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stabilize const_{size,align}_of_val
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RalfJung committed Dec 2, 2024
1 parent 3bff51e commit 2b88e4c
Showing 7 changed files with 8 additions and 11 deletions.
2 changes: 1 addition & 1 deletion library/core/src/alloc/layout.rs
Original file line number Diff line number Diff line change
@@ -179,6 +179,7 @@ impl Layout {
/// or other unsized type like a slice).
#[stable(feature = "alloc_layout", since = "1.28.0")]
#[rustc_const_unstable(feature = "const_alloc_layout", issue = "67521")]
#[rustc_const_stable_indirect]
#[must_use]
#[inline]
pub const fn for_value<T: ?Sized>(t: &T) -> Self {
@@ -215,7 +216,6 @@ impl Layout {
/// [trait object]: ../../book/ch17-02-trait-objects.html
/// [extern type]: ../../unstable-book/language-features/extern-types.html
#[unstable(feature = "layout_for_ptr", issue = "69835")]
#[rustc_const_unstable(feature = "layout_for_ptr", issue = "69835")]
#[must_use]
pub const unsafe fn for_value_raw<T: ?Sized>(t: *const T) -> Self {
// SAFETY: we pass along the prerequisites of these functions to the caller
2 changes: 2 additions & 0 deletions library/core/src/intrinsics/mod.rs
Original file line number Diff line number Diff line change
@@ -4099,6 +4099,7 @@ pub const fn variant_count<T>() -> usize {
#[unstable(feature = "core_intrinsics", issue = "none")]
#[rustc_intrinsic]
#[rustc_intrinsic_must_be_overridden]
#[rustc_intrinsic_const_stable_indirect]
pub const unsafe fn size_of_val<T: ?Sized>(_ptr: *const T) -> usize {
unreachable!()
}
@@ -4114,6 +4115,7 @@ pub const unsafe fn size_of_val<T: ?Sized>(_ptr: *const T) -> usize {
#[unstable(feature = "core_intrinsics", issue = "none")]
#[rustc_intrinsic]
#[rustc_intrinsic_must_be_overridden]
#[rustc_intrinsic_const_stable_indirect]
pub const unsafe fn min_align_of_val<T: ?Sized>(_ptr: *const T) -> usize {
unreachable!()
}
6 changes: 2 additions & 4 deletions library/core/src/mem/mod.rs
Original file line number Diff line number Diff line change
@@ -333,7 +333,7 @@ pub const fn size_of<T>() -> usize {
#[inline]
#[must_use]
#[stable(feature = "rust1", since = "1.0.0")]
#[rustc_const_unstable(feature = "const_size_of_val", issue = "46571")]
#[rustc_const_stable(feature = "const_size_of_val", since = "CURRENT_RUSTC_VERSION")]
#[cfg_attr(not(test), rustc_diagnostic_item = "mem_size_of_val")]
pub const fn size_of_val<T: ?Sized>(val: &T) -> usize {
// SAFETY: `val` is a reference, so it's a valid raw pointer
@@ -390,7 +390,6 @@ pub const fn size_of_val<T: ?Sized>(val: &T) -> usize {
#[inline]
#[must_use]
#[unstable(feature = "layout_for_ptr", issue = "69835")]
#[rustc_const_unstable(feature = "const_size_of_val_raw", issue = "46571")]
pub const unsafe fn size_of_val_raw<T: ?Sized>(val: *const T) -> usize {
// SAFETY: the caller must provide a valid raw pointer
unsafe { intrinsics::size_of_val(val) }
@@ -485,7 +484,7 @@ pub const fn align_of<T>() -> usize {
#[inline]
#[must_use]
#[stable(feature = "rust1", since = "1.0.0")]
#[rustc_const_unstable(feature = "const_align_of_val", issue = "46571")]
#[rustc_const_stable(feature = "const_align_of_val", since = "CURRENT_RUSTC_VERSION")]
#[allow(deprecated)]
pub const fn align_of_val<T: ?Sized>(val: &T) -> usize {
// SAFETY: val is a reference, so it's a valid raw pointer
@@ -534,7 +533,6 @@ pub const fn align_of_val<T: ?Sized>(val: &T) -> usize {
#[inline]
#[must_use]
#[unstable(feature = "layout_for_ptr", issue = "69835")]
#[rustc_const_unstable(feature = "const_align_of_val_raw", issue = "46571")]
pub const unsafe fn align_of_val_raw<T: ?Sized>(val: *const T) -> usize {
// SAFETY: the caller must provide a valid raw pointer
unsafe { intrinsics::min_align_of_val(val) }
1 change: 0 additions & 1 deletion library/core/tests/lib.rs
Original file line number Diff line number Diff line change
@@ -13,7 +13,6 @@
#![feature(bigint_helper_methods)]
#![feature(cell_update)]
#![feature(clone_to_uninit)]
#![feature(const_align_of_val_raw)]
#![feature(const_black_box)]
#![feature(const_eval_select)]
#![feature(const_nonnull_new)]
Original file line number Diff line number Diff line change
@@ -1,6 +1,5 @@
#![feature(extern_types)]
#![feature(core_intrinsics)]
#![feature(const_size_of_val, const_align_of_val)]

use std::intrinsics::{min_align_of_val, size_of_val};

Original file line number Diff line number Diff line change
@@ -1,11 +1,11 @@
error[E0080]: evaluation of constant value failed
--> $DIR/const-size_of_val-align_of_val-extern-type.rs:11:31
--> $DIR/const-size_of_val-align_of_val-extern-type.rs:10:31
|
LL | const _SIZE: usize = unsafe { size_of_val(&4 as *const i32 as *const Opaque) };
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ `extern type` does not have known layout

error[E0080]: evaluation of constant value failed
--> $DIR/const-size_of_val-align_of_val-extern-type.rs:12:32
--> $DIR/const-size_of_val-align_of_val-extern-type.rs:11:32
|
LL | const _ALIGN: usize = unsafe { min_align_of_val(&4 as *const i32 as *const Opaque) };
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ `extern type` does not have known layout
3 changes: 1 addition & 2 deletions tests/ui/consts/const-size_of_val-align_of_val.rs
Original file line number Diff line number Diff line change
@@ -1,7 +1,6 @@
//@ run-pass

#![feature(const_size_of_val, const_align_of_val)]
#![feature(const_size_of_val_raw, const_align_of_val_raw, layout_for_ptr)]
#![feature(layout_for_ptr)]

use std::{mem, ptr};

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