Auto merge of #47445 - kennytm:rollup, r=kennytm

Rollup of 10 pull requests

- Successful merges: #47120, #47126, #47277, #47330, #47368, #47372, #47414, #47417, #47432, #47443
- Failed merges: #47334

src/liballoc/lib.rs

@@ -124,6 +124,7 @@
 #![feature(unsize)]
 #![feature(allocator_internals)]
 #![feature(on_unimplemented)]
+#![feature(exact_chunks)]
 
 #![cfg_attr(not(test), feature(fused, fn_traits, placement_new_protocol, swap_with_slice, i128))]
 #![cfg_attr(test, feature(test, box_heap))]

src/liballoc/slice.rs

@@ -123,6 +123,8 @@ pub use core::slice::{from_raw_parts, from_raw_parts_mut};
 pub use core::slice::{from_ref, from_ref_mut};
 #[unstable(feature = "slice_get_slice", issue = "35729")]
 pub use core::slice::SliceIndex;
+#[unstable(feature = "exact_chunks", issue = "47115")]
+pub use core::slice::{ExactChunks, ExactChunksMut};
 
 ////////////////////////////////////////////////////////////////////////////////
 // Basic slice extension methods
@@ -611,6 +613,9 @@ impl<T> [T] {
     /// not divide the length of the slice, then the last chunk will
     /// not have length `chunk_size`.
     ///
+    /// See [`exact_chunks`] for a variant of this iterator that returns chunks
+    /// of always exactly `chunk_size` elements.
+    ///
     /// # Panics
     ///
     /// Panics if `chunk_size` is 0.
@@ -631,11 +636,44 @@ impl<T> [T] {
         core_slice::SliceExt::chunks(self, chunk_size)
     }
 
+    /// Returns an iterator over `chunk_size` elements of the slice at a
+    /// time. The chunks are slices and do not overlap. If `chunk_size` does
+    /// not divide the length of the slice, then the last up to `chunk_size-1`
+    /// elements will be omitted.
+    ///
+    /// Due to each chunk having exactly `chunk_size` elements, the compiler
+    /// can often optimize the resulting code better than in the case of
+    /// [`chunks`].
+    ///
+    /// # Panics
+    ///
+    /// Panics if `chunk_size` is 0.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// #![feature(exact_chunks)]
+    ///
+    /// let slice = ['l', 'o', 'r', 'e', 'm'];
+    /// let mut iter = slice.exact_chunks(2);
+    /// assert_eq!(iter.next().unwrap(), &['l', 'o']);
+    /// assert_eq!(iter.next().unwrap(), &['r', 'e']);
+    /// assert!(iter.next().is_none());
+    /// ```
+    #[unstable(feature = "exact_chunks", issue = "47115")]
+    #[inline]
+    pub fn exact_chunks(&self, chunk_size: usize) -> ExactChunks<T> {
+        core_slice::SliceExt::exact_chunks(self, chunk_size)
+    }
+
     /// Returns an iterator over `chunk_size` elements of the slice at a time.
     /// The chunks are mutable slices, and do not overlap. If `chunk_size` does
     /// not divide the length of the slice, then the last chunk will not
     /// have length `chunk_size`.
     ///
+    /// See [`exact_chunks_mut`] for a variant of this iterator that returns chunks
+    /// of always exactly `chunk_size` elements.
+    ///
     /// # Panics
     ///
     /// Panics if `chunk_size` is 0.
@@ -660,6 +698,42 @@ impl<T> [T] {
         core_slice::SliceExt::chunks_mut(self, chunk_size)
     }
 
+    /// Returns an iterator over `chunk_size` elements of the slice at a time.
+    /// The chunks are mutable slices, and do not overlap. If `chunk_size` does
+    /// not divide the length of the slice, then the last up to `chunk_size-1`
+    /// elements will be omitted.
+    ///
+    ///
+    /// Due to each chunk having exactly `chunk_size` elements, the compiler
+    /// can often optimize the resulting code better than in the case of
+    /// [`chunks_mut`].
+    ///
+    /// # Panics
+    ///
+    /// Panics if `chunk_size` is 0.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// #![feature(exact_chunks)]
+    ///
+    /// let v = &mut [0, 0, 0, 0, 0];
+    /// let mut count = 1;
+    ///
+    /// for chunk in v.exact_chunks_mut(2) {
+    ///     for elem in chunk.iter_mut() {
+    ///         *elem += count;
+    ///     }
+    ///     count += 1;
+    /// }
+    /// assert_eq!(v, &[1, 1, 2, 2, 0]);
+    /// ```
+    #[unstable(feature = "exact_chunks", issue = "47115")]
+    #[inline]
+    pub fn exact_chunks_mut(&mut self, chunk_size: usize) -> ExactChunksMut<T> {
+        core_slice::SliceExt::exact_chunks_mut(self, chunk_size)
+    }
+
     /// Divides one slice into two at an index.
     ///
     /// The first will contain all indices from `[0, mid)` (excluding

src/liballoc/tests/lib.rs

@@ -30,6 +30,7 @@
 #![feature(string_retain)]
 #![feature(unboxed_closures)]
 #![feature(unicode)]
+#![feature(exact_chunks)]
 
 extern crate alloc_system;
 extern crate std_unicode;

