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stabilize const_cell_into_inner
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RalfJung committed Sep 28, 2024
1 parent 3a00bff commit b8c2a2a
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Showing 5 changed files with 11 additions and 51 deletions.
51 changes: 6 additions & 45 deletions core/src/cell.rs
Original file line number Diff line number Diff line change
Expand Up @@ -514,7 +514,8 @@ impl<T> Cell<T> {
/// assert_eq!(five, 5);
/// ```
#[stable(feature = "move_cell", since = "1.17.0")]
#[rustc_const_unstable(feature = "const_cell_into_inner", issue = "78729")]
#[rustc_const_stable(feature = "const_cell_into_inner", since = "CURRENT_RUSTC_VERSION")]
#[rustc_allow_const_fn_unstable(const_precise_live_drops)]
pub const fn into_inner(self) -> T {
self.value.into_inner()
}
Expand Down Expand Up @@ -857,7 +858,8 @@ impl<T> RefCell<T> {
/// let five = c.into_inner();
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[rustc_const_unstable(feature = "const_cell_into_inner", issue = "78729")]
#[rustc_const_stable(feature = "const_cell_into_inner", since = "CURRENT_RUSTC_VERSION")]
#[rustc_allow_const_fn_unstable(const_precise_live_drops)]
#[inline]
pub const fn into_inner(self) -> T {
// Since this function takes `self` (the `RefCell`) by value, the
Expand Down Expand Up @@ -2098,8 +2100,8 @@ impl<T> UnsafeCell<T> {
/// ```
#[inline(always)]
#[stable(feature = "rust1", since = "1.0.0")]
// When this is const stabilized, please remove `primitive_into_inner` below.
#[rustc_const_unstable(feature = "const_cell_into_inner", issue = "78729")]
#[rustc_const_stable(feature = "const_cell_into_inner", since = "CURRENT_RUSTC_VERSION")]
#[rustc_allow_const_fn_unstable(const_precise_live_drops)]
pub const fn into_inner(self) -> T {
self.value
}
Expand Down Expand Up @@ -2245,47 +2247,6 @@ impl<T: CoerceUnsized<U>, U> CoerceUnsized<UnsafeCell<U>> for UnsafeCell<T> {}
#[unstable(feature = "dispatch_from_dyn", issue = "none")]
impl<T: DispatchFromDyn<U>, U> DispatchFromDyn<UnsafeCell<U>> for UnsafeCell<T> {}

// Special cases of UnsafeCell::into_inner where T is a primitive. These are
// used by Atomic*::into_inner.
//
// The real UnsafeCell::into_inner cannot be used yet in a stable const function.
// That is blocked on a "precise drop analysis" unstable const feature.
// https://github.com/rust-lang/rust/issues/73255
macro_rules! unsafe_cell_primitive_into_inner {
($($primitive:ident $atomic:literal)*) => {
$(
#[cfg(target_has_atomic_load_store = $atomic)]
impl UnsafeCell<$primitive> {
pub(crate) const fn primitive_into_inner(self) -> $primitive {
self.value
}
}
)*
};
}

unsafe_cell_primitive_into_inner! {
i8 "8"
u8 "8"
i16 "16"
u16 "16"
i32 "32"
u32 "32"
i64 "64"
u64 "64"
i128 "128"
u128 "128"
isize "ptr"
usize "ptr"
}

#[cfg(target_has_atomic_load_store = "ptr")]
impl<T> UnsafeCell<*mut T> {
pub(crate) const fn primitive_into_inner(self) -> *mut T {
self.value
}
}

/// [`UnsafeCell`], but [`Sync`].
///
/// This is just an `UnsafeCell`, except it implements `Sync`
Expand Down
3 changes: 2 additions & 1 deletion core/src/cell/once.rs
Original file line number Diff line number Diff line change
Expand Up @@ -309,7 +309,8 @@ impl<T> OnceCell<T> {
/// ```
#[inline]
#[stable(feature = "once_cell", since = "1.70.0")]
#[rustc_const_unstable(feature = "const_cell_into_inner", issue = "78729")]
#[rustc_const_stable(feature = "const_cell_into_inner", since = "CURRENT_RUSTC_VERSION")]
#[rustc_allow_const_fn_unstable(const_precise_live_drops)]
pub const fn into_inner(self) -> Option<T> {
// Because `into_inner` takes `self` by value, the compiler statically verifies
// that it is not currently borrowed. So it is safe to move out `Option<T>`.
Expand Down
1 change: 0 additions & 1 deletion core/src/lib.rs
Original file line number Diff line number Diff line change
Expand Up @@ -118,7 +118,6 @@
#![feature(const_array_into_iter_constructors)]
#![feature(const_bigint_helper_methods)]
#![feature(const_black_box)]
#![feature(const_cell_into_inner)]
#![feature(const_char_encode_utf16)]
#![feature(const_char_encode_utf8)]
#![feature(const_eval_select)]
Expand Down
6 changes: 3 additions & 3 deletions core/src/sync/atomic.rs
Original file line number Diff line number Diff line change
Expand Up @@ -577,7 +577,7 @@ impl AtomicBool {
#[stable(feature = "atomic_access", since = "1.15.0")]
#[rustc_const_stable(feature = "const_atomic_into_inner", since = "1.79.0")]
pub const fn into_inner(self) -> bool {
self.v.primitive_into_inner() != 0
self.v.into_inner() != 0
}

/// Loads a value from the bool.
Expand Down Expand Up @@ -1394,7 +1394,7 @@ impl<T> AtomicPtr<T> {
#[stable(feature = "atomic_access", since = "1.15.0")]
#[rustc_const_stable(feature = "const_atomic_into_inner", since = "1.79.0")]
pub const fn into_inner(self) -> *mut T {
self.p.primitive_into_inner()
self.p.into_inner()
}

/// Loads a value from the pointer.
Expand Down Expand Up @@ -2389,7 +2389,7 @@ macro_rules! atomic_int {
#[$stable_access]
#[rustc_const_stable(feature = "const_atomic_into_inner", since = "1.79.0")]
pub const fn into_inner(self) -> $int_type {
self.v.primitive_into_inner()
self.v.into_inner()
}

/// Loads a value from the atomic integer.
Expand Down
1 change: 0 additions & 1 deletion core/tests/lib.rs
Original file line number Diff line number Diff line change
Expand Up @@ -18,7 +18,6 @@
#![feature(const_align_offset)]
#![feature(const_array_from_ref)]
#![feature(const_black_box)]
#![feature(const_cell_into_inner)]
#![feature(const_hash)]
#![feature(const_heap)]
#![feature(const_ip)]
Expand Down

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