The Unstable Book
1.
Compiler flags
1.1.
autodiff
1.2.
branch_protection
1.3.
cf_protection
1.4.
codegen_backend
1.5.
codegen_options
1.6.
control_flow_guard
1.7.
coverage_options
1.8.
debug_info_for_profiling
1.9.
debug_info_type_line_numbers
1.10.
default_visibility
1.11.
direct_access_external_data
1.12.
dump_mono_stats
1.13.
dump_mono_stats_format
1.14.
dwarf_version
1.15.
dylib_lto
1.16.
embed_source
1.17.
emit_stack_sizes
1.18.
emscripten_wasm_eh
1.19.
env_set
1.20.
export_executable_symbols
1.21.
extern_options
1.22.
external_clangrt
1.23.
fixed_x18
1.24.
fmt_debug
1.25.
function_return
1.26.
instrument_xray
1.27.
link_native_libraries
1.28.
linker_features
1.29.
lint_llvm_ir
1.30.
llvm_module_flag
1.31.
location_detail
1.32.
min_function_alignment
1.33.
move_size_limit
1.34.
no_jump_tables
1.35.
no_parallel_llvm
1.36.
no_unique_section_names
1.37.
on_broken_pipe
1.38.
patchable_function_entry
1.39.
print_check_cfg
1.40.
profile_sample_use
1.41.
randomize_layout
1.42.
reg_struct_return
1.43.
regparm
1.44.
remap_cwd_prefix
1.45.
remap_path_scope
1.46.
report_time
1.47.
sanitizer
1.48.
self_profile
1.49.
self_profile_events
1.50.
shell_argfiles
1.51.
small_data_threshold
1.52.
src_hash_algorithm
1.53.
temps_dir
1.54.
tiny_const_eval_limit
1.55.
tls_model
1.56.
ub_checks
1.57.
unsound_mir_opts
1.58.
verbose_asm
1.59.
virtual_function_elimination
1.60.
wasm_c_abi
2.
Language features
2.1.
aarch64_unstable_target_feature
2.2.
aarch64_ver_target_feature
2.3.
abi_avr_interrupt
2.4.
abi_c_cmse_nonsecure_call
2.5.
abi_gpu_kernel
2.6.
abi_msp430_interrupt
2.7.
abi_ptx
2.8.
abi_riscv_interrupt
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_self_types
2.19.
arbitrary_self_types_pointers
2.20.
arm_target_feature
2.21.
asm_experimental_arch
2.22.
asm_experimental_reg
2.23.
asm_goto
2.24.
asm_goto_with_outputs
2.25.
asm_unwind
2.26.
associated_const_equality
2.27.
associated_type_defaults
2.28.
async_fn_in_dyn_trait
2.29.
async_fn_track_caller
2.30.
async_for_loop
2.31.
async_trait_bounds
2.32.
auto_traits
2.33.
avx512_target_feature
2.34.
box_patterns
2.35.
bpf_target_feature
2.36.
builtin_syntax
2.37.
c_variadic
2.38.
cfg_boolean_literals
2.39.
cfg_contract_checks
2.40.
cfg_emscripten_wasm_eh
2.41.
cfg_overflow_checks
2.42.
cfg_relocation_model
2.43.
cfg_sanitize
2.44.
cfg_sanitizer_cfi
2.45.
cfg_target_compact
2.46.
cfg_target_has_atomic
2.47.
cfg_target_has_atomic_equal_alignment
2.48.
cfg_target_thread_local
2.49.
cfg_ub_checks
2.50.
cfg_version
2.51.
cfi_encoding
2.52.
closure_lifetime_binder
2.53.
closure_track_caller
2.54.
cmse_nonsecure_entry
2.55.
compiler_builtins
2.56.
const_async_blocks
2.57.
const_closures
2.58.
const_destruct
2.59.
const_for
2.60.
const_precise_live_drops
2.61.
