lib.rs

//! # The Rust Core Library
//!
//! The Rust Core Library is the dependency-free[^free] foundation of [The
//! Rust Standard Library](../std/index.html). It is the portable glue
//! between the language and its libraries, defining the intrinsic and
//! primitive building blocks of all Rust code. It links to no
//! upstream libraries, no system libraries, and no libc.
//!
//! [^free]: Strictly speaking, there are some symbols which are needed but
//!          they aren't always necessary.
//!
//! The core library is *minimal*: it isn't even aware of heap allocation,
//! nor does it provide concurrency or I/O. These things require
//! platform integration, and this library is platform-agnostic.
//!
//! # How to use the core library
//!
//! Please note that all of these details are currently not considered stable.
//!
// FIXME: Fill me in with more detail when the interface settles
//! This library is built on the assumption of a few existing symbols:
//!
//! * `memcpy`, `memmove`, `memset`, `memcmp`, `bcmp`, `strlen` - These are core memory routines
//!   which are generated by Rust codegen backends. Additionally, this library can make explicit
//!   calls to `strlen`. Their signatures are the same as found in C, but there are extra
//!   assumptions about their semantics: For `memcpy`, `memmove`, `memset`, `memcmp`, and `bcmp`, if
//!   the `n` parameter is 0, the function is assumed to not be UB, even if the pointers are NULL or
//!   dangling. (Note that making extra assumptions about these functions is common among compilers:
//!   [clang](https://reviews.llvm.org/D86993) and [GCC](https://gcc.gnu.org/onlinedocs/gcc/Standards.html#C-Language) do the same.)
//!   These functions are often provided by the system libc, but can also be provided by the
//!   [compiler-builtins crate](https://crates.io/crates/compiler_builtins).
//!   Note that the library does not guarantee that it will always make these assumptions, so Rust
//!   user code directly calling the C functions should follow the C specification! The advice for
//!   Rust user code is to call the functions provided by this library instead (such as
//!   `ptr::copy`).
//!
//! * Panic handler - This function takes one argument, a `&panic::PanicInfo`. It is up to consumers of this core
//!   library to define this panic function; it is only required to never
//!   return. You should mark your implementation using `#[panic_handler]`.
//!
//! * `rust_eh_personality` - is used by the failure mechanisms of the
//!    compiler. This is often mapped to GCC's personality function, but crates
//!    which do not trigger a panic can be assured that this function is never
//!    called. The `lang` attribute is called `eh_personality`.

