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

The Rust Unstable Book

Language features