Rollup of 18 pull requests

Cargo.lock

@@ -1272,9 +1272,10 @@ name = "installer"
 version = "0.0.0"
 dependencies = [
  "clap 2.32.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "error-chain 0.12.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "failure 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "flate2 1.0.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "lazy_static 1.3.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "num_cpus 1.8.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "rayon 1.0.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "tar 0.4.20 (registry+https://github.com/rust-lang/crates.io-index)",
  "walkdir 2.2.7 (registry+https://github.com/rust-lang/crates.io-index)",

src/etc/cpu-usage-over-time-plot.sh

@@ -16,7 +16,7 @@
 
 set -ex
 
-bucket=rust-lang-ci-evalazure
+bucket=rust-lang-ci2
 commit=$1
 builder=$2
 

src/liballoc/boxed.rs

@@ -728,6 +728,14 @@ impl<I: Iterator + ?Sized> Iterator for Box<I> {
         (**self).nth(n)
     }
 }
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<I: Iterator + Sized> Iterator for Box<I> {
+    fn last(self) -> Option<I::Item> where I: Sized {
+        (*self).last()
+    }
+}
+
 #[stable(feature = "rust1", since = "1.0.0")]
 impl<I: DoubleEndedIterator + ?Sized> DoubleEndedIterator for Box<I> {
     fn next_back(&mut self) -> Option<I::Item> {

src/liballoc/collections/binary_heap.rs

@@ -1035,6 +1035,11 @@ impl<'a, T> Iterator for Iter<'a, T> {
     fn size_hint(&self) -> (usize, Option<usize>) {
         self.iter.size_hint()
     }
+
+    #[inline]
+    fn last(self) -> Option<&'a T> {
+        self.iter.last()
+    }
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]

src/liballoc/collections/btree/map.rs

@@ -770,8 +770,8 @@ impl<K: Ord, V> BTreeMap<K, V> {
         }
 
         // First, we merge `self` and `other` into a sorted sequence in linear time.
-        let self_iter = mem::replace(self, BTreeMap::new()).into_iter();
-        let other_iter = mem::replace(other, BTreeMap::new()).into_iter();
+        let self_iter = mem::take(self).into_iter();
+        let other_iter = mem::take(other).into_iter();
         let iter = MergeIter {
             left: self_iter.peekable(),
             right: other_iter.peekable(),
@@ -1193,6 +1193,10 @@ impl<'a, K: 'a, V: 'a> Iterator for Iter<'a, K, V> {
     fn size_hint(&self) -> (usize, Option<usize>) {
         (self.length, Some(self.length))
     }
+
+    fn last(mut self) -> Option<(&'a K, &'a V)> {
+        self.next_back()
+    }
 }
 
 #[stable(feature = "fused", since = "1.26.0")]
@@ -1253,6 +1257,10 @@ impl<'a, K: 'a, V: 'a> Iterator for IterMut<'a, K, V> {
     fn size_hint(&self) -> (usize, Option<usize>) {
         (self.length, Some(self.length))
     }
+
+    fn last(mut self) -> Option<(&'a K, &'a mut V)> {
+        self.next_back()
+    }
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
@@ -1421,6 +1429,10 @@ impl<'a, K, V> Iterator for Keys<'a, K, V> {
     fn size_hint(&self) -> (usize, Option<usize>) {
         self.inner.size_hint()
     }
+
+    fn last(mut self) -> Option<&'a K> {
+        self.next_back()
+    }
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
@@ -1458,6 +1470,10 @@ impl<'a, K, V> Iterator for Values<'a, K, V> {
     fn size_hint(&self) -> (usize, Option<usize>) {
         self.inner.size_hint()
     }
+
+    fn last(mut self) -> Option<&'a V> {
+        self.next_back()
+    }
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
@@ -1495,6 +1511,10 @@ impl<'a, K, V> Iterator for Range<'a, K, V> {
             unsafe { Some(self.next_unchecked()) }
         }
     }
+
+    fn last(mut self) -> Option<(&'a K, &'a V)> {
+        self.next_back()
+    }
 }
 
