The Unstable Book
1.
Compiler flags
1.1.
codegen_backend
1.2.
control_flow_guard
1.3.
debug_info_for_profiling
1.4.
emit_stack_sizes
1.5.
extern_location
1.6.
instrument_coverage
1.7.
move_size_limit
1.8.
profile
1.9.
profile_sample_use
1.10.
remap_cwd_prefix
1.11.
report_time
1.12.
sanitizer
1.13.
self_profile
1.14.
self_profile_events
1.15.
source_based_code_coverage
1.16.
src_hash_algorithm
1.17.
strip
1.18.
tls_model
1.19.
unsound_mir_opts
2.
Language features
2.1.
aarch64_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.
adx_target_feature
2.14.
alloc_error_handler
2.15.
allocator_internals
2.16.
allow_fail
2.17.
allow_internal_unsafe
2.18.
allow_internal_unstable
2.19.
arbitrary_enum_discriminant
2.20.
arbitrary_self_types
2.21.
arm_target_feature
2.22.
associated_type_bounds
2.23.
associated_type_defaults
2.24.
async_closure
2.25.
auto_traits
2.26.
avx512_target_feature
2.27.
box_patterns
2.28.
box_syntax
2.29.
bpf_target_feature
2.30.
c_unwind
2.31.
c_variadic
2.32.
capture_disjoint_fields
2.33.
cfg_panic
2.34.
cfg_sanitize
2.35.
cfg_target_abi
2.36.
cfg_target_has_atomic
2.37.
cfg_target_thread_local
2.38.
cfg_version
2.39.
closure_track_caller
2.40.
cmpxchg16b_target_feature
2.41.
cmse_nonsecure_entry
2.42.
compiler_builtins
2.43.
const_async_blocks
2.44.
const_eval_limit
2.45.
const_extern_fn
2.46.
const_fn_floating_point_arithmetic
2.47.
const_fn_fn_ptr_basics
2.48.
const_fn_trait_bound
2.49.
const_for
2.50.
const_generics_defaults
2.51.
const_impl_trait
2.52.
const_mut_refs
2.53.
const_precise_live_drops
2.54.
const_raw_ptr_deref
2.55.
const_refs_to_cell
2.56.
const_trait_impl
2.57.
const_try
2.58.
crate_visibility_modifier
2.59.
custom_inner_attributes
2.60.
custom_test_frameworks
2.61.
decl_macro
2.62.
default_alloc_error_handler
2.63.
default_type_parameter_fallback
2.64.
derive_default_enum
2.65.
destructuring_assignment
2.66.
doc_auto_cfg
2.67.
doc_cfg
2.68.
doc_cfg_hide
2.69.
doc_keyword
2.70.
doc_masked
2.71.
doc_notable_trait
2.72.
doc_primitive
2.73.
dropck_eyepatch
2.74.
ermsb_target_feature
2.75.
exclusive_range_pattern
2.76.
exhaustive_patterns
2.77.
explicit_generic_args_with_impl_trait
2.78.
extern_types
2.79.
f16c_target_feature
2.80.
ffi_const
2.81.
ffi_pure
2.82.
ffi_returns_twice
2.83.
fn_align
2.84.
format_args_capture
2.85.
fundamental
2.86.
generators
2.87.
generic_arg_infer
2.88.
generic_associated_types
2.89.
generic_const_exprs
2.90.
half_open_range_patterns
2.91.
hexagon_target_feature
2.92.
if_let_guard
2.93.
imported_main
2.94.
in_band_lifetimes
2.95.
infer_static_outlives_requirements
2.96.
inherent_associated_types
2.97.
inline_const
2.98.
intra_doc_pointers
2.99.
intrinsics
2.100.
isa_attribute
2.101.
label_break_value
2.102.
lang_items
2.103.
large_assignments
2.104.
let_chains
2.105.
let_else
2.106.
link_cfg
2.107.
link_llvm_intrinsics
2.108.
linkage
2.109.
lint_reasons
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
2.118.
native_link_modifiers_as_needed
2.119.
native_link_modifiers_bundle
2.120.
native_link_modifiers_verbatim
2.121.
native_link_modifiers_whole_archive
2.122.
needs_panic_runtime
2.123.
