diff --git a/src/bootstrap/doc.rs b/src/bootstrap/doc.rs
index 201129b92df05..e9c27a3f3cf31 100644
--- a/src/bootstrap/doc.rs
+++ b/src/bootstrap/doc.rs
@@ -697,9 +697,6 @@ impl Step for Rustc {
             return;
         }
 
-        // Build libstd docs so that we generate relative links.
-        builder.ensure(Std { stage, target });
-
         // Build rustc.
         builder.ensure(compile::Rustc { compiler, target });
 
@@ -718,12 +715,16 @@ impl Step for Rustc {
 
         // Find dependencies for top level crates.
         let mut compiler_crates = HashSet::new();
-        for root_crate in &["rustc", "rustc_driver", "rustc_codegen_llvm"] {
+        for root_crate in &["rustc_driver", "rustc_codegen_llvm", "rustc_codegen_ssa"] {
             let interned_root_crate = INTERNER.intern_str(root_crate);
             find_compiler_crates(builder, &interned_root_crate, &mut compiler_crates);
         }
 
         for krate in &compiler_crates {
+            // Create all crate output directories first to make sure rustdoc uses
+            // relative links.
+            // FIXME: Cargo should probably do this itself.
+            t!(fs::create_dir_all(out_dir.join(krate)));
             cargo.arg("-p").arg(krate);
         }
 
@@ -797,8 +798,8 @@ impl Step for Rustdoc {
             return;
         }
 
-        // Build libstd docs so that we generate relative links.
-        builder.ensure(Std { stage, target });
+        // Build rustc docs so that we generate relative links.
+        builder.ensure(Rustc { stage, target });
 
         // Build rustdoc.
         builder.ensure(tool::Rustdoc { host: compiler.host });
@@ -822,6 +823,10 @@ impl Step for Rustdoc {
             &[]
         );
 
+        // Only include compiler crates, no dependencies of those, such as `libc`.
+        cargo.arg("--no-deps");
+        cargo.arg("-p").arg("rustdoc");
+
         cargo.env("RUSTDOCFLAGS", "--document-private-items");
         builder.run(&mut cargo);
     }
diff --git a/src/liballoc/rc.rs b/src/liballoc/rc.rs
index 3ca6de191de2d..c0a947e701108 100644
--- a/src/liballoc/rc.rs
+++ b/src/liballoc/rc.rs
@@ -1187,8 +1187,9 @@ impl<T: ?Sized + Unsize<U>, U: ?Sized> DispatchFromDyn<Weak<U>> for Weak<T> {}
 
 impl<T> Weak<T> {
     /// Constructs a new `Weak<T>`, without allocating any memory.
-    /// Calling [`upgrade`][Weak::upgrade] on the return value always gives [`None`].
+    /// Calling [`upgrade`] on the return value always gives [`None`].
     ///
+    /// [`upgrade`]: #method.upgrade
     /// [`None`]: ../../std/option/enum.Option.html
     ///
     /// # Examples
@@ -1260,6 +1261,52 @@ impl<T: ?Sized> Weak<T> {
             Some(unsafe { self.ptr.as_ref() })
         }
     }
+
+    /// Returns true if the two `Weak`s point to the same value (not just values
+    /// that compare as equal).
+    ///
+    /// # Notes
+    ///
+    /// Since this compares pointers it means that `Weak::new()` will equal each
+    /// other, even though they don't point to any value.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// #![feature(weak_ptr_eq)]
+    /// use std::rc::{Rc, Weak};
+    ///
+    /// let first_rc = Rc::new(5);
+    /// let first = Rc::downgrade(&first_rc);
+    /// let second = Rc::downgrade(&first_rc);
+    ///
+    /// assert!(Weak::ptr_eq(&first, &second));
+    ///
+    /// let third_rc = Rc::new(5);
+    /// let third = Rc::downgrade(&third_rc);
+    ///
+    /// assert!(!Weak::ptr_eq(&first, &third));
+    /// ```
+    ///
+    /// Comparing `Weak::new`.
+    ///
+    /// ```
+    /// #![feature(weak_ptr_eq)]
+    /// use std::rc::{Rc, Weak};
+    ///
+    /// let first = Weak::new();
+    /// let second = Weak::new();
+    /// assert!(Weak::ptr_eq(&first, &second));
+    ///
+    /// let third_rc = Rc::new(());
+    /// let third = Rc::downgrade(&third_rc);
+    /// assert!(!Weak::ptr_eq(&first, &third));
+    /// ```
+    #[inline]
+    #[unstable(feature = "weak_ptr_eq", issue = "55981")]
+    pub fn ptr_eq(this: &Self, other: &Self) -> bool {
+        this.ptr.as_ptr() == other.ptr.as_ptr()
+    }
 }
 