const_trait_impl
2.62.
const_try
2.63.
contracts
2.64.
contracts_internals
2.65.
coroutine_clone
2.66.
coroutines
2.67.
coverage_attribute
2.68.
csky_target_feature
2.69.
custom_inner_attributes
2.70.
custom_mir
2.71.
custom_test_frameworks
2.72.
decl_macro
2.73.
default_field_values
2.74.
deprecated_safe
2.75.
deprecated_suggestion
2.76.
deref_patterns
2.77.
doc_auto_cfg
2.78.
doc_cfg
2.79.
doc_cfg_hide
2.80.
doc_masked
2.81.
doc_notable_trait
2.82.
dropck_eyepatch
2.83.
dyn_star
2.84.
ermsb_target_feature
2.85.
exhaustive_patterns
2.86.
explicit_tail_calls
2.87.
extended_varargs_abi_support
2.88.
extern_system_varargs
2.89.
extern_types
2.90.
f128
2.91.
f16
2.92.
ffi_const
2.93.
ffi_pure
2.94.
fmt_debug
2.95.
fn_align
2.96.
fn_delegation
2.97.
freeze_impls
2.98.
fundamental
2.99.
gen_blocks
2.100.
generic_arg_infer
2.101.
generic_assert
2.102.
generic_const_exprs
2.103.
generic_const_items
2.104.
generic_const_parameter_types
2.105.
generic_pattern_types
2.106.
global_registration
2.107.
guard_patterns
2.108.
half_open_range_patterns_in_slices
2.109.
hexagon_target_feature
2.110.
if_let_guard
2.111.
impl_trait_in_assoc_type
2.112.
impl_trait_in_bindings
2.113.
impl_trait_in_fn_trait_return
2.114.
import_trait_associated_functions
2.115.
inherent_associated_types
2.116.
inline_const_pat
2.117.
intra_doc_pointers
2.118.
intrinsics
2.119.
keylocker_x86
2.120.
lahfsahf_target_feature
2.121.
lang_items
2.122.
large_assignments
2.123.
lazy_type_alias
2.124.
let_chains
2.125.
link_arg_attribute
2.126.
link_cfg
2.127.
link_llvm_intrinsics
2.128.
linkage
2.129.
loongarch_target_feature
2.130.
m68k_target_feature
2.131.
macro_metavar_expr
2.132.
macro_metavar_expr_concat
2.133.
marker_trait_attr
2.134.
min_generic_const_args
2.135.
min_specialization
2.136.
mips_target_feature
2.137.
more_maybe_bounds
2.138.
more_qualified_paths
2.139.
multiple_supertrait_upcastable
2.140.
must_not_suspend
2.141.
mut_ref
2.142.
naked_functions
2.143.
native_link_modifiers_as_needed
2.144.
needs_panic_runtime
2.145.
negative_bounds
2.146.
negative_impls
2.147.
never_patterns
2.148.
never_type
2.149.
never_type_fallback
2.150.
new_range
2.151.
no_core
2.152.
no_sanitize
2.153.
non_exhaustive_omitted_patterns_lint
2.154.
non_lifetime_binders
2.155.
offset_of_enum
2.156.
offset_of_slice
2.157.
omit_gdb_pretty_printer_section
2.158.
optimize_attribute
2.159.
panic_runtime
2.160.
patchable_function_entry
2.161.
pattern_complexity_limit
2.162.
pattern_types
2.163.
pin_ergonomics
2.164.
postfix_match
2.165.
powerpc_target_feature
2.166.
precise_capturing_in_traits
2.167.
prelude_import
2.168.
prfchw_target_feature
2.169.
proc_macro_hygiene
2.170.
profiler_runtime
2.171.
ref_pat_eat_one_layer_2024
2.172.
ref_pat_eat_one_layer_2024_structural
2.173.
register_tool
2.174.
repr_simd
2.175.
repr128
2.176.