negative_impls
2.124.
never_type
2.125.
never_type_fallback
2.126.
nll
2.127.
no_core
2.128.
no_coverage
2.129.
no_niche
2.130.
no_sanitize
2.131.
non_exhaustive_omitted_patterns_lint
2.132.
object_safe_for_dispatch
2.133.
omit_gdb_pretty_printer_section
2.134.
optimize_attribute
2.135.
panic_runtime
2.136.
platform_intrinsics
2.137.
plugin
2.138.
powerpc_target_feature
2.139.
precise_pointer_size_matching
2.140.
prelude_import
2.141.
proc_macro_hygiene
2.142.
profiler_runtime
2.143.
raw_dylib
2.144.
raw_ref_op
2.145.
register_attr
2.146.
register_tool
2.147.
relaxed_struct_unsize
2.148.
repr_simd
2.149.
repr128
2.150.
riscv_target_feature
2.151.
rtm_target_feature
2.152.
rustc_allow_const_fn_unstable
2.153.
rustc_attrs
2.154.
rustc_private
2.155.
simd_ffi
2.156.
specialization
2.157.
sse4a_target_feature
2.158.
staged_api
2.159.
start
2.160.
static_nobundle
2.161.
stmt_expr_attributes
2.162.
structural_match
2.163.
target_feature_11
2.164.
tbm_target_feature
2.165.
test_2018_feature
2.166.
thread_local
2.167.
trait_alias
2.168.
trait_upcasting
2.169.
transparent_unions
2.170.
trivial_bounds
2.171.
try_blocks
2.172.
type_alias_impl_trait
2.173.
type_ascription
2.174.
unboxed_closures
2.175.
unsized_fn_params
2.176.
unsized_locals
2.177.
unsized_tuple_coercion
2.178.
untagged_unions
2.179.
wasm_abi
2.180.
wasm_target_feature
3.
Library Features
3.1.
alloc_error_hook
3.2.
alloc_internals
3.3.
alloc_layout_extra
3.4.
allocator_api
3.5.
arc_new_cyclic
3.6.
array_chunks
3.7.
array_error_internals
3.8.
array_from_fn
3.9.
array_methods
3.10.
array_windows
3.11.
array_zip
3.12.
as_array_of_cells
3.13.
asm
3.14.
assert_matches
3.15.
async_stream
3.16.
atomic_from_mut
3.17.
atomic_mut_ptr
3.18.
available_parallelism
3.19.
backtrace
3.20.
backtrace_frames
3.21.
bench_black_box
3.22.
bigint_helper_methods
3.23.
binary_heap_as_slice
3.24.
binary_heap_drain_sorted
3.25.
binary_heap_into_iter_sorted
3.26.
binary_heap_retain
3.27.
bool_to_option
3.28.
bound_as_ref
3.29.
bound_map
3.30.
box_into_boxed_slice
3.31.
box_into_inner
3.32.
box_into_pin
3.33.
btree_drain_filter
3.34.
buf_read_has_data_left
3.35.
build_hasher_simple_hash_one
3.36.
c_size_t
3.37.
c_void_variant
3.38.
can_vector
3.39.
cell_filter_map
3.40.
cell_leak
3.41.
cell_update
3.42.
cfg_accessible
3.43.
cfg_eval
3.44.
char_error_internals
3.45.
char_indices_offset
3.46.
char_internals
3.47.
coerce_unsized
3.48.
concat_idents
3.49.
const_align_of_val
3.50.
const_align_of_val_raw
3.51.
const_alloc_layout
3.52.
const_arguments_as_str
3.53.
const_assert_type
3.54.
const_assume
3.55.
const_bigint_helper_methods
3.56.
const_btree_new
3.57.
const_caller_location
3.58.
const_cell_into_inner
3.59.
const_cow_is_borrowed
3.60.
const_cstr_unchecked
3.61.
const_default_impls
3.62.
const_deref
3.63.
const_discriminant
3.64.
const_eval_select
3.65.
const_float_bits_conv
3.66.
const_float_classify
3.67.
const_fmt_arguments_new
3.68.
const_format_args
3.69.
const_heap
3.70.
const_inherent_unchecked_arith
3.71.
const_int_unchecked_arith
3.72.
