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make Cell unstably const #131281

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Merged
merged 1 commit into from
Oct 5, 2024
Merged

make Cell unstably const #131281

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18 changes: 12 additions & 6 deletions library/core/src/cell.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -494,8 +494,9 @@ impl<T> Cell<T> {
/// ```
#[inline]
#[stable(feature = "move_cell", since = "1.17.0")]
#[rustc_const_unstable(feature = "const_cell", issue = "131283")]
#[rustc_confusables("swap")]
pub fn replace(&self, val: T) -> T {
pub const fn replace(&self, val: T) -> T {
// SAFETY: This can cause data races if called from a separate thread,
// but `Cell` is `!Sync` so this won't happen.
mem::replace(unsafe { &mut *self.value.get() }, val)
Expand Down Expand Up @@ -535,7 +536,8 @@ impl<T: Copy> Cell<T> {
/// ```
#[inline]
#[stable(feature = "rust1", since = "1.0.0")]
pub fn get(&self) -> T {
#[rustc_const_unstable(feature = "const_cell", issue = "131283")]
pub const fn get(&self) -> T {
// SAFETY: This can cause data races if called from a separate thread,
// but `Cell` is `!Sync` so this won't happen.
unsafe { *self.value.get() }
Expand Down Expand Up @@ -613,7 +615,8 @@ impl<T: ?Sized> Cell<T> {
/// ```
#[inline]
#[stable(feature = "cell_get_mut", since = "1.11.0")]
pub fn get_mut(&mut self) -> &mut T {
#[rustc_const_unstable(feature = "const_cell", issue = "131283")]
pub const fn get_mut(&mut self) -> &mut T {
self.value.get_mut()
}

Expand All @@ -632,7 +635,8 @@ impl<T: ?Sized> Cell<T> {
/// ```
#[inline]
#[stable(feature = "as_cell", since = "1.37.0")]
pub fn from_mut(t: &mut T) -> &Cell<T> {
#[rustc_const_unstable(feature = "const_cell", issue = "131283")]
pub const fn from_mut(t: &mut T) -> &Cell<T> {
// SAFETY: `&mut` ensures unique access.
unsafe { &*(t as *mut T as *const Cell<T>) }
}
Expand Down Expand Up @@ -686,7 +690,8 @@ impl<T> Cell<[T]> {
/// assert_eq!(slice_cell.len(), 3);
/// ```
#[stable(feature = "as_cell", since = "1.37.0")]
pub fn as_slice_of_cells(&self) -> &[Cell<T>] {
#[rustc_const_unstable(feature = "const_cell", issue = "131283")]
pub const fn as_slice_of_cells(&self) -> &[Cell<T>] {
// SAFETY: `Cell<T>` has the same memory layout as `T`.
unsafe { &*(self as *const Cell<[T]> as *const [Cell<T>]) }
}
Expand All @@ -706,7 +711,8 @@ impl<T, const N: usize> Cell<[T; N]> {
/// let array_cell: &[Cell<i32>; 3] = cell_array.as_array_of_cells();
/// ```
#[unstable(feature = "as_array_of_cells", issue = "88248")]
pub fn as_array_of_cells(&self) -> &[Cell<T>; N] {
#[rustc_const_unstable(feature = "as_array_of_cells", issue = "88248")]
pub const fn as_array_of_cells(&self) -> &[Cell<T>; N] {
// SAFETY: `Cell<T>` has the same memory layout as `T`.
unsafe { &*(self as *const Cell<[T; N]> as *const [Cell<T>; N]) }
}
Expand Down
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