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_subset"), feature(array_ptr_get))]
102#![cfg_attr(not(feature = "ferrocene_subset"), feature(asm_experimental_arch))]
103#![cfg_attr(not(feature = "ferrocene_subset"), feature(bigint_helper_methods))]
104#![cfg_attr(not(feature = "ferrocene_subset"), feature(bstr))]
105#![cfg_attr(not(feature = "ferrocene_subset"), feature(bstr_internals))]
106#![feature(cfg_select)]
107#![cfg_attr(not(feature = "ferrocene_subset"), feature(cfg_target_has_reliable_f16_f128))]
108#![cfg_attr(not(feature = "ferrocene_subset"), feature(const_carrying_mul_add))]
109#![cfg_attr(not(feature = "ferrocene_subset"), feature(const_cmp))]
110#![feature(const_destruct)]
111#![feature(const_eval_select)]
112#![cfg_attr(not(feature = "ferrocene_subset"), feature(const_select_unpredictable))]
113#![feature(core_intrinsics)]
114#![feature(coverage_attribute)]
115#![feature(disjoint_bitor)]
116#![feature(internal_impls_macro)]
117#![cfg_attr(not(feature = "ferrocene_subset"), feature(ip))]
118#![cfg_attr(not(feature = "ferrocene_subset"), feature(is_ascii_octdigit))]
119#![cfg_attr(not(feature = "ferrocene_subset"), feature(lazy_get))]
120#![cfg_attr(not(feature = "ferrocene_subset"), feature(link_cfg))]
121#![cfg_attr(not(feature = "ferrocene_subset"), feature(offset_of_enum))]
122#![feature(panic_internals)]
123#![cfg_attr(not(feature = "ferrocene_subset"), feature(ptr_alignment_type))]
124#![cfg_attr(not(feature = "ferrocene_subset"), feature(ptr_metadata))]
125#![cfg_attr(not(feature = "ferrocene_subset"), feature(set_ptr_value))]
126#![cfg_attr(not(feature = "ferrocene_subset"), feature(slice_ptr_get))]
127#![cfg_attr(not(feature = "ferrocene_subset"), feature(str_internals))]
128#![cfg_attr(not(feature = "ferrocene_subset"), feature(str_split_inclusive_remainder))]
129#![cfg_attr(not(feature = "ferrocene_subset"), feature(str_split_remainder))]
130#![cfg_attr(not(feature = "ferrocene_subset"), feature(pattern_type_macro))]
131#![feature(ub_checks)]
132#![cfg_attr(not(feature = "ferrocene_subset"), feature(unsafe_pinned))]
133#![cfg_attr(not(feature = "ferrocene_subset"), feature(utf16_extra))]
134#![cfg_attr(not(feature = "ferrocene_subset"), feature(variant_count))]
135// not-alphabetical-end
136//
137// Language features:
138// not-alphabetical-start
139#![feature(abi_unadjusted)]
140#![feature(adt_const_params)]
141#![feature(allow_internal_unsafe)]
142#![feature(allow_internal_unstable)]
143#![feature(auto_traits)]
144#![cfg_attr(not(feature = "ferrocene_subset"), feature(cfg_sanitize))]
145#![feature(cfg_target_has_atomic)]
146#![feature(cfg_target_has_atomic_equal_alignment)]
147#![feature(cfg_ub_checks)]
148#![feature(const_precise_live_drops)]
149#![feature(const_trait_impl)]
150#![feature(decl_macro)]
151#![feature(deprecated_suggestion)]
152#![feature(derive_const)]
153#![feature(diagnostic_on_const)]
154#![feature(doc_cfg)]
155#![cfg_attr(not(feature = "ferrocene_subset"), feature(doc_notable_trait))]
156#![feature(extern_types)]
157#![feature(f128)]
158#![feature(f16)]
159#![feature(freeze_impls)]
160#![feature(fundamental)]
161#![feature(funnel_shifts)]
162#![cfg_attr(not(feature = "ferrocene_subset"), feature(if_let_guard))]
163#![feature(intra_doc_pointers)]
164#![feature(intrinsics)]