const_intrinsic_copy
3.73.
const_intrinsic_forget
3.74.
const_intrinsic_raw_eq
3.75.
const_io_structs
3.76.
const_ip
3.77.
const_ipv4
3.78.
const_ipv6
3.79.
const_likely
3.80.
const_maybe_uninit_as_ptr
3.81.
const_maybe_uninit_assume_init
3.82.
const_maybe_uninit_write
3.83.
const_nonnull_slice_from_raw_parts
3.84.
const_num_from_num
3.85.
const_option
3.86.
const_pin
3.87.
const_pref_align_of
3.88.
const_ptr_is_null
3.89.
const_ptr_offset
3.90.
const_ptr_offset_from
3.91.
const_ptr_read
3.92.
const_ptr_write
3.93.
const_raw_ptr_comparison
3.94.
const_replace
3.95.
const_result
3.96.
const_size_of_val
3.97.
const_size_of_val_raw
3.98.
const_slice_first_last
3.99.
const_slice_from_raw_parts
3.100.
const_slice_ptr_len
3.101.
const_socketaddr
3.102.
const_swap
3.103.
const_transmute_copy
3.104.
const_type_id
3.105.
const_type_name
3.106.
const_unsafecell_get_mut
3.107.
container_error_extra
3.108.
control_flow_enum
3.109.
convert_float_to_int
3.110.
core_intrinsics
3.111.
core_panic
3.112.
core_private_bignum
3.113.
core_private_diy_float
3.114.
cow_is_borrowed
3.115.
cstring_from_vec_with_nul
3.116.
cursor_remaining
3.117.
deadline_api
3.118.
dec2flt
3.119.
default_free_fn
3.120.
derive_clone_copy
3.121.
derive_eq
3.122.
dir_entry_ext2
3.123.
discriminant_kind
3.124.
dispatch_from_dyn
3.125.
div_duration
3.126.
drain_filter
3.127.
duration_checked_float
3.128.
duration_constants
3.129.
duration_consts_2
3.130.
edition_panic
3.131.
entry_insert
3.132.
error_iter
3.133.
error_type_id
3.134.
exact_size_is_empty
3.135.
exit_status_error
3.136.
extend_one
3.137.
fd
3.138.
fd_read
3.139.
float_interpolation
3.140.
flt2dec
3.141.
fmt_internals
3.142.
fn_traits
3.143.
forget_unsized
3.144.
format_args_nl
3.145.
future_poll_fn
3.146.
gen_future
3.147.
generator_trait
3.148.
get_mut_unchecked
3.149.
global_asm
3.150.
hash_drain_filter
3.151.
hash_raw_entry
3.152.
hash_set_entry
3.153.
hashmap_internals
3.154.
inherent_ascii_escape
3.155.
inplace_iteration
3.156.
int_abs_diff
3.157.
int_error_internals
3.158.
int_log
3.159.
int_roundings
3.160.
integer_atomics
3.161.
internal_output_capture
3.162.
into_future
3.163.
io_error_more
3.164.
io_error_uncategorized
3.165.
io_read_to_string
3.166.
io_safety
3.167.
io_slice_advance
3.168.
ip
3.169.
is_sorted
3.170.
is_symlink
3.171.
iter_advance_by
3.172.
iter_intersperse
3.173.
iter_is_partitioned
3.174.
iter_order_by
3.175.
iter_partition_in_place
3.176.
iter_zip
3.177.
layout_for_ptr
3.178.
liballoc_internals
3.179.
libstd_sys_internals
3.180.
libstd_thread_internals
3.181.
linked_list_cursors
3.182.
linked_list_remove
3.183.
linux_pidfd
3.184.
llvm_asm
3.185.
log_syntax
3.186.
map_entry_replace
3.187.
map_first_last
3.188.
map_try_insert
3.189.
maybe_uninit_array_assume_init
3.190.
maybe_uninit_extra
3.191.
maybe_uninit_slice
3.192.
maybe_uninit_uninit_array
3.193.
maybe_uninit_write_slice
3.194.
mixed_integer_ops
3.195.
mutex_unlock
3.196.
new_uninit
3.197.
nonnull_slice_from_raw_parts
3.198.
nonzero_is_power_of_two
3.199.
