Rollup merge of #133762 - RalfJung:const-size-of-val, r=workingjubilee

stabilize const_{size,align}_of_val

FCP passed [here](https://github.com/rust-lang/rust/issues/46571#issuecomment-2460285288).

Fixes https://github.com/rust-lang/rust/issues/46571.

library/core/src/alloc/layout.rs

@@ -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

library/core/src/intrinsics/mod.rs

@@ -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!()
 }

library/core/src/mem/mod.rs

@@ -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) }

library/core/tests/lib.rs

@@ -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)]

tests/ui/consts/const-size_of_val-align_of_val-extern-type.rs

@@ -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};
 

tests/ui/consts/const-size_of_val-align_of_val-extern-type.stderr

@@ -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

tests/ui/consts/const-size_of_val-align_of_val.rs

@@ -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};