5830ca216d
It lints against features that are inteded to be internal to the compiler and standard library. Implements MCP #596. We allow `internal_features` in the standard library and compiler as those use many features and this _is_ the standard library from the "internal to the compiler and standard library" after all. Marking some features as internal wasn't exactly the most scientific approach, I just marked some mostly obvious features. While there is a categorization in the macro, it's not very well upheld (should probably be fixed in another PR). We always pass `-Ainternal_features` in the testsuite About 400 UI tests and several other tests use internal features. Instead of throwing the attribute on each one, just always allow them. There's nothing wrong with testing internal features^^
280 lines
9.2 KiB
Rust
280 lines
9.2 KiB
Rust
//! # The Rust core allocation and collections library
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//!
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//! This library provides smart pointers and collections for managing
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//! heap-allocated values.
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//!
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//! This library, like core, normally doesn’t need to be used directly
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//! since its contents are re-exported in the [`std` crate](../std/index.html).
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//! Crates that use the `#![no_std]` attribute however will typically
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//! not depend on `std`, so they’d use this crate instead.
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//!
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//! ## Boxed values
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//!
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//! The [`Box`] type is a smart pointer type. There can only be one owner of a
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//! [`Box`], and the owner can decide to mutate the contents, which live on the
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//! heap.
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//!
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//! This type can be sent among threads efficiently as the size of a `Box` value
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//! is the same as that of a pointer. Tree-like data structures are often built
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//! with boxes because each node often has only one owner, the parent.
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//!
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//! ## Reference counted pointers
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//!
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//! The [`Rc`] type is a non-threadsafe reference-counted pointer type intended
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//! for sharing memory within a thread. An [`Rc`] pointer wraps a type, `T`, and
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//! only allows access to `&T`, a shared reference.
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//!
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//! This type is useful when inherited mutability (such as using [`Box`]) is too
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//! constraining for an application, and is often paired with the [`Cell`] or
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//! [`RefCell`] types in order to allow mutation.
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//!
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//! ## Atomically reference counted pointers
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//!
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//! The [`Arc`] type is the threadsafe equivalent of the [`Rc`] type. It
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//! provides all the same functionality of [`Rc`], except it requires that the
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//! contained type `T` is shareable. Additionally, [`Arc<T>`][`Arc`] is itself
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//! sendable while [`Rc<T>`][`Rc`] is not.
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//!
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//! This type allows for shared access to the contained data, and is often
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//! paired with synchronization primitives such as mutexes to allow mutation of
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//! shared resources.
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//!
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//! ## Collections
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//!
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//! Implementations of the most common general purpose data structures are
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//! defined in this library. They are re-exported through the
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//! [standard collections library](../std/collections/index.html).
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//!
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//! ## Heap interfaces
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//!
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//! The [`alloc`](alloc/index.html) module defines the low-level interface to the
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//! default global allocator. It is not compatible with the libc allocator API.
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//!
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//! [`Arc`]: sync
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//! [`Box`]: boxed
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//! [`Cell`]: core::cell
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//! [`Rc`]: rc
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//! [`RefCell`]: core::cell
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// To run alloc tests without x.py without ending up with two copies of alloc, Miri needs to be
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// able to "empty" this crate. See <https://github.com/rust-lang/miri-test-libstd/issues/4>.
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// rustc itself never sets the feature, so this line has no affect there.
