core/
lib.rs

1//! # The Rust Core Library
2//!
3//! The Rust Core Library is the dependency-free[^free] foundation of [The
4//! Rust Standard Library](../std/index.html). It is the portable glue
5//! between the language and its libraries, defining the intrinsic and
6//! primitive building blocks of all Rust code. It links to no
7//! upstream libraries, no system libraries, and no libc.
8//!
9//! [^free]: Strictly speaking, there are some symbols which are needed but
10//!          they aren't always necessary.
11//!
12//! The core library is *minimal*: it isn't even aware of heap allocation,
13//! nor does it provide concurrency or I/O. These things require
14//! platform integration, and this library is platform-agnostic.
15//!
16//! # How to use the core library
17//!
18//! Please note that all of these details are currently not considered stable.
19//!
20// FIXME: Fill me in with more detail when the interface settles
21//! This library is built on the assumption of a few existing symbols:
22//!
23//! * `memcpy`, `memmove`, `memset`, `memcmp`, `bcmp`, `strlen` - These are core memory routines
24//!   which are generated by Rust codegen backends. Additionally, this library can make explicit
25//!   calls to `strlen`. Their signatures are the same as found in C, but there are extra
26//!   assumptions about their semantics: For `memcpy`, `memmove`, `memset`, `memcmp`, and `bcmp`, if
27//!   the `n` parameter is 0, the function is assumed to not be UB, even if the pointers are NULL or
28//!   dangling. (Note that making extra assumptions about these functions is common among compilers:
29//!   [clang](https://reviews.llvm.org/D86993) and [GCC](https://gcc.gnu.org/onlinedocs/gcc/Standards.html#C-Language) do the same.)
30//!   These functions are often provided by the system libc, but can also be provided by the
31//!   [compiler-builtins crate](https://crates.io/crates/compiler_builtins).
32//!   Note that the library does not guarantee that it will always make these assumptions, so Rust
33//!   user code directly calling the C functions should follow the C specification! The advice for
34//!   Rust user code is to call the functions provided by this library instead (such as
35//!   `ptr::copy`).
36//!
37//! * Panic handler - This function takes one argument, a `&panic::PanicInfo`. It is up to consumers of this core
38//!   library to define this panic function; it is only required to never
39//!   return. You should mark your implementation using `#[panic_handler]`.
40//!
41//! * `rust_eh_personality` - is used by the failure mechanisms of the
42//!   compiler. This is often mapped to GCC's personality function, but crates
43//!   which do not trigger a panic can be assured that this function is never
44//!   called. The `lang` attribute is called `eh_personality`.
45
46#![stable(feature = "core", since = "1.6.0")]
47#![doc(
48    html_playground_url = "https://play.rust-lang.org/",
49    issue_tracker_base_url = "https://github.com/rust-lang/rust/issues/",
50    test(no_crate_inject, attr(deny(warnings))),
51    test(attr(allow(dead_code, deprecated, unused_variables, unused_mut)))
52)]
53#![doc(rust_logo)]
54#![doc(auto_cfg(hide(
55    no_fp_fmt_parse,
56    target_pointer_width = "16",
57    target_pointer_width = "32",
58    target_pointer_width = "64",
59    target_has_atomic = "8",
60    target_has_atomic = "16",
61    target_has_atomic = "32",
62    target_has_atomic = "64",
63    target_has_atomic = "ptr",
64    target_has_atomic_equal_alignment = "8",
65    target_has_atomic_equal_alignment = "16",
66    target_has_atomic_equal_alignment = "32",
67    target_has_atomic_equal_alignment = "64",
68    target_has_atomic_equal_alignment = "ptr",
69    target_has_atomic_load_store = "8",
70    target_has_atomic_load_store = "16",
71    target_has_atomic_load_store = "32",
72    target_has_atomic_load_store = "64",
73    target_has_atomic_load_store = "ptr",
74)))]
75#![no_core]
76#![rustc_coherence_is_core]
77#![rustc_preserve_ub_checks]
78//
79// Lints:
80#![deny(rust_2021_incompatible_or_patterns)]
81#![deny(unsafe_op_in_unsafe_fn)]
82#![deny(fuzzy_provenance_casts)]
83#![warn(deprecated_in_future)]
84#![warn(missing_debug_implementations)]
85#![warn(missing_docs)]
86#![allow(explicit_outlives_requirements)]
87#![allow(incomplete_features)]
88#![warn(multiple_supertrait_upcastable)]
89#![allow(internal_features)]
90#![deny(ffi_unwind_calls)]
91#![warn(unreachable_pub)]
92// Do not check link redundancy on bootstrapping phase
93#![allow(rustdoc::redundant_explicit_links)]
94#![warn(rustdoc::unescaped_backticks)]
95//
96// Ferrocene addition: We removed the tidy directives for alphabetical ordering to reduce the number
97// of conflicts we have when merging main.
