Rollup merge of #44640 - budziq:stabilize_splice, r=dtolnay

Stabilized vec_splice and modified splice tracking issue

This stabilizes the vec_splice (Vec part of splice RFC)
Fixes #32310.

src/doc/unstable-book/src/library-features/splice.md

@@ -1,14 +1,13 @@
 # `splice`
 
-The tracking issue for this feature is: [#32310]
+The tracking issue for this feature is: [#44643]
 
-[#32310]: https://github.com/rust-lang/rust/issues/32310
+[#44643]: https://github.com/rust-lang/rust/issues/44643
 
 ------------------------
 
-The `splice()` method on `Vec` and `String` allows you to replace a range
-of values in a vector or string with another range of values, and returns
-the replaced values.
+The `splice()` method on `String` allows you to replace a range
+of values in a string with another range of values.
 
 A simple example:
 
@@ -20,4 +19,4 @@ let beta_offset = s.find('β').unwrap_or(s.len());
 // Replace the range up until the β from the string
 s.splice(..beta_offset, "Α is capital alpha; ");
 assert_eq!(s, "Α is capital alpha; β is beta");
-```
+```

src/liballoc/string.rs

@@ -1451,7 +1451,7 @@ pub fn drain<R>(&mut self, range: R) -> Drain
     /// s.splice(..beta_offset, "Α is capital alpha; ");
     /// assert_eq!(s, "Α is capital alpha; β is beta");
     /// ```
-    #[unstable(feature = "splice", reason = "recently added", issue = "32310")]
+    #[unstable(feature = "splice", reason = "recently added", issue = "44643")]
     pub fn splice<R>(&mut self, range: R, replace_with: &str)
         where R: RangeArgument<usize>
     {

src/liballoc/vec.rs

@@ -1943,7 +1943,6 @@ fn extend_desugared<I: Iterator<Item = T>>(&mut self, mut iterator: I) {
     /// # Examples
     ///
     /// ```
-    /// #![feature(splice)]
     /// let mut v = vec![1, 2, 3];
     /// let new = [7, 8];
     /// let u: Vec<_> = v.splice(..2, new.iter().cloned()).collect();
@@ -1951,7 +1950,7 @@ fn extend_desugared<I: Iterator<Item = T>>(&mut self, mut iterator: I) {
     /// assert_eq!(u, &[1, 2]);
     /// ```
     #[inline]
-    #[unstable(feature = "splice", reason = "recently added", issue = "32310")]
+    #[stable(feature = "vec_splice", since = "1.22.0")]
     pub fn splice<R, I>(&mut self, range: R, replace_with: I) -> Splice<I::IntoIter>
         where R: RangeArgument<usize>, I: IntoIterator<Item=T>
     {
@@ -2554,13 +2553,13 @@ unsafe fn finalize(mut self) -> &'a mut T {
 /// [`splice()`]: struct.Vec.html#method.splice
 /// [`Vec`]: struct.Vec.html
 #[derive(Debug)]
-#[unstable(feature = "splice", reason = "recently added", issue = "32310")]
+#[stable(feature = "vec_splice", since = "1.22.0")]
 pub struct Splice<'a, I: Iterator + 'a> {
     drain: Drain<'a, I::Item>,
     replace_with: I,
 }
 
-#[unstable(feature = "splice", reason = "recently added", issue = "32310")]
+#[stable(feature = "vec_splice", since = "1.22.0")]
 impl<'a, I: Iterator> Iterator for Splice<'a, I> {
     type Item = I::Item;
 
@@ -2573,18 +2572,18 @@ fn size_hint(&self) -> (usize, Option<usize>) {
     }
 }
 
-#[unstable(feature = "splice", reason = "recently added", issue = "32310")]
+#[stable(feature = "vec_splice", since = "1.22.0")]
 impl<'a, I: Iterator> DoubleEndedIterator for Splice<'a, I> {
     fn next_back(&mut self) -> Option<Self::Item> {
         self.drain.next_back()
     }
 }
 
-#[unstable(feature = "splice", reason = "recently added", issue = "32310")]
+#[stable(feature = "vec_splice", since = "1.22.0")]
 impl<'a, I: Iterator> ExactSizeIterator for Splice<'a, I> {}
 
 
-#[unstable(feature = "splice", reason = "recently added", issue = "32310")]
+#[stable(feature = "vec_splice", since = "1.22.0")]
 impl<'a, I: Iterator> Drop for Splice<'a, I> {
     fn drop(&mut self) {
         // exhaust drain first