return_type_notation
2.177.
riscv_target_feature
2.178.
rtm_target_feature
2.179.
rust_cold_cc
2.180.
rustc_allow_const_fn_unstable
2.181.
rustc_attrs
2.182.
rustc_private
2.183.
rustdoc_internals
2.184.
rustdoc_missing_doc_code_examples
2.185.
s390x_target_feature
2.186.
sha512_sm_x86
2.187.
simd_ffi
2.188.
sparc_target_feature
2.189.
specialization
2.190.
sse4a_target_feature
2.191.
staged_api
2.192.
stmt_expr_attributes
2.193.
strict_provenance_lints
2.194.
string_deref_patterns
2.195.
structural_match
2.196.
supertrait_item_shadowing
2.197.
tbm_target_feature
2.198.
test_unstable_lint
2.199.
thread_local
2.200.
trait_alias
2.201.
transmute_generic_consts
2.202.
transparent_unions
2.203.
trivial_bounds
2.204.
try_blocks
2.205.
type_alias_impl_trait
2.206.
type_changing_struct_update
2.207.
unboxed_closures
2.208.
unqualified_local_imports
2.209.
unsafe_binders
2.210.
unsafe_fields
2.211.
unsized_const_params
2.212.
unsized_fn_params
2.213.
unsized_locals
2.214.
unsized_tuple_coercion
2.215.
used_with_arg
2.216.
wasm_target_feature
2.217.
where_clause_attrs
2.218.
with_negative_coherence
2.219.
x86_amx_intrinsics
2.220.
x87_target_feature
2.221.
xop_target_feature
2.222.
yeet_expr
3.
Library Features
3.1.
abort_unwind
3.2.
acceptfilter
3.3.
addr_parse_ascii
3.4.
alloc_error_hook
3.5.
alloc_internals
3.6.
alloc_layout_extra
3.7.
allocator_api
3.8.
anonymous_pipe
3.9.
array_chunks
3.10.
array_into_iter_constructors
3.11.
array_ptr_get
3.12.
array_repeat
3.13.
array_try_from_fn
3.14.
array_try_map
3.15.
array_windows
3.16.
as_array_of_cells
3.17.
ascii_char
3.18.
ascii_char_variants
3.19.
assert_matches
3.20.
async_drop
3.21.
async_fn_traits
3.22.
async_gen_internals
3.23.
async_iter_from_iter
3.24.
async_iterator
3.25.
atomic_from_mut
3.26.
atomic_try_update
3.27.
autodiff
3.28.
backtrace_frames
3.29.
bigint_helper_methods
3.30.
bikeshed_guaranteed_no_drop
3.31.
binary_heap_drain_sorted
3.32.
binary_heap_into_iter_sorted
3.33.
bound_as_ref
3.34.
box_as_ptr
3.35.
box_into_boxed_slice
3.36.
box_into_inner
3.37.
box_uninit_write
3.38.
box_vec_non_null
3.39.
breakpoint
3.40.
bstr
3.41.
bstr_internals
3.42.
btree_cursors
3.43.
btree_entry_insert
3.44.
btree_extract_if
3.45.
btree_set_entry
3.46.
btreemap_alloc
3.47.
buf_read_has_data_left
3.48.
bufreader_peek
3.49.
c_size_t
3.50.
c_str_module
3.51.
c_void_variant
3.52.
can_vector
3.53.
cell_leak
3.54.
cell_update
3.55.
cfg_accessible
3.56.
cfg_eval
3.57.
cfg_match
3.58.
char_internals
3.59.
char_max_len
3.60.
clone_to_uninit
3.61.
cmp_minmax
3.62.
coerce_pointee_validated
3.63.
coerce_unsized
3.64.
cold_path
3.65.
concat_bytes
3.66.
concat_idents
3.67.
const_alloc_error
3.68.
const_array_as_mut_slice
3.69.
const_array_each_ref
3.70.