98//
99// Library features:
100// not-alphabetical-start
101#![cfg_attr(not(feature = "ferrocene_certified"), feature(array_ptr_get))]
102#![cfg_attr(not(feature = "ferrocene_certified"), feature(asm_experimental_arch))]
103#![cfg_attr(not(feature = "ferrocene_certified"), feature(bigint_helper_methods))]
104#![cfg_attr(not(feature = "ferrocene_certified"), feature(bstr))]
105#![cfg_attr(not(feature = "ferrocene_certified"), feature(bstr_internals))]
106#![cfg_attr(not(feature = "ferrocene_certified"), feature(cfg_select))]
107#![cfg_attr(not(feature = "ferrocene_certified"), feature(cfg_target_has_reliable_f16_f128))]
108#![cfg_attr(not(feature = "ferrocene_certified"), feature(const_carrying_mul_add))]
109#![cfg_attr(not(feature = "ferrocene_certified"), feature(const_cmp))]
110#![feature(const_destruct)]
111#![feature(const_eval_select)]
112#![feature(core_intrinsics)]
113#![feature(coverage_attribute)]
114#![cfg_attr(not(feature = "ferrocene_certified"), feature(disjoint_bitor))]
115#![feature(internal_impls_macro)]
116#![cfg_attr(not(feature = "ferrocene_certified"), feature(ip))]
117#![cfg_attr(not(feature = "ferrocene_certified"), feature(is_ascii_octdigit))]
118#![cfg_attr(not(feature = "ferrocene_certified"), feature(lazy_get))]
119#![cfg_attr(not(feature = "ferrocene_certified"), feature(link_cfg))]
120#![cfg_attr(not(feature = "ferrocene_certified"), feature(offset_of_enum))]
121#![cfg_attr(not(feature = "ferrocene_certified"), feature(panic_internals))]
122#![cfg_attr(not(feature = "ferrocene_certified"), feature(ptr_alignment_type))]
123#![cfg_attr(not(feature = "ferrocene_certified"), feature(ptr_metadata))]
124#![cfg_attr(not(feature = "ferrocene_certified"), feature(set_ptr_value))]
125#![cfg_attr(not(feature = "ferrocene_certified"), feature(slice_as_array))]
126#![cfg_attr(not(feature = "ferrocene_certified"), feature(slice_ptr_get))]
127#![cfg_attr(not(feature = "ferrocene_certified"), feature(str_internals))]
128#![cfg_attr(not(feature = "ferrocene_certified"), feature(str_split_inclusive_remainder))]
129#![cfg_attr(not(feature = "ferrocene_certified"), feature(str_split_remainder))]
130#![feature(ub_checks)]
131#![cfg_attr(not(feature = "ferrocene_certified"), feature(unchecked_neg))]
132#![cfg_attr(not(feature = "ferrocene_certified"), feature(unchecked_shifts))]
133#![cfg_attr(not(feature = "ferrocene_certified"), feature(unsafe_pinned))]
134#![cfg_attr(not(feature = "ferrocene_certified"), feature(utf16_extra))]
135#![cfg_attr(not(feature = "ferrocene_certified"), feature(variant_count))]
136// not-alphabetical-end
137//
138// Language features:
139// not-alphabetical-start
140#![cfg_attr(not(feature = "ferrocene_certified"), feature(abi_unadjusted))]
141#![feature(adt_const_params)]
142#![feature(allow_internal_unsafe)]
143#![feature(allow_internal_unstable)]
144#![feature(auto_traits)]
145#![cfg_attr(not(feature = "ferrocene_certified"), feature(cfg_sanitize))]
146#![feature(cfg_target_has_atomic)]
147#![feature(cfg_target_has_atomic_equal_alignment)]
148#![feature(cfg_ub_checks)]
149#![feature(const_precise_live_drops)]
150#![feature(const_trait_impl)]
151#![feature(decl_macro)]
152#![cfg_attr(not(feature = "ferrocene_certified"), feature(deprecated_suggestion))]
153#![cfg_attr(not(feature = "ferrocene_certified"), feature(derive_const))]
154#![feature(doc_cfg)]
155#![cfg_attr(not(feature = "ferrocene_certified"), feature(doc_notable_trait))]
156#![cfg_attr(not(feature = "ferrocene_certified"), feature(extern_types))]
