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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#![allow(unused_features)]
91#![deny(ffi_unwind_calls)]
92#![warn(unreachable_pub)]
93// Do not check link redundancy on bootstrapping phase
94#![allow(rustdoc::redundant_explicit_links)]
95#![warn(rustdoc::unescaped_backticks)]
96//
97// Ferrocene addition: We removed the tidy directives for alphabetical ordering to reduce the number
98// of conflicts we have when merging main.
99//
100// Library features:
101// not-alphabetical-start
102#![cfg_attr(not(feature = "ferrocene_subset"), feature(asm_experimental_arch))]
103#![cfg_attr(not(feature = "ferrocene_subset"), feature(bstr_internals))]
104#![feature(cfg_target_has_reliable_f16_f128)]
105#![feature(const_carrying_mul_add)]
106#![feature(const_cmp)]
107#![feature(const_destruct)]
108#![feature(const_eval_select)]
109#![feature(const_select_unpredictable)]
110#![feature(core_intrinsics)]
111#![feature(coverage_attribute)]
112#![feature(disjoint_bitor)]
113#![feature(internal_impls_macro)]
114#![cfg_attr(not(feature = "ferrocene_subset"), feature(link_cfg))]
115#![cfg_attr(not(feature = "ferrocene_subset"), feature(offset_of_enum))]
116#![feature(panic_internals)]
117#![feature(pattern_type_macro)]
118#![feature(ub_checks)]
119// not-alphabetical-end
120//
121// Language features:
122// not-alphabetical-start
123#![feature(abi_unadjusted)]
124#![feature(adt_const_params)]
125#![feature(allow_internal_unsafe)]
126#![feature(allow_internal_unstable)]
127#![feature(auto_traits)]
128#![feature(cfg_sanitize)]
129#![feature(cfg_target_has_atomic)]
130#![feature(cfg_target_has_atomic_equal_alignment)]
131#![feature(cfg_ub_checks)]
132#![feature(const_precise_live_drops)]
133#![feature(const_trait_impl)]
134#![feature(decl_macro)]
135#![feature(deprecated_suggestion)]
136#![feature(derive_const)]
137#![feature(diagnostic_on_const)]
138#![feature(doc_cfg)]
139#![cfg_attr(not(feature = "ferrocene_subset"), feature(doc_notable_trait))]
140#![feature(extern_types)]
141#![feature(f128)]
142#![feature(f16)]
143#![feature(field_projections)]
144#![feature(freeze_impls)]
145#![feature(fundamental)]
146#![feature(funnel_shifts)]
147#![feature(intra_doc_pointers)]
148#![feature(intrinsics)]
149#![feature(lang_items)]
150#![feature(link_llvm_intrinsics)]
151#![feature(macro_metavar_expr)]
152#![feature(macro_metavar_expr_concat)]
153#![feature(marker_trait_attr)]
154#![feature(min_specialization)]
155#![feature(multiple_supertrait_upcastable)]
156#![feature(must_not_suspend)]
157#![feature(negative_impls)]
158#![feature(never_type)]
159#![feature(no_core)]
160#![feature(optimize_attribute)]
161#![feature(pattern_types)]
162#![feature(prelude_import)]
163#![feature(repr_simd)]
164#![feature(rustc_attrs)]
165#![feature(rustdoc_internals)]
166#![feature(simd_ffi)]
167#![feature(staged_api)]
168#![feature(stmt_expr_attributes)]
169#![feature(strict_provenance_lints)]
170#![feature(target_feature_inline_always)]
171#![feature(trait_alias)]
172#![feature(transparent_unions)]
173#![feature(try_blocks)]
174#![feature(uint_carryless_mul)]
175#![feature(unboxed_closures)]
176#![feature(unsized_fn_params)]
177#![cfg_attr(not(feature = "ferrocene_subset"), feature(with_negative_coherence))]
178// not-alphabetical-end
179//
180// Target features:
181// not-alphabetical-start
182#![cfg_attr(not(feature = "ferrocene_subset"), feature(aarch64_unstable_target_feature))]
183#![feature(arm_target_feature)]
184#![cfg_attr(not(feature = "ferrocene_subset"), feature(avx10_target_feature))]
185#![cfg_attr(not(feature = "ferrocene_subset"), feature(hexagon_target_feature))]
186#![cfg_attr(not(feature = "ferrocene_subset"), feature(loongarch_target_feature))]
187#![cfg_attr(not(feature = "ferrocene_subset"), feature(mips_target_feature))]
188#![cfg_attr(not(feature = "ferrocene_subset"), feature(powerpc_target_feature))]
189#![cfg_attr(not(feature = "ferrocene_subset"), feature(nvptx_target_feature))]
190#![cfg_attr(not(feature = "ferrocene_subset"), feature(riscv_target_feature))]
191#![cfg_attr(not(feature = "ferrocene_subset"), feature(rtm_target_feature))]
192#![cfg_attr(not(feature = "ferrocene_subset"), feature(s390x_target_feature))]
193#![cfg_attr(not(feature = "ferrocene_subset"), feature(wasm_target_feature))]
194#![cfg_attr(not(feature = "ferrocene_subset"), feature(x86_amx_intrinsics))]
195// not-alphabetical-end
196//
197// Ferrocene lints/features:
198#![cfg_attr(
199    feature = "ferrocene_subset",
200    expect(rustdoc::broken_intra_doc_links),
201    expect(rustdoc::private_intra_doc_links)
202)]
203#![feature(register_tool)]
204#![register_tool(ferrocene)]
205#![doc(auto_cfg(hide(feature = "ferrocene_subset")))]
206
207// allow using `core::` in intra-doc links
208#[allow(unused_extern_crates)]
209extern crate self as core;
210
211/* The core prelude, not as all-encompassing as the std prelude */
212// The compiler expects the prelude definition to be defined before it's use statement.
