Unrolled build for #147540

Rollup merge of #147540 - bjoernager:slice-as-array, r=Amanieu

Stabilise `as_array` in `[_]` and `*const [_]`; stabilise `as_mut_array` in `[_]` and `*mut [_]`.

Tracking issue: #133508

Closes: #133508

This PR stabilises the `as_array` and `as_mut_array` associated functions from the `core_slice_as_array` feature gate:

```rust
// core::slice

impl<T> [T] {
    pub const fn as_array<const N: usize>(&self) -> Option<&[T; N]>;

    pub const fn as_mut_array<const N: usize>(&mut self) -> Option<&mut [T; N]>;
}

// core::ptr

impl<T> *const [T] {
    pub const fn as_array<const N: usize>(self) -> Option<*const [T; N]>;
}

impl<T> *mut [T] {
    pub const fn as_mut_array<const N: usize>(self) -> Option<*mut [T; N]>;
}
```

It also updates the feature gates and tracking issues for all items associated with the previous `slice_as_array` tracking issue (including these four that are being stabilised).

~~FCP missing.~~

Author: rust-timer

compiler/rustc_codegen_llvm/src/lib.rs

@@ -5,14 +5,14 @@
 //! This API is completely unstable and subject to change.
 
 // tidy-alphabetical-start
+#![cfg_attr(bootstrap, feature(slice_as_array))]
 #![feature(assert_matches)]
 #![feature(extern_types)]
 #![feature(file_buffered)]
 #![feature(if_let_guard)]
 #![feature(impl_trait_in_assoc_type)]
 #![feature(iter_intersperse)]
 #![feature(macro_derive)]
-#![feature(slice_as_array)]
 #![feature(trim_prefix_suffix)]
 #![feature(try_blocks)]
 // tidy-alphabetical-end

library/alloc/src/boxed.rs

@@ -850,7 +850,7 @@ impl<T> Box<[T]> {
     /// This operation does not reallocate; the underlying array of the slice is simply reinterpreted as an array type.
     ///
     /// If `N` is not exactly equal to the length of `self`, then this method returns `None`.
-    #[unstable(feature = "slice_as_array", issue = "133508")]
+    #[unstable(feature = "alloc_slice_into_array", issue = "148082")]
     #[inline]
     #[must_use]
     pub fn into_array<const N: usize>(self) -> Option<Box<[T; N]>> {

library/alloc/src/rc.rs

@@ -1166,7 +1166,7 @@ impl<T> Rc<[T]> {
     /// This operation does not reallocate; the underlying array of the slice is simply reinterpreted as an array type.
     ///
     /// If `N` is not exactly equal to the length of `self`, then this method returns `None`.
-    #[unstable(feature = "slice_as_array", issue = "133508")]
+    #[unstable(feature = "alloc_slice_into_array", issue = "148082")]
     #[inline]
     #[must_use]
     pub fn into_array<const N: usize>(self) -> Option<Rc<[T; N]>> {

library/alloc/src/sync.rs

@@ -1314,7 +1314,7 @@ impl<T> Arc<[T]> {
     /// This operation does not reallocate; the underlying array of the slice is simply reinterpreted as an array type.
     ///
     /// If `N` is not exactly equal to the length of `self`, then this method returns `None`.
-    #[unstable(feature = "slice_as_array", issue = "133508")]
+    #[unstable(feature = "alloc_slice_into_array", issue = "148082")]
     #[inline]
     #[must_use]
     pub fn into_array<const N: usize>(self) -> Option<Arc<[T; N]>> {

library/core/src/lib.rs

@@ -121,7 +121,6 @@
 #![feature(ptr_alignment_type)]
 #![feature(ptr_metadata)]
 #![feature(set_ptr_value)]
-#![feature(slice_as_array)]
 #![feature(slice_ptr_get)]
 #![feature(str_internals)]
 #![feature(str_split_inclusive_remainder)]

library/core/src/ptr/const_ptr.rs

@@ -1462,7 +1462,8 @@ impl<T> *const [T] {
     /// Gets a raw pointer to the underlying array.
     ///
     /// If `N` is not exactly equal to the length of `self`, then this method returns `None`.
-    #[unstable(feature = "slice_as_array", issue = "133508")]
+    #[stable(feature = "core_slice_as_array", since = "CURRENT_RUSTC_VERSION")]
+    #[rustc_const_stable(feature = "core_slice_as_array", since = "CURRENT_RUSTC_VERSION")]
     #[inline]
     #[must_use]
     pub const fn as_array<const N: usize>(self) -> Option<*const [T; N]> {

library/core/src/ptr/mut_ptr.rs

@@ -1712,7 +1712,8 @@ impl<T> *mut [T] {
     /// Gets a raw, mutable pointer to the underlying array.
     ///
     /// If `N` is not exactly equal to the length of `self`, then this method returns `None`.
-    #[unstable(feature = "slice_as_array", issue = "133508")]
+    #[stable(feature = "core_slice_as_array", since = "CURRENT_RUSTC_VERSION")]
+    #[rustc_const_stable(feature = "core_slice_as_array", since = "CURRENT_RUSTC_VERSION")]
     #[inline]
     #[must_use]
     pub const fn as_mut_array<const N: usize>(self) -> Option<*mut [T; N]> {

library/core/src/slice/mod.rs

@@ -841,7 +841,8 @@ impl<T> [T] {
     /// Gets a reference to the underlying array.
     ///
     /// If `N` is not exactly equal to the length of `self`, then this method returns `None`.
-    #[unstable(feature = "slice_as_array", issue = "133508")]
+    #[stable(feature = "core_slice_as_array", since = "CURRENT_RUSTC_VERSION")]
+    #[rustc_const_stable(feature = "core_slice_as_array", since = "CURRENT_RUSTC_VERSION")]
     #[inline]
     #[must_use]
     pub const fn as_array<const N: usize>(&self) -> Option<&[T; N]> {
@@ -859,7 +860,8 @@ impl<T> [T] {
     /// Gets a mutable reference to the slice's underlying array.
     ///
     /// If `N` is not exactly equal to the length of `self`, then this method returns `None`.
-    #[unstable(feature = "slice_as_array", issue = "133508")]
+    #[stable(feature = "core_slice_as_array", since = "CURRENT_RUSTC_VERSION")]
+    #[rustc_const_stable(feature = "core_slice_as_array", since = "CURRENT_RUSTC_VERSION")]
     #[inline]
     #[must_use]
     pub const fn as_mut_array<const N: usize>(&mut self) -> Option<&mut [T; N]> {