157#![cfg_attr(not(feature = "ferrocene_certified"), feature(f16))]
158#![cfg_attr(not(feature = "ferrocene_certified"), feature(f128))]
159#![feature(freeze_impls)]
160#![feature(fundamental)]
161#![cfg_attr(not(feature = "ferrocene_certified"), feature(funnel_shifts))]
162#![cfg_attr(not(feature = "ferrocene_certified"), feature(if_let_guard))]
163#![feature(intra_doc_pointers)]
164#![feature(intrinsics)]
165#![feature(lang_items)]
166#![cfg_attr(not(feature = "ferrocene_certified"), feature(link_llvm_intrinsics))]
167#![cfg_attr(not(feature = "ferrocene_certified"), feature(macro_metavar_expr))]
168#![cfg_attr(not(feature = "ferrocene_certified"), feature(macro_metavar_expr_concat))]
169#![cfg_attr(not(feature = "ferrocene_certified"), feature(marker_trait_attr))]
170#![cfg_attr(not(feature = "ferrocene_certified"), feature(min_specialization))]
171#![feature(multiple_supertrait_upcastable)]
172#![cfg_attr(not(feature = "ferrocene_certified"), feature(must_not_suspend))]
173#![feature(negative_impls)]
174#![feature(never_type)]
175#![feature(no_core)]
176#![feature(optimize_attribute)]
177#![feature(prelude_import)]
178#![feature(reborrow)]
179#![cfg_attr(not(feature = "ferrocene_certified"), feature(repr_simd))]
180#![feature(rustc_allow_const_fn_unstable)]
181#![feature(rustc_attrs)]
182#![feature(rustdoc_internals)]
183#![cfg_attr(not(feature = "ferrocene_certified"), feature(simd_ffi))]
184#![feature(staged_api)]
185#![cfg_attr(not(feature = "ferrocene_certified"), feature(stmt_expr_attributes))]
186#![feature(strict_provenance_lints)]
187#![feature(trait_alias)]
188#![cfg_attr(not(feature = "ferrocene_certified"), feature(transparent_unions))]
189#![feature(try_blocks)]
190#![feature(unboxed_closures)]
191#![cfg_attr(not(feature = "ferrocene_certified"), feature(unsized_fn_params))]
192#![cfg_attr(not(feature = "ferrocene_certified"), feature(with_negative_coherence))]
193// not-alphabetical-end
194//
195// Target features:
196// not-alphabetical-start
197#![cfg_attr(not(feature = "ferrocene_certified"), feature(aarch64_unstable_target_feature))]
198#![cfg_attr(not(feature = "ferrocene_certified"), feature(arm_target_feature))]
199#![cfg_attr(not(feature = "ferrocene_certified"), feature(hexagon_target_feature))]
200#![cfg_attr(not(feature = "ferrocene_certified"), feature(loongarch_target_feature))]
201#![cfg_attr(not(feature = "ferrocene_certified"), feature(mips_target_feature))]
202#![cfg_attr(not(feature = "ferrocene_certified"), feature(powerpc_target_feature))]
203#![cfg_attr(not(feature = "ferrocene_certified"), feature(nvptx_target_feature))]
204#![cfg_attr(not(feature = "ferrocene_certified"), feature(riscv_target_feature))]
205#![cfg_attr(not(feature = "ferrocene_certified"), feature(rtm_target_feature))]
206#![cfg_attr(not(feature = "ferrocene_certified"), feature(s390x_target_feature))]
207#![cfg_attr(not(feature = "ferrocene_certified"), feature(wasm_target_feature))]
208#![cfg_attr(not(feature = "ferrocene_certified"), feature(x86_amx_intrinsics))]
209// not-alphabetical-end
210//
211// Ferrocene lints/features:
212#![allow(unused_attributes)]
213#![cfg_attr(feature = "ferrocene_certified", allow(rustdoc::broken_intra_doc_links))]
214
215// allow using `core::` in intra-doc links
216#[allow(unused_extern_crates)]
217extern crate self as core;
218
219/* The core prelude, not as all-encompassing as the std prelude */
220// The compiler expects the prelude definition to be defined before it's use statement.
