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

core/
lib.rs