src/liballoc/tests/slice.rs

@@ -945,6 +945,30 @@ fn test_chunksator_0() {
     let _it = v.chunks(0);
 }
 
+#[test]
+fn test_exact_chunksator() {
+    let v = &[1, 2, 3, 4, 5];
+
+    assert_eq!(v.exact_chunks(2).len(), 2);
+
+    let chunks: &[&[_]] = &[&[1, 2], &[3, 4]];
+    assert_eq!(v.exact_chunks(2).collect::<Vec<_>>(), chunks);
+    let chunks: &[&[_]] = &[&[1, 2, 3]];
+    assert_eq!(v.exact_chunks(3).collect::<Vec<_>>(), chunks);
+    let chunks: &[&[_]] = &[];
+    assert_eq!(v.exact_chunks(6).collect::<Vec<_>>(), chunks);
+
+    let chunks: &[&[_]] = &[&[3, 4], &[1, 2]];
+    assert_eq!(v.exact_chunks(2).rev().collect::<Vec<_>>(), chunks);
+}
+
+#[test]
+#[should_panic]
+fn test_exact_chunksator_0() {
+    let v = &[1, 2, 3, 4];
+    let _it = v.exact_chunks(0);
+}
+
 #[test]
 fn test_reverse_part() {
     let mut values = [1, 2, 3, 4, 5];
@@ -1159,7 +1183,7 @@ fn test_mut_chunks() {
         }
     }
     let result = [0, 0, 0, 1, 1, 1, 2];
-    assert!(v == result);
+    assert_eq!(v, result);
 }
 
 #[test]
@@ -1171,7 +1195,7 @@ fn test_mut_chunks_rev() {
         }
     }
     let result = [2, 2, 2, 1, 1, 1, 0];
-    assert!(v == result);
+    assert_eq!(v, result);
 }
 
 #[test]
@@ -1181,6 +1205,38 @@ fn test_mut_chunks_0() {
     let _it = v.chunks_mut(0);
 }
 
+#[test]
+fn test_mut_exact_chunks() {
+    let mut v = [0, 1, 2, 3, 4, 5, 6];
+    assert_eq!(v.exact_chunks_mut(2).len(), 3);
+    for (i, chunk) in v.exact_chunks_mut(3).enumerate() {
+        for x in chunk {
+            *x = i as u8;
+        }
+    }
+    let result = [0, 0, 0, 1, 1, 1, 6];
+    assert_eq!(v, result);
+}
+
+#[test]
+fn test_mut_exact_chunks_rev() {
+    let mut v = [0, 1, 2, 3, 4, 5, 6];
+    for (i, chunk) in v.exact_chunks_mut(3).rev().enumerate() {
+        for x in chunk {
+            *x = i as u8;
+        }
+    }
+    let result = [1, 1, 1, 0, 0, 0, 6];
+    assert_eq!(v, result);
+}
+
+#[test]
+#[should_panic]
+fn test_mut_exact_chunks_0() {
+    let mut v = [1, 2, 3, 4];
+    let _it = v.exact_chunks_mut(0);
+}
+
 #[test]
 fn test_mut_last() {
     let mut x = [1, 2, 3, 4, 5];

src/libcore/slice/mod.rs

@@ -104,6 +104,9 @@ pub trait SliceExt {
     #[stable(feature = "core", since = "1.6.0")]
     fn chunks(&self, size: usize) -> Chunks<Self::Item>;
 
+    #[unstable(feature = "exact_chunks", issue = "47115")]
+    fn exact_chunks(&self, size: usize) -> ExactChunks<Self::Item>;
+
     #[stable(feature = "core", since = "1.6.0")]
     fn get<I>(&self, index: I) -> Option<&I::Output>
         where I: SliceIndex<Self>;
@@ -181,6 +184,9 @@ pub trait SliceExt {
     #[stable(feature = "core", since = "1.6.0")]
     fn chunks_mut(&mut self, chunk_size: usize) -> ChunksMut<Self::Item>;
 
+    #[unstable(feature = "exact_chunks", issue = "47115")]
+    fn exact_chunks_mut(&mut self, size: usize) -> ExactChunksMut<Self::Item>;
+
     #[stable(feature = "core", since = "1.6.0")]
     fn swap(&mut self, a: usize, b: usize);
 
@@ -356,6 +362,14 @@ impl<T> SliceExt for [T] {
         Chunks { v: self, chunk_size: chunk_size }
     }
 
+    #[inline]
+    fn exact_chunks(&self, chunk_size: usize) -> ExactChunks<T> {
+        assert!(chunk_size != 0);
+        let rem = self.len() % chunk_size;
+        let len = self.len() - rem;
+        ExactChunks { v: &self[..len], chunk_size: chunk_size}
+    }
+
     #[inline]
     fn get<I>(&self, index: I) -> Option<&I::Output>
         where I: SliceIndex<[T]>
@@ -539,6 +553,14 @@ impl<T> SliceExt for [T] {
         ChunksMut { v: self, chunk_size: chunk_size }
     }
 
+    #[inline]
+    fn exact_chunks_mut(&mut self, chunk_size: usize) -> ExactChunksMut<T> {
+        assert!(chunk_size != 0);
+        let rem = self.len() % chunk_size;
+        let len = self.len() - rem;
+        ExactChunksMut { v: &mut self[..len], chunk_size: chunk_size}
+    }
+
     #[inline]
     fn swap(&mut self, a: usize, b: usize) {
         unsafe {
@@ -2378,6 +2400,209 @@ unsafe impl<'a, T> TrustedRandomAccess for ChunksMut<'a, T> {
     fn may_have_side_effect() -> bool { false }
 }
 