165#![feature(lang_items)]
166#![feature(link_llvm_intrinsics)]
167#![feature(macro_metavar_expr)]
168#![cfg_attr(not(feature = "ferrocene_subset"), feature(macro_metavar_expr_concat))]
169#![feature(marker_trait_attr)]
170#![feature(min_specialization)]
171#![feature(multiple_supertrait_upcastable)]
172#![feature(must_not_suspend)]
173#![feature(negative_impls)]
174#![feature(never_type)]
175#![feature(no_core)]
176#![feature(optimize_attribute)]
177#![feature(pattern_types)]
178#![feature(prelude_import)]
179#![feature(reborrow)]
180#![feature(repr_simd)]
181#![feature(rustc_allow_const_fn_unstable)]
182#![feature(rustc_attrs)]
183#![feature(rustdoc_internals)]
184#![feature(simd_ffi)]
185#![feature(staged_api)]
186#![feature(stmt_expr_attributes)]
187#![feature(strict_provenance_lints)]
188#![feature(trait_alias)]
189#![feature(transparent_unions)]
190#![feature(try_blocks)]
191#![feature(unboxed_closures)]
192#![feature(unsized_fn_params)]
193#![cfg_attr(not(feature = "ferrocene_subset"), feature(with_negative_coherence))]
194// not-alphabetical-end
195//
196// Target features:
197// not-alphabetical-start
198#![cfg_attr(not(feature = "ferrocene_subset"), feature(aarch64_unstable_target_feature))]
199#![feature(arm_target_feature)]
200#![cfg_attr(not(feature = "ferrocene_subset"), feature(avx10_target_feature))]
201#![cfg_attr(not(feature = "ferrocene_subset"), feature(hexagon_target_feature))]
202#![cfg_attr(not(feature = "ferrocene_subset"), feature(loongarch_target_feature))]
203#![cfg_attr(not(feature = "ferrocene_subset"), feature(mips_target_feature))]
204#![cfg_attr(not(feature = "ferrocene_subset"), feature(powerpc_target_feature))]
205#![cfg_attr(not(feature = "ferrocene_subset"), feature(nvptx_target_feature))]
206#![cfg_attr(not(feature = "ferrocene_subset"), feature(riscv_target_feature))]
207#![cfg_attr(not(feature = "ferrocene_subset"), feature(rtm_target_feature))]
208#![cfg_attr(not(feature = "ferrocene_subset"), feature(s390x_target_feature))]
209#![cfg_attr(not(feature = "ferrocene_subset"), feature(wasm_target_feature))]
210#![cfg_attr(not(feature = "ferrocene_subset"), feature(x86_amx_intrinsics))]
211// not-alphabetical-end
212//
213// Ferrocene lints/features:
214#![cfg_attr(
215    feature = "ferrocene_subset",
216    expect(rustdoc::broken_intra_doc_links),
217    expect(rustdoc::private_intra_doc_links)
218)]
219#![feature(register_tool)]
220#![register_tool(ferrocene)]
221#![doc(auto_cfg(hide(feature = "ferrocene_subset")))]
222// Ferrocene addition: deals with all the unused code due to the lack of formatting machinery for
223// panics in the certified runtime
224#![cfg_attr(feature = "ferrocene_certified_runtime", expect(unused_variables))]
225
226// Ferrocene addition: ensure we don't instrument core without the certified panic
227#[cfg(all(ferrocene_coverage, not(feature = "ferrocene_certified_runtime")))]
228compile_error!("Cannot instrument core without the \"ferrocene_certified_runtime\" feature");
229
230// allow using `core::` in intra-doc links
231#[allow(unused_extern_crates)]
232extern crate self as core;
233
234/* The core prelude, not as all-encompassing as the std prelude */
235// The compiler expects the prelude definition to be defined before it's use statement.
