The Unstable Book
1.
Compiler flags
1.1.
branch_protection
1.2.
cf_protection
1.3.
check_cfg
1.4.
codegen_backend
1.5.
control_flow_guard
1.6.
debug_info_for_profiling
1.7.
dwarf_version
1.8.
emit_stack_sizes
1.9.
extern_options
1.10.
location_detail
1.11.
move_size_limit
1.12.
no_unique_section_names
1.13.
profile
1.14.
profile_sample_use
1.15.
remap_cwd_prefix
1.16.
report_time
1.17.
sanitizer
1.18.
self_profile
1.19.
self_profile_events
1.20.
src_hash_algorithm
1.21.
temps_dir
1.22.
tls_model
1.23.
unsound_mir_opts
1.24.
virtual_function_elimination
2.
Language features
2.1.
aarch64_ver_target_feature
2.2.
abi_amdgpu_kernel
2.3.
abi_avr_interrupt
2.4.
abi_c_cmse_nonsecure_call
2.5.
abi_efiapi
2.6.
abi_msp430_interrupt
2.7.
abi_ptx
2.8.
abi_thiscall
2.9.
abi_unadjusted
2.10.
abi_vectorcall
2.11.
abi_x86_interrupt
2.12.
adt_const_params
2.13.
alloc_error_handler
2.14.
allocator_internals
2.15.
allow_internal_unsafe
2.16.
allow_internal_unstable
2.17.
anonymous_lifetime_in_impl_trait
2.18.
arbitrary_enum_discriminant
2.19.
arbitrary_self_types
2.20.
arm_target_feature
2.21.
asm_const
2.22.
asm_experimental_arch
2.23.
asm_sym
2.24.
asm_unwind
2.25.
associated_const_equality
2.26.
associated_type_bounds
2.27.
associated_type_defaults
2.28.
async_closure
2.29.
async_fn_in_trait
2.30.
auto_traits
2.31.
avx512_target_feature
2.32.
box_patterns
2.33.
box_syntax
2.34.
bpf_target_feature
2.35.
c_unwind
2.36.
c_variadic
2.37.
capture_disjoint_fields
2.38.
cfg_sanitize
2.39.
cfg_target_abi
2.40.
cfg_target_compact
2.41.
cfg_target_has_atomic
2.42.
cfg_target_has_atomic_equal_alignment
2.43.
cfg_target_thread_local
2.44.
cfg_version
2.45.
closure_lifetime_binder
2.46.
closure_track_caller
2.47.
cmpxchg16b_target_feature
2.48.
cmse_nonsecure_entry
2.49.
collapse_debuginfo
2.50.
compiler_builtins
2.51.
const_async_blocks
2.52.
const_eval_limit
2.53.
const_extern_fn
2.54.
const_fn_floating_point_arithmetic
2.55.
const_for
2.56.
const_mut_refs
2.57.
const_precise_live_drops
2.58.
const_refs_to_cell
2.59.
const_trait_impl
2.60.
const_try
2.61.
custom_inner_attributes
2.62.
custom_test_frameworks
2.63.
debugger_visualizer
2.64.
decl_macro
2.65.
default_alloc_error_handler
2.66.
default_type_parameter_fallback
2.67.
deprecated_safe
2.68.
deprecated_suggestion
2.69.
doc_auto_cfg
2.70.
doc_cfg
2.71.
doc_cfg_hide
2.72.
doc_masked
2.73.
doc_notable_trait
2.74.
dropck_eyepatch
2.75.
dyn_star
2.76.
ermsb_target_feature
2.77.
exclusive_range_pattern
2.78.
exhaustive_patterns
2.79.
extern_types
2.80.
f16c_target_feature
2.81.
ffi_const
2.82.
ffi_pure
2.83.
ffi_returns_twice
2.84.
fn_align
2.85.
fundamental
2.86.
generator_clone
2.87.
generators
2.88.
generic_arg_infer
2.89.
generic_assert
2.90.
generic_associated_types_extended
2.91.
generic_const_exprs
2.92.
half_open_range_patterns
2.93.
hexagon_target_feature
2.94.
if_let_guard
2.95.
imported_main
2.96.
inherent_associated_types
2.97.
inline_const
2.98.
inline_const_pat
2.99.