+/// An iterator over a slice in (non-overlapping) chunks (`chunk_size` elements at a
+/// time).
+///
+/// When the slice len is not evenly divided by the chunk size, the last
+/// up to `chunk_size-1` elements will be omitted.
+///
+/// This struct is created by the [`exact_chunks`] method on [slices].
+///
+/// [`exact_chunks`]: ../../std/primitive.slice.html#method.exact_chunks
+/// [slices]: ../../std/primitive.slice.html
+#[derive(Debug)]
+#[unstable(feature = "exact_chunks", issue = "47115")]
+pub struct ExactChunks<'a, T:'a> {
+    v: &'a [T],
+    chunk_size: usize
+}
+
+// FIXME(#26925) Remove in favor of `#[derive(Clone)]`
+#[unstable(feature = "exact_chunks", issue = "47115")]
+impl<'a, T> Clone for ExactChunks<'a, T> {
+    fn clone(&self) -> ExactChunks<'a, T> {
+        ExactChunks {
+            v: self.v,
+            chunk_size: self.chunk_size,
+        }
+    }
+}
+
+#[unstable(feature = "exact_chunks", issue = "47115")]
+impl<'a, T> Iterator for ExactChunks<'a, T> {
+    type Item = &'a [T];
+
+    #[inline]
+    fn next(&mut self) -> Option<&'a [T]> {
+        if self.v.len() < self.chunk_size {
+            None
+        } else {
+            let (fst, snd) = self.v.split_at(self.chunk_size);
+            self.v = snd;
+            Some(fst)
+        }
+    }
+
+    #[inline]
+    fn size_hint(&self) -> (usize, Option<usize>) {
+        let n = self.v.len() / self.chunk_size;
+        (n, Some(n))
+    }
+
+    #[inline]
+    fn count(self) -> usize {
+        self.len()
+    }
+
+    #[inline]
+    fn nth(&mut self, n: usize) -> Option<Self::Item> {
+        let (start, overflow) = n.overflowing_mul(self.chunk_size);
+        if start >= self.v.len() || overflow {
+            self.v = &[];
+            None
+        } else {
+            let (_, snd) = self.v.split_at(start);
+            self.v = snd;
+            self.next()
+        }
+    }
+
+    #[inline]
+    fn last(mut self) -> Option<Self::Item> {
+        self.next_back()
+    }
+}
+
+#[unstable(feature = "exact_chunks", issue = "47115")]
+impl<'a, T> DoubleEndedIterator for ExactChunks<'a, T> {
+    #[inline]
+    fn next_back(&mut self) -> Option<&'a [T]> {
+        if self.v.len() < self.chunk_size {
+            None
+        } else {
+            let (fst, snd) = self.v.split_at(self.v.len() - self.chunk_size);
+            self.v = fst;
+            Some(snd)
+        }
+    }
+}
+
+#[unstable(feature = "exact_chunks", issue = "47115")]
+impl<'a, T> ExactSizeIterator for ExactChunks<'a, T> {
+    fn is_empty(&self) -> bool {
+        self.v.is_empty()
+    }
+}
+
+#[unstable(feature = "fused", issue = "35602")]
+impl<'a, T> FusedIterator for ExactChunks<'a, T> {}
+
+#[doc(hidden)]
+unsafe impl<'a, T> TrustedRandomAccess for ExactChunks<'a, T> {
+    unsafe fn get_unchecked(&mut self, i: usize) -> &'a [T] {
+        let start = i * self.chunk_size;
+        from_raw_parts(self.v.as_ptr().offset(start as isize), self.chunk_size)
+    }
+    fn may_have_side_effect() -> bool { false }
+}
+
+/// An iterator over a slice in (non-overlapping) mutable chunks (`chunk_size`
+/// elements at a time). When the slice len is not evenly divided by the chunk
+/// size, the last up to `chunk_size-1` elements will be omitted.
+///
+/// This struct is created by the [`exact_chunks_mut`] method on [slices].
+///
+/// [`exact_chunks_mut`]: ../../std/primitive.slice.html#method.exact_chunks_mut
+/// [slices]: ../../std/primitive.slice.html
+#[derive(Debug)]
+#[unstable(feature = "exact_chunks", issue = "47115")]
+pub struct ExactChunksMut<'a, T:'a> {
+    v: &'a mut [T],
+    chunk_size: usize
+}
+
+#[unstable(feature = "exact_chunks", issue = "47115")]
+impl<'a, T> Iterator for ExactChunksMut<'a, T> {
+    type Item = &'a mut [T];
+
+    #[inline]
+    fn next(&mut self) -> Option<&'a mut [T]> {
+        if self.v.len() < self.chunk_size {
+            None
+        } else {
+            let tmp = mem::replace(&mut self.v, &mut []);
+            let (head, tail) = tmp.split_at_mut(self.chunk_size);
+            self.v = tail;
+            Some(head)
+        }
+    }
+
+    #[inline]
+    fn size_hint(&self) -> (usize, Option<usize>) {
+        let n = self.v.len() / self.chunk_size;
+        (n, Some(n))
+    }
+
+    #[inline]
+    fn count(self) -> usize {
+        self.len()
+    }
+
+    #[inline]
+    fn nth(&mut self, n: usize) -> Option<&'a mut [T]> {
+        let (start, overflow) = n.overflowing_mul(self.chunk_size);
+        if start >= self.v.len() || overflow {
+            self.v = &mut [];
+            None
+        } else {
+            let tmp = mem::replace(&mut self.v, &mut []);
+            let (_, snd) = tmp.split_at_mut(start);
+            self.v = snd;
+            self.next()
+        }
+    }
+
+    #[inline]
+    fn last(mut self) -> Option<Self::Item> {
+        self.next_back()
+    }
+}
+
+#[unstable(feature = "exact_chunks", issue = "47115")]
+impl<'a, T> DoubleEndedIterator for ExactChunksMut<'a, T> {
+    #[inline]
+    fn next_back(&mut self) -> Option<&'a mut [T]> {
+        if self.v.len() < self.chunk_size {
+            None
+        } else {
+            let tmp = mem::replace(&mut self.v, &mut []);
+            let tmp_len = tmp.len();
+            let (head, tail) = tmp.split_at_mut(tmp_len - self.chunk_size);
+            self.v = head;
+            Some(tail)
+        }
+    }
+}
+
+#[unstable(feature = "exact_chunks", issue = "47115")]
+impl<'a, T> ExactSizeIterator for ExactChunksMut<'a, T> {
+    fn is_empty(&self) -> bool {
+        self.v.is_empty()
+    }
+}
+
+#[unstable(feature = "fused", issue = "35602")]
+impl<'a, T> FusedIterator for ExactChunksMut<'a, T> {}
+
+#[doc(hidden)]
+unsafe impl<'a, T> TrustedRandomAccess for ExactChunksMut<'a, T> {
+    unsafe fn get_unchecked(&mut self, i: usize) -> &'a mut [T] {
+        let start = i * self.chunk_size;
+        from_raw_parts_mut(self.v.as_mut_ptr().offset(start as isize), self.chunk_size)
+    }
+    fn may_have_side_effect() -> bool { false }
+}
+
 //
 // Free functions
 //

