Auto merge of #48768 - kennytm:rollup, r=kennytm

Rollup of 14 pull requests

- Successful merges: #48403, #48432, #48546, #48573, #48590, #48657, #48727, #48732, #48753, #48754, #48761, #48474, #48507, #47463
- Failed merges:

src/liballoc/binary_heap.rs

@@ -964,7 +964,7 @@ impl<'a, T> ExactSizeIterator for Iter<'a, T> {
     }
 }
 
-#[unstable(feature = "fused", issue = "35602")]
+#[stable(feature = "fused", since = "1.26.0")]
 impl<'a, T> FusedIterator for Iter<'a, T> {}
 
 /// An owning iterator over the elements of a `BinaryHeap`.
@@ -1019,7 +1019,7 @@ impl<T> ExactSizeIterator for IntoIter<T> {
     }
 }
 
-#[unstable(feature = "fused", issue = "35602")]
+#[stable(feature = "fused", since = "1.26.0")]
 impl<T> FusedIterator for IntoIter<T> {}
 
 /// A draining iterator over the elements of a `BinaryHeap`.
@@ -1065,7 +1065,7 @@ impl<'a, T: 'a> ExactSizeIterator for Drain<'a, T> {
     }
 }
 
-#[unstable(feature = "fused", issue = "35602")]
+#[stable(feature = "fused", since = "1.26.0")]
 impl<'a, T: 'a> FusedIterator for Drain<'a, T> {}
 
 #[stable(feature = "binary_heap_extras_15", since = "1.5.0")]

src/liballoc/boxed.rs

@@ -722,7 +722,7 @@ impl<I: ExactSizeIterator + ?Sized> ExactSizeIterator for Box<I> {
     }
 }
 
-#[unstable(feature = "fused", issue = "35602")]
+#[stable(feature = "fused", since = "1.26.0")]
 impl<I: FusedIterator + ?Sized> FusedIterator for Box<I> {}
 
 

src/liballoc/btree/map.rs

@@ -1156,7 +1156,7 @@ impl<'a, K: 'a, V: 'a> Iterator for Iter<'a, K, V> {
     }
 }
 
-#[unstable(feature = "fused", issue = "35602")]
+#[stable(feature = "fused", since = "1.26.0")]
 impl<'a, K, V> FusedIterator for Iter<'a, K, V> {}
 
 #[stable(feature = "rust1", since = "1.0.0")]
@@ -1235,7 +1235,7 @@ impl<'a, K: 'a, V: 'a> ExactSizeIterator for IterMut<'a, K, V> {
     }
 }
 
-#[unstable(feature = "fused", issue = "35602")]
+#[stable(feature = "fused", since = "1.26.0")]
 impl<'a, K, V> FusedIterator for IterMut<'a, K, V> {}
 
 #[stable(feature = "rust1", since = "1.0.0")]
@@ -1365,7 +1365,7 @@ impl<K, V> ExactSizeIterator for IntoIter<K, V> {
     }
 }
 
-#[unstable(feature = "fused", issue = "35602")]
+#[stable(feature = "fused", since = "1.26.0")]
 impl<K, V> FusedIterator for IntoIter<K, V> {}
 
 #[stable(feature = "rust1", since = "1.0.0")]
@@ -1395,7 +1395,7 @@ impl<'a, K, V> ExactSizeIterator for Keys<'a, K, V> {
     }
 }
 
-#[unstable(feature = "fused", issue = "35602")]
+#[stable(feature = "fused", since = "1.26.0")]
 impl<'a, K, V> FusedIterator for Keys<'a, K, V> {}
 
 #[stable(feature = "rust1", since = "1.0.0")]
@@ -1432,7 +1432,7 @@ impl<'a, K, V> ExactSizeIterator for Values<'a, K, V> {
     }
 }
 
-#[unstable(feature = "fused", issue = "35602")]
+#[stable(feature = "fused", since = "1.26.0")]
 impl<'a, K, V> FusedIterator for Values<'a, K, V> {}
 
 #[stable(feature = "rust1", since = "1.0.0")]
@@ -1482,7 +1482,7 @@ impl<'a, K, V> ExactSizeIterator for ValuesMut<'a, K, V> {
     }
 }
 
-#[unstable(feature = "fused", issue = "35602")]
+#[stable(feature = "fused", since = "1.26.0")]
 impl<'a, K, V> FusedIterator for ValuesMut<'a, K, V> {}
 
 
@@ -1561,7 +1561,7 @@ impl<'a, K, V> Range<'a, K, V> {
     }
 }
 
-#[unstable(feature = "fused", issue = "35602")]
+#[stable(feature = "fused", since = "1.26.0")]
 impl<'a, K, V> FusedIterator for Range<'a, K, V> {}
 
