Auto merge of #54907 - pietroalbini:beta-backports, r=pietroalbini

[beta] Rollup backports

Merged and approved:

* #54851: Fix a regression in 1.30 by reverting #53564
* #54865: Backport 1.29.2 release notes to master
* #54810: Fix dead code lint for functions using impl Trait

r? @ghost

RELEASES.md

@@ -1,3 +1,11 @@
+Version 1.29.2 (2018-10-11)
+===========================
+
+- [Workaround for an aliasing-related LLVM bug, which caused miscompilation.][54639]
+- The `rls-preview` component on the windows-gnu targets has been restored.
+
+[54639]: https://github.com/rust-lang/rust/pull/54639
+
 Version 1.29.1 (2018-09-25)
 ===========================
 

src/liballoc/collections/vec_deque.rs

@@ -19,7 +19,6 @@
 
 use core::cmp::Ordering;
 use core::fmt;
-use core::isize;
 use core::iter::{repeat, FromIterator, FusedIterator};
 use core::mem;
 use core::ops::Bound::{Excluded, Included, Unbounded};
@@ -203,33 +202,6 @@ impl<T> VecDeque<T> {
                                  len);
     }
 
-    /// Copies all values from `src` to the back of `self`, wrapping around if needed.
-    ///
-    /// # Safety
-    ///
-    /// The capacity must be sufficient to hold self.len() + src.len() elements.
-    /// If so, this function never panics.
-    #[inline]
-    unsafe fn copy_slice(&mut self, src: &[T]) {
-        /// This is guaranteed by `RawVec`.
-        debug_assert!(self.capacity() <= isize::MAX as usize);
-
-        let expected_new_len = self.len() + src.len();
-        debug_assert!(self.capacity() >= expected_new_len);
-
-        let dst_high_ptr = self.ptr().add(self.head);
-        let dst_high_len = self.cap() - self.head;
-
-        let split = cmp::min(src.len(), dst_high_len);
-        let (src_high, src_low) = src.split_at(split);
-
-        ptr::copy_nonoverlapping(src_high.as_ptr(), dst_high_ptr, src_high.len());
-        ptr::copy_nonoverlapping(src_low.as_ptr(), self.ptr(), src_low.len());
-
-        self.head = self.wrap_add(self.head, src.len());
-        debug_assert!(self.len() == expected_new_len);
-    }
-
     /// Copies a potentially wrapping block of memory len long from src to dest.
     /// (abs(dst - src) + len) must be no larger than cap() (There must be at
     /// most one continuous overlapping region between src and dest).
@@ -1052,7 +1024,7 @@ impl<T> VecDeque<T> {
             iter: Iter {
                 tail: drain_tail,
                 head: drain_head,
-                ring: unsafe { self.buffer_as_slice() },
+                ring: unsafe { self.buffer_as_mut_slice() },
             },
         }
     }
@@ -1862,22 +1834,8 @@ impl<T> VecDeque<T> {
     #[inline]
     #[stable(feature = "append", since = "1.4.0")]
     pub fn append(&mut self, other: &mut Self) {
-        unsafe {
-            // Guarantees there is space in `self` for `other`.
-            self.reserve(other.len());
-
-            {
-                let (src_high, src_low) = other.as_slices();
-
-                // This is only safe because copy_slice never panics when capacity is sufficient.
-                self.copy_slice(src_low);
-                self.copy_slice(src_high);
-            }
-
-            // Some values now exist in both `other` and `self` but are made inaccessible
-            // in`other`.
-            other.tail = other.head;
-        }
+        // naive impl
+        self.extend(other.drain(..));
     }
 
     /// Retains only the elements specified by the predicate.
@@ -2635,8 +2593,8 @@ impl<T> From<VecDeque<T>> for Vec<T> {
                         let mut right_offset = 0;
                         for i in left_edge..right_edge {
                             right_offset = (i - left_edge) % (cap - right_edge);
-                            let src = right_edge + right_offset;
-                            ptr::swap(buf.add(i), buf.add(src));
+                            let src: isize = (right_edge + right_offset) as isize;
+                            ptr::swap(buf.add(i), buf.offset(src));
                         }
                         let n_ops = right_edge - left_edge;
                         left_edge += n_ops;