src/libcore/tests/lib.rs

@@ -42,6 +42,7 @@
 #![feature(try_from)]
 #![feature(try_trait)]
 #![feature(unique)]
+#![feature(exact_chunks)]
 
 extern crate core;
 extern crate test;

src/libcore/tests/slice.rs

@@ -117,12 +117,12 @@ fn test_chunks_count() {
 fn test_chunks_nth() {
     let v: &[i32] = &[0, 1, 2, 3, 4, 5];
     let mut c = v.chunks(2);
-    assert_eq!(c.nth(1).unwrap()[1], 3);
-    assert_eq!(c.next().unwrap()[0], 4);
+    assert_eq!(c.nth(1).unwrap(), &[2, 3]);
+    assert_eq!(c.next().unwrap(), &[4, 5]);
 
     let v2: &[i32] = &[0, 1, 2, 3, 4];
     let mut c2 = v2.chunks(3);
-    assert_eq!(c2.nth(1).unwrap()[1], 4);
+    assert_eq!(c2.nth(1).unwrap(), &[3, 4]);
     assert_eq!(c2.next(), None);
 }
 
@@ -168,12 +168,12 @@ fn test_chunks_mut_count() {
 fn test_chunks_mut_nth() {
     let v: &mut [i32] = &mut [0, 1, 2, 3, 4, 5];
     let mut c = v.chunks_mut(2);
-    assert_eq!(c.nth(1).unwrap()[1], 3);
-    assert_eq!(c.next().unwrap()[0], 4);
+    assert_eq!(c.nth(1).unwrap(), &[2, 3]);
+    assert_eq!(c.next().unwrap(), &[4, 5]);
 
     let v2: &mut [i32] = &mut [0, 1, 2, 3, 4];
     let mut c2 = v2.chunks_mut(3);
-    assert_eq!(c2.nth(1).unwrap()[1], 4);
+    assert_eq!(c2.nth(1).unwrap(), &[3, 4]);
     assert_eq!(c2.next(), None);
 }
 
@@ -181,11 +181,11 @@ fn test_chunks_mut_nth() {
 fn test_chunks_mut_last() {
     let v: &mut [i32] = &mut [0, 1, 2, 3, 4, 5];
     let c = v.chunks_mut(2);
-    assert_eq!(c.last().unwrap()[1], 5);
+    assert_eq!(c.last().unwrap(), &[4, 5]);
 
     let v2: &mut [i32] = &mut [0, 1, 2, 3, 4];
     let c2 = v2.chunks_mut(2);
-    assert_eq!(c2.last().unwrap()[0], 4);
+    assert_eq!(c2.last().unwrap(), &[4]);
 }
 
 #[test]
@@ -202,6 +202,110 @@ fn test_chunks_mut_zip() {
     assert_eq!(v1, [13, 14, 19, 20, 14]);
 }
 
