fixup compile

Signed-off-by: tison <wander4096@gmail.com>

Author: tisonkun

library/alloc/src/collections/vec_deque/extract_if.rs

@@ -12,6 +12,8 @@ use crate::alloc::{Allocator, Global};
 /// # Example
 ///
 /// ```
+/// #![feature(vec_deque_extract_if)]
+///
 /// use std::collections::vec_deque::ExtractIf;
 /// use std::collections::vec_deque::VecDeque;
 ///
@@ -40,14 +42,16 @@ pub struct ExtractIf<
 }
 
 impl<'a, T, F, A: Allocator> ExtractIf<'a, T, F, A> {
-    pub(super) fn new<R: RangeBounds<usize>>(vec: &'a mut Vec<T, A>, pred: F, range: R) -> Self {
+    pub(super) fn new<R: RangeBounds<usize>>(
+        vec: &'a mut VecDeque<T, A>,
+        pred: F,
+        range: R,
+    ) -> Self {
         let old_len = vec.len();
         let Range { start, end } = slice::range(range, ..old_len);
 
         // Guard against the deque getting leaked (leak amplification)
-        unsafe {
-            vec.len = len;
-        }
+        vec.len = 0;
         ExtractIf { vec, idx: start, del: 0, end, old_len, pred }
     }
 
@@ -78,8 +82,8 @@ where
             //
             //  Note: we can't use `vec.get_mut(i).unwrap()` here since the precondition for that
             //  function is that i < vec.len, but we've set vec's length to zero.
-            let idx = self.to_physical_idx(index);
-            let cur = unsafe { &mut *self.ptr().add(idx) };
+            let idx = self.vec.to_physical_idx(i);
+            let cur = unsafe { &mut *self.vec.ptr().add(idx) };
             let drained = (self.pred)(cur);
             // Update the index *after* the predicate is called. If the index
             // is updated prior and the predicate panics, the element at this
@@ -110,7 +114,7 @@ where
 impl<T, F, A: Allocator> Drop for ExtractIf<'_, T, F, A> {
     fn drop(&mut self) {
         if self.del > 0 {
-            let idx = self.to_physical_idx(self.idx);
+            let idx = self.vec.to_physical_idx(self.idx);
             // SAFETY: Trailing unchecked items must be valid since we never touch them.
             unsafe {
                 ptr::copy(
@@ -121,9 +125,7 @@ impl<T, F, A: Allocator> Drop for ExtractIf<'_, T, F, A> {
             }
         }
         // SAFETY: After filling holes, all items are in contiguous memory.
-        unsafe {
-            self.vec.set_len(self.old_len - self.del);
-        }
+        self.vec.len = self.old_len - self.del;
     }
 }
 

library/alloc/src/collections/vec_deque/mod.rs

@@ -565,8 +565,10 @@ impl<T, A: Allocator> VecDeque<T, A> {
     /// Using this method is equivalent to the following code:
     ///
     /// ```
+    /// #![feature(vec_deque_extract_if)]
+    /// # use std::collections::VecDeque;
     /// # let some_predicate = |x: &mut i32| { *x % 2 == 1 };
-    /// # let mut deq = (0..10).collect();
+    /// # let mut deq: VecDeque<_> = (0..10).collect();
     /// # let mut deq2 = deq.clone();
     /// # let range = 1..5;
     /// let mut i = range.start;
@@ -575,7 +577,7 @@ impl<T, A: Allocator> VecDeque<T, A> {
     ///
     /// while i < deq.len() - end_items {
     ///     if some_predicate(&mut deq[i]) {
-    ///         let val = deq.remove(i);
+    ///         let val = deq.remove(i).unwrap();
     ///         // your code here
     /// #         extracted.push(val);
     ///     } else {
@@ -603,6 +605,9 @@ impl<T, A: Allocator> VecDeque<T, A> {
     /// Splitting a deque into even and odd values, reusing the original deque:
     ///
     /// ```
+    /// #![feature(vec_deque_extract_if)]
+    /// use std::collections::VecDeque;
+    ///
     /// let mut numbers = VecDeque::from([1, 2, 3, 4, 5, 6, 8, 9, 11, 13, 14, 15]);
     ///
     /// let evens = numbers.extract_if(.., |x| *x % 2 == 0).collect::<VecDeque<_>>();
@@ -615,6 +620,9 @@ impl<T, A: Allocator> VecDeque<T, A> {
     /// Using the range argument to only process a part of the deque:
     ///
     /// ```
+    /// #![feature(vec_deque_extract_if)]
+    /// use std::collections::VecDeque;
+    ///
     /// let mut items = VecDeque::from([0, 0, 0, 0, 0, 0, 0, 1, 2, 1, 2, 1, 2]);
     /// let ones = items.extract_if(7.., |x| *x == 1).collect::<VecDeque<_>>();
     /// assert_eq!(items, VecDeque::from([0, 0, 0, 0, 0, 0, 0, 2, 2, 2]));