
    103. 2.103. let_chains
    104. 2.104. link_cfg
    105. 2.105. link_llvm_intrinsics
    106. 2.106. linkage
    107. 2.107. lint_reasons
    108. 2.108. macro_attributes_in_derive_output
    109. 2.109. marker_trait_attr
    110. 2.110. member_constraints
    111. 2.111. min_specialization
    112. 2.112. min_type_alias_impl_trait
    113. 2.113. mips_target_feature
    114. 2.114. movbe_target_feature
    115. 2.115. naked_functions
    116. 2.116. needs_panic_runtime
    117. 2.117. negative_impls
    118. 2.118. never_type
    119. 2.119. never_type_fallback
    120. 2.120. nll
    121. 2.121. no_core
    122. 2.122. no_coverage
    123. 2.123. no_niche
    124. 2.124. no_sanitize
    125. 2.125. object_safe_for_dispatch
    126. 2.126. omit_gdb_pretty_printer_section
    127. 2.127. optimize_attribute
    128. 2.128. panic_runtime
    129. 2.129. platform_intrinsics
    130. 2.130. plugin
    131. 2.131. plugin_registrar
    132. 2.132. powerpc_target_feature
    133. 2.133. precise_pointer_size_matching
    134. 2.134. prelude_import
    135. 2.135. proc_macro_hygiene
    136. 2.136. profiler_runtime
    137. 2.137. raw_dylib
    138. 2.138. raw_ref_op
    139. 2.139. register_attr
    140. 2.140. register_tool
    141. 2.141. relaxed_struct_unsize
    142. 2.142. repr_simd
    143. 2.143. repr128
    144. 2.144. riscv_target_feature
    145. 2.145. rtm_target_feature
    146. 2.146. rustc_allow_const_fn_unstable
    147. 2.147. rustc_attrs
    148. 2.148. rustc_private
    149. 2.149. simd_ffi
    150. 2.150. specialization
    151. 2.151. sse4a_target_feature
    152. 2.152. staged_api
    153. 2.153. start
    154. 2.154. static_nobundle
    155. 2.155. stmt_expr_attributes
    156. 2.156. structural_match
    157. 2.157. target_feature_11
    158. 2.158. tbm_target_feature
    159. 2.159. test_2018_feature
    160. 2.160. thread_local
    161. 2.161. trait_alias
    162. 2.162. transparent_unions
    163. 2.163. trivial_bounds
    164. 2.164. try_blocks
    165. 2.165. type_alias_impl_trait
    166. 2.166. type_ascription
    167. 2.167. unboxed_closures
    168. 2.168. unsized_fn_params
    169. 2.169. unsized_locals
    170. 2.170. unsized_tuple_coercion
    171. 2.171. untagged_unions
    172. 2.172. unwind_attributes
    173. 2.173. wasm_abi
    174. 2.174. wasm_target_feature
  4. 3. Library Features
    1. 3.1. alloc_error_hook
    2. 3.2. alloc_internals
    3. 3.3. alloc_layout_extra
    4. 3.4. alloc_prelude
    5. 3.5. allocator_api
    6. 3.6. arc_new_cyclic
    7. 3.7. array_chunks
    8. 3.8. array_error_internals
    9. 3.9. array_map
    10. 3.10. array_methods
    11. 3.11. array_windows
    12. 3.12. array_zip
    13. 3.13. asm
    14. 3.14. async_stream
    15. 3.15. atomic_from_mut
    16. 3.16. atomic_mut_ptr
    17. 3.17. available_concurrency
    18. 3.18. backtrace
    19. 3.19. backtrace_frames
    20. 3.20. bench_black_box
    21. 3.21. binary_heap_as_slice
    22. 3.22. binary_heap_drain_sorted
    23. 3.23. binary_heap_into_iter_sorted
    24. 3.24. binary_heap_retain
    25. 3.25. bool_to_option
    26. 3.26. bound_as_ref
    27. 3.27. bound_cloned
    28. 3.28. box_into_boxed_slice
    29. 3.29. box_into_inner
    30. 3.30. box_into_pin
    31. 3.31. btree_drain_filter
    32. 3.32. bufwriter_into_raw_parts
    33. 3.33. c_void_variant
    34. 3.34. can_vector
    35. 3.35. cell_filter_map
    36. 3.36. cell_leak
    37. 3.37. cell_update
    38. 3.38. cfg_accessible
    39. 3.39. cfg_eval
    40. 3.40. char_error_internals
    41. 3.41. char_indices_offset
    42. 3.42. char_internals
    43. 3.43. coerce_unsized
    44. 3.44. command_access
    45. 3.45. concat_idents
    46. 3.46. const_align_of_val
    47. 3.47. const_align_of_val_raw
    48. 3.48. const_alloc_layout
    49. 3.49. const_assert_type
    50. 3.50. const_assume
    51. 3.51. const_btree_new
    52. 3.52. const_caller_location
    53. 3.53. const_cell_into_inner
    54. 3.54. const_cow_is_borrowed
