Auto merge of #41437 - cuviper:remove-unstable-deprecated, r=alexcrichton

Remove items that are unstable and deprecated

This removes unstable items that have been deprecated for more than one cycle.

- Since 1.16.0, `#![feature(enumset)]`
    - All of `mod collections::enum_set`
- Since 1.15.0, `#![feature(borrow_state)]`
    - `cell::BorrowState`
    - `RefCell::borrow_state()`
- Since 1.15.0, `#![feature(is_unique)]`
    - `Rc::is_unique()` (made private like `Arc::is_unique()`)
- Since 1.15.0, `#![feature(rc_would_unwrap)]`
    - `Rc::would_wrap()`
- Since 1.13.0, `#![feature(binary_heap_extras)]`
    - `BinaryHeap::push_pop()`
    - `BinaryHeap::replace()`
- Since 1.12.0, `#![feature(as_unsafe_cell)]`
    - `Cell::as_unsafe_cell()`
    - `RefCell::as_unsafe_cell()`
- Since 1.12.0, `#![feature(map_entry_recover_keys)]`
    - `btree_map::OccupiedEntry::remove_pair()`
    - `hash_map::OccupiedEntry::remove_pair()`
- Since 1.11.0, `#![feature(float_extras)]`
    - `Float::nan()`
    - `Float::infinity()`
    - `Float::neg_infinity()`
    - `Float::neg_zero()`
    - `Float::zero()`
    - `Float::one()`
    - `Float::integer_decode()`
    - `f32::integer_decode()`
    - `f32::ldexp()`
    - `f32::frexp()`
    - `f32::next_after()`
    - `f64::integer_decode()`
    - `f64::ldexp()`
    - `f64::frexp()`
    - `f64::next_after()`
- Since 1.11.0, `#![feature(zero_one)]`
    - `num::Zero`
    - `num::One`

Author: bors

src/doc/unstable-book/src/SUMMARY.md

@@ -102,11 +102,8 @@
     - [alloc_system](library-features/alloc-system.md)
     - [alloc](library-features/alloc.md)
     - [as_c_str](library-features/as-c-str.md)
-    - [as_unsafe_cell](library-features/as-unsafe-cell.md)
     - [ascii_ctype](library-features/ascii-ctype.md)
-    - [binary_heap_extras](library-features/binary-heap-extras.md)
     - [binary_heap_peek_mut_pop](library-features/binary-heap-peek-mut-pop.md)
-    - [borrow_state](library-features/borrow-state.md)
     - [box_heap](library-features/box-heap.md)
     - [c_void_variant](library-features/c-void-variant.md)
     - [char_escape_debug](library-features/char-escape-debug.md)
@@ -131,14 +128,12 @@
     - [derive_clone_copy](library-features/derive-clone-copy.md)
     - [derive_eq](library-features/derive-eq.md)
     - [discriminant_value](library-features/discriminant-value.md)
-    - [enumset](library-features/enumset.md)
     - [error_type_id](library-features/error-type-id.md)
     - [exact_size_is_empty](library-features/exact-size-is-empty.md)
     - [fd](library-features/fd.md)
     - [fd_read](library-features/fd-read.md)
     - [fixed_size_array](library-features/fixed-size-array.md)
     - [float_bits_conv](library-features/float-bits-conv.md)
-    - [float_extras](library-features/float-extras.md)
     - [flt2dec](library-features/flt2dec.md)
     - [fmt_flags_align](library-features/fmt-flags-align.md)
     - [fmt_internals](library-features/fmt-internals.md)
@@ -158,15 +153,13 @@
     - [io_error_internals](library-features/io-error-internals.md)
     - [io](library-features/io.md)
     - [ip](library-features/ip.md)
-    - [is_unique](library-features/is-unique.md)
     - [iter_rfind](library-features/iter-rfind.md)
     - [libstd_io_internals](library-features/libstd-io-internals.md)
     - [libstd_sys_internals](library-features/libstd-sys-internals.md)
     - [libstd_thread_internals](library-features/libstd-thread-internals.md)
     - [linked_list_extras](library-features/linked-list-extras.md)
     - [lookup_host](library-features/lookup-host.md)
     - [manually_drop](library-features/manually-drop.md)
-    - [map_entry_recover_keys](library-features/map-entry-recover-keys.md)
     - [mpsc_select](library-features/mpsc-select.md)
     - [n16](library-features/n16.md)
     - [never_type_impls](library-features/never-type-impls.md)
@@ -189,7 +182,6 @@
     - [rand](library-features/rand.md)
     - [range_contains](library-features/range-contains.md)
     - [raw](library-features/raw.md)
-    - [rc_would_unwrap](library-features/rc-would-unwrap.md)
     - [retain_hash_collection](library-features/retain-hash-collection.md)
     - [reverse_cmp_key](library-features/reverse-cmp-key.md)
     - [rt](library-features/rt.md)
@@ -225,5 +217,3 @@
     - [windows_handle](library-features/windows-handle.md)
     - [windows_net](library-features/windows-net.md)
     - [windows_stdio](library-features/windows-stdio.md)
-    - [zero_one](library-features/zero-one.md)
->>>>>> Add top level sections to the Unstable Book.