intra_doc_pointers
2.100.
intrinsics
2.101.
isa_attribute
2.102.
lang_items
2.103.
large_assignments
2.104.
let_chains
2.105.
link_cfg
2.106.
link_llvm_intrinsics
2.107.
linkage
2.108.
lint_reasons
2.109.
macro_metavar_expr
2.110.
marker_trait_attr
2.111.
min_specialization
2.112.
mips_target_feature
2.113.
more_qualified_paths
2.114.
movbe_target_feature
2.115.
must_not_suspend
2.116.
naked_functions
2.117.
native_link_modifiers_as_needed
2.118.
native_link_modifiers_verbatim
2.119.
needs_panic_runtime
2.120.
negative_impls
2.121.
never_type
2.122.
never_type_fallback
2.123.
no_core
2.124.
no_coverage
2.125.
no_sanitize
2.126.
non_exhaustive_omitted_patterns_lint
2.127.
object_safe_for_dispatch
2.128.
omit_gdb_pretty_printer_section
2.129.
optimize_attribute
2.130.
panic_runtime
2.131.
platform_intrinsics
2.132.
plugin
2.133.
powerpc_target_feature
2.134.
precise_pointer_size_matching
2.135.
prelude_import
2.136.
proc_macro_hygiene
2.137.
profiler_runtime
2.138.
raw_dylib
2.139.
raw_ref_op
2.140.
register_tool
2.141.
repr_simd
2.142.
repr128
2.143.
return_position_impl_trait_in_trait
2.144.
riscv_target_feature
2.145.
rtm_target_feature
2.146.
rust_cold_cc
2.147.
rustc_allow_const_fn_unstable
2.148.
rustc_attrs
2.149.
rustc_private
2.150.
rustdoc_internals
2.151.
rustdoc_missing_doc_code_examples
2.152.
simd_ffi
2.153.
specialization
2.154.
sse4a_target_feature
2.155.
staged_api
2.156.
start
2.157.
stmt_expr_attributes
2.158.
strict_provenance
2.159.
structural_match
2.160.
target_feature_11
2.161.
tbm_target_feature
2.162.
test_2018_feature
2.163.
test_unstable_lint
2.164.
thread_local
2.165.
trait_alias
2.166.
trait_upcasting
2.167.
transparent_unions
2.168.
trivial_bounds
2.169.
try_blocks
2.170.
type_alias_impl_trait
2.171.
type_ascription
2.172.
type_changing_struct_update
2.173.
unboxed_closures
2.174.
unix_sigpipe
2.175.
unsafe_pin_internals
2.176.
unsized_fn_params
2.177.
unsized_locals
2.178.
unsized_tuple_coercion
2.179.
used_with_arg
2.180.
wasm_abi
2.181.
wasm_target_feature
2.182.
with_negative_coherence
2.183.
yeet_expr
3.
Library Features
3.1.
absolute_path
3.2.
addr_parse_ascii
3.3.
alloc_error_hook
3.4.
alloc_internals
3.5.
alloc_layout_extra
3.6.
allocator_api
3.7.
arc_unwrap_or_clone
3.8.
array_chunks
3.9.
array_error_internals
3.10.
array_into_iter_constructors
3.11.
array_methods
3.12.
array_try_from_fn
3.13.
array_try_map
3.14.
array_windows
3.15.
array_zip
3.16.
as_array_of_cells
3.17.
assert_matches
3.18.
async_iter_from_iter
3.19.
async_iterator
3.20.
atomic_bool_fetch_not
3.21.
atomic_from_mut
3.22.
atomic_mut_ptr
3.23.
backtrace_frames
3.24.
bigint_helper_methods
3.25.
binary_heap_as_slice
3.26.
binary_heap_drain_sorted
3.27.
binary_heap_into_iter_sorted
3.28.
binary_heap_retain
3.29.
bound_as_ref
3.30.
bound_map
3.31.
box_into_boxed_slice
3.32.
box_into_inner
3.33.
btree_drain_filter
3.34.
btreemap_alloc
3.35.
buf_read_has_data_left
3.36.
build_hasher_simple_hash_one
3.37.
byte_slice_trim_ascii
3.38.
c_size_t
3.39.
c_void_variant
3.40.