// Since core defines many fundamental lang items, all tests live in a
// separate crate, coretests (library/coretests), to avoid bizarre issues.
//
// Here we explicitly #[cfg]-out this whole crate when testing. If we don't do
// this, both the generated test artifact and the linked libtest (which
// transitively includes core) will both define the same set of lang items,
// and this will cause the E0152 "found duplicate lang item" error. See
// discussion in #50466 for details.
//
// This cfg won't affect doc tests.
#![cfg(not(test))]
//
#![stable(feature = "core", since = "1.6.0")]
#![doc(
    html_playground_url = "https://play.rust-lang.org/",
    issue_tracker_base_url = "https://github.com/rust-lang/rust/issues/",
    test(no_crate_inject, attr(deny(warnings))),
    test(attr(allow(dead_code, deprecated, unused_variables, unused_mut)))
)]
#![doc(rust_logo)]
#![doc(cfg_hide(
    not(test),
    no_fp_fmt_parse,
    target_pointer_width = "16",
    target_pointer_width = "32",
    target_pointer_width = "64",
    target_has_atomic = "8",
    target_has_atomic = "16",
    target_has_atomic = "32",
    target_has_atomic = "64",
    target_has_atomic = "ptr",
    target_has_atomic_equal_alignment = "8",
    target_has_atomic_equal_alignment = "16",
    target_has_atomic_equal_alignment = "32",
    target_has_atomic_equal_alignment = "64",
    target_has_atomic_equal_alignment = "ptr",
    target_has_atomic_load_store = "8",
    target_has_atomic_load_store = "16",
    target_has_atomic_load_store = "32",
    target_has_atomic_load_store = "64",
    target_has_atomic_load_store = "ptr",
))]
#![no_core]
#![rustc_coherence_is_core]
#![rustc_preserve_ub_checks]
//
// Lints:
#![deny(rust_2021_incompatible_or_patterns)]
#![deny(unsafe_op_in_unsafe_fn)]
#![deny(fuzzy_provenance_casts)]
#![warn(deprecated_in_future)]
#![warn(missing_debug_implementations)]
#![warn(missing_docs)]
#![allow(explicit_outlives_requirements)]
#![allow(incomplete_features)]
#![warn(multiple_supertrait_upcastable)]
#![allow(internal_features)]
#![deny(ffi_unwind_calls)]
#![warn(unreachable_pub)]
// Do not check link redundancy on bootstraping phase
#![allow(rustdoc::redundant_explicit_links)]
#![warn(rustdoc::unescaped_backticks)]
//
// Library features:
// tidy-alphabetical-start
#![cfg_attr(not(bootstrap), feature(contracts))]
#![feature(array_ptr_get)]
#![feature(asm_experimental_arch)]
#![feature(bigint_helper_methods)]
#![feature(bstr)]
#![feature(bstr_internals)]
#![feature(closure_track_caller)]
#![feature(const_carrying_mul_add)]
#![feature(const_eval_select)]
#![feature(core_intrinsics)]
#![feature(coverage_attribute)]
#![feature(disjoint_bitor)]
#![feature(internal_impls_macro)]
#![feature(ip)]
#![feature(is_ascii_octdigit)]
#![feature(lazy_get)]
#![feature(link_cfg)]
#![feature(non_null_from_ref)]
#![feature(offset_of_enum)]
#![feature(panic_internals)]
#![feature(ptr_alignment_type)]
#![feature(ptr_metadata)]
#![feature(set_ptr_value)]
#![feature(slice_as_array)]
#![feature(slice_as_chunks)]
#![feature(slice_ptr_get)]
#![feature(str_internals)]
#![feature(str_split_inclusive_remainder)]
#![feature(str_split_remainder)]
#![feature(ub_checks)]
#![feature(unchecked_neg)]
#![feature(unchecked_shifts)]
#![feature(utf16_extra)]
#![feature(variant_count)]
// tidy-alphabetical-end
//
// Language features:
// tidy-alphabetical-start
#![feature(abi_unadjusted)]
#![feature(adt_const_params)]
#![feature(allow_internal_unsafe)]
#![feature(allow_internal_unstable)]
#![feature(auto_traits)]
#![feature(cfg_sanitize)]
#![feature(cfg_target_has_atomic)]
#![feature(cfg_target_has_atomic_equal_alignment)]
#![feature(cfg_ub_checks)]
#![feature(const_precise_live_drops)]
#![feature(const_trait_impl)]
#![feature(decl_macro)]
#![feature(deprecated_suggestion)]
#![feature(doc_cfg)]
#![feature(doc_cfg_hide)]
#![feature(doc_notable_trait)]
#![feature(extern_types)]
#![feature(f128)]
#![feature(f16)]
#![feature(freeze_impls)]
#![feature(fundamental)]
#![feature(generic_arg_infer)]
#![feature(if_let_guard)]
#![feature(intra_doc_pointers)]
#![feature(intrinsics)]
#![feature(lang_items)]
#![feature(let_chains)]
#![feature(link_llvm_intrinsics)]
#![feature(macro_metavar_expr)]
#![feature(marker_trait_attr)]
#![feature(min_specialization)]
#![feature(multiple_supertrait_upcastable)]
#![feature(must_not_suspend)]
#![feature(negative_impls)]
#![feature(never_type)]
#![feature(no_core)]
#![feature(no_sanitize)]
#![feature(optimize_attribute)]
#![feature(prelude_import)]
#![feature(repr_simd)]
#![feature(rustc_allow_const_fn_unstable)]
#![feature(rustc_attrs)]
#![feature(rustdoc_internals)]
#![feature(simd_ffi)]
#![feature(staged_api)]
#![feature(stmt_expr_attributes)]
#![feature(strict_provenance_lints)]
#![feature(trait_alias)]
#![feature(transparent_unions)]
#![feature(try_blocks)]
#![feature(unboxed_closures)]
#![feature(unsized_fn_params)]
#![feature(with_negative_coherence)]
// tidy-alphabetical-end
//
// Target features:
// tidy-alphabetical-start
#![feature(aarch64_unstable_target_feature)]
#![feature(arm_target_feature)]
#![feature(avx512_target_feature)]
#![feature(hexagon_target_feature)]
#![feature(keylocker_x86)]
#![feature(loongarch_target_feature)]
#![feature(mips_target_feature)]
#![feature(powerpc_target_feature)]
#![feature(riscv_target_feature)]
#![feature(rtm_target_feature)]
#![feature(s390x_target_feature)]
#![feature(sha512_sm_x86)]
#![feature(sse4a_target_feature)]
#![feature(tbm_target_feature)]
#![feature(wasm_target_feature)]
#![feature(x86_amx_intrinsics)]
// tidy-alphabetical-end