 #[stable(feature = "map_values_mut", since = "1.10.0")]
@@ -1508,6 +1528,10 @@ impl<'a, K, V> Iterator for ValuesMut<'a, K, V> {
     fn size_hint(&self) -> (usize, Option<usize>) {
         self.inner.size_hint()
     }
+
+    fn last(mut self) -> Option<&'a mut V> {
+        self.next_back()
+    }
 }
 
 #[stable(feature = "map_values_mut", since = "1.10.0")]
@@ -1626,6 +1650,10 @@ impl<'a, K, V> Iterator for RangeMut<'a, K, V> {
             unsafe { Some(self.next_unchecked()) }
         }
     }
+
+    fn last(mut self) -> Option<(&'a K, &'a mut V)> {
+        self.next_back()
+    }
 }
 
 impl<'a, K, V> RangeMut<'a, K, V> {
@@ -2004,7 +2032,7 @@ impl<K, V> BTreeMap<K, V> {
     /// assert_eq!(keys, [1, 2]);
     /// ```
     #[stable(feature = "rust1", since = "1.0.0")]
-    pub fn keys<'a>(&'a self) -> Keys<'a, K, V> {
+    pub fn keys(&self) -> Keys<'_, K, V> {
         Keys { inner: self.iter() }
     }
 
@@ -2025,7 +2053,7 @@ impl<K, V> BTreeMap<K, V> {
     /// assert_eq!(values, ["hello", "goodbye"]);
     /// ```
     #[stable(feature = "rust1", since = "1.0.0")]
-    pub fn values<'a>(&'a self) -> Values<'a, K, V> {
+    pub fn values(&self) -> Values<'_, K, V> {
         Values { inner: self.iter() }
     }
 
@@ -2529,8 +2557,8 @@ enum UnderflowResult<'a, K, V> {
     Stole(NodeRef<marker::Mut<'a>, K, V, marker::Internal>),
 }
 
-fn handle_underfull_node<'a, K, V>(node: NodeRef<marker::Mut<'a>, K, V, marker::LeafOrInternal>)
-                                   -> UnderflowResult<'a, K, V> {
+fn handle_underfull_node<K, V>(node: NodeRef<marker::Mut<'_>, K, V, marker::LeafOrInternal>)
+                               -> UnderflowResult<'_, K, V> {
     let parent = if let Ok(parent) = node.ascend() {
         parent
     } else {

src/liballoc/collections/btree/node.rs

@@ -394,7 +394,7 @@ impl<BorrowType, K, V, Type> NodeRef<BorrowType, K, V, Type> {
     }
 
     /// Temporarily takes out another, immutable reference to the same node.
-    fn reborrow<'a>(&'a self) -> NodeRef<marker::Immut<'a>, K, V, Type> {
+    fn reborrow(&self) -> NodeRef<marker::Immut<'_>, K, V, Type> {
         NodeRef {
             height: self.height,
             node: self.node,

src/liballoc/collections/btree/set.rs

@@ -1019,6 +1019,9 @@ impl<'a, T> Iterator for Iter<'a, T> {
     fn size_hint(&self) -> (usize, Option<usize>) {
         self.iter.size_hint()
     }
+    fn last(mut self) -> Option<&'a T> {
+        self.next_back()
+    }
 }
 #[stable(feature = "rust1", since = "1.0.0")]
 impl<'a, T> DoubleEndedIterator for Iter<'a, T> {
@@ -1073,6 +1076,10 @@ impl<'a, T> Iterator for Range<'a, T> {
     fn next(&mut self) -> Option<&'a T> {
         self.iter.next().map(|(k, _)| k)
     }
+
+    fn last(mut self) -> Option<&'a T> {
+        self.next_back()
+    }
 }
 