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#![cfg(any(not(feature = "miri-test-libstd"), test, doctest))]
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//
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#![allow(unused_attributes)]
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#![stable(feature = "alloc", since = "1.36.0")]
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#![doc(
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html_playground_url = "https://play.rust-lang.org/",
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issue_tracker_base_url = "https://github.com/rust-lang/rust/issues/",
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test(no_crate_inject, attr(allow(unused_variables), deny(warnings)))
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)]
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#![doc(cfg_hide(
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not(test),
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not(any(test, bootstrap)),
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any(not(feature = "miri-test-libstd"), test, doctest),
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no_global_oom_handling,
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not(no_global_oom_handling),
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not(no_rc),
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not(no_sync),
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target_has_atomic = "ptr"
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))]
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#![no_std]
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#![needs_allocator]
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// Lints:
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#![deny(unsafe_op_in_unsafe_fn)]
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#![deny(fuzzy_provenance_casts)]
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#![warn(deprecated_in_future)]
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#![warn(missing_debug_implementations)]
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#![warn(missing_docs)]
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#![allow(explicit_outlives_requirements)]
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#![warn(multiple_supertrait_upcastable)]
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#![cfg_attr(not(bootstrap), allow(internal_features))]
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//
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// Library features:
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// tidy-alphabetical-start
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#![cfg_attr(not(no_global_oom_handling), feature(const_alloc_error))]
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#![cfg_attr(not(no_global_oom_handling), feature(const_btree_len))]
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#![cfg_attr(test, feature(is_sorted))]
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#![cfg_attr(test, feature(new_uninit))]
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#![feature(alloc_layout_extra)]
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#![feature(allocator_api)]
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#![feature(array_chunks)]
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#![feature(array_into_iter_constructors)]
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#![feature(array_methods)]
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#![feature(array_windows)]
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#![feature(ascii_char)]
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#![feature(assert_matches)]
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#![feature(async_iterator)]
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#![feature(coerce_unsized)]
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#![feature(const_align_of_val)]
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#![feature(const_box)]
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#![feature(const_cow_is_borrowed)]
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#![feature(const_eval_select)]
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#![feature(const_maybe_uninit_as_mut_ptr)]
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#![feature(const_maybe_uninit_write)]
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#![feature(const_maybe_uninit_zeroed)]
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#![feature(const_pin)]
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#![feature(const_refs_to_cell)]
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#![feature(const_size_of_val)]
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#![feature(const_waker)]
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#![feature(core_intrinsics)]
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#![feature(core_panic)]
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#![feature(dispatch_from_dyn)]
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#![feature(error_generic_member_access)]
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#![feature(error_in_core)]
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#![feature(exact_size_is_empty)]
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#![feature(extend_one)]
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#![feature(fmt_internals)]
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#![feature(fn_traits)]
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#![feature(hasher_prefixfree_extras)]
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#![feature(inline_const)]
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#![feature(inplace_iteration)]
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#![feature(iter_advance_by)]
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#![feature(iter_next_chunk)]
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#![feature(iter_repeat_n)]
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#![feature(layout_for_ptr)]
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#![feature(maybe_uninit_slice)]
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#![feature(maybe_uninit_uninit_array)]
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#![feature(maybe_uninit_uninit_array_transpose)]
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#![feature(pattern)]
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#![feature(pointer_byte_offsets)]
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#![feature(provide_any)]
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#![feature(ptr_internals)]
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#![feature(ptr_metadata)]
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#![feature(ptr_sub_ptr)]
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#![feature(receiver_trait)]
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#![feature(saturating_int_impl)]
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#![feature(set_ptr_value)]
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#![feature(sized_type_properties)]
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#![feature(slice_from_ptr_range)]
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#![feature(slice_group_by)]
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#![feature(slice_ptr_get)]
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#![feature(slice_ptr_len)]
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#![feature(slice_range)]
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#![feature(std_internals)]
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#![feature(str_internals)]
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#![feature(strict_provenance)]
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#![feature(trusted_len)]
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#![feature(trusted_random_access)]
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#![feature(try_trait_v2)]
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#![feature(tuple_trait)]
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#![feature(unchecked_math)]
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#![feature(unicode_internals)]
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#![feature(unsize)]
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#![feature(utf8_chunks)]
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// tidy-alphabetical-end
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//
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// Language features:
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// tidy-alphabetical-start