    55. 3.55. const_cstr_unchecked
    56. 3.56. const_discriminant
    57. 3.57. const_float_bits_conv
    58. 3.58. const_float_classify
    59. 3.59. const_heap
    60. 3.60. const_int_unchecked_arith
    61. 3.61. const_intrinsic_copy
    62. 3.62. const_intrinsic_forget
    63. 3.63. const_io_structs
    64. 3.64. const_ip
    65. 3.65. const_ipv4
    66. 3.66. const_ipv6
    67. 3.67. const_likely
    68. 3.68. const_maybe_uninit_as_ptr
    69. 3.69. const_maybe_uninit_assume_init
    70. 3.70. const_nonnull_slice_from_raw_parts
    71. 3.71. const_option
    72. 3.72. const_pin
    73. 3.73. const_pref_align_of
    74. 3.74. const_ptr_is_null
    75. 3.75. const_ptr_offset
    76. 3.76. const_ptr_offset_from
    77. 3.77. const_ptr_read
    78. 3.78. const_ptr_write
    79. 3.79. const_raw_ptr_comparison
    80. 3.80. const_result
    81. 3.81. const_size_of_val
    82. 3.82. const_size_of_val_raw
    83. 3.83. const_slice_first_last
    84. 3.84. const_slice_from_raw_parts
    85. 3.85. const_slice_ptr_len
    86. 3.86. const_socketaddr
    87. 3.87. const_str_from_utf8_unchecked
    88. 3.88. const_swap
    89. 3.89. const_transmute_copy
    90. 3.90. const_type_id
    91. 3.91. const_type_name
    92. 3.92. const_unreachable_unchecked
    93. 3.93. container_error_extra
    94. 3.94. control_flow_enum
    95. 3.95. convert_float_to_int
    96. 3.96. core_intrinsics
    97. 3.97. core_panic
    98. 3.98. core_private_bignum
    99. 3.99. core_private_diy_float
    100. 3.100. cow_is_borrowed
    101. 3.101. cstring_from_vec_with_nul
    102. 3.102. deadline_api
    103. 3.103. dec2flt
    104. 3.104. default_free_fn
    105. 3.105. derive_clone_copy
    106. 3.106. derive_eq
    107. 3.107. discriminant_kind
    108. 3.108. dispatch_from_dyn
    109. 3.109. div_duration
    110. 3.110. drain_filter
    111. 3.111. duration_constants
    112. 3.112. duration_consts_2
    113. 3.113. edition_panic
    114. 3.114. entry_insert
    115. 3.115. error_iter
    116. 3.116. error_type_id
    117. 3.117. exact_size_is_empty
    118. 3.118. extend_one
    119. 3.119. fd
    120. 3.120. fd_read
    121. 3.121. flt2dec
    122. 3.122. fmt_internals
    123. 3.123. fn_traits
    124. 3.124. forget_unsized
    125. 3.125. format_args_nl
    126. 3.126. future_poll_fn
    127. 3.127. gen_future
    128. 3.128. generator_trait
    129. 3.129. get_mut_unchecked
    130. 3.130. global_asm
    131. 3.131. hash_drain_filter
    132. 3.132. hash_raw_entry
    133. 3.133. hash_set_entry
    134. 3.134. hashmap_internals
    135. 3.135. inherent_ascii_escape
    136. 3.136. inplace_iteration
    137. 3.137. int_error_internals
    138. 3.138. int_error_matching
    139. 3.139. integer_atomics
    140. 3.140. internal_output_capture
    141. 3.141. into_future
    142. 3.142. io_into_inner_error_parts
    143. 3.143. io_read_to_string
    144. 3.144. io_slice_advance
    145. 3.145. ip
    146. 3.146. is_sorted
    147. 3.147. iter_advance_by
    148. 3.148. iter_intersperse
    149. 3.149. iter_is_partitioned
    150. 3.150. iter_map_while
    151. 3.151. iter_order_by
    152. 3.152. iter_partition_in_place
    153. 3.153. iter_zip
    154. 3.154. layout_for_ptr
    155. 3.155. liballoc_internals
    156. 3.156. libstd_sys_internals
    157. 3.157. libstd_thread_internals
    158. 3.158. linked_list_cursors
    159. 3.159. linked_list_prepend
    160. 3.160. linked_list_remove
    161. 3.161. llvm_asm
    162. 3.162. log_syntax
    163. 3.163. map_entry_replace
    164. 3.164. map_first_last
    165. 3.165. map_into_keys_values
    166. 3.166. map_try_insert
    167. 3.167. maybe_uninit_array_assume_init
    168. 3.168. maybe_uninit_extra
    169. 3.169. maybe_uninit_ref
    170. 3.170. maybe_uninit_slice
    171. 3.171. maybe_uninit_uninit_array
    172. 3.172. maybe_uninit_write_slice
    173. 3.173. mutex_unlock
    174. 3.174. new_uninit
    175. 3.175. nonnull_slice_from_raw_parts
    176. 3.176. nonzero_is_power_of_two
