Rollup merge of #67462 - DutchGhost:const_slice_from_raw_parts, r=dtolnay

Make ptr::slice_from_raw_parts a const fn available under a feature flag

A first step in the direction of https://github.com/rust-lang/rust/issues/67456 .
This makes `ptr::slice_from_raw_parts` and `ptr::slice_from_raw_parts_mut` available as a const fn under a feature flag.

1 files changed, 4 insertions, 2 deletions

diff --git a/src/libcore/ptr/mod.rs b/src/libcore/ptr/mod.rs
index a3a73ff6c6c..924563fc44f 100644
--- a/src/libcore/ptr/mod.rs
+++ b/src/libcore/ptr/mod.rs
@@ -259,7 +259,8 @@ pub(crate) struct FatPtr<T> {
 /// ```
 #[inline]
 #[unstable(feature = "slice_from_raw_parts", reason = "recently added", issue = "36925")]
-pub fn slice_from_raw_parts<T>(data: *const T, len: usize) -> *const [T] {
+#[rustc_const_unstable(feature = "const_slice_from_raw_parts", issue = "67456")]
+pub const fn slice_from_raw_parts<T>(data: *const T, len: usize) -> *const [T] {
     unsafe { Repr { raw: FatPtr { data, len } }.rust }
 }
 
@@ -275,7 +276,8 @@ pub fn slice_from_raw_parts<T>(data: *const T, len: usize) -> *const [T] {
 /// [`from_raw_parts_mut`]: ../../std/slice/fn.from_raw_parts_mut.html
 #[inline]
 #[unstable(feature = "slice_from_raw_parts", reason = "recently added", issue = "36925")]
-pub fn slice_from_raw_parts_mut<T>(data: *mut T, len: usize) -> *mut [T] {
+#[rustc_const_unstable(feature = "const_slice_from_raw_parts", issue = "67456")]
+pub const fn slice_from_raw_parts_mut<T>(data: *mut T, len: usize) -> *mut [T] {
     unsafe { Repr { raw: FatPtr { data, len } }.rust_mut }
 }