236pub mod prelude;
237
238#[prelude_import]
239#[allow(unused)]
240use prelude::rust_2024::*;
241
242#[macro_use]
243mod macros;
244
245#[unstable(feature = "assert_matches", issue = "82775")]
246/// Unstable module containing the unstable `assert_matches` macro.
247#[cfg(not(feature = "ferrocene_subset"))]
248pub mod assert_matches {
249    #[unstable(feature = "assert_matches", issue = "82775")]
250    pub use crate::macros::{assert_matches, debug_assert_matches};
251}
252
253#[unstable(feature = "derive_from", issue = "144889")]
254/// Unstable module containing the unstable `From` derive macro.
255pub mod from {
256    #[unstable(feature = "derive_from", issue = "144889")]
257    pub use crate::macros::builtin::From;
258}
259
260// We don't export this through #[macro_export] for now, to avoid breakage.
261#[unstable(feature = "autodiff", issue = "124509")]
262/// Unstable module containing the unstable `autodiff` macro.
263pub mod autodiff {
264    #[unstable(feature = "autodiff", issue = "124509")]
265    pub use crate::macros::builtin::{autodiff_forward, autodiff_reverse};
266}
267
268#[unstable(feature = "contracts", issue = "128044")]
269#[cfg(not(feature = "ferrocene_subset"))]
270pub mod contracts;
271
272#[unstable(feature = "cfg_select", issue = "115585")]
273pub use crate::macros::cfg_select;
274
275#[macro_use]
276mod internal_macros;
277
278#[path = "num/shells/legacy_int_modules.rs"]
279#[cfg(not(feature = "ferrocene_subset"))]
280mod legacy_int_modules;
281#[stable(feature = "rust1", since = "1.0.0")]
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_subset"))]
285pub use legacy_int_modules::{i8, i16, i32, i64, isize, u8, u16, u32, u64, usize};
286#[stable(feature = "i128", since = "1.26.0")]
287#[allow(clippy::useless_attribute)] // FIXME false positive (https://github.com/rust-lang/rust-clippy/issues/15636)
288#[allow(deprecated_in_future)]
289#[cfg(not(feature = "ferrocene_subset"))]
290pub use legacy_int_modules::{i128, u128};
291
292#[path = "num/f128.rs"]
293#[cfg(not(feature = "ferrocene_subset"))]
294pub mod f128;
295#[path = "num/f16.rs"]
296#[cfg(not(feature = "ferrocene_subset"))]
297pub mod f16;
298#[path = "num/f32.rs"]
299pub mod f32;
300#[path = "num/f64.rs"]
301pub mod f64;
302
303#[macro_use]
304pub mod num;
305
306/* Core modules for ownership management */
307
308pub mod hint;
309pub mod intrinsics;
310pub mod mem;
311#[unstable(feature = "profiling_marker_api", issue = "148197")]
312pub mod profiling;
313pub mod ptr;
314#[unstable(feature = "ub_checks", issue = "none")]
315pub mod ub_checks;
316
317/* Core language traits */
318
319pub mod borrow;
320pub mod clone;
321pub mod cmp;
322pub mod convert;
323pub mod default;
324#[cfg(not(feature = "ferrocene_subset"))]
325pub mod error;
326#[cfg(not(feature = "ferrocene_subset"))]
327pub mod index;
328pub mod marker;
329pub mod ops;
330
331/* Core types and methods on primitives */
332
333pub mod any;
334pub mod array;
335#[cfg(not(feature = "ferrocene_subset"))]
336pub mod ascii;
337#[cfg(not(feature = "ferrocene_subset"))]
338pub mod asserting;
339#[unstable(feature = "async_iterator", issue = "79024")]
340#[cfg(not(feature = "ferrocene_subset"))]
341pub mod async_iter;
342#[unstable(feature = "bstr", issue = "134915")]
343#[cfg(not(feature = "ferrocene_subset"))]
344pub mod bstr;
345pub mod cell;
346pub mod char;
347pub mod ffi;
348#[unstable(feature = "core_io_borrowed_buf", issue = "117693")]