can_vector
3.41.
cell_leak
3.42.
cell_update
3.43.
cfg_accessible
3.44.
cfg_eval
3.45.
char_error_internals
3.46.
char_indices_offset
3.47.
char_internals
3.48.
coerce_unsized
3.49.
concat_bytes
3.50.
concat_idents
3.51.
const_align_of_val
3.52.
const_align_of_val_raw
3.53.
const_align_offset
3.54.
const_alloc_error
3.55.
const_alloc_layout
3.56.
const_arguments_as_str
3.57.
const_array_from_ref
3.58.
const_array_into_iter_constructors
3.59.
const_assert_type2
3.60.
const_assume
3.61.
const_bigint_helper_methods
3.62.
const_black_box
3.63.
const_bool_to_option
3.64.
const_borrow
3.65.
const_box
3.66.
const_btree_len
3.67.
const_caller_location
3.68.
const_cell_into_inner
3.69.
const_char_convert
3.70.
const_clone
3.71.
const_cmp
3.72.
const_convert
3.73.
const_cow_is_borrowed
3.74.
const_cstr_methods
3.75.
const_default_impls
3.76.
const_deref
3.77.
const_discriminant
3.78.
const_eval_select
3.79.
const_float_bits_conv
3.80.
const_float_classify
3.81.
const_fmt_arguments_new
3.82.
const_fn_trait_ref_impls
3.83.
const_format_args
3.84.
const_heap
3.85.
const_index_range_slice_index
3.86.
const_inherent_unchecked_arith
3.87.
const_int_unchecked_arith
3.88.
const_intoiterator_identity
3.89.
const_intrinsic_forget
3.90.
const_intrinsic_raw_eq
3.91.
const_io_structs
3.92.
const_ip
3.93.
const_ipv4
3.94.
const_ipv6
3.95.
const_is_char_boundary
3.96.
const_likely
3.97.
const_maybe_uninit_array_assume_init
3.98.
const_maybe_uninit_as_mut_ptr
3.99.
const_maybe_uninit_assume_init
3.100.
const_maybe_uninit_assume_init_read
3.101.
const_maybe_uninit_uninit_array
3.102.
const_maybe_uninit_write
3.103.
const_maybe_uninit_zeroed
3.104.
const_nonnull_new
3.105.
const_nonnull_slice_from_raw_parts
3.106.
const_num_from_num
3.107.
const_ops
3.108.
const_option
3.109.
const_option_cloned
3.110.
const_option_ext
3.111.
const_pin
3.112.
const_pointer_byte_offsets
3.113.
const_pref_align_of
3.114.
const_ptr_as_ref
3.115.
const_ptr_is_null
3.116.
const_ptr_read
3.117.
const_ptr_sub_ptr
3.118.
const_ptr_write
3.119.
const_raw_ptr_comparison
3.120.
const_replace
3.121.
const_result
3.122.
const_result_drop
3.123.
const_reverse
3.124.
const_size_of_val
3.125.
const_size_of_val_raw
3.126.
const_slice_first_last
3.127.
const_slice_from_mut_ptr_range
3.128.
const_slice_from_ptr_range
3.129.
const_slice_from_raw_parts_mut
3.130.
const_slice_from_ref
3.131.
const_slice_index
3.132.
const_slice_ptr_len
3.133.
const_slice_split_at_mut
3.134.
const_slice_split_at_not_mut
3.135.
const_socketaddr
3.136.
const_str_from_utf8
3.137.
const_str_from_utf8_unchecked_mut
3.138.
const_swap
3.139.
const_transmute_copy
3.140.
const_type_id
3.141.
const_type_name
3.142.
const_unicode_case_lookup
3.143.
const_unsafecell_get_mut
3.144.
const_waker
3.145.
const_weak_new
3.146.
container_error_extra
3.147.
control_flow_enum
3.148.
convert_float_to_int
3.149.
core_intrinsics
3.150.
core_panic
3.151.
core_private_bignum
3.152.
core_private_diy_float
3.153.
cow_is_borrowed
3.154.
cstr_from_bytes_until_nul
3.155.
cstr_internals
3.156.
cursor_remaining
3.157.
deadline_api
3.158.
dec2flt
3.159.
default_free_fn
3.160.
