Rollup merge of #50945 - stjepang:stabilize-from-ref, r=SimonSapin

Stabilize feature from_ref

Function `from_ref_mut` is now renamed to `from_mut`, as discussed in #45703.

Closes #45703.

r? @SimonSapin

src/liballoc/slice.rs

@@ -119,8 +119,8 @@
 pub use core::slice::{RSplit, RSplitMut};
 #[stable(feature = "rust1", since = "1.0.0")]
 pub use core::slice::{from_raw_parts, from_raw_parts_mut};
-#[unstable(feature = "from_ref", issue = "45703")]
-pub use core::slice::{from_ref, from_ref_mut};
+#[stable(feature = "from_ref", since = "1.28.0")]
+pub use core::slice::{from_ref, from_mut};
 #[unstable(feature = "slice_get_slice", issue = "35729")]
 pub use core::slice::SliceIndex;
 #[unstable(feature = "exact_chunks", issue = "47115")]

src/libcore/slice/mod.rs

@@ -3884,7 +3884,7 @@ pub unsafe fn from_raw_parts_mut<'a, T>(data: *mut T, len: usize) -> &'a mut [T]
 }
 
 /// Converts a reference to T into a slice of length 1 (without copying).
-#[unstable(feature = "from_ref", issue = "45703")]
+#[stable(feature = "from_ref", since = "1.28.0")]
 pub fn from_ref<T>(s: &T) -> &[T] {
     unsafe {
         from_raw_parts(s, 1)
@@ -3892,8 +3892,8 @@ pub fn from_ref<T>(s: &T) -> &[T] {
 }
 
 /// Converts a reference to T into a slice of length 1 (without copying).
-#[unstable(feature = "from_ref", issue = "45703")]
-pub fn from_ref_mut<T>(s: &mut T) -> &mut [T] {
+#[stable(feature = "from_ref", since = "1.28.0")]
+pub fn from_mut<T>(s: &mut T) -> &mut [T] {
     unsafe {
         from_raw_parts_mut(s, 1)
     }

src/librustc/mir/mod.rs

@@ -948,7 +948,7 @@ pub fn successors_mut(&mut self) -> SuccessorsMut {
             Drop { target: ref mut t, unwind: Some(ref mut u), .. } |
             Assert { target: ref mut t, cleanup: Some(ref mut u), .. } |
             FalseUnwind { real_target: ref mut t, unwind: Some(ref mut u) } => {
-                Some(t).into_iter().chain(slice::from_ref_mut(u))
+                Some(t).into_iter().chain(slice::from_mut(u))
             }
             SwitchInt { ref mut targets, .. } => {
                 None.into_iter().chain(&mut targets[..])