213pub mod prelude;
214
215#[prelude_import]
216#[allow(unused)]
217use prelude::rust_2024::*;
218
219#[macro_use]
220mod macros;
221
222/// Ferrocene addition: Hidden module to test crate-internal functionality
223#[doc(hidden)]
224#[unstable(feature = "ferrocene_test", issue = "none")]
225#[cfg(not(feature = "ferrocene_subset"))]
226pub mod ferrocene_test;
227
228#[stable(feature = "assert_matches", since = "CURRENT_RUSTC_VERSION")]
229pub use crate::macros::{assert_matches, debug_assert_matches};
230
231#[unstable(feature = "derive_from", issue = "144889")]
232/// Unstable module containing the unstable `From` derive macro.
233pub mod from {
234    #[unstable(feature = "derive_from", issue = "144889")]
235    pub use crate::macros::builtin::From;
236}
237
238// We don't export this through #[macro_export] for now, to avoid breakage.
239#[unstable(feature = "autodiff", issue = "124509")]
240/// Unstable module containing the unstable `autodiff` macro.
241pub mod autodiff {
242    #[unstable(feature = "autodiff", issue = "124509")]
243    pub use crate::macros::builtin::{autodiff_forward, autodiff_reverse};
244}
245
246#[unstable(feature = "contracts", issue = "128044")]
247#[cfg(not(feature = "ferrocene_subset"))]
248pub mod contracts;
249
250#[stable(feature = "cfg_select", since = "CURRENT_RUSTC_VERSION")]
251pub use crate::macros::cfg_select;
252
253#[macro_use]
254mod internal_macros;
255
256#[path = "num/shells/legacy_int_modules.rs"]
257#[cfg(not(feature = "ferrocene_subset"))]
258mod legacy_int_modules;
259#[stable(feature = "rust1", since = "1.0.0")]
260#[allow(clippy::useless_attribute)] // FIXME false positive (https://github.com/rust-lang/rust-clippy/issues/15636)
261#[allow(deprecated_in_future)]
262#[cfg(not(feature = "ferrocene_subset"))]
263pub use legacy_int_modules::{i8, i16, i32, i64, isize, u8, u16, u32, u64, usize};
264#[stable(feature = "i128", since = "1.26.0")]
265#[allow(clippy::useless_attribute)] // FIXME false positive (https://github.com/rust-lang/rust-clippy/issues/15636)
266#[allow(deprecated_in_future)]
267#[cfg(not(feature = "ferrocene_subset"))]
268pub use legacy_int_modules::{i128, u128};
269
270#[path = "num/f128.rs"]
271#[cfg(not(feature = "ferrocene_subset"))]
272pub mod f128;
273#[path = "num/f16.rs"]
274pub mod f16;
275#[path = "num/f32.rs"]
276pub mod f32;
277#[path = "num/f64.rs"]
278pub mod f64;
279
280#[macro_use]
281pub mod num;
282
283/* Core modules for ownership management */
284
285pub mod hint;
286pub mod intrinsics;
287pub mod mem;
288#[unstable(feature = "profiling_marker_api", issue = "148197")]
289pub mod profiling;
290pub mod ptr;
291#[unstable(feature = "ub_checks", issue = "none")]
292pub mod ub_checks;
293
294/* Core language traits */
295
296pub mod borrow;
297pub mod clone;
298pub mod cmp;
299pub mod convert;
300pub mod default;
301#[cfg(not(feature = "ferrocene_subset"))]
302pub mod error;
303#[unstable(feature = "field_projections", issue = "145383")]
304#[cfg(not(feature = "ferrocene_subset"))]
305pub mod field;
306#[cfg(not(feature = "ferrocene_subset"))]
307pub mod index;
308pub mod marker;
309pub mod ops;
310
311/* Core types and methods on primitives */
312
313pub mod any;
314pub mod array;
315pub mod ascii;
316#[cfg(not(feature = "ferrocene_subset"))]
317pub mod asserting;
318#[unstable(feature = "async_iterator", issue = "79024")]
319#[cfg(not(feature = "ferrocene_subset"))]
320pub mod async_iter;