 #[stable(feature = "btree_range", since = "1.17.0")]

src/liballoc/collections/linked_list.rs

@@ -708,7 +708,7 @@ impl<T> LinkedList<T> {
         let len = self.len();
         assert!(at <= len, "Cannot split off at a nonexistent index");
         if at == 0 {
-            return mem::replace(self, Self::new());
+            return mem::take(self);
         } else if at == len {
             return Self::new();
         }
@@ -832,6 +832,11 @@ impl<'a, T> Iterator for Iter<'a, T> {
     fn size_hint(&self) -> (usize, Option<usize>) {
         (self.len, Some(self.len))
     }
+
+    #[inline]
+    fn last(mut self) -> Option<&'a T> {
+        self.next_back()
+    }
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
@@ -881,6 +886,11 @@ impl<'a, T> Iterator for IterMut<'a, T> {
     fn size_hint(&self) -> (usize, Option<usize>) {
         (self.len, Some(self.len))
     }
+
+    #[inline]
+    fn last(mut self) -> Option<&'a mut T> {
+        self.next_back()
+    }
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]

src/liballoc/collections/vec_deque.rs

@@ -2206,6 +2206,11 @@ impl<'a, T> Iterator for Iter<'a, T> {
         self.tail = self.head - iter.len();
         final_res
     }
+
+    #[inline]
+    fn last(mut self) -> Option<&'a T> {
+        self.next_back()
+    }
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
@@ -2319,6 +2324,11 @@ impl<'a, T> Iterator for IterMut<'a, T> {
         accum = front.iter_mut().fold(accum, &mut f);
         back.iter_mut().fold(accum, &mut f)
     }
+
+    #[inline]
+    fn last(mut self) -> Option<&'a mut T> {
+        self.next_back()
+    }
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]

src/liballoc/lib.rs

@@ -112,6 +112,7 @@
 #![feature(maybe_uninit_extra, maybe_uninit_slice, maybe_uninit_array)]
 #![feature(alloc_layout_extra)]
 #![feature(try_trait)]
+#![feature(mem_take)]
 
 // Allow testing this library
 

src/liballoc/str.rs

@@ -203,7 +203,7 @@ impl ToOwned for str {
     }
 
     fn clone_into(&self, target: &mut String) {
-        let mut b = mem::replace(target, String::new()).into_bytes();
+        let mut b = mem::take(target).into_bytes();
         self.as_bytes().clone_into(&mut b);
         *target = unsafe { String::from_utf8_unchecked(b) }
     }

src/liballoc/string.rs

@@ -552,7 +552,7 @@ impl String {
     /// assert_eq!("Hello �World", output);
     /// ```
     #[stable(feature = "rust1", since = "1.0.0")]
-    pub fn from_utf8_lossy<'a>(v: &'a [u8]) -> Cow<'a, str> {
+    pub fn from_utf8_lossy(v: &[u8]) -> Cow<'_, str> {
         let mut iter = lossy::Utf8Lossy::from_bytes(v).chunks();
 
         let (first_valid, first_broken) = if let Some(chunk) = iter.next() {
@@ -2385,6 +2385,11 @@ impl Iterator for Drain<'_> {
     fn size_hint(&self) -> (usize, Option<usize>) {
         self.iter.size_hint()
     }
+
+    #[inline]
+    fn last(mut self) -> Option<char> {
+        self.next_back()
+    }
 }
 
 #[stable(feature = "drain", since = "1.6.0")]

src/liballoc/tests/vec.rs

@@ -761,7 +761,6 @@ fn from_into_inner() {
     it.next().unwrap();
     let vec = it.collect::<Vec<_>>();
     assert_eq!(vec, [2, 3]);
-    #[cfg(not(miri))] // Miri does not support comparing dangling pointers
     assert!(ptr != vec.as_ptr());
 }
 

src/libcore/ascii.rs

@@ -117,6 +117,7 @@ impl Iterator for EscapeDefault {
     type Item = u8;
     fn next(&mut self) -> Option<u8> { self.range.next().map(|i| self.data[i]) }
     fn size_hint(&self) -> (usize, Option<usize>) { self.range.size_hint() }
+    fn last(mut self) -> Option<u8> { self.next_back() }
 }
 #[stable(feature = "rust1", since = "1.0.0")]
 impl DoubleEndedIterator for EscapeDefault {

src/libcore/lib.rs

@@ -126,6 +126,7 @@
 #![feature(adx_target_feature)]
 #![feature(maybe_uninit_slice, maybe_uninit_array)]
 #![feature(external_doc)]
+#![feature(mem_take)]
 