 #[stable(feature = "btree_range", since = "1.17.0")]
@@ -1630,7 +1630,7 @@ impl<'a, K, V> DoubleEndedIterator for RangeMut<'a, K, V> {
     }
 }
 
-#[unstable(feature = "fused", issue = "35602")]
+#[stable(feature = "fused", since = "1.26.0")]
 impl<'a, K, V> FusedIterator for RangeMut<'a, K, V> {}
 
 impl<'a, K, V> RangeMut<'a, K, V> {

src/liballoc/btree/set.rs

@@ -946,7 +946,7 @@ impl<'a, T> ExactSizeIterator for Iter<'a, T> {
     fn len(&self) -> usize { self.iter.len() }
 }
 
-#[unstable(feature = "fused", issue = "35602")]
+#[stable(feature = "fused", since = "1.26.0")]
 impl<'a, T> FusedIterator for Iter<'a, T> {}
 
 #[stable(feature = "rust1", since = "1.0.0")]
@@ -971,7 +971,7 @@ impl<T> ExactSizeIterator for IntoIter<T> {
     fn len(&self) -> usize { self.iter.len() }
 }
 
-#[unstable(feature = "fused", issue = "35602")]
+#[stable(feature = "fused", since = "1.26.0")]
 impl<T> FusedIterator for IntoIter<T> {}
 
 #[stable(feature = "btree_range", since = "1.17.0")]
@@ -997,7 +997,7 @@ impl<'a, T> DoubleEndedIterator for Range<'a, T> {
     }
 }
 
-#[unstable(feature = "fused", issue = "35602")]
+#[stable(feature = "fused", since = "1.26.0")]
 impl<'a, T> FusedIterator for Range<'a, T> {}
 
 /// Compare `x` and `y`, but return `short` if x is None and `long` if y is None
@@ -1044,7 +1044,7 @@ impl<'a, T: Ord> Iterator for Difference<'a, T> {
     }
 }
 
-#[unstable(feature = "fused", issue = "35602")]
+#[stable(feature = "fused", since = "1.26.0")]
 impl<'a, T: Ord> FusedIterator for Difference<'a, T> {}
 
 #[stable(feature = "rust1", since = "1.0.0")]
@@ -1078,7 +1078,7 @@ impl<'a, T: Ord> Iterator for SymmetricDifference<'a, T> {
     }
 }
 
-#[unstable(feature = "fused", issue = "35602")]
+#[stable(feature = "fused", since = "1.26.0")]
 impl<'a, T: Ord> FusedIterator for SymmetricDifference<'a, T> {}
 
 #[stable(feature = "rust1", since = "1.0.0")]
@@ -1116,7 +1116,7 @@ impl<'a, T: Ord> Iterator for Intersection<'a, T> {
     }
 }
 
-#[unstable(feature = "fused", issue = "35602")]
+#[stable(feature = "fused", since = "1.26.0")]
 impl<'a, T: Ord> FusedIterator for Intersection<'a, T> {}
 
 #[stable(feature = "rust1", since = "1.0.0")]
@@ -1150,5 +1150,5 @@ impl<'a, T: Ord> Iterator for Union<'a, T> {
     }
 }
 
-#[unstable(feature = "fused", issue = "35602")]
+#[stable(feature = "fused", since = "1.26.0")]
 impl<'a, T: Ord> FusedIterator for Union<'a, T> {}

src/liballoc/lib.rs

@@ -96,7 +96,6 @@
 #![feature(fmt_internals)]
 #![feature(from_ref)]
 #![feature(fundamental)]
-#![feature(fused)]
 #![feature(generic_param_attrs)]
 #![feature(i128_type)]
 #![feature(inclusive_range)]
@@ -124,8 +123,9 @@
 #![feature(allocator_internals)]
 #![feature(on_unimplemented)]
 #![feature(exact_chunks)]
+#![feature(pointer_methods)]
 
-#![cfg_attr(not(test), feature(fused, fn_traits, placement_new_protocol, swap_with_slice, i128))]
+#![cfg_attr(not(test), feature(fn_traits, placement_new_protocol, swap_with_slice, i128))]
 #![cfg_attr(test, feature(test, box_heap))]
 
 // Allow testing this library

src/liballoc/linked_list.rs

@@ -897,7 +897,7 @@ impl<'a, T> DoubleEndedIterator for Iter<'a, T> {
 #[stable(feature = "rust1", since = "1.0.0")]
 impl<'a, T> ExactSizeIterator for Iter<'a, T> {}
 
-#[unstable(feature = "fused", issue = "35602")]
+#[stable(feature = "fused", since = "1.26.0")]
 impl<'a, T> FusedIterator for Iter<'a, T> {}
 