derive_clone_copy
3.161.
derive_eq
3.162.
dir_entry_ext2
3.163.
discriminant_kind
3.164.
dispatch_from_dyn
3.165.
div_duration
3.166.
downcast_unchecked
3.167.
drain_filter
3.168.
drain_keep_rest
3.169.
duration_checked_float
3.170.
duration_constants
3.171.
duration_consts_float
3.172.
edition_panic
3.173.
entry_insert
3.174.
error_generic_member_access
3.175.
error_in_core
3.176.
error_iter
3.177.
error_reporter
3.178.
error_type_id
3.179.
exact_size_is_empty
3.180.
exclusive_wrapper
3.181.
exit_status_error
3.182.
exitcode_exit_method
3.183.
extend_one
3.184.
fd
3.185.
fd_read
3.186.
file_create_new
3.187.
file_set_times
3.188.
float_minimum_maximum
3.189.
float_next_up_down
3.190.
flt2dec
3.191.
fmt_helpers_for_derive
3.192.
fmt_internals
3.193.
fn_traits
3.194.
forget_unsized
3.195.
format_args_nl
3.196.
fs_try_exists
3.197.
future_join
3.198.
gen_future
3.199.
generator_trait
3.200.
generic_assert_internals
3.201.
get_mut_unchecked
3.202.
hash_drain_filter
3.203.
hash_raw_entry
3.204.
hash_set_entry
3.205.
hasher_prefixfree_extras
3.206.
hashmap_internals
3.207.
hint_must_use
3.208.
inplace_iteration
3.209.
int_error_internals
3.210.
int_log
3.211.
int_roundings
3.212.
integer_atomics
3.213.
internal_output_capture
3.214.
io_error_downcast
3.215.
io_error_more
3.216.
io_error_other
3.217.
io_error_uncategorized
3.218.
io_slice_advance
3.219.
ip
3.220.
is_some_with
3.221.
is_sorted
3.222.
iter_advance_by
3.223.
iter_array_chunks
3.224.
iter_collect_into
3.225.
iter_from_generator
3.226.
iter_intersperse
3.227.
iter_is_partitioned
3.228.
iter_next_chunk
3.229.
iter_order_by
3.230.
iter_partition_in_place
3.231.
iterator_try_collect
3.232.
iterator_try_reduce
3.233.
layout_for_ptr
3.234.
liballoc_internals
3.235.
libstd_sys_internals
3.236.
libstd_thread_internals
3.237.
linked_list_cursors
3.238.
linked_list_remove
3.239.
linux_pidfd
3.240.
local_key_cell_methods
3.241.
log_syntax
3.242.
main_separator_str
3.243.
map_entry_replace
3.244.
map_first_last
3.245.
map_many_mut
3.246.
map_try_insert
3.247.
maybe_uninit_array_assume_init
3.248.
maybe_uninit_as_bytes
3.249.
maybe_uninit_slice
3.250.
maybe_uninit_uninit_array
3.251.
maybe_uninit_write_slice
3.252.
mem_copy_fn
3.253.
mutex_unlock
3.254.
mutex_unpoison
3.255.
new_uninit
3.256.
nonnull_slice_from_raw_parts
3.257.
nonzero_bits
3.258.
nonzero_min_max
3.259.
nonzero_negation_ops
3.260.
nonzero_ops
3.261.
numfmt
3.262.
once_cell
3.263.
one_sided_range
3.264.
option_get_or_insert_default
3.265.
option_result_contains
3.266.
option_zip
3.267.
os_fd
3.268.
panic_abort
3.269.
panic_always_abort
3.270.
panic_backtrace_config
3.271.
panic_can_unwind
3.272.
panic_info_message
3.273.
panic_internals
3.274.
panic_unwind
3.275.
panic_update_hook
3.276.
path_file_prefix
3.277.
pattern
3.278.
peer_credentials_unix_socket
3.279.
pin_deref_mut
3.280.
pin_macro
3.281.
pointer_byte_offsets
3.282.
pointer_is_aligned
3.283.
poll_ready
3.284.
portable_simd
3.285.
prelude_2024
3.286.
print_internals
3.287.
proc_macro_def_site
3.288.
proc_macro_diagnostic
3.289.
proc_macro_expand
3.290.
