4 files changed, 6 insertions, 5 deletions
diff --git a/library/alloc/src/borrow.rs b/library/alloc/src/borrow.rs
index f86face3f90..dbfd2e74abe 100644
--- a/library/alloc/src/borrow.rs
+++ b/library/alloc/src/borrow.rs
@@ -225,7 +225,6 @@ impl<B: ?Sized + ToOwned> Cow<'_, B> {
     /// assert!(!bull.is_borrowed());
     /// ```
     #[unstable(feature = "cow_is_borrowed", issue = "65143")]
-    #[rustc_const_unstable(feature = "const_cow_is_borrowed", issue = "65143")]
     pub const fn is_borrowed(&self) -> bool {
         match *self {
             Borrowed(_) => true,
@@ -248,7 +247,6 @@ impl<B: ?Sized + ToOwned> Cow<'_, B> {
     /// assert!(!bull.is_owned());
     /// ```
     #[unstable(feature = "cow_is_borrowed", issue = "65143")]
-    #[rustc_const_unstable(feature = "const_cow_is_borrowed", issue = "65143")]
     pub const fn is_owned(&self) -> bool {
         !self.is_borrowed()
     }
diff --git a/library/alloc/src/lib.rs b/library/alloc/src/lib.rs
index 1d7b7a03454..72b3dda1c26 100644
--- a/library/alloc/src/lib.rs
+++ b/library/alloc/src/lib.rs
@@ -108,7 +108,6 @@
 #![feature(coerce_unsized)]
 #![feature(const_align_of_val)]
 #![feature(const_box)]
-#![feature(const_cow_is_borrowed)]
 #![feature(const_eval_select)]
 #![feature(const_heap)]
 #![feature(const_maybe_uninit_write)]
diff --git a/library/alloc/tests/lib.rs b/library/alloc/tests/lib.rs
index 4d146f1f5fd..3ec4332c71b 100644
--- a/library/alloc/tests/lib.rs
+++ b/library/alloc/tests/lib.rs
@@ -4,7 +4,6 @@
 #![feature(assert_matches)]
 #![feature(btree_extract_if)]
 #![feature(cow_is_borrowed)]
-#![feature(const_cow_is_borrowed)]
 #![feature(const_heap)]
 #![cfg_attr(bootstrap, feature(const_mut_refs))]
 #![feature(const_try)]
diff --git a/library/std/src/io/stdio.rs b/library/std/src/io/stdio.rs
index bf242e715bd..35b38ed783f 100644
--- a/library/std/src/io/stdio.rs
+++ b/library/std/src/io/stdio.rs
@@ -370,7 +370,12 @@ impl Stdin {
     /// Locks this handle and reads a line of input, appending it to the specified buffer.
     ///
     /// For detailed semantics of this method, see the documentation on
-    /// [`BufRead::read_line`].
+    /// [`BufRead::read_line`]. In particular:
+    /// * Previous content of the buffer will be preserved. To avoid appending
+    ///   to the buffer, you need to [`clear`] it first.
+    /// * The trailing newline character, if any, is included in the buffer.
+    ///
+    /// [`clear`]: String::clear
     ///
     /// # Examples
     ///