 #[prelude_import]
 #[allow(unused)]

src/libcore/marker.rs

@@ -498,7 +498,7 @@ macro_rules! impls{
 /// #     end: *const T,
 /// #     phantom: PhantomData<&'a T>,
 /// # }
-/// fn borrow_vec<'a, T>(vec: &'a Vec<T>) -> Slice<'a, T> {
+/// fn borrow_vec<T>(vec: &Vec<T>) -> Slice<'_, T> {
 ///     let ptr = vec.as_ptr();
 ///     Slice {
 ///         start: ptr,

src/libcore/mem/mod.rs

@@ -552,6 +552,12 @@ pub fn swap<T>(x: &mut T, y: &mut T) {
 ///         mem::take(&mut self.buf)
 ///     }
 /// }
+///
+/// let mut buffer = Buffer { buf: vec![0, 1] };
+/// assert_eq!(buffer.buf.len(), 2);
+///
+/// assert_eq!(buffer.get_and_reset(), vec![0, 1]);
+/// assert_eq!(buffer.buf.len(), 0);
 /// ```
 ///
 /// [`Clone`]: ../../std/clone/trait.Clone.html
@@ -586,17 +592,17 @@ pub fn take<T: Default>(dest: &mut T) -> T {
 /// struct Buffer<T> { buf: Vec<T> }
 ///
 /// impl<T> Buffer<T> {
-///     fn get_and_reset(&mut self) -> Vec<T> {
+///     fn replace_index(&mut self, i: usize, v: T) -> T {
 ///         // error: cannot move out of dereference of `&mut`-pointer
-///         let buf = self.buf;
-///         self.buf = Vec::new();
-///         buf
+///         let t = self.buf[i];
+///         self.buf[i] = v;
+///         t
 ///     }
 /// }
 /// ```
 ///
-/// Note that `T` does not necessarily implement [`Clone`], so it can't even clone and reset
-/// `self.buf`. But `replace` can be used to disassociate the original value of `self.buf` from
+/// Note that `T` does not necessarily implement [`Clone`], so we can't even clone `self.buf[i]` to
+/// avoid the move. But `replace` can be used to disassociate the original value at that index from
 /// `self`, allowing it to be returned:
 ///
 /// ```
@@ -605,10 +611,16 @@ pub fn take<T: Default>(dest: &mut T) -> T {
 ///
 /// # struct Buffer<T> { buf: Vec<T> }
 /// impl<T> Buffer<T> {
-///     fn get_and_reset(&mut self) -> Vec<T> {
-///         mem::replace(&mut self.buf, Vec::new())
+///     fn replace_index(&mut self, i: usize, v: T) -> T {
+///         mem::replace(&mut self.buf[i], v)
 ///     }
 /// }
+///
+/// let mut buffer = Buffer { buf: vec![0, 1] };
+/// assert_eq!(buffer.buf[0], 0);
+///
+/// assert_eq!(buffer.replace_index(0, 2), 0);
+/// assert_eq!(buffer.buf[0], 2);
 /// ```
 ///
 /// [`Clone`]: ../../std/clone/trait.Clone.html

src/libcore/ops/index.rs

@@ -105,7 +105,7 @@ pub trait Index<Idx: ?Sized> {
 /// impl Index<Side> for Balance {
 ///     type Output = Weight;
 ///
-///     fn index<'a>(&'a self, index: Side) -> &'a Self::Output {
+///     fn index(&self, index: Side) -> &Self::Output {
 ///         println!("Accessing {:?}-side of balance immutably", index);
 ///         match index {
 ///             Side::Left => &self.left,
@@ -115,7 +115,7 @@ pub trait Index<Idx: ?Sized> {
 /// }
 ///
 /// impl IndexMut<Side> for Balance {
-///     fn index_mut<'a>(&'a mut self, index: Side) -> &'a mut Self::Output {
+///     fn index_mut(&mut self, index: Side) -> &mut Self::Output {
 ///         println!("Accessing {:?}-side of balance mutably", index);
 ///         match index {
 ///             Side::Left => &mut self.left,