221pub mod prelude;
222
223#[prelude_import]
224#[allow(unused)]
225use prelude::rust_2024::*;
226
227#[macro_use]
228mod macros;
229
230#[unstable(feature = "assert_matches", issue = "82775")]
231/// Unstable module containing the unstable `assert_matches` macro.
232#[cfg(not(feature = "ferrocene_certified"))]
233pub mod assert_matches {
234    #[unstable(feature = "assert_matches", issue = "82775")]
235    pub use crate::macros::{assert_matches, debug_assert_matches};
236}
237
238#[unstable(feature = "derive_from", issue = "144889")]
239/// Unstable module containing the unstable `From` derive macro.
240pub mod from {
241    #[unstable(feature = "derive_from", issue = "144889")]
242    pub use crate::macros::builtin::From;
243}
244
245// We don't export this through #[macro_export] for now, to avoid breakage.
246#[unstable(feature = "autodiff", issue = "124509")]
247/// Unstable module containing the unstable `autodiff` macro.
248pub mod autodiff {
249    #[unstable(feature = "autodiff", issue = "124509")]
250    pub use crate::macros::builtin::{autodiff_forward, autodiff_reverse};
251}
252
253#[unstable(feature = "contracts", issue = "128044")]
254#[cfg(not(feature = "ferrocene_certified"))]
255pub mod contracts;
256
257#[unstable(feature = "cfg_select", issue = "115585")]
258#[cfg(not(feature = "ferrocene_certified"))]
259pub use crate::macros::cfg_select;
260
261#[macro_use]
262mod internal_macros;
263
264#[path = "num/shells/legacy_int_modules.rs"]
265#[cfg(not(feature = "ferrocene_certified"))]
266mod legacy_int_modules;
267#[stable(feature = "rust1", since = "1.0.0")]
268#[allow(clippy::useless_attribute)] // FIXME false positive (https://github.com/rust-lang/rust-clippy/issues/15636)
269#[allow(deprecated_in_future)]
270#[cfg(not(feature = "ferrocene_certified"))]
271pub use legacy_int_modules::{i8, i16, i32, i64, isize, u8, u16, u32, u64, usize};
272#[stable(feature = "i128", since = "1.26.0")]
273#[allow(clippy::useless_attribute)] // FIXME false positive (https://github.com/rust-lang/rust-clippy/issues/15636)
274#[allow(deprecated_in_future)]
275#[cfg(not(feature = "ferrocene_certified"))]
276pub use legacy_int_modules::{i128, u128};
277
278#[path = "num/f128.rs"]
279#[cfg(not(feature = "ferrocene_certified"))]
280pub mod f128;
281#[path = "num/f16.rs"]
282#[cfg(not(feature = "ferrocene_certified"))]
283pub mod f16;
284#[path = "num/f32.rs"]
285#[cfg(not(feature = "ferrocene_certified"))]
286pub mod f32;
287#[path = "num/f64.rs"]
288#[cfg(not(feature = "ferrocene_certified"))]
289pub mod f64;
290
291#[macro_use]
292pub mod num;
293
294/* Core modules for ownership management */
295
296pub mod hint;
297pub mod intrinsics;
298pub mod mem;
299pub mod ptr;
300#[unstable(feature = "ub_checks", issue = "none")]
301pub mod ub_checks;
302
303/* Core language traits */
304
305#[cfg(not(feature = "ferrocene_certified"))]
306pub mod borrow;
307pub mod clone;
308pub mod cmp;
309pub mod convert;
310pub mod default;
311#[cfg(not(feature = "ferrocene_certified"))]
312pub mod error;
313pub mod marker;
314pub mod ops;
315
316/* Core types and methods on primitives */
317
318#[cfg(not(feature = "ferrocene_certified"))]
319pub mod any;
320pub mod array;
321#[cfg(not(feature = "ferrocene_certified"))]
322pub mod ascii;
323#[cfg(not(feature = "ferrocene_certified"))]
324pub mod asserting;
325#[unstable(feature = "async_iterator", issue = "79024")]
326#[cfg(not(feature = "ferrocene_certified"))]
327pub mod async_iter;
328#[unstable(feature = "bstr", issue = "134915")]
329#[cfg(not(feature = "ferrocene_certified"))]
330pub mod bstr;
331pub mod cell;
332#[cfg(not(feature = "ferrocene_certified"))]
333pub mod char;
334#[cfg(not(feature = "ferrocene_certified"))]
335pub mod ffi;
336#[unstable(feature = "core_io_borrowed_buf", issue = "117693")]