+#[test]
+fn test_exact_chunks_count() {
+    let v: &[i32] = &[0, 1, 2, 3, 4, 5];
+    let c = v.exact_chunks(3);
+    assert_eq!(c.count(), 2);
+
+    let v2: &[i32] = &[0, 1, 2, 3, 4];
+    let c2 = v2.exact_chunks(2);
+    assert_eq!(c2.count(), 2);
+
+    let v3: &[i32] = &[];
+    let c3 = v3.exact_chunks(2);
+    assert_eq!(c3.count(), 0);
+}
+
+#[test]
+fn test_exact_chunks_nth() {
+    let v: &[i32] = &[0, 1, 2, 3, 4, 5];
+    let mut c = v.exact_chunks(2);
+    assert_eq!(c.nth(1).unwrap(), &[2, 3]);
+    assert_eq!(c.next().unwrap(), &[4, 5]);
+
+    let v2: &[i32] = &[0, 1, 2, 3, 4, 5, 6];
+    let mut c2 = v2.exact_chunks(3);
+    assert_eq!(c2.nth(1).unwrap(), &[3, 4, 5]);
+    assert_eq!(c2.next(), None);
+}
+
+#[test]
+fn test_exact_chunks_last() {
+    let v: &[i32] = &[0, 1, 2, 3, 4, 5];
+    let c = v.exact_chunks(2);
+    assert_eq!(c.last().unwrap(), &[4, 5]);
+
+    let v2: &[i32] = &[0, 1, 2, 3, 4];
+    let c2 = v2.exact_chunks(2);
+    assert_eq!(c2.last().unwrap(), &[2, 3]);
+}
+
+#[test]
+fn test_exact_chunks_zip() {
+    let v1: &[i32] = &[0, 1, 2, 3, 4];
+    let v2: &[i32] = &[6, 7, 8, 9, 10];
+
+    let res = v1.exact_chunks(2)
+        .zip(v2.exact_chunks(2))
+        .map(|(a, b)| a.iter().sum::<i32>() + b.iter().sum::<i32>())
+        .collect::<Vec<_>>();
+    assert_eq!(res, vec![14, 22]);
+}
+
+#[test]
+fn test_exact_chunks_mut_count() {
+    let v: &mut [i32] = &mut [0, 1, 2, 3, 4, 5];
+    let c = v.exact_chunks_mut(3);
+    assert_eq!(c.count(), 2);
+
+    let v2: &mut [i32] = &mut [0, 1, 2, 3, 4];
+    let c2 = v2.exact_chunks_mut(2);
+    assert_eq!(c2.count(), 2);
+
+    let v3: &mut [i32] = &mut [];
+    let c3 = v3.exact_chunks_mut(2);
+    assert_eq!(c3.count(), 0);
+}
+
+#[test]
+fn test_exact_chunks_mut_nth() {
+    let v: &mut [i32] = &mut [0, 1, 2, 3, 4, 5];
+    let mut c = v.exact_chunks_mut(2);
+    assert_eq!(c.nth(1).unwrap(), &[2, 3]);
+    assert_eq!(c.next().unwrap(), &[4, 5]);
+
+    let v2: &mut [i32] = &mut [0, 1, 2, 3, 4, 5, 6];
+    let mut c2 = v2.exact_chunks_mut(3);
+    assert_eq!(c2.nth(1).unwrap(), &[3, 4, 5]);
+    assert_eq!(c2.next(), None);
+}
+
+#[test]
+fn test_exact_chunks_mut_last() {
+    let v: &mut [i32] = &mut [0, 1, 2, 3, 4, 5];
+    let c = v.exact_chunks_mut(2);
+    assert_eq!(c.last().unwrap(), &[4, 5]);
+
+    let v2: &mut [i32] = &mut [0, 1, 2, 3, 4];
+    let c2 = v2.exact_chunks_mut(2);
+    assert_eq!(c2.last().unwrap(), &[2, 3]);
+}
+
+#[test]
+fn test_exact_chunks_mut_zip() {
+    let v1: &mut [i32] = &mut [0, 1, 2, 3, 4];
+    let v2: &[i32] = &[6, 7, 8, 9, 10];
+
+    for (a, b) in v1.exact_chunks_mut(2).zip(v2.exact_chunks(2)) {
+        let sum = b.iter().sum::<i32>();
+        for v in a {
+            *v += sum;
+        }
+    }
+    assert_eq!(v1, [13, 14, 19, 20, 4]);
+}
+
 #[test]
 fn test_windows_count() {
     let v: &[i32] = &[0, 1, 2, 3, 4, 5];

src/librustc_driver/driver.rs

@@ -37,7 +37,7 @@ use rustc_typeck as typeck;
 use rustc_privacy;
 use rustc_plugin::registry::Registry;
 use rustc_plugin as plugin;
-use rustc_passes::{self, ast_validation, no_asm, loops, consts, static_recursion, hir_stats};
+use rustc_passes::{self, ast_validation, loops, consts, static_recursion, hir_stats};
 use rustc_const_eval::{self, check_match};
 use super::Compilation;
 use ::DefaultTransCrate;
@@ -852,10 +852,6 @@ pub fn phase_2_configure_and_expand<F>(sess: &Session,
         println!("{}", json::as_json(&krate));
     }
 
-    time(time_passes,
-         "checking for inline asm in case the target doesn't support it",
-         || no_asm::check_crate(sess, &krate));
-
     time(time_passes,
          "AST validation",
          || ast_validation::check_crate(sess, &krate));

src/librustc_metadata/native_libs.rs

@@ -92,9 +92,19 @@ impl<'a, 'tcx> ItemLikeVisitor<'tcx> for Collector<'a, 'tcx> {
             let cfg = items.iter().find(|k| {
                 k.check_name("cfg")
             }).and_then(|a| a.meta_item_list());
-            let cfg = cfg.map(|list| {
-                list[0].meta_item().unwrap().clone()
-            });
+            let cfg = if let Some(list) = cfg {
+                if list.is_empty() {
+                    self.tcx.sess.span_err(m.span(), "`cfg()` must have an argument");
+                    return;
+                } else if let cfg @ Some(..) = list[0].meta_item() {
+                    cfg.cloned()
+                } else {
+                    self.tcx.sess.span_err(list[0].span(), "invalid argument for `cfg(..)`");
+                    return;
+                }
+            } else {
+                None
+            };
             let foreign_items = fm.items.iter()
                 .map(|it| self.tcx.hir.local_def_id(it.id))
                 .collect();

src/librustc_passes/ast_validation.rs

@@ -149,6 +149,9 @@ impl<'a> Visitor<'a> for AstValidator<'a> {
             ExprKind::Continue(Some(ident)) => {
                 self.check_label(ident.node, ident.span);
             }
+            ExprKind::InlineAsm(..) if !self.session.target.target.options.allow_asm => {
+                span_err!(self.session, expr.span, E0472, "asm! is unsupported on this target");
+            }
             _ => {}
         }
 

src/librustc_passes/lib.rs

@@ -42,7 +42,6 @@ pub mod consts;
 pub mod hir_stats;
 pub mod loops;
 mod mir_stats;
-pub mod no_asm;
 pub mod static_recursion;
 
