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#![cfg_attr(not(feature = "ferrocene_certified"), feature(const_select_unpredictable))]
113#![feature(core_intrinsics)]
114#![feature(coverage_attribute)]
115#![cfg_attr(not(feature = "ferrocene_certified"), feature(disjoint_bitor))]
116#![feature(internal_impls_macro)]
117#![cfg_attr(not(feature = "ferrocene_certified"), feature(ip))]
118#![cfg_attr(not(feature = "ferrocene_certified"), feature(is_ascii_octdigit))]
119#![cfg_attr(not(feature = "ferrocene_certified"), feature(lazy_get))]
120#![cfg_attr(not(feature = "ferrocene_certified"), feature(link_cfg))]
121#![cfg_attr(not(feature = "ferrocene_certified"), feature(offset_of_enum))]
122#![feature(panic_internals)]
123#![cfg_attr(not(feature = "ferrocene_certified"), feature(ptr_alignment_type))]
124#![cfg_attr(not(feature = "ferrocene_certified"), feature(ptr_metadata))]
125#![cfg_attr(not(feature = "ferrocene_certified"), feature(set_ptr_value))]
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#![cfg_attr(not(feature = "ferrocene_certified"), feature(pattern_type_macro))]
131#![feature(ub_checks)]
132#![cfg_attr(not(feature = "ferrocene_certified"), feature(unchecked_neg))]
133#![cfg_attr(not(feature = "ferrocene_certified"), feature(unchecked_shifts))]
134#![cfg_attr(not(feature = "ferrocene_certified"), feature(unsafe_pinned))]
135#![cfg_attr(not(feature = "ferrocene_certified"), feature(utf16_extra))]
136#![cfg_attr(not(feature = "ferrocene_certified"), feature(variant_count))]
137// not-alphabetical-end
138//
139// Language features:
140// not-alphabetical-start
141#![cfg_attr(not(feature = "ferrocene_certified"), feature(abi_unadjusted))]
142#![feature(adt_const_params)]
143#![feature(allow_internal_unsafe)]
144#![feature(allow_internal_unstable)]
145#![feature(auto_traits)]
146#![cfg_attr(not(feature = "ferrocene_certified"), feature(cfg_sanitize))]
147#![feature(cfg_target_has_atomic)]
148#![feature(cfg_target_has_atomic_equal_alignment)]
149#![feature(cfg_ub_checks)]
150#![feature(const_precise_live_drops)]
151#![feature(const_trait_impl)]
152#![feature(decl_macro)]
153#![cfg_attr(not(feature = "ferrocene_certified"), feature(deprecated_suggestion))]
154#![feature(derive_const)]
155#![feature(doc_cfg)]
156#![cfg_attr(not(feature = "ferrocene_certified"), feature(doc_notable_trait))]
157#![feature(extern_types)]
158#![feature(f128)]
159#![feature(f16)]
160#![feature(freeze_impls)]
161#![feature(fundamental)]
162#![cfg_attr(not(feature = "ferrocene_certified"), feature(funnel_shifts))]
163#![cfg_attr(not(feature = "ferrocene_certified"), feature(if_let_guard))]
164#![feature(intra_doc_pointers)]
165#![feature(intrinsics)]
166#![feature(lang_items)]
167#![cfg_attr(not(feature = "ferrocene_certified"), feature(link_llvm_intrinsics))]
168#![feature(macro_metavar_expr)]
169#![cfg_attr(not(feature = "ferrocene_certified"), feature(macro_metavar_expr_concat))]
170#![feature(marker_trait_attr)]
171#![feature(min_specialization)]
172#![feature(multiple_supertrait_upcastable)]
173#![cfg_attr(not(feature = "ferrocene_certified"), feature(must_not_suspend))]
174#![feature(negative_impls)]
175#![feature(never_type)]
176#![feature(no_core)]
177#![feature(optimize_attribute)]
178#![feature(pattern_types)]
179#![feature(prelude_import)]
180#![feature(reborrow)]