337#[cfg(not(feature = "ferrocene_certified"))]
338pub mod io;
339pub mod iter;
340#[cfg(not(feature = "ferrocene_certified"))]
341pub mod net;
342pub mod option;
343#[cfg(not(feature = "ferrocene_certified"))]
344pub mod os;
345pub mod panic;
346pub mod panicking;
347#[unstable(feature = "pattern_type_macro", issue = "123646")]
348#[cfg(not(feature = "ferrocene_certified"))]
349pub mod pat;
350#[cfg(not(feature = "ferrocene_certified"))]
351pub mod pin;
352#[unstable(feature = "random", issue = "130703")]
353#[cfg(not(feature = "ferrocene_certified"))]
354pub mod random;
355#[unstable(feature = "new_range_api", issue = "125687")]
356#[cfg(not(feature = "ferrocene_certified"))]
357pub mod range;
358pub mod result;
359pub mod sync;
360#[unstable(feature = "unsafe_binders", issue = "130516")]
361#[cfg(not(feature = "ferrocene_certified"))]
362pub mod unsafe_binder;
363
364pub mod fmt;
365#[cfg(not(feature = "ferrocene_certified"))]
366pub mod hash;
367#[cfg(not(feature = "ferrocene_certified"))]
368pub mod slice;
369#[cfg(not(feature = "ferrocene_certified"))]
370pub mod str;
371#[cfg(not(feature = "ferrocene_certified"))]
372pub mod time;
373
374#[cfg(not(feature = "ferrocene_certified"))]
375pub mod wtf8;
376
377#[cfg(not(feature = "ferrocene_certified"))]
378pub mod unicode;
379
380/* Async */
381#[cfg(not(feature = "ferrocene_certified"))]
382pub mod future;
383#[cfg(not(feature = "ferrocene_certified"))]
384pub mod task;
385
386/* Heap memory allocator trait */
387#[allow(missing_docs)]
388pub mod alloc;
389
390// note: does not need to be public
391mod bool;
392#[cfg(not(feature = "ferrocene_certified"))]
393mod escape;
394#[cfg(not(feature = "ferrocene_certified"))]
395mod tuple;
396#[cfg(not(feature = "ferrocene_certified"))]
397mod unit;
398
399#[stable(feature = "core_primitive", since = "1.43.0")]
400#[cfg(not(feature = "ferrocene_certified"))]
401pub mod primitive;
402
403// Pull in the `core_arch` crate directly into core. The contents of
404// `core_arch` are in a different repository: rust-lang/stdarch.
405//
406// `core_arch` depends on core, but the contents of this module are
407// set up in such a way that directly pulling it here works such that the
408// crate uses the this crate as its core.
409#[path = "../../stdarch/crates/core_arch/src/mod.rs"]
410#[allow(
411    missing_docs,
412    missing_debug_implementations,
413    dead_code,
414    unused_imports,
415    unsafe_op_in_unsafe_fn,
416    ambiguous_glob_reexports,
417    deprecated_in_future,
418    unreachable_pub
419)]
420#[allow(rustdoc::bare_urls)]
421#[cfg(not(feature = "ferrocene_certified"))]
422mod core_arch;
423
424#[stable(feature = "simd_arch", since = "1.27.0")]
425#[cfg(not(feature = "ferrocene_certified"))]
426pub mod arch;
427
428// Pull in the `core_simd` crate directly into core. The contents of
429// `core_simd` are in a different repository: rust-lang/portable-simd.
430//
431// `core_simd` depends on core, but the contents of this module are
432// set up in such a way that directly pulling it here works such that the
433// crate uses this crate as its core.
434#[path = "../../portable-simd/crates/core_simd/src/mod.rs"]
435#[allow(missing_debug_implementations, dead_code, unsafe_op_in_unsafe_fn)]
436#[allow(rustdoc::bare_urls)]
437#[unstable(feature = "portable_simd", issue = "86656")]
438#[cfg(not(feature = "ferrocene_certified"))]
439mod core_simd;
440
441#[unstable(feature = "portable_simd", issue = "86656")]
442#[cfg(not(feature = "ferrocene_certified"))]
443pub mod simd {
444    #![doc = include_str!("../../portable-simd/crates/core_simd/src/core_simd_docs.md")]
445
446    #[unstable(feature = "portable_simd", issue = "86656")]
447    pub use crate::core_simd::simd::*;
448}
449
450include!("primitive_docs.rs");
core/lib.rs

core/
lib.rs