 #[cfg(not(stage0))] // remove after the next snapshot

src/librustc_passes/no_asm.rs

@@ -1,47 +0,0 @@
-// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
-// file at the top-level directory of this distribution and at
-// http://rust-lang.org/COPYRIGHT.
-//
-// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
-// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
-// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
-// option. This file may not be copied, modified, or distributed
-// except according to those terms.
-
-/// Run over the whole crate and check for ExprInlineAsm.
-/// Inline asm isn't allowed on virtual ISA based targets, so we reject it
-/// here.
-
-use rustc::session::Session;
-
-use syntax::ast;
-use syntax::visit::Visitor;
-use syntax::visit;
-
-pub fn check_crate(sess: &Session, krate: &ast::Crate) {
-    if sess.target.target.options.allow_asm {
-        return;
-    }
-
-    visit::walk_crate(&mut CheckNoAsm { sess: sess }, krate);
-}
-
-#[derive(Copy, Clone)]
-struct CheckNoAsm<'a> {
-    sess: &'a Session,
-}
-
-impl<'a> Visitor<'a> for CheckNoAsm<'a> {
-    fn visit_expr(&mut self, e: &'a ast::Expr) {
-        match e.node {
-            ast::ExprKind::InlineAsm(_) => {
-                span_err!(self.sess,
-                          e.span,
-                          E0472,
-                          "asm! is unsupported on this target")
-            }
-            _ => {}
-        }
-        visit::walk_expr(self, e)
-    }
-}

src/libstd/f32.rs

@@ -472,20 +472,19 @@ impl f32 {
 
     /// Returns the logarithm of the number with respect to an arbitrary base.
     ///
+    /// The result may not be correctly rounded owing to implementation details;
+    /// `self.log2()` can produce more accurate results for base 2, and
+    /// `self.log10()` can produce more accurate results for base 10.
+    ///
     /// ```
     /// use std::f32;
     ///
-    /// let ten = 10.0f32;
-    /// let two = 2.0f32;
+    /// let five = 5.0f32;
     ///
-    /// // log10(10) - 1 == 0
-    /// let abs_difference_10 = (ten.log(10.0) - 1.0).abs();
+    /// // log5(5) - 1 == 0
+    /// let abs_difference = (five.log(5.0) - 1.0).abs();
     ///
-    /// // log2(2) - 1 == 0
-    /// let abs_difference_2 = (two.log(2.0) - 1.0).abs();
-    ///
-    /// assert!(abs_difference_10 <= f32::EPSILON);
-    /// assert!(abs_difference_2 <= f32::EPSILON);
+    /// assert!(abs_difference <= f32::EPSILON);
     /// ```
     #[stable(feature = "rust1", since = "1.0.0")]
     #[inline]

src/libstd/f64.rs

@@ -432,18 +432,17 @@ impl f64 {
 
     /// Returns the logarithm of the number with respect to an arbitrary base.
     ///
+    /// The result may not be correctly rounded owing to implementation details;
+    /// `self.log2()` can produce more accurate results for base 2, and
+    /// `self.log10()` can produce more accurate results for base 10.
+    ///
     /// ```
-    /// let ten = 10.0_f64;
-    /// let two = 2.0_f64;
+    /// let five = 5.0_f64;
     ///
-    /// // log10(10) - 1 == 0
-    /// let abs_difference_10 = (ten.log(10.0) - 1.0).abs();
+    /// // log5(5) - 1 == 0
+    /// let abs_difference = (five.log(5.0) - 1.0).abs();
     ///
-    /// // log2(2) - 1 == 0
-    /// let abs_difference_2 = (two.log(2.0) - 1.0).abs();
-    ///
-    /// assert!(abs_difference_10 < 1e-10);
-    /// assert!(abs_difference_2 < 1e-10);
+    /// assert!(abs_difference < 1e-10);
     /// ```
     #[stable(feature = "rust1", since = "1.0.0")]
     #[inline]

src/libstd/io/buffered.rs

@@ -345,8 +345,8 @@ impl<R: Seek> Seek for BufReader<R> {
 ///
 /// let mut stream = TcpStream::connect("127.0.0.1:34254").unwrap();
 ///
-/// for i in 1..10 {
-///     stream.write(&[i]).unwrap();
+/// for i in 0..10 {
+///     stream.write(&[i+1]).unwrap();
 /// }
 /// ```
 ///
@@ -361,8 +361,8 @@ impl<R: Seek> Seek for BufReader<R> {
 ///
 /// let mut stream = BufWriter::new(TcpStream::connect("127.0.0.1:34254").unwrap());
 ///
-/// for i in 1..10 {
-///     stream.write(&[i]).unwrap();
+/// for i in 0..10 {
+///     stream.write(&[i+1]).unwrap();
 /// }
 /// ```
 ///

src/libstd/io/error.rs

@@ -62,12 +62,18 @@ pub type Result<T> = result::Result<T, Error>;
 /// [`Write`]: ../io/trait.Write.html
 /// [`Seek`]: ../io/trait.Seek.html
 /// [`ErrorKind`]: enum.ErrorKind.html
-#[derive(Debug)]
 #[stable(feature = "rust1", since = "1.0.0")]
 pub struct Error {
     repr: Repr,
 }
 