349#[cfg(not(feature = "ferrocene_subset"))]
350pub mod io;
351pub mod iter;
352#[cfg(not(feature = "ferrocene_subset"))]
353pub mod net;
354pub mod option;
355#[cfg(not(feature = "ferrocene_subset"))]
356pub mod os;
357pub mod panic;
358pub mod panicking;
359#[unstable(feature = "pattern_type_macro", issue = "123646")]
360#[cfg(not(feature = "ferrocene_subset"))]
361pub mod pat;
362#[cfg(not(feature = "ferrocene_subset"))]
363pub mod pin;
364#[unstable(feature = "random", issue = "130703")]
365#[cfg(not(feature = "ferrocene_subset"))]
366pub mod random;
367#[unstable(feature = "new_range_api", issue = "125687")]
368#[cfg(not(feature = "ferrocene_subset"))]
369pub mod range;
370pub mod result;
371pub mod sync;
372#[unstable(feature = "unsafe_binders", issue = "130516")]
373#[cfg(not(feature = "ferrocene_subset"))]
374pub mod unsafe_binder;
375
376pub mod fmt;
377pub mod hash;
378pub mod slice;
379pub mod str;
380pub mod time;
381
382#[cfg(not(feature = "ferrocene_subset"))]
383pub mod wtf8;
384
385#[cfg(not(feature = "ferrocene_subset"))]
386pub mod unicode;
387
388/* Async */
389#[cfg(not(feature = "ferrocene_subset"))]
390pub mod future;
391#[cfg(not(feature = "ferrocene_subset"))]
392pub mod task;
393
394/* Heap memory allocator trait */
395#[allow(missing_docs)]
396pub mod alloc;
397
398// note: does not need to be public
399mod bool;
400#[cfg(not(feature = "ferrocene_subset"))]
401mod escape;
402mod tuple;
403#[cfg(not(feature = "ferrocene_subset"))]
404mod unit;
405
406#[stable(feature = "core_primitive", since = "1.43.0")]
407#[cfg(not(feature = "ferrocene_subset"))]
408pub mod primitive;
409
410// Pull in the `core_arch` crate directly into core. The contents of
411// `core_arch` are in a different repository: rust-lang/stdarch.
412//
413// `core_arch` depends on core, but the contents of this module are
414// set up in such a way that directly pulling it here works such that the
415// crate uses the this crate as its core.
416#[path = "../../stdarch/crates/core_arch/src/mod.rs"]
417#[allow(
418    missing_docs,
419    missing_debug_implementations,
420    dead_code,
421    unused_imports,
422    unsafe_op_in_unsafe_fn,
423    ambiguous_glob_reexports,
424    deprecated_in_future,
425    unreachable_pub
426)]
427#[allow(rustdoc::bare_urls)]
428mod core_arch;
429
430#[stable(feature = "simd_arch", since = "1.27.0")]
431pub mod arch;
432
433// Pull in the `core_simd` crate directly into core. The contents of
434// `core_simd` are in a different repository: rust-lang/portable-simd.
435//
436// `core_simd` depends on core, but the contents of this module are
437// set up in such a way that directly pulling it here works such that the
438// crate uses this crate as its core.
439#[path = "../../portable-simd/crates/core_simd/src/mod.rs"]
440#[allow(missing_debug_implementations, dead_code, unsafe_op_in_unsafe_fn)]
441#[allow(rustdoc::bare_urls)]
442#[unstable(feature = "portable_simd", issue = "86656")]
443#[cfg(not(feature = "ferrocene_subset"))]
444mod core_simd;
445
446#[unstable(feature = "portable_simd", issue = "86656")]
447#[cfg(not(feature = "ferrocene_subset"))]
448pub mod simd {
449    #![doc = include_str!("../../portable-simd/crates/core_simd/src/core_simd_docs.md")]
450
451    #[unstable(feature = "portable_simd", issue = "86656")]
452    pub use crate::core_simd::simd::*;
453}
454
455include!("primitive_docs.rs");
core/lib.rs

core/
lib.rs