 #[stable(feature = "rc_weak", since = "1.4.0")]
diff --git a/src/liballoc/sync.rs b/src/liballoc/sync.rs
index 4f4031e3c4e32..0a397f79103db 100644
--- a/src/liballoc/sync.rs
+++ b/src/liballoc/sync.rs
@@ -1130,6 +1130,53 @@ impl<T: ?Sized> Weak<T> {
             Some(unsafe { self.ptr.as_ref() })
         }
     }
+
+    /// Returns true if the two `Weak`s point to the same value (not just values
+    /// that compare as equal).
+    ///
+    /// # Notes
+    ///
+    /// Since this compares pointers it means that `Weak::new()` will equal each
+    /// other, even though they don't point to any value.
+    ///
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// #![feature(weak_ptr_eq)]
+    /// use std::sync::{Arc, Weak};
+    ///
+    /// let first_rc = Arc::new(5);
+    /// let first = Arc::downgrade(&first_rc);
+    /// let second = Arc::downgrade(&first_rc);
+    ///
+    /// assert!(Weak::ptr_eq(&first, &second));
+    ///
+    /// let third_rc = Arc::new(5);
+    /// let third = Arc::downgrade(&third_rc);
+    ///
+    /// assert!(!Weak::ptr_eq(&first, &third));
+    /// ```
+    ///
+    /// Comparing `Weak::new`.
+    ///
+    /// ```
+    /// #![feature(weak_ptr_eq)]
+    /// use std::sync::{Arc, Weak};
+    ///
+    /// let first = Weak::new();
+    /// let second = Weak::new();
+    /// assert!(Weak::ptr_eq(&first, &second));
+    ///
+    /// let third_rc = Arc::new(());
+    /// let third = Arc::downgrade(&third_rc);
+    /// assert!(!Weak::ptr_eq(&first, &third));
+    /// ```
+    #[inline]
+    #[unstable(feature = "weak_ptr_eq", issue = "55981")]
+    pub fn ptr_eq(this: &Self, other: &Self) -> bool {
+        this.ptr.as_ptr() == other.ptr.as_ptr()
+    }
 }
 
 #[stable(feature = "arc_weak", since = "1.4.0")]
diff --git a/src/libcore/macros.rs b/src/libcore/macros.rs
index 8b1855800c2fd..5ba0e949483ae 100644
--- a/src/libcore/macros.rs
+++ b/src/libcore/macros.rs
@@ -238,6 +238,10 @@ macro_rules! debug_assert_ne {
 /// with converting downstream errors.
 ///
 /// The `?` operator was added to replace `try!` and should be used instead.
+/// Furthermore, `try` is a reserved word in Rust 2018, so if you must use
+/// it, you will need to use the [raw-identifier syntax][ris]: `r#try`.
+///
+/// [ris]: https://doc.rust-lang.org/nightly/rust-by-example/compatibility/raw_identifiers.html
 ///
 /// `try!` matches the given [`Result`]. In case of the `Ok` variant, the
 /// expression has the value of the wrapped value.
diff --git a/src/libcore/ptr.rs b/src/libcore/ptr.rs
index d3a74ed2a6856..c56e91bbe4d2d 100644
--- a/src/libcore/ptr.rs
+++ b/src/libcore/ptr.rs
@@ -2516,6 +2516,36 @@ pub fn eq<T: ?Sized>(a: *const T, b: *const T) -> bool {
     a == b
 }
 