+#[stable(feature = "rust1", since = "1.0.0")]
+impl fmt::Debug for Error {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        fmt::Debug::fmt(&self.repr, f)
+    }
+}
+
 enum Repr {
     Os(i32),
     Simple(ErrorKind),
@@ -511,10 +517,12 @@ impl Error {
 impl fmt::Debug for Repr {
     fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
         match *self {
-            Repr::Os(ref code) =>
-                fmt.debug_struct("Os").field("code", code)
-                   .field("message", &sys::os::error_string(*code)).finish(),
-            Repr::Custom(ref c) => fmt.debug_tuple("Custom").field(c).finish(),
+            Repr::Os(code) =>
+                fmt.debug_struct("Os")
+                    .field("code", &code)
+                    .field("kind", &sys::decode_error_kind(code))
+                    .field("message", &sys::os::error_string(code)).finish(),
+            Repr::Custom(ref c) => fmt::Debug::fmt(&c, fmt),
             Repr::Simple(kind) => fmt.debug_tuple("Kind").field(&kind).finish(),
         }
     }
@@ -559,17 +567,36 @@ fn _assert_error_is_sync_send() {
 
 #[cfg(test)]
 mod test {
-    use super::{Error, ErrorKind};
+    use super::{Error, ErrorKind, Repr, Custom};
     use error;
     use fmt;
     use sys::os::error_string;
+    use sys::decode_error_kind;
 
     #[test]
     fn test_debug_error() {
         let code = 6;
         let msg = error_string(code);
-        let err = Error { repr: super::Repr::Os(code) };
-        let expected = format!("Error {{ repr: Os {{ code: {:?}, message: {:?} }} }}", code, msg);
+        let kind = decode_error_kind(code);
+        let err = Error {
+            repr: Repr::Custom(box Custom {
+                kind: ErrorKind::InvalidInput,
+                error: box Error {
+                    repr: super::Repr::Os(code)
+                },
+            })
+        };
+        let expected = format!(
+            "Custom {{ \
+                kind: InvalidInput, \
+                error: Os {{ \
+                    code: {:?}, \
+                    kind: {:?}, \
+                    message: {:?} \
+                }} \
+            }}",
+            code, kind, msg
+        );
         assert_eq!(format!("{:?}", err), expected);
     }
 

src/libstd/rand/reader.rs

@@ -1,108 +0,0 @@
-// Copyright 2013 The Rust Project Developers. See the COPYRIGHT
-// file at the top-level directory of this distribution and at
-// http://rust-lang.org/COPYRIGHT.
-//
-// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
-// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
-// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
-// option. This file may not be copied, modified, or distributed
-// except according to those terms.
-
-//! A wrapper around any Read to treat it as an RNG.
-
-#![allow(dead_code)]
-
-use io::prelude::*;
-use rand::Rng;
-
-/// An RNG that reads random bytes straight from a `Read`. This will
-/// work best with an infinite reader, but this is not required.
-///
-/// # Panics
-///
-/// It will panic if it there is insufficient data to fulfill a request.
-pub struct ReaderRng<R> {
-    reader: R
-}
-
-impl<R: Read> ReaderRng<R> {
-    /// Create a new `ReaderRng` from a `Read`.
-    pub fn new(r: R) -> ReaderRng<R> {
-        ReaderRng {
-            reader: r
-        }
-    }
-}
-
-impl<R: Read> Rng for ReaderRng<R> {
-    fn next_u32(&mut self) -> u32 {
-        // This is designed for speed: reading a LE integer on a LE
-        // platform just involves blitting the bytes into the memory
-        // of the u32, similarly for BE on BE; avoiding byteswapping.
-        let mut bytes = [0; 4];
-        self.fill_bytes(&mut bytes);
-        unsafe { *(bytes.as_ptr() as *const u32) }
-    }
-    fn next_u64(&mut self) -> u64 {
-        // see above for explanation.
-        let mut bytes = [0; 8];
-        self.fill_bytes(&mut bytes);
-        unsafe { *(bytes.as_ptr() as *const u64) }
-    }
-    fn fill_bytes(&mut self, mut v: &mut [u8]) {
-        while !v.is_empty() {
-            let t = v;
-            match self.reader.read(t) {
-                Ok(0) => panic!("ReaderRng.fill_bytes: EOF reached"),
-                Ok(n) => v = t.split_at_mut(n).1,
-                Err(e) => panic!("ReaderRng.fill_bytes: {}", e),
-            }
-        }
-    }
-}
-
-#[cfg(test)]
-mod tests {
-    use super::ReaderRng;
-    use rand::Rng;
-
-    #[test]
-    fn test_reader_rng_u64() {
-        // transmute from the target to avoid endianness concerns.
-        let v = &[0, 0, 0, 0, 0, 0, 0, 1,
-                  0, 0, 0, 0, 0, 0, 0, 2,
-                  0, 0, 0, 0, 0, 0, 0, 3][..];
-        let mut rng = ReaderRng::new(v);
-
-        assert_eq!(rng.next_u64(), 1u64.to_be());
-        assert_eq!(rng.next_u64(), 2u64.to_be());
-        assert_eq!(rng.next_u64(), 3u64.to_be());
-    }
-    #[test]
-    fn test_reader_rng_u32() {
-        let v = &[0, 0, 0, 1, 0, 0, 0, 2, 0, 0, 0, 3][..];
-        let mut rng = ReaderRng::new(v);
-
-        assert_eq!(rng.next_u32(), 1u32.to_be());
-        assert_eq!(rng.next_u32(), 2u32.to_be());
-        assert_eq!(rng.next_u32(), 3u32.to_be());
-    }
-    #[test]
-    fn test_reader_rng_fill_bytes() {
-        let v = [1, 2, 3, 4, 5, 6, 7, 8];
-        let mut w = [0; 8];
-
-        let mut rng = ReaderRng::new(&v[..]);
-        rng.fill_bytes(&mut w);
-
-        assert!(v == w);
-    }
-
-    #[test]
-    #[should_panic]
-    fn test_reader_rng_insufficient_bytes() {
-        let mut rng = ReaderRng::new(&[][..]);
-        let mut v = [0; 3];
-        rng.fill_bytes(&mut v);
-    }
-}