src/librustc/middle/dead.rs

@@ -395,7 +395,13 @@ fn create_and_seed_worklist<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
                                       krate: &hir::Crate)
                                       -> Vec<ast::NodeId>
 {
-    let worklist = access_levels.map.iter().map(|(&id, _)| id).chain(
+    let worklist = access_levels.map.iter().filter_map(|(&id, level)| {
+        if level >= &privacy::AccessLevel::Reachable {
+            Some(id)
+        } else {
+            None
+        }
+    }).chain(
         // Seed entry point
         tcx.sess.entry_fn.borrow().map(|(id, _, _)| id)
     ).collect::<Vec<_>>();

src/test/run-pass/async-await.rs

@@ -183,6 +183,7 @@ fn main() {
         async_closure,
         async_fn,
         async_fn_with_internal_borrow,
+        Foo::async_method,
         |x| {
             async move {
                 unsafe { await!(unsafe_async_fn(x)) }

src/test/run-pass/impl-trait/existential-minimal.stderr

@@ -0,0 +1,8 @@
+warning: function is never used: `foo`
+  --> $DIR/existential-minimal.rs:15:1
+   |
+LL | fn foo() -> impl std::fmt::Debug { "cake" }
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: #[warn(dead_code)] on by default
+

src/test/run-pass/impl-trait/issue-42479.stderr

@@ -0,0 +1,14 @@
+warning: struct is never constructed: `Foo`
+  --> $DIR/issue-42479.rs:15:1
+   |
+LL | struct Foo {
+   | ^^^^^^^^^^
+   |
+   = note: #[warn(dead_code)] on by default
+
+warning: method is never used: `inside`
+  --> $DIR/issue-42479.rs:20:5
+   |
+LL |     fn inside(&self) -> impl Iterator<Item = &i32> {
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+

src/test/run-pass/impl-trait/issue-49376.stderr

@@ -0,0 +1,32 @@
+warning: function is never used: `gen`
+  --> $DIR/issue-49376.rs:18:1
+   |
+LL | fn gen() -> impl PartialOrd + PartialEq + Debug { }
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: #[warn(dead_code)] on by default
+
+warning: struct is never constructed: `Bar`
+  --> $DIR/issue-49376.rs:20:1
+   |
+LL | struct Bar {}
+   | ^^^^^^^^^^
+
+warning: function is never used: `foo`
+  --> $DIR/issue-49376.rs:24:1
+   |
+LL | fn foo() -> impl Foo {
+   | ^^^^^^^^^^^^^^^^^^^^
+
+warning: function is never used: `test_impl_ops`
+  --> $DIR/issue-49376.rs:28:1
+   |
+LL | fn test_impl_ops() -> impl Add + Sub + Mul + Div { 1 }
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+warning: function is never used: `test_impl_assign_ops`
+  --> $DIR/issue-49376.rs:29:1
+   |
+LL | fn test_impl_assign_ops() -> impl AddAssign + SubAssign + MulAssign + DivAssign { 1 }
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+

src/test/run-pass/issues/issue-49556.stderr

@@ -0,0 +1,8 @@
+warning: function is never used: `iter`
+  --> $DIR/issue-49556.rs:12:1
+   |
+LL | fn iter<'a>(data: &'a [usize]) -> impl Iterator<Item = usize> + 'a {
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: #[warn(dead_code)] on by default
+

src/test/run-pass/traits/conservative_impl_trait.stderr

@@ -0,0 +1,8 @@
+warning: function is never used: `batches`
+  --> $DIR/conservative_impl_trait.rs:14:1
+   |
+LL | fn batches(n: &u32) -> impl Iterator<Item=&u32> {
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: #[warn(dead_code)] on by default
+

src/test/ui/lint/lint-dead-code-1.rs

@@ -109,6 +109,10 @@ fn bar() { //~ ERROR: function is never used
     foo();
 }
 
+fn baz() -> impl Copy { //~ ERROR: function is never used
+    "I'm unused, too"
+}
+
 // Code with #[allow(dead_code)] should be marked live (and thus anything it
 // calls is marked live)
 #[allow(dead_code)]

src/test/ui/lint/lint-dead-code-1.stderr

@@ -58,5 +58,11 @@ error: function is never used: `bar`
 LL | fn bar() { //~ ERROR: function is never used
    | ^^^^^^^^
 
-error: aborting due to 9 previous errors
+error: function is never used: `baz`
+  --> $DIR/lint-dead-code-1.rs:112:1
+   |
+LL | fn baz() -> impl Copy { //~ ERROR: function is never used
+   | ^^^^^^^^^^^^^^^^^^^^^
+
+error: aborting due to 10 previous errors