src/doc/unstable-book/src/library-features/as-unsafe-cell.md

@@ -340,19 +340,6 @@ impl<T> Rc<T> {
         }
     }
 
-    /// Checks whether [`Rc::try_unwrap`][try_unwrap] would return
-    /// [`Ok`].
-    ///
-    /// [try_unwrap]: struct.Rc.html#method.try_unwrap
-    /// [`Ok`]: ../../std/result/enum.Result.html#variant.Ok
-    #[unstable(feature = "rc_would_unwrap",
-               reason = "just added for niche usecase",
-               issue = "28356")]
-    #[rustc_deprecated(since = "1.15.0", reason = "too niche; use `strong_count` instead")]
-    pub fn would_unwrap(this: &Self) -> bool {
-        Rc::strong_count(&this) == 1
-    }
-
     /// Consumes the `Rc`, returning the wrapped pointer.
     ///
     /// To avoid a memory leak the pointer must be converted back to an `Rc` using
@@ -532,11 +519,7 @@ impl<T: ?Sized> Rc<T> {
     ///
     /// [weak]: struct.Weak.html
     #[inline]
-    #[unstable(feature = "is_unique", reason = "uniqueness has unclear meaning",
-               issue = "28356")]
-    #[rustc_deprecated(since = "1.15.0",
-                       reason = "too niche; use `strong_count` and `weak_count` instead")]
-    pub fn is_unique(this: &Self) -> bool {
+    fn is_unique(this: &Self) -> bool {
         Rc::weak_count(this) == 0 && Rc::strong_count(this) == 1
     }
 

src/doc/unstable-book/src/library-features/binary-heap-extras.md

@@ -555,82 +555,6 @@ impl<T: Ord> BinaryHeap<T> {
         self.sift_up(0, old_len);
     }
 
-    /// Pushes an item onto the binary heap, then pops the greatest item off the queue in
-    /// an optimized fashion.
-    ///
-    /// # Examples
-    ///
-    /// Basic usage:
-    ///
-    /// ```
-    /// #![feature(binary_heap_extras)]
-    /// #![allow(deprecated)]
-    ///
-    /// use std::collections::BinaryHeap;
-    /// let mut heap = BinaryHeap::new();
-    /// heap.push(1);
-    /// heap.push(5);
-    ///
-    /// assert_eq!(heap.push_pop(3), 5);
-    /// assert_eq!(heap.push_pop(9), 9);
-    /// assert_eq!(heap.len(), 2);
-    /// assert_eq!(heap.peek(), Some(&3));
-    /// ```
-    #[unstable(feature = "binary_heap_extras",
-               reason = "needs to be audited",
-               issue = "28147")]
-    #[rustc_deprecated(since = "1.13.0", reason = "use `peek_mut` instead")]
-    pub fn push_pop(&mut self, mut item: T) -> T {
-        match self.data.get_mut(0) {
-            None => return item,
-            Some(top) => {
-                if *top > item {
-                    swap(&mut item, top);
-                } else {
-                    return item;
-                }
-            }
-        }
-
-        self.sift_down(0);
-        item
-    }
-
-    /// Pops the greatest item off the binary heap, then pushes an item onto the queue in
-    /// an optimized fashion. The push is done regardless of whether the binary heap
-    /// was empty.
-    ///
-    /// # Examples
-    ///
-    /// Basic usage:
-    ///
-    /// ```
-    /// #![feature(binary_heap_extras)]
-    /// #![allow(deprecated)]
-    ///
-    /// use std::collections::BinaryHeap;
-    /// let mut heap = BinaryHeap::new();
-    ///
-    /// assert_eq!(heap.replace(1), None);
-    /// assert_eq!(heap.replace(3), Some(1));
-    /// assert_eq!(heap.len(), 1);
-    /// assert_eq!(heap.peek(), Some(&3));
-    /// ```
-    #[unstable(feature = "binary_heap_extras",
-               reason = "needs to be audited",
-               issue = "28147")]
-    #[rustc_deprecated(since = "1.13.0", reason = "use `peek_mut` instead")]
-    pub fn replace(&mut self, mut item: T) -> Option<T> {
-        if !self.is_empty() {
-            swap(&mut item, &mut self.data[0]);
-            self.sift_down(0);
-            Some(item)
-        } else {
-            self.push(item);
-            None
-        }
-    }
-
     /// Consumes the `BinaryHeap` and returns the underlying vector
     /// in arbitrary order.
     ///

src/doc/unstable-book/src/library-features/borrow-state.md

@@ -2217,13 +2217,6 @@ impl<'a, K: Ord, V> OccupiedEntry<'a, K, V> {
         self.handle.reborrow().into_kv().0
     }
 
-    /// Deprecated, renamed to `remove_entry`
-    #[unstable(feature = "map_entry_recover_keys", issue = "34285")]
-    #[rustc_deprecated(since = "1.12.0", reason = "renamed to `remove_entry`")]
-    pub fn remove_pair(self) -> (K, V) {
-        self.remove_entry()
-    }
-
     /// Take ownership of the key and value from the map.
     ///
     /// # Examples