src/test/compile-fail/issue-43925.rs

@@ -0,0 +1,16 @@
+// Copyright 2018 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+#![feature(attr_literals)]
+
+#[link(name="foo", cfg("rlib"))] //~ ERROR invalid argument for `cfg(..)`
+extern {}
+
+fn main() {}

src/test/compile-fail/issue-43926.rs

@@ -0,0 +1,14 @@
+// Copyright 2018 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+#[link(name="foo", cfg())] //~ ERROR `cfg()` must have an argument
+extern {}
+
+fn main() {}

src/test/ui/nll/borrowed-referent-issue-38899.rs

@@ -0,0 +1,30 @@
+// Copyright 2018 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+// Regression test for issue #38899
+
+#![feature(nll)]
+#![allow(dead_code)]
+
+pub struct Block<'a> {
+    current: &'a u8,
+    unrelated: &'a u8,
+}
+
+fn bump<'a>(mut block: &mut Block<'a>) {
+    let x = &mut block;
+    println!("{}", x.current);
+    let p: &'a u8 = &*block.current;
+    //~^ ERROR cannot borrow `*block.current` as immutable because it is also borrowed as mutable
+    drop(x);
+    drop(p);
+}
+
+fn main() {}

src/test/ui/nll/borrowed-referent-issue-38899.stderr

@@ -0,0 +1,11 @@
+error[E0502]: cannot borrow `*block.current` as immutable because it is also borrowed as mutable
+  --> $DIR/borrowed-referent-issue-38899.rs:24:21
+   |
+22 |     let x = &mut block;
+   |             ---------- mutable borrow occurs here
+23 |     println!("{}", x.current);
+24 |     let p: &'a u8 = &*block.current;
+   |                     ^^^^^^^^^^^^^^^ immutable borrow occurs here
+
+error: aborting due to previous error
+

src/test/ui/nll/return-ref-mut-issue-46557.rs

@@ -0,0 +1,21 @@
+// Copyright 2018 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+// Regression test for issue #46557
+
+#![feature(nll)]
+#![allow(dead_code)]
+
+fn gimme_static_mut() -> &'static mut u32 {
+    let ref mut x = 1234543; //~ ERROR borrowed value does not live long enough [E0597]
+    x
+}
+
+fn main() {}

src/test/ui/nll/return-ref-mut-issue-46557.stderr

@@ -0,0 +1,13 @@
+error[E0597]: borrowed value does not live long enough
+  --> $DIR/return-ref-mut-issue-46557.rs:17:21
+   |
+17 |     let ref mut x = 1234543; //~ ERROR borrowed value does not live long enough [E0597]
+   |                     ^^^^^^^ temporary value does not live long enough
+18 |     x
+19 | }
+   |  - temporary value only lives until here
+   |
+   = note: borrowed value must be valid for lifetime '_#2r...
+
+error: aborting due to previous error
+

src/tools/tidy/src/unstable_book.rs

@@ -49,7 +49,7 @@ pub fn collect_unstable_feature_names(features: &Features) -> BTreeSet<String> {
     features
         .iter()
         .filter(|&(_, ref f)| f.level == Status::Unstable)
-        .map(|(name, _)| name.to_owned())
+        .map(|(name, _)| name.replace('_', "-"))
         .collect()
 }
 
@@ -60,7 +60,7 @@ pub fn collect_unstable_book_section_file_names(dir: &path::Path) -> BTreeSet<St
         .map(|entry| entry.expect("could not read directory entry"))
         .filter(dir_entry_is_file)
         .map(|entry| entry.file_name().into_string().unwrap())
-        .map(|n| n.trim_right_matches(".md").replace('-', "_"))
+        .map(|n| n.trim_right_matches(".md").to_owned())
         .collect()
 }
 

src/tools/unstable-book-gen/src/main.rs

@@ -53,9 +53,9 @@ fn set_to_summary_str(set: &BTreeSet<String>, dir: &str
     set
         .iter()
         .map(|ref n| format!("    - [{}]({}/{}.md)",
-                                      n,
+                                      n.replace('-', "_"),
                                       dir,
-                                      n.replace('_', "-")))
+                                      n))
         .fold("".to_owned(), |s, a| s + &a + "\n")
 }
 
@@ -96,14 +96,17 @@ fn generate_unstable_book_files(src :&Path, out: &Path, features :&Features) {
     let unstable_section_file_names = collect_unstable_book_section_file_names(src);
     t!(fs::create_dir_all(&out));
     for feature_name in &unstable_features - &unstable_section_file_names {
-        let file_name = format!("{}.md", feature_name.replace('_', "-"));
+        let feature_name_underscore = feature_name.replace('-', "_");
+        let file_name = format!("{}.md", feature_name);
         let out_file_path = out.join(&file_name);
-        let feature = &features[&feature_name];
+        let feature = &features[&feature_name_underscore];
 
         if has_valid_tracking_issue(&feature) {
-            generate_stub_issue(&out_file_path, &feature_name, feature.tracking_issue.unwrap());
+            generate_stub_issue(&out_file_path,
+                                &feature_name_underscore,
+                                feature.tracking_issue.unwrap());
         } else {
-            generate_stub_no_issue(&out_file_path, &feature_name);
+            generate_stub_no_issue(&out_file_path, &feature_name_underscore);
         }
     }
 }