proc_macro_internals
3.291.
proc_macro_quote
3.292.
proc_macro_span
3.293.
proc_macro_span_shrink
3.294.
proc_macro_tracked_env
3.295.
process_exitcode_internals
3.296.
process_internals
3.297.
profiler_runtime_lib
3.298.
provide_any
3.299.
ptr_as_uninit
3.300.
ptr_internals
3.301.
ptr_mask
3.302.
ptr_metadata
3.303.
ptr_sub_ptr
3.304.
ptr_to_from_bits
3.305.
pub_crate_should_not_need_unstable_attr
3.306.
raw_os_nonzero
3.307.
raw_slice_split
3.308.
raw_vec_internals
3.309.
read_buf
3.310.
receiver_trait
3.311.
restricted_std
3.312.
result_contains_err
3.313.
result_flattening
3.314.
result_option_inspect
3.315.
round_char_boundary
3.316.
rt
3.317.
saturating_int_assign_impl
3.318.
saturating_int_impl
3.319.
sealed
3.320.
seek_stream_len
3.321.
set_ptr_value
3.322.
setgroups
3.323.
sgx_platform
3.324.
sized_type_properties
3.325.
slice_as_chunks
3.326.
slice_concat_ext
3.327.
slice_concat_trait
3.328.
slice_flatten
3.329.
slice_from_ptr_range
3.330.
slice_group_by
3.331.
slice_index_methods
3.332.
slice_internals
3.333.
slice_iter_mut_as_mut_slice
3.334.
slice_partition_dedup
3.335.
slice_pattern
3.336.
slice_ptr_get
3.337.
slice_ptr_len
3.338.
slice_range
3.339.
slice_split_at_unchecked
3.340.
slice_swap_unchecked
3.341.
slice_take
3.342.
solid_ext
3.343.
sort_floats
3.344.
sort_internals
3.345.
split_array
3.346.
split_as_slice
3.347.
std_internals
3.348.
stdio_makes_pipe
3.349.
stdsimd
3.350.
step_trait
3.351.
str_internals
3.352.
str_split_as_str
3.353.
str_split_inclusive_as_str
3.354.
str_split_whitespace_as_str
3.355.
strict_provenance_atomic_ptr
3.356.
string_extend_from_within
3.357.
string_remove_matches
3.358.
sync_unsafe_cell
3.359.
tcp_linger
3.360.
tcp_quickack
3.361.
tcplistener_into_incoming
3.362.
test
3.363.
thin_box
3.364.
thread_id_value
3.365.
thread_local_internals
3.366.
thread_spawn_unchecked
3.367.
trace_macros
3.368.
track_path
3.369.
transmutability
3.370.
trusted_len
3.371.
trusted_random_access
3.372.
trusted_step
3.373.
try_find
3.374.
try_reserve_kind
3.375.
try_trait_v2
3.376.
try_trait_v2_residual
3.377.
try_trait_v2_yeet
3.378.
tuple_trait
3.379.
type_name_of_val
3.380.
unchecked_math
3.381.
unicode_internals
3.382.
unix_chown
3.383.
unix_set_mark
3.384.
unix_socket_abstract
3.385.
unix_socket_ancillary_data
3.386.
unix_socket_peek
3.387.
unsize
3.388.
unwrap_infallible
3.389.
unzip_option
3.390.
update_panic_count
3.391.
utf16_extra
3.392.
utf16_extra_const
3.393.
utf8_chunks
3.394.
variant_count
3.395.
vec_into_raw_parts
3.396.
vec_split_at_spare
3.397.
waker_getters
3.398.
wasi_ext
3.399.
windows_by_handle
3.400.
windows_c
3.401.
windows_handle
3.402.
windows_net
3.403.
windows_process_exit_code_from
3.404.
windows_process_extensions_async_pipes
3.405.
windows_process_extensions_force_quotes
3.406.
windows_process_extensions_main_thread_handle
3.407.
windows_stdio
3.408.
wrapping_int_impl
3.409.
wrapping_next_power_of_two
3.410.
write_all_vectored
3.411.
yeet_desugar_details
Light (default)
Rust
Coal
Navy
Ayu
The Rust Unstable Book
const_btree_len
The tracking issue for this feature is:
#71835