181#![cfg_attr(not(feature = "ferrocene_certified"), feature(repr_simd))]
182#![feature(rustc_allow_const_fn_unstable)]
183#![feature(rustc_attrs)]
184#![feature(rustdoc_internals)]
185#![cfg_attr(not(feature = "ferrocene_certified"), feature(simd_ffi))]
186#![feature(staged_api)]
187#![feature(stmt_expr_attributes)]
188#![feature(strict_provenance_lints)]
189#![feature(trait_alias)]
190#![feature(transparent_unions)]
191#![feature(try_blocks)]
192#![feature(unboxed_closures)]
193#![cfg_attr(not(feature = "ferrocene_certified"), feature(unsized_fn_params))]
194#![cfg_attr(not(feature = "ferrocene_certified"), feature(with_negative_coherence))]
195// not-alphabetical-end
196//
197// Target features:
198// not-alphabetical-start
199#![cfg_attr(not(feature = "ferrocene_certified"), feature(aarch64_unstable_target_feature))]
200#![cfg_attr(not(feature = "ferrocene_certified"), feature(arm_target_feature))]
201#![cfg_attr(not(feature = "ferrocene_certified"), feature(hexagon_target_feature))]
202#![cfg_attr(not(feature = "ferrocene_certified"), feature(loongarch_target_feature))]
203#![cfg_attr(not(feature = "ferrocene_certified"), feature(mips_target_feature))]
204#![cfg_attr(not(feature = "ferrocene_certified"), feature(powerpc_target_feature))]
205#![cfg_attr(not(feature = "ferrocene_certified"), feature(nvptx_target_feature))]
206#![cfg_attr(not(feature = "ferrocene_certified"), feature(riscv_target_feature))]
207#![cfg_attr(not(feature = "ferrocene_certified"), feature(rtm_target_feature))]
208#![cfg_attr(not(feature = "ferrocene_certified"), feature(s390x_target_feature))]
209#![cfg_attr(not(feature = "ferrocene_certified"), feature(wasm_target_feature))]
210#![cfg_attr(not(feature = "ferrocene_certified"), feature(x86_amx_intrinsics))]
211// not-alphabetical-end
212//
213// Ferrocene lints/features:
214#![cfg_attr(
215    feature = "ferrocene_certified",
216    expect(rustdoc::broken_intra_doc_links),
217    expect(rustdoc::private_intra_doc_links),
218    expect(unused_attributes)
219)]
220#![feature(register_tool)]
221#![register_tool(ferrocene)]
222#![doc(auto_cfg(hide(feature = "ferrocene_certified")))]
223
224// allow using `core::` in intra-doc links
225#[allow(unused_extern_crates)]
226extern crate self as core;
227
228/* The core prelude, not as all-encompassing as the std prelude */
229// The compiler expects the prelude definition to be defined before it's use statement.
230pub mod prelude;
231
232#[prelude_import]
233#[allow(unused)]
234use prelude::rust_2024::*;
235
236#[macro_use]
237mod macros;
238
239#[unstable(feature = "assert_matches", issue = "82775")]
240/// Unstable module containing the unstable `assert_matches` macro.
241#[cfg(not(feature = "ferrocene_certified"))]
242pub mod assert_matches {
243    #[unstable(feature = "assert_matches", issue = "82775")]
244    pub use crate::macros::{assert_matches, debug_assert_matches};
245}
246
247#[unstable(feature = "derive_from", issue = "144889")]
248/// Unstable module containing the unstable `From` derive macro.
249pub mod from {
250    #[unstable(feature = "derive_from", issue = "144889")]
251    pub use crate::macros::builtin::From;
252}
253
254// We don't export this through #[macro_export] for now, to avoid breakage.
255#[unstable(feature = "autodiff", issue = "124509")]
256/// Unstable module containing the unstable `autodiff` macro.