 #[stable(feature = "rust1", since = "1.0.0")]
@@ -946,7 +946,7 @@ impl<'a, T> DoubleEndedIterator for IterMut<'a, T> {
 #[stable(feature = "rust1", since = "1.0.0")]
 impl<'a, T> ExactSizeIterator for IterMut<'a, T> {}
 
-#[unstable(feature = "fused", issue = "35602")]
+#[stable(feature = "fused", since = "1.26.0")]
 impl<'a, T> FusedIterator for IterMut<'a, T> {}
 
 impl<'a, T> IterMut<'a, T> {
@@ -1117,7 +1117,7 @@ impl<T> DoubleEndedIterator for IntoIter<T> {
 #[stable(feature = "rust1", since = "1.0.0")]
 impl<T> ExactSizeIterator for IntoIter<T> {}
 
-#[unstable(feature = "fused", issue = "35602")]
+#[stable(feature = "fused", since = "1.26.0")]
 impl<T> FusedIterator for IntoIter<T> {}
 
 #[stable(feature = "rust1", since = "1.0.0")]

src/liballoc/str.rs

@@ -43,6 +43,7 @@ use core::str as core_str;
 use core::str::pattern::Pattern;
 use core::str::pattern::{Searcher, ReverseSearcher, DoubleEndedSearcher};
 use core::mem;
+use core::ptr;
 use core::iter::FusedIterator;
 use std_unicode::str::{UnicodeStr, Utf16Encoder};
 
@@ -171,7 +172,7 @@ impl<'a> Iterator for EncodeUtf16<'a> {
     }
 }
 
-#[unstable(feature = "fused", issue = "35602")]
+#[stable(feature = "fused", since = "1.26.0")]
 impl<'a> FusedIterator for EncodeUtf16<'a> {}
 
 #[stable(feature = "rust1", since = "1.0.0")]
@@ -2066,9 +2067,59 @@ impl str {
     /// ```
     #[stable(feature = "repeat_str", since = "1.16.0")]
     pub fn repeat(&self, n: usize) -> String {
-        let mut s = String::with_capacity(self.len() * n);
-        s.extend((0..n).map(|_| self));
-        s
+        if n == 0 {
+            return String::new();
+        }
+
+        // If `n` is larger than zero, it can be split as
+        // `n = 2^expn + rem (2^expn > rem, expn >= 0, rem >= 0)`.
+        // `2^expn` is the number represented by the leftmost '1' bit of `n`,
+        // and `rem` is the remaining part of `n`.
+
+        // Using `Vec` to access `set_len()`.
+        let mut buf = Vec::with_capacity(self.len() * n);
+
+        // `2^expn` repetition is done by doubling `buf` `expn`-times.
+        buf.extend(self.as_bytes());
+        {
+            let mut m = n >> 1;
+            // If `m > 0`, there are remaining bits up to the leftmost '1'.
+            while m > 0 {
+                // `buf.extend(buf)`:
+                unsafe {
+                    ptr::copy_nonoverlapping(
+                        buf.as_ptr(),
+                        (buf.as_mut_ptr() as *mut u8).add(buf.len()),
+                        buf.len(),
+                    );
+                    // `buf` has capacity of `self.len() * n`.
+                    let buf_len = buf.len();
+                    buf.set_len(buf_len * 2);
+                }
+
+                m >>= 1;
+            }
+        }
+
+        // `rem` (`= n - 2^expn`) repetition is done by copying
+        // first `rem` repetitions from `buf` itself.
+        let rem_len = self.len() * n - buf.len(); // `self.len() * rem`
+        if rem_len > 0 {
+            // `buf.extend(buf[0 .. rem_len])`:
+            unsafe {
+                // This is non-overlapping since `2^expn > rem`.
+                ptr::copy_nonoverlapping(
+                    buf.as_ptr(),
+                    (buf.as_mut_ptr() as *mut u8).add(buf.len()),
+                    rem_len,
+                );
+                // `buf.len() + rem_len` equals to `buf.capacity()` (`= self.len() * n`).
+                let buf_cap = buf.capacity();
+                buf.set_len(buf_cap);
+            }
+        }
+
+        unsafe { String::from_utf8_unchecked(buf) }
     }
 
     /// Checks if all characters in this string are within the ASCII range.

src/liballoc/string.rs

@@ -2254,5 +2254,5 @@ impl<'a> DoubleEndedIterator for Drain<'a> {
     }
 }
 
-#[unstable(feature = "fused", issue = "35602")]
+#[stable(feature = "fused", since = "1.26.0")]
 impl<'a> FusedIterator for Drain<'a> {}