321#[unstable(feature = "bstr", issue = "134915")]
322pub mod bstr;
323pub mod cell;
324pub mod char;
325pub mod ffi;
326#[unstable(feature = "core_io_borrowed_buf", issue = "117693")]
327#[cfg(not(feature = "ferrocene_subset"))]
328pub mod io;
329pub mod iter;
330#[cfg(not(feature = "ferrocene_subset"))]
331pub mod net;
332pub mod option;
333#[cfg(not(feature = "ferrocene_subset"))]
334pub mod os;
335pub mod panic;
336pub mod panicking;
337#[unstable(feature = "pattern_type_macro", issue = "123646")]
338pub mod pat;
339#[cfg(not(feature = "ferrocene_subset"))]
340pub mod pin;
341#[unstable(feature = "random", issue = "130703")]
342#[cfg(not(feature = "ferrocene_subset"))]
343pub mod random;
344#[cfg(not(feature = "ferrocene_subset"))]
345#[stable(feature = "new_range_inclusive_api", since = "CURRENT_RUSTC_VERSION")]
346pub mod range;
347pub mod result;
348pub mod sync;
349#[unstable(feature = "unsafe_binders", issue = "130516")]
350#[cfg(not(feature = "ferrocene_subset"))]
351pub mod unsafe_binder;
352
353pub mod fmt;
354pub mod hash;
355pub mod slice;
356pub mod str;
357pub mod time;
358
359#[cfg(not(feature = "ferrocene_subset"))]
360pub mod wtf8;
361
362pub mod unicode;
363
364/* Async */
365#[cfg(not(feature = "ferrocene_subset"))]
366pub mod future;
367#[cfg(not(feature = "ferrocene_subset"))]
368pub mod task;
369
370/* Heap memory allocator trait */
371#[allow(missing_docs)]
372pub mod alloc;
373
374// note: does not need to be public
375mod bool;
376mod escape;
377mod tuple;
378mod unit;
379
380#[stable(feature = "core_primitive", since = "1.43.0")]
381#[cfg(not(feature = "ferrocene_subset"))]
382pub mod primitive;
383
384// Pull in the `core_arch` crate directly into core. The contents of
385// `core_arch` are in a different repository: rust-lang/stdarch.
386//
387// `core_arch` depends on core, but the contents of this module are
388// set up in such a way that directly pulling it here works such that the
389// crate uses the this crate as its core.
390#[path = "../../stdarch/crates/core_arch/src/mod.rs"]
391#[allow(
392    missing_docs,
393    missing_debug_implementations,
394    dead_code,
395    unused_imports,
396    unsafe_op_in_unsafe_fn,
397    ambiguous_glob_reexports,
398    deprecated_in_future,
399    unreachable_pub
400)]
401#[allow(rustdoc::bare_urls)]
402mod core_arch;
403
404#[stable(feature = "simd_arch", since = "1.27.0")]
405pub mod arch;
406
407// Pull in the `core_simd` crate directly into core. The contents of
408// `core_simd` are in a different repository: rust-lang/portable-simd.
409//
410// `core_simd` depends on core, but the contents of this module are
411// set up in such a way that directly pulling it here works such that the
412// crate uses this crate as its core.
413#[path = "../../portable-simd/crates/core_simd/src/mod.rs"]
414#[allow(missing_debug_implementations, dead_code, unsafe_op_in_unsafe_fn)]
415#[allow(rustdoc::bare_urls)]
416#[unstable(feature = "portable_simd", issue = "86656")]
417#[cfg(not(feature = "ferrocene_subset"))]
418mod core_simd;
419
420#[unstable(feature = "portable_simd", issue = "86656")]
421#[cfg(not(feature = "ferrocene_subset"))]
422pub mod simd {
423    #![doc = include_str!("../../portable-simd/crates/core_simd/src/core_simd_docs.md")]
424
425    #[unstable(feature = "portable_simd", issue = "86656")]
426    pub use crate::core_simd::simd::*;
427}
428
429include!("primitive_docs.rs");