const_box
3.71.
const_btree_len
3.72.
const_carrying_mul_add
3.73.
const_cell
3.74.
const_char_classify
3.75.
const_copy_from_slice
3.76.
const_deref
3.77.
const_eq_ignore_ascii_case
3.78.
const_eval_select
3.79.
const_format_args
3.80.
const_heap
3.81.
const_ops
3.82.
const_range_bounds
3.83.
const_raw_ptr_comparison
3.84.
const_slice_from_mut_ptr_range
3.85.
const_slice_from_ptr_range
3.86.
const_slice_reverse
3.87.
const_sockaddr_setters
3.88.
const_swap_nonoverlapping
3.89.
const_type_id
3.90.
const_type_name
3.91.
const_vec_string_slice
3.92.
container_error_extra
3.93.
context_ext
3.94.
control_flow_into_value
3.95.
convert_float_to_int
3.96.
core_intrinsics
3.97.
core_intrinsics_fallbacks
3.98.
core_io_borrowed_buf
3.99.
core_private_bignum
3.100.
core_private_diy_float
3.101.
coroutine_trait
3.102.
cow_is_borrowed
3.103.
cstr_bytes
3.104.
cstr_internals
3.105.
cursor_split
3.106.
deadline_api
3.107.
debug_closure_helpers
3.108.
dec2flt
3.109.
deref_pure_trait
3.110.
derive_clone_copy
3.111.
derive_coerce_pointee
3.112.
derive_const
3.113.
derive_eq
3.114.
dir_entry_ext2
3.115.
discriminant_kind
3.116.
disjoint_bitor
3.117.
dispatch_from_dyn
3.118.
downcast_unchecked
3.119.
drain_keep_rest
3.120.
duration_constants
3.121.
duration_constructors
3.122.
duration_millis_float
3.123.
duration_units
3.124.
edition_panic
3.125.
error_generic_member_access
3.126.
error_iter
3.127.
error_reporter
3.128.
error_type_id
3.129.
exact_size_is_empty
3.130.
exclusive_wrapper
3.131.
exit_status_error
3.132.
exitcode_exit_method
3.133.
extend_one
3.134.
extend_one_unchecked
3.135.
fd
3.136.
fd_read
3.137.
file_buffered
3.138.
float_erf
3.139.
float_gamma
3.140.
float_minimum_maximum
3.141.
flt2dec
3.142.
fmt_helpers_for_derive
3.143.
fmt_internals
3.144.
fn_ptr_trait
3.145.
fn_traits
3.146.
forget_unsized
3.147.
format_args_nl
3.148.
formatting_options
3.149.
freeze
3.150.
future_join
3.151.
gen_future
3.152.
generic_assert_internals
3.153.
get_disjoint_mut_helpers
3.154.
get_mut_unchecked
3.155.
hash_raw_entry
3.156.
hash_set_entry
3.157.
hasher_prefixfree_extras
3.158.
hashmap_internals
3.159.
hint_must_use
3.160.
inplace_iteration
3.161.
int_from_ascii
3.162.
int_roundings
3.163.
integer_atomics
3.164.
internal_impls_macro
3.165.
internal_output_capture
3.166.
io_const_error
3.167.
io_const_error_internals
3.168.
io_error_inprogress
3.169.
io_error_more
3.170.
io_error_uncategorized
3.171.
io_slice_as_bytes
3.172.
ip
3.173.
ip_as_octets
3.174.
ip_from
3.175.
is_ascii_octdigit
3.176.
is_loongarch_feature_detected
3.177.
is_riscv_feature_detected
3.178.
isolate_most_least_significant_one
3.179.
iter_advance_by
3.180.
iter_array_chunks
3.181.
iter_chain
3.182.
iter_collect_into
3.183.
iter_from_coroutine
3.184.
iter_intersperse
3.185.
iter_is_partitioned
3.186.