// allow using `core::` in intra-doc links
#[allow(unused_extern_crates)]
extern crate self as core;

#[prelude_import]
#[allow(unused)]
use prelude::rust_2024::*;

#[cfg(not(test))] // See #65860
#[macro_use]
mod macros;

// We don't export this through #[macro_export] for now, to avoid breakage.
// See https://github.com/rust-lang/rust/issues/82913
#[cfg(not(test))]
#[unstable(feature = "assert_matches", issue = "82775")]
/// Unstable module containing the unstable `assert_matches` macro.
pub mod assert_matches {
    #[unstable(feature = "assert_matches", issue = "82775")]
    pub use crate::macros::{assert_matches, debug_assert_matches};
}

// We don't export this through #[macro_export] for now, to avoid breakage.
#[unstable(feature = "autodiff", issue = "124509")]
/// Unstable module containing the unstable `autodiff` macro.
pub mod autodiff {
    #[unstable(feature = "autodiff", issue = "124509")]
    pub use crate::macros::builtin::autodiff;
}

#[unstable(feature = "contracts", issue = "128044")]
pub mod contracts;

#[unstable(feature = "cfg_match", issue = "115585")]
pub use crate::macros::cfg_match;

#[macro_use]
mod internal_macros;

#[path = "num/shells/int_macros.rs"]
#[macro_use]
mod int_macros;

#[rustc_diagnostic_item = "i128_legacy_mod"]
#[path = "num/shells/i128.rs"]
pub mod i128;
#[rustc_diagnostic_item = "i16_legacy_mod"]
#[path = "num/shells/i16.rs"]
pub mod i16;
#[rustc_diagnostic_item = "i32_legacy_mod"]
#[path = "num/shells/i32.rs"]
pub mod i32;
#[rustc_diagnostic_item = "i64_legacy_mod"]
#[path = "num/shells/i64.rs"]
pub mod i64;
#[rustc_diagnostic_item = "i8_legacy_mod"]
#[path = "num/shells/i8.rs"]
pub mod i8;
#[rustc_diagnostic_item = "isize_legacy_mod"]
#[path = "num/shells/isize.rs"]
pub mod isize;

#[rustc_diagnostic_item = "u128_legacy_mod"]
#[path = "num/shells/u128.rs"]
pub mod u128;
#[rustc_diagnostic_item = "u16_legacy_mod"]
#[path = "num/shells/u16.rs"]
pub mod u16;
#[rustc_diagnostic_item = "u32_legacy_mod"]
#[path = "num/shells/u32.rs"]
pub mod u32;
#[rustc_diagnostic_item = "u64_legacy_mod"]
#[path = "num/shells/u64.rs"]
pub mod u64;
#[rustc_diagnostic_item = "u8_legacy_mod"]
#[path = "num/shells/u8.rs"]
pub mod u8;
#[rustc_diagnostic_item = "usize_legacy_mod"]
#[path = "num/shells/usize.rs"]
pub mod usize;