nonzero_ops
3.200.
numfmt
3.201.
once_cell
3.202.
option_get_or_insert_default
3.203.
option_result_contains
3.204.
option_result_unwrap_unchecked
3.205.
option_zip
3.206.
panic_abort
3.207.
panic_always_abort
3.208.
panic_info_message
3.209.
panic_internals
3.210.
panic_unwind
3.211.
path_file_prefix
3.212.
path_try_exists
3.213.
pattern
3.214.
peer_credentials_unix_socket
3.215.
pin_deref_mut
3.216.
pin_static_ref
3.217.
poll_ready
3.218.
print_internals
3.219.
proc_macro_def_site
3.220.
proc_macro_diagnostic
3.221.
proc_macro_internals
3.222.
proc_macro_quote
3.223.
proc_macro_span
3.224.
proc_macro_span_shrink
3.225.
proc_macro_tracked_env
3.226.
process_exitcode_placeholder
3.227.
process_internals
3.228.
profiler_runtime_lib
3.229.
ptr_as_uninit
3.230.
ptr_internals
3.231.
ptr_metadata
3.232.
raw_os_nonzero
3.233.
raw_vec_internals
3.234.
read_initializer
3.235.
ready_macro
3.236.
receiver_trait
3.237.
restricted_std
3.238.
result_cloned
3.239.
result_contains_err
3.240.
result_copied
3.241.
result_flattening
3.242.
result_into_ok_or_err
3.243.
rt
3.244.
saturating_div
3.245.
saturating_int_impl
3.246.
sealed
3.247.
seek_stream_len
3.248.
set_ptr_value
3.249.
setgroups
3.250.
sgx_platform
3.251.
slice_as_chunks
3.252.
slice_concat_ext
3.253.
slice_concat_trait
3.254.
slice_group_by
3.255.
slice_index_methods
3.256.
slice_internals
3.257.
slice_partition_at_index
3.258.
slice_partition_dedup
3.259.
slice_pattern
3.260.
slice_ptr_get
3.261.
slice_ptr_len
3.262.
slice_range
3.263.
slice_split_at_unchecked
3.264.
slice_swap_unchecked
3.265.
solid_ext
3.266.
sort_internals
3.267.
std_internals
3.268.
stdin_forwarders
3.269.
stdio_locked
3.270.
stdsimd
3.271.
step_trait
3.272.
str_internals
3.273.
str_split_as_str
3.274.
str_split_inclusive_as_str
3.275.
str_split_whitespace_as_str
3.276.
stream_from_iter
3.277.
string_extend_from_within
3.278.
string_remove_matches
3.279.
tcp_linger
3.280.
tcplistener_into_incoming
3.281.
termination_trait_lib
3.282.
test
3.283.
thread_id_value
3.284.
thread_local_const_init
3.285.
thread_local_internals
3.286.
thread_spawn_unchecked
3.287.
toowned_clone_into
3.288.
total_cmp
3.289.
trace_macros
3.290.
track_path
3.291.
trusted_len
3.292.
trusted_random_access
3.293.
trusted_step
3.294.
try_find
3.295.
try_reserve_kind
3.296.
try_trait_v2
3.297.
type_name_of_val
3.298.
unchecked_math
3.299.
unicode_internals
3.300.
unix_chown
3.301.
unix_process_wait_more
3.302.
unix_socket_abstract
3.303.
unix_socket_ancillary_data
3.304.
unix_socket_peek
3.305.
unsize
3.306.
unwrap_infallible
3.307.
unzip_option
3.308.
update_panic_count
3.309.
variant_count
3.310.
vec_into_raw_parts
3.311.
vec_spare_capacity
3.312.
vec_split_at_spare
3.313.
wasi_ext
3.314.
windows_by_handle
3.315.
windows_c
3.316.
windows_file_type_ext
3.317.
windows_handle
3.318.
windows_net
3.319.
windows_process_extensions_force_quotes
3.320.
windows_process_extensions_raw_arg
3.321.
windows_stdio
3.322.
with_options
3.323.
wrapping_int_impl
3.324.
wrapping_next_power_of_two
3.325.
write_all_vectored
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The Rust Unstable Book
result_contains_err
The tracking issue for this feature is:
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