iter_map_windows
3.187.
iter_next_chunk
3.188.
iter_order_by
3.189.
iter_partition_in_place
3.190.
iterator_try_collect
3.191.
iterator_try_reduce
3.192.
junction_point
3.193.
layout_for_ptr
3.194.
lazy_cell_into_inner
3.195.
lazy_get
3.196.
legacy_receiver_trait
3.197.
liballoc_internals
3.198.
libstd_sys_internals
3.199.
likely_unlikely
3.200.
linked_list_cursors
3.201.
linked_list_remove
3.202.
linked_list_retain
3.203.
linux_pidfd
3.204.
local_waker
3.205.
lock_value_accessors
3.206.
log_syntax
3.207.
map_try_insert
3.208.
mapped_lock_guards
3.209.
maybe_uninit_array_assume_init
3.210.
maybe_uninit_as_bytes
3.211.
maybe_uninit_fill
3.212.
maybe_uninit_slice
3.213.
maybe_uninit_uninit_array_transpose
3.214.
maybe_uninit_write_slice
3.215.
mem_copy_fn
3.216.
mixed_integer_ops_unsigned_sub
3.217.
more_float_constants
3.218.
mpmc_channel
3.219.
new_range_api
3.220.
new_zeroed_alloc
3.221.
non_null_from_ref
3.222.
nonnull_provenance
3.223.
nonzero_bitwise
3.224.
nonzero_from_mut
3.225.
nonzero_internals
3.226.
nonzero_ops
3.227.
numfmt
3.228.
once_cell_get_mut
3.229.
once_cell_try
3.230.
once_cell_try_insert
3.231.
one_sided_range
3.232.
option_array_transpose
3.233.
option_zip
3.234.
os_str_slice
3.235.
os_string_pathbuf_leak
3.236.
os_string_truncate
3.237.
panic_abort
3.238.
panic_always_abort
3.239.
panic_backtrace_config
3.240.
panic_can_unwind
3.241.
panic_internals
3.242.
panic_payload_as_str
3.243.
panic_unwind
3.244.
panic_update_hook
3.245.
path_add_extension
3.246.
path_file_prefix
3.247.
pattern
3.248.
pattern_type_macro
3.249.
peer_credentials_unix_socket
3.250.
phantom_variance_markers
3.251.
pin_coerce_unsized_trait
3.252.
pointer_is_aligned_to
3.253.
pointer_like_trait
3.254.
portable_simd
3.255.
print_internals
3.256.
proc_macro_def_site
3.257.
proc_macro_diagnostic
3.258.
proc_macro_expand
3.259.
proc_macro_internals
3.260.
proc_macro_quote
3.261.
proc_macro_span
3.262.
proc_macro_totokens
3.263.
proc_macro_tracked_env
3.264.
process_exitcode_internals
3.265.
process_internals
3.266.
profiler_runtime_lib
3.267.
ptr_alignment_type
3.268.
ptr_as_ref_unchecked
3.269.
ptr_as_uninit
3.270.
ptr_internals
3.271.
ptr_mask
3.272.
ptr_metadata
3.273.
pub_crate_should_not_need_unstable_attr
3.274.
random
3.275.
range_bounds_is_empty
3.276.
range_into_bounds
3.277.
raw_os_error_ty
3.278.
raw_slice_split
3.279.
raw_vec_internals
3.280.
read_buf
3.281.
reentrant_lock
3.282.
restricted_std
3.283.
result_flattening
3.284.
round_char_boundary
3.285.
rt
3.286.
rwlock_downgrade
3.287.
sealed
3.288.
seek_stream_len
3.289.
select_unpredictable
3.290.
set_ptr_value
3.291.
setgroups
3.292.
sgx_platform
3.293.
sized_type_properties
3.294.
slice_as_array
3.295.
slice_as_chunks
3.296.
slice_concat_ext
3.297.
slice_concat_trait
3.298.