#[path = "num/f128.rs"]
pub mod f128;
#[path = "num/f16.rs"]
pub mod f16;
#[path = "num/f32.rs"]
pub mod f32;
#[path = "num/f64.rs"]
pub mod f64;

#[macro_use]
pub mod num;

/* The core prelude, not as all-encompassing as the std prelude */

pub mod prelude;

/* Core modules for ownership management */

pub mod hint;
pub mod intrinsics;
pub mod mem;
pub mod ptr;
#[unstable(feature = "ub_checks", issue = "none")]
pub mod ub_checks;

/* Core language traits */

pub mod borrow;
pub mod clone;
pub mod cmp;
pub mod convert;
pub mod default;
pub mod error;
pub mod marker;
pub mod ops;

/* Core types and methods on primitives */

pub mod any;
pub mod array;
pub mod ascii;
pub mod asserting;
#[unstable(feature = "async_iterator", issue = "79024")]
pub mod async_iter;
#[unstable(feature = "bstr", issue = "134915")]
pub mod bstr;
pub mod cell;
pub mod char;
pub mod ffi;
#[unstable(feature = "core_io_borrowed_buf", issue = "117693")]
pub mod io;
pub mod iter;
pub mod net;
pub mod option;
pub mod panic;
pub mod panicking;
#[unstable(feature = "pattern_type_macro", issue = "123646")]
pub mod pat;
pub mod pin;
#[unstable(feature = "random", issue = "130703")]
pub mod random;
#[unstable(feature = "new_range_api", issue = "125687")]
pub mod range;
pub mod result;
pub mod sync;
#[unstable(feature = "unsafe_binders", issue = "130516")]
pub mod unsafe_binder;

pub mod fmt;
pub mod hash;
pub mod slice;
pub mod str;
pub mod time;

pub mod unicode;

/* Async */
pub mod future;
pub mod task;

/* Heap memory allocator trait */
#[allow(missing_docs)]
pub mod alloc;

// note: does not need to be public
mod bool;
mod escape;
mod tuple;
mod unit;

#[stable(feature = "core_primitive", since = "1.43.0")]
pub mod primitive;

// Pull in the `core_arch` crate directly into core. The contents of
// `core_arch` are in a different repository: rust-lang/stdarch.
//
// `core_arch` depends on core, but the contents of this module are
// set up in such a way that directly pulling it here works such that the
// crate uses the this crate as its core.
#[path = "../../stdarch/crates/core_arch/src/mod.rs"]
#[allow(
    missing_docs,
    missing_debug_implementations,
    dead_code,
    unused_imports,
    unsafe_op_in_unsafe_fn,
    ambiguous_glob_reexports,
    deprecated_in_future,
    unreachable_pub
)]
#[allow(rustdoc::bare_urls)]
mod core_arch;

#[stable(feature = "simd_arch", since = "1.27.0")]
pub mod arch;

// Pull in the `core_simd` crate directly into core. The contents of
// `core_simd` are in a different repository: rust-lang/portable-simd.
//
// `core_simd` depends on core, but the contents of this module are
// set up in such a way that directly pulling it here works such that the
// crate uses this crate as its core.
#[path = "../../portable-simd/crates/core_simd/src/mod.rs"]
#[allow(missing_debug_implementations, dead_code, unsafe_op_in_unsafe_fn)]
#[allow(rustdoc::bare_urls)]
#[unstable(feature = "portable_simd", issue = "86656")]
mod core_simd;

#[unstable(feature = "portable_simd", issue = "86656")]
pub mod simd {
    #![doc = include_str!("../../portable-simd/crates/core_simd/src/core_simd_docs.md")]

    #[unstable(feature = "portable_simd", issue = "86656")]
    pub use crate::core_simd::simd::*;
}

include!("primitive_docs.rs");