Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Jump to bottom

Use inline const blocks to create arrays of MaybeUninit. #125995

Merged
merged 2 commits into from
Jun 5, 2024
Merged

Use inline const blocks to create arrays of MaybeUninit. #125995

Changes from all commits
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
ac96fa4
Use inline const instead of unsafe to construct arrays in `MaybeUnini…
kpreid May 13, 2024
ec8fa17
Use inline const instead of unsafe to implement `MaybeUninit::uninit_…
kpreid May 13, 2024
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
17 changes: 5 additions & 12 deletions library/core/src/mem/maybe_uninit.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -120,12 +120,8 @@ use crate::slice;
/// use std::mem::{self, MaybeUninit};
///
/// let data = {
/// // Create an uninitialized array of `MaybeUninit`. The `assume_init` is
/// // safe because the type we are claiming to have initialized here is a
/// // bunch of `MaybeUninit`s, which do not require initialization.
/// let mut data: [MaybeUninit<Vec<u32>>; 1000] = unsafe {
/// MaybeUninit::uninit().assume_init()
/// };
/// // Create an uninitialized array of `MaybeUninit`.
/// let mut data: [MaybeUninit<Vec<u32>>; 1000] = [const { MaybeUninit::uninit() }; 1000];
///
/// // Dropping a `MaybeUninit` does nothing, so if there is a panic during this loop,
/// // we have a memory leak, but there is no memory safety issue.
Expand All @@ -147,10 +143,8 @@ use crate::slice;
/// ```
/// use std::mem::MaybeUninit;
///
/// // Create an uninitialized array of `MaybeUninit`. The `assume_init` is
/// // safe because the type we are claiming to have initialized here is a
/// // bunch of `MaybeUninit`s, which do not require initialization.
/// let mut data: [MaybeUninit<String>; 1000] = unsafe { MaybeUninit::uninit().assume_init() };
/// // Create an uninitialized array of `MaybeUninit`.
/// let mut data: [MaybeUninit<String>; 1000] = [const { MaybeUninit::uninit() }; 1000];
/// // Count the number of elements we have assigned.
/// let mut data_len: usize = 0;
///
Expand Down Expand Up @@ -348,8 +342,7 @@ impl<T> MaybeUninit<T> {
#[must_use]
#[inline(always)]
pub const fn uninit_array<const N: usize>() -> [Self; N] {
// SAFETY: An uninitialized `[MaybeUninit<_>; LEN]` is valid.
unsafe { MaybeUninit::<[MaybeUninit<T>; N]>::uninit().assume_init() }
[const { MaybeUninit::uninit() }; N]
}

/// Creates a new `MaybeUninit<T>` in an uninitialized state, with the memory being
Expand Down
Loading