    177. 3.177. num_as_ne_bytes
    178. 3.178. once_cell
    179. 3.179. option_get_or_insert_default
    180. 3.180. option_result_contains
    181. 3.181. option_result_unwrap_unchecked
    182. 3.182. option_zip
    183. 3.183. panic_abort
    184. 3.184. panic_info_message
    185. 3.185. panic_internals
    186. 3.186. panic_unwind
    187. 3.187. path_try_exists
    188. 3.188. pattern
    189. 3.189. peer_credentials_unix_socket
    190. 3.190. pin_static_ref
    191. 3.191. prelude_2015
    192. 3.192. prelude_2018
    193. 3.193. prelude_2021
    194. 3.194. print_internals
    195. 3.195. proc_macro_def_site
    196. 3.196. proc_macro_diagnostic
    197. 3.197. proc_macro_internals
    198. 3.198. proc_macro_is_available
    199. 3.199. proc_macro_quote
    200. 3.200. proc_macro_span
    201. 3.201. proc_macro_tracked_env
    202. 3.202. process_exitcode_placeholder
    203. 3.203. process_internals
    204. 3.204. profiler_runtime_lib
    205. 3.205. ptr_as_uninit
    206. 3.206. ptr_internals
    207. 3.207. ptr_metadata
    208. 3.208. raw
    209. 3.209. raw_os_nonzero
    210. 3.210. raw_vec_internals
    211. 3.211. read_initializer
    212. 3.212. ready_macro
    213. 3.213. receiver_trait
    214. 3.214. restricted_std
    215. 3.215. result_cloned
    216. 3.216. result_contains_err
    217. 3.217. result_copied
    218. 3.218. result_flattening
    219. 3.219. result_into_ok_or_err
    220. 3.220. rt
    221. 3.221. sealed
    222. 3.222. seek_stream_len
    223. 3.223. set_ptr_value
    224. 3.224. setgroups
    225. 3.225. sgx_platform
    226. 3.226. shrink_to
    227. 3.227. slice_as_chunks
    228. 3.228. slice_concat_ext
    229. 3.229. slice_concat_trait
    230. 3.230. slice_group_by
    231. 3.231. slice_index_methods
    232. 3.232. slice_internals
    233. 3.233. slice_partition_at_index
    234. 3.234. slice_partition_dedup
    235. 3.235. slice_pattern
    236. 3.236. slice_ptr_get
    237. 3.237. slice_ptr_len
    238. 3.238. slice_range
    239. 3.239. slice_split_at_unchecked
    240. 3.240. sort_internals
    241. 3.241. std_internals
    242. 3.242. stdsimd
    243. 3.243. step_trait
    244. 3.244. step_trait_ext
    245. 3.245. str_internals
    246. 3.246. str_split_as_str
    247. 3.247. str_split_inclusive_as_str
    248. 3.248. str_split_whitespace_as_str
    249. 3.249. string_drain_as_str
    250. 3.250. string_remove_matches
    251. 3.251. termination_trait_lib
    252. 3.252. test
    253. 3.253. thread_id_value
    254. 3.254. thread_local_const_init
    255. 3.255. thread_local_internals
    256. 3.256. thread_spawn_unchecked
    257. 3.257. toowned_clone_into
    258. 3.258. total_cmp
    259. 3.259. trace_macros
    260. 3.260. trusted_len
    261. 3.261. trusted_random_access
    262. 3.262. try_find
    263. 3.263. try_reserve
    264. 3.264. try_trait
    265. 3.265. try_trait_transition
    266. 3.266. try_trait_v2
    267. 3.267. type_name_of_val
    268. 3.268. unchecked_math
    269. 3.269. unicode_internals
    270. 3.270. unix_chroot
    271. 3.271. unix_process_wait_more
    272. 3.272. unix_socket_ancillary_data
    273. 3.273. unix_socket_peek
    274. 3.274. unsafe_cell_raw_get
    275. 3.275. unsize
    276. 3.276. unwrap_infallible
    277. 3.277. update_panic_count
    278. 3.278. variant_count
    279. 3.279. vec_into_raw_parts
    280. 3.280. vec_spare_capacity
    281. 3.281. vec_split_at_spare
    282. 3.282. vecdeque_binary_search
    283. 3.283. wasi_ext
    284. 3.284. windows_by_handle
    285. 3.285. windows_c
    286. 3.286. windows_file_type_ext
    287. 3.287. windows_handle
    288. 3.288. windows_net
    289. 3.289. windows_process_extensions_force_quotes
    290. 3.290. windows_stdio
    291. 3.291. with_options
    292. 3.292. wrapping_int_impl
    293. 3.293. wrapping_next_power_of_two
    294. 3.294. write_all_vectored

The Rust Unstable Book

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