257pub mod autodiff {
258    #[unstable(feature = "autodiff", issue = "124509")]
259    pub use crate::macros::builtin::{autodiff_forward, autodiff_reverse};
260}
261
262#[unstable(feature = "contracts", issue = "128044")]
263#[cfg(not(feature = "ferrocene_certified"))]
264pub mod contracts;
265
266#[unstable(feature = "cfg_select", issue = "115585")]
267#[cfg(not(feature = "ferrocene_certified"))]
268pub use crate::macros::cfg_select;
269
270#[macro_use]
271mod internal_macros;
272
273#[path = "num/shells/legacy_int_modules.rs"]
274#[cfg(not(feature = "ferrocene_certified"))]
275mod legacy_int_modules;
276#[stable(feature = "rust1", since = "1.0.0")]
277#[allow(clippy::useless_attribute)] // FIXME false positive (https://github.com/rust-lang/rust-clippy/issues/15636)
278#[allow(deprecated_in_future)]
279#[cfg(not(feature = "ferrocene_certified"))]
280pub use legacy_int_modules::{i8, i16, i32, i64, isize, u8, u16, u32, u64, usize};
281#[stable(feature = "i128", since = "1.26.0")]
282#[allow(clippy::useless_attribute)] // FIXME false positive (https://github.com/rust-lang/rust-clippy/issues/15636)
283#[allow(deprecated_in_future)]
284#[cfg(not(feature = "ferrocene_certified"))]
285pub use legacy_int_modules::{i128, u128};
286
287#[path = "num/f128.rs"]
288#[cfg(not(feature = "ferrocene_certified"))]
289pub mod f128;
290#[path = "num/f16.rs"]
291#[cfg(not(feature = "ferrocene_certified"))]
292pub mod f16;
293#[path = "num/f32.rs"]
294pub mod f32;
295#[path = "num/f64.rs"]
296pub mod f64;
297
298#[macro_use]
299pub mod num;
300
301/* Core modules for ownership management */
302
303pub mod hint;
304pub mod intrinsics;
305pub mod mem;
306#[unstable(feature = "profiling_marker_api", issue = "148197")]
307pub mod profiling;
308pub mod ptr;
309#[unstable(feature = "ub_checks", issue = "none")]
310pub mod ub_checks;
311
312/* Core language traits */
313
314#[cfg(not(feature = "ferrocene_certified"))]
315pub mod borrow;
316pub mod clone;
317pub mod cmp;
318pub mod convert;
319pub mod default;
320#[cfg(not(feature = "ferrocene_certified"))]
321pub mod error;
322#[cfg(not(feature = "ferrocene_certified"))]
323pub mod index;
324pub mod marker;
325pub mod ops;
326
327/* Core types and methods on primitives */
328
329pub mod any;
330pub mod array;
331#[cfg(not(feature = "ferrocene_certified"))]
332pub mod ascii;
333#[cfg(not(feature = "ferrocene_certified"))]
334pub mod asserting;
335#[unstable(feature = "async_iterator", issue = "79024")]
336#[cfg(not(feature = "ferrocene_certified"))]
337pub mod async_iter;
338#[unstable(feature = "bstr", issue = "134915")]
339#[cfg(not(feature = "ferrocene_certified"))]
340pub mod bstr;
341pub mod cell;
342#[cfg(not(feature = "ferrocene_certified"))]
343pub mod char;
344#[cfg(not(feature = "ferrocene_certified"))]
345pub mod ffi;
346#[unstable(feature = "core_io_borrowed_buf", issue = "117693")]
347#[cfg(not(feature = "ferrocene_certified"))]
348pub mod io;
349pub mod iter;
350#[cfg(not(feature = "ferrocene_certified"))]
351pub mod net;
352pub mod option;
353#[cfg(not(feature = "ferrocene_certified"))]
354pub mod os;
355pub mod panic;
356pub mod panicking;
357#[unstable(feature = "pattern_type_macro", issue = "123646")]
358#[cfg(not(feature = "ferrocene_certified"))]
