Auto merge of #50017 - tinaun:stabilize-all-the-things, r=sfackler

stabilize a bunch of minor api additions

besides `ptr::NonNull::cast` (which is 4 days away from end of FCP) all of these have been finished with FCP for a few weeks now with minimal issues raised

* Closes #41020
* Closes #42818
* Closes #44030
* Closes #44400
* Closes #46507
* Closes #47653
* Closes #46344

the following functions will be stabilized in 1.27:
* `[T]::rsplit`
* `[T]::rsplit_mut`
* `[T]::swap_with_slice`
* `ptr::swap_nonoverlapping`
* `NonNull::cast`
* `Duration::from_micros`
* `Duration::from_nanos`
* `Duration::subsec_millis`
* `Duration::subsec_micros`
* `HashMap::remove_entry`

src/liballoc/lib.rs

@@ -99,7 +99,6 @@
 #![feature(lang_items)]
 #![feature(libc)]
 #![feature(needs_allocator)]
-#![feature(nonnull_cast)]
 #![feature(nonzero)]
 #![feature(optin_builtin_traits)]
 #![feature(pattern)]
@@ -108,7 +107,6 @@
 #![feature(ptr_offset_from)]
 #![feature(rustc_attrs)]
 #![feature(slice_get_slice)]
-#![feature(slice_rsplit)]
 #![feature(specialization)]
 #![feature(staged_api)]
 #![feature(str_internals)]
@@ -124,7 +122,7 @@
 #![feature(inclusive_range_fields)]
 #![cfg_attr(stage0, feature(generic_param_attrs))]
 
-#![cfg_attr(not(test), feature(fn_traits, swap_with_slice, i128))]
+#![cfg_attr(not(test), feature(fn_traits, i128))]
 #![cfg_attr(test, feature(test))]
 
 // Allow testing this library

src/liballoc/slice.rs

@@ -116,7 +116,7 @@ pub use core::slice::{Iter, IterMut};
 pub use core::slice::{SplitMut, ChunksMut, Split};
 #[stable(feature = "rust1", since = "1.0.0")]
 pub use core::slice::{SplitN, RSplitN, SplitNMut, RSplitNMut};
-#[unstable(feature = "slice_rsplit", issue = "41020")]
+#[stable(feature = "slice_rsplit", since = "1.27.0")]
 pub use core::slice::{RSplit, RSplitMut};
 #[stable(feature = "rust1", since = "1.0.0")]
 pub use core::slice::{from_raw_parts, from_raw_parts_mut};
@@ -888,7 +888,6 @@ impl<T> [T] {
     /// # Examples
     ///
     /// ```
-    /// #![feature(slice_rsplit)]
     ///
     /// let slice = [11, 22, 33, 0, 44, 55];
     /// let mut iter = slice.rsplit(|num| *num == 0);
@@ -902,8 +901,6 @@ impl<T> [T] {
     /// slice will be the first (or last) item returned by the iterator.
     ///
     /// ```
-    /// #![feature(slice_rsplit)]
-    ///
     /// let v = &[0, 1, 1, 2, 3, 5, 8];
     /// let mut it = v.rsplit(|n| *n % 2 == 0);
     /// assert_eq!(it.next().unwrap(), &[]);
@@ -912,7 +909,7 @@ impl<T> [T] {
     /// assert_eq!(it.next().unwrap(), &[]);
     /// assert_eq!(it.next(), None);
     /// ```
-    #[unstable(feature = "slice_rsplit", issue = "41020")]
+    #[stable(feature = "slice_rsplit", since = "1.27.0")]
     #[inline]
     pub fn rsplit<F>(&self, pred: F) -> RSplit<T, F>
         where F: FnMut(&T) -> bool
@@ -927,8 +924,6 @@ impl<T> [T] {
     /// # Examples
     ///
     /// ```
-    /// #![feature(slice_rsplit)]
-    ///
     /// let mut v = [100, 400, 300, 200, 600, 500];
     ///
     /// let mut count = 0;
@@ -939,7 +934,7 @@ impl<T> [T] {
     /// assert_eq!(v, [3, 400, 300, 2, 600, 1]);
     /// ```
     ///
-    #[unstable(feature = "slice_rsplit", issue = "41020")]
+    #[stable(feature = "slice_rsplit", since = "1.27.0")]
     #[inline]
     pub fn rsplit_mut<F>(&mut self, pred: F) -> RSplitMut<T, F>
         where F: FnMut(&T) -> bool
@@ -1707,8 +1702,6 @@ impl<T> [T] {
     /// Swapping two elements across slices:
     ///
     /// ```
-    /// #![feature(swap_with_slice)]
-    ///
     /// let mut slice1 = [0, 0];
     /// let mut slice2 = [1, 2, 3, 4];
     ///
@@ -1724,8 +1717,6 @@ impl<T> [T] {
     /// a compile failure:
     ///
     /// ```compile_fail
-    /// #![feature(swap_with_slice)]
-    ///
     /// let mut slice = [1, 2, 3, 4, 5];
     /// slice[..2].swap_with_slice(&mut slice[3..]); // compile fail!
     /// ```
@@ -1734,8 +1725,6 @@ impl<T> [T] {
     /// mutable sub-slices from a slice:
     ///
     /// ```
-    /// #![feature(swap_with_slice)]
-    ///
     /// let mut slice = [1, 2, 3, 4, 5];
     ///
     /// {
@@ -1747,7 +1736,7 @@ impl<T> [T] {
     /// ```
     ///
     /// [`split_at_mut`]: #method.split_at_mut
-    #[unstable(feature = "swap_with_slice", issue = "44030")]
+    #[stable(feature = "swap_with_slice", since = "1.27.0")]
     pub fn swap_with_slice(&mut self, other: &mut [T]) {
         core_slice::SliceExt::swap_with_slice(self, other)
     }