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#![cfg_attr(not(test), feature(generator_trait))]
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#![cfg_attr(test, feature(panic_update_hook))]
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#![cfg_attr(test, feature(test))]
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#![feature(allocator_internals)]
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#![feature(allow_internal_unstable)]
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#![feature(associated_type_bounds)]
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#![feature(c_unwind)]
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#![feature(cfg_sanitize)]
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#![feature(const_mut_refs)]
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#![feature(const_precise_live_drops)]
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#![feature(const_ptr_write)]
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#![feature(const_trait_impl)]
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#![feature(const_try)]
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#![feature(dropck_eyepatch)]
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#![feature(exclusive_range_pattern)]
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#![feature(fundamental)]
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#![feature(hashmap_internals)]
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#![feature(lang_items)]
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#![feature(min_specialization)]
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#![feature(multiple_supertrait_upcastable)]
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#![feature(negative_impls)]
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#![feature(never_type)]
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#![feature(pointer_is_aligned)]
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#![feature(rustc_allow_const_fn_unstable)]
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#![feature(rustc_attrs)]
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#![feature(slice_internals)]
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#![feature(staged_api)]
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#![feature(stmt_expr_attributes)]
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#![feature(unboxed_closures)]
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#![feature(unsized_fn_params)]
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#![feature(with_negative_coherence)]
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// tidy-alphabetical-end
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//
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// Rustdoc features:
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#![feature(doc_cfg)]
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#![feature(doc_cfg_hide)]
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// Technically, this is a bug in rustdoc: rustdoc sees the documentation on `#[lang = slice_alloc]`
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// blocks is for `&[T]`, which also has documentation using this feature in `core`, and gets mad
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// that the feature-gate isn't enabled. Ideally, it wouldn't check for the feature gate for docs
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// from other crates, but since this can only appear for lang items, it doesn't seem worth fixing.
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#![feature(intra_doc_pointers)]
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// Allow testing this library
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#[cfg(test)]
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#[macro_use]
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extern crate std;
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#[cfg(test)]
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extern crate test;
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#[cfg(test)]
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mod testing;
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// Module with internal macros used by other modules (needs to be included before other modules).
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#[macro_use]
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mod macros;
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mod raw_vec;
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// Heaps provided for low-level allocation strategies
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pub mod alloc;
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// Primitive types using the heaps above
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// Need to conditionally define the mod from `boxed.rs` to avoid
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// duplicating the lang-items when building in test cfg; but also need
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// to allow code to have `use boxed::Box;` declarations.
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#[cfg(not(test))]
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pub mod boxed;
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#[cfg(test)]
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mod boxed {
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pub use std::boxed::Box;
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}
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pub mod borrow;
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pub mod collections;
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#[cfg(all(not(no_rc), not(no_sync), not(no_global_oom_handling)))]
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pub mod ffi;
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pub mod fmt;
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#[cfg(not(no_rc))]
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pub mod rc;
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pub mod slice;
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pub mod str;
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pub mod string;
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#[cfg(all(not(no_rc), not(no_sync), target_has_atomic = "ptr"))]
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pub mod sync;
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#[cfg(all(not(no_global_oom_handling), not(no_rc), not(no_sync), target_has_atomic = "ptr"))]
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pub mod task;
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#[cfg(test)]
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mod tests;
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pub mod vec;
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#[doc(hidden)]
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#[unstable(feature = "liballoc_internals", issue = "none", reason = "implementation detail")]
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pub mod __export {
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pub use core::format_args;
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}
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#[cfg(test)]
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#[allow(dead_code)] // Not used in all configurations
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pub(crate) mod test_helpers {
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/// Copied from `std::test_helpers::test_rng`, since these tests rely on the
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/// seed not being the same for every RNG invocation too.
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pub(crate) fn test_rng() -> rand_xorshift::XorShiftRng {
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use std::hash::{BuildHasher, Hash, Hasher};
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let mut hasher = std::collections::hash_map::RandomState::new().build_hasher();
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std::panic::Location::caller().hash(&mut hasher);
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let hc64 = hasher.finish();
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let seed_vec =
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hc64.to_le_bytes().into_iter().chain(0u8..8).collect::<crate::vec::Vec<u8>>();
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let seed: [u8; 16] = seed_vec.as_slice().try_into().unwrap();
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rand::SeedableRng::from_seed(seed)
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}
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}
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