359pub mod pat;
360#[cfg(not(feature = "ferrocene_certified"))]
361pub mod pin;
362#[unstable(feature = "random", issue = "130703")]
363#[cfg(not(feature = "ferrocene_certified"))]
364pub mod random;
365#[unstable(feature = "new_range_api", issue = "125687")]
366#[cfg(not(feature = "ferrocene_certified"))]
367pub mod range;
368pub mod result;
369pub mod sync;
370#[unstable(feature = "unsafe_binders", issue = "130516")]
371#[cfg(not(feature = "ferrocene_certified"))]
372pub mod unsafe_binder;
373
374pub mod fmt;
375#[cfg(not(feature = "ferrocene_certified"))]
376pub mod hash;
377pub mod slice;
378pub mod str;
379pub mod time;
380
381#[cfg(not(feature = "ferrocene_certified"))]
382pub mod wtf8;
383
384#[cfg(not(feature = "ferrocene_certified"))]
385pub mod unicode;
386
387/* Async */
388#[cfg(not(feature = "ferrocene_certified"))]
389pub mod future;
390#[cfg(not(feature = "ferrocene_certified"))]
391pub mod task;
392
393/* Heap memory allocator trait */
394#[allow(missing_docs)]
395pub mod alloc;
396
397// note: does not need to be public
398mod bool;
399#[cfg(not(feature = "ferrocene_certified"))]
400mod escape;
401mod tuple;
402#[cfg(not(feature = "ferrocene_certified"))]
403mod unit;
404
405#[stable(feature = "core_primitive", since = "1.43.0")]
406#[cfg(not(feature = "ferrocene_certified"))]
407pub mod primitive;
408
409// Pull in the `core_arch` crate directly into core. The contents of
410// `core_arch` are in a different repository: rust-lang/stdarch.
411//
412// `core_arch` depends on core, but the contents of this module are
413// set up in such a way that directly pulling it here works such that the
414// crate uses the this crate as its core.
415#[path = "../../stdarch/crates/core_arch/src/mod.rs"]
416#[allow(
417    missing_docs,
418    missing_debug_implementations,
419    dead_code,
420    unused_imports,
421    unsafe_op_in_unsafe_fn,
422    ambiguous_glob_reexports,
423    deprecated_in_future,
424    unreachable_pub
425)]
426#[allow(rustdoc::bare_urls)]
427#[cfg(not(feature = "ferrocene_certified"))]
428mod core_arch;
429
430#[stable(feature = "simd_arch", since = "1.27.0")]
431#[cfg(not(feature = "ferrocene_certified"))]
432pub mod arch;
433
434// Pull in the `core_simd` crate directly into core. The contents of
435// `core_simd` are in a different repository: rust-lang/portable-simd.
436//
437// `core_simd` depends on core, but the contents of this module are
438// set up in such a way that directly pulling it here works such that the
439// crate uses this crate as its core.
440#[path = "../../portable-simd/crates/core_simd/src/mod.rs"]
441#[allow(missing_debug_implementations, dead_code, unsafe_op_in_unsafe_fn)]
442#[allow(rustdoc::bare_urls)]
443#[unstable(feature = "portable_simd", issue = "86656")]
444#[cfg(not(feature = "ferrocene_certified"))]
445mod core_simd;
446
447#[unstable(feature = "portable_simd", issue = "86656")]
448#[cfg(not(feature = "ferrocene_certified"))]
449pub mod simd {
450    #![doc = include_str!("../../portable-simd/crates/core_simd/src/core_simd_docs.md")]
451
452    #[unstable(feature = "portable_simd", issue = "86656")]
453    pub use crate::core_simd::simd::*;
454}
455
456include!("primitive_docs.rs");
core/lib.rs

core/
lib.rs