slice_from_ptr_range
3.299.
slice_index_methods
3.300.
slice_internals
3.301.
slice_iter_mut_as_mut_slice
3.302.
slice_partition_dedup
3.303.
slice_pattern
3.304.
slice_ptr_get
3.305.
slice_range
3.306.
slice_split_once
3.307.
slice_swap_unchecked
3.308.
slice_take
3.309.
solid_ext
3.310.
sort_floats
3.311.
split_array
3.312.
split_as_slice
3.313.
std_internals
3.314.
stdarch_arm_feature_detection
3.315.
stdarch_mips_feature_detection
3.316.
stdarch_powerpc_feature_detection
3.317.
stdio_makes_pipe
3.318.
step_trait
3.319.
str_as_str
3.320.
str_from_raw_parts
3.321.
str_from_utf16_endian
3.322.
str_internals
3.323.
str_lines_remainder
3.324.
str_split_inclusive_remainder
3.325.
str_split_remainder
3.326.
str_split_whitespace_remainder
3.327.
strict_overflow_ops
3.328.
strict_provenance_atomic_ptr
3.329.
string_extend_from_within
3.330.
string_from_utf8_lossy_owned
3.331.
string_into_chars
3.332.
string_remove_matches
3.333.
substr_range
3.334.
sync_poison_mod
3.335.
sync_unsafe_cell
3.336.
tcp_deferaccept
3.337.
tcp_linger
3.338.
tcp_quickack
3.339.
tcplistener_into_incoming
3.340.
temporary_niche_types
3.341.
test
3.342.
thin_box
3.343.
thread_id_value
3.344.
thread_local_internals
3.345.
thread_raw
3.346.
thread_sleep_until
3.347.
thread_spawn_hook
3.348.
trace_macros
3.349.
track_path
3.350.
transmutability
3.351.
trusted_fused
3.352.
trusted_len
3.353.
trusted_len_next_unchecked
3.354.
trusted_random_access
3.355.
trusted_step
3.356.
try_find
3.357.
try_reserve_kind
3.358.
try_trait_v2
3.359.
try_trait_v2_residual
3.360.
try_trait_v2_yeet
3.361.
try_with_capacity
3.362.
tuple_trait
3.363.
type_ascription
3.364.
ub_checks
3.365.
uefi_std
3.366.
unchecked_neg
3.367.
unchecked_shifts
3.368.
unicode_internals
3.369.
unique_rc_arc
3.370.
unix_file_vectored_at
3.371.
unix_set_mark
3.372.
unix_socket_ancillary_data
3.373.
unix_socket_peek
3.374.
unsafe_cell_access
3.375.
unsafe_pin_internals
3.376.
unsigned_nonzero_div_ceil
3.377.
unsigned_signed_diff
3.378.
unsize
3.379.
unwrap_infallible
3.380.
update_panic_count
3.381.
utf16_extra
3.382.
variant_count
3.383.
vec_deque_iter_as_slices
3.384.
vec_deque_pop_if
3.385.
vec_into_raw_parts
3.386.
vec_push_within_capacity
3.387.
vec_split_at_spare
3.388.
wasi_ext
3.389.
windows_by_handle
3.390.
windows_c
3.391.
windows_change_time
3.392.
windows_handle
3.393.
windows_net
3.394.
windows_process_exit_code_from
3.395.
windows_process_extensions_async_pipes
3.396.
windows_process_extensions_force_quotes
3.397.
windows_process_extensions_main_thread_handle
3.398.
windows_process_extensions_raw_attribute
3.399.
windows_process_extensions_show_window
3.400.
windows_stdio
3.401.
wrapping_int_impl
3.402.
wrapping_next_power_of_two
3.403.
write_all_vectored
3.404.
yeet_desugar_details
Light
Rust
Coal
Navy
Ayu
The Rust Unstable Book
char_max_len
The tracking issue for this feature is:
#121714