+/// Hash the raw pointer address behind a reference, rather than the value
+/// it points to.
+///
+/// # Examples
+///
+/// ```
+/// #![feature(ptr_hash)]
+/// use std::collections::hash_map::DefaultHasher;
+/// use std::hash::{Hash, Hasher};
+/// use std::ptr;
+///
+/// let five = 5;
+/// let five_ref = &five;
+///
+/// let mut hasher = DefaultHasher::new();
+/// ptr::hash(five_ref, &mut hasher);
+/// let actual = hasher.finish();
+///
+/// let mut hasher = DefaultHasher::new();
+/// (five_ref as *const i32).hash(&mut hasher);
+/// let expected = hasher.finish();
+///
+/// assert_eq!(actual, expected);
+/// ```
+#[unstable(feature = "ptr_hash", reason = "newly added", issue = "56286")]
+pub fn hash<T, S: hash::Hasher>(hashee: *const T, into: &mut S) {
+    use hash::Hash;
+    hashee.hash(into);
+}
+
 // Impls for function pointers
 macro_rules! fnptr_impls_safety_abi {
     ($FnTy: ty, $($Arg: ident),*) => {
diff --git a/src/libcore/str/mod.rs b/src/libcore/str/mod.rs
index 89efa120a6fab..6c953d1b9a0ac 100644
--- a/src/libcore/str/mod.rs
+++ b/src/libcore/str/mod.rs
@@ -536,10 +536,9 @@ fn next_code_point_reverse<'a, I>(bytes: &mut I) -> Option<u32>
     where I: DoubleEndedIterator<Item = &'a u8>,
 {
     // Decode UTF-8
-    let w = match bytes.next_back() {
-        None => return None,
-        Some(&next_byte) if next_byte < 128 => return Some(next_byte as u32),
-        Some(&back_byte) => back_byte,
+    let w = match *bytes.next_back()? {
+        next_byte if next_byte < 128 => return Some(next_byte as u32),
+        back_byte => back_byte,
     };
 
     // Multibyte case follows
diff --git a/src/librustc/middle/dead.rs b/src/librustc/middle/dead.rs
index 282b5d13e2c61..bb7a6a6ee7b72 100644
--- a/src/librustc/middle/dead.rs
+++ b/src/librustc/middle/dead.rs
@@ -166,6 +166,7 @@ impl<'a, 'tcx> MarkSymbolVisitor<'a, 'tcx> {
                     hir::ItemKind::Fn(..)
                     | hir::ItemKind::Ty(..)
                     | hir::ItemKind::Static(..)
+                    | hir::ItemKind::Existential(..)
                     | hir::ItemKind::Const(..) => {
                         intravisit::walk_item(self, &item);
                     }
diff --git a/src/librustc/middle/region.rs b/src/librustc/middle/region.rs
index 35d1a4dd2cb7c..3c2551f5cd436 100644
--- a/src/librustc/middle/region.rs
+++ b/src/librustc/middle/region.rs
@@ -592,10 +592,7 @@ impl<'tcx> ScopeTree {
                 return Some(scope.item_local_id());
             }
 
-            match self.opt_encl_scope(scope) {
-                None => return None,
-                Some(parent) => scope = parent,
-            }
+            scope = self.opt_encl_scope(scope)?;
         }
     }
 
diff --git a/src/librustc/session/search_paths.rs b/src/librustc/session/search_paths.rs
index 768d4f1e5fb65..6b0a8a0af2b9d 100644
--- a/src/librustc/session/search_paths.rs
+++ b/src/librustc/session/search_paths.rs
@@ -67,14 +67,13 @@ impl<'a> Iterator for Iter<'a> {
 
     fn next(&mut self) -> Option<(&'a Path, PathKind)> {
         loop {
-            match self.iter.next() {
-                Some(&(kind, ref p)) if self.kind == PathKind::All ||
-                                        kind == PathKind::All ||
-                                        kind == self.kind => {
+            match *self.iter.next()? {
+                (kind, ref p) if self.kind == PathKind::All ||
+                                  kind == PathKind::All ||
+                                  kind == self.kind => {
                     return Some((p, kind))
                 }
-                Some(..) => {}
-                None => return None,
+                _ => {}
             }
         }
     }
diff --git a/src/librustc_borrowck/borrowck/check_loans.rs b/src/librustc_borrowck/borrowck/check_loans.rs
index a802729e3fbdb..e47e95afb1643 100644
--- a/src/librustc_borrowck/borrowck/check_loans.rs
+++ b/src/librustc_borrowck/borrowck/check_loans.rs
@@ -615,7 +615,7 @@ impl<'a, 'tcx> CheckLoanCtxt<'a, 'tcx> {
                     let new_loan_str = &new_loan.kind.to_user_str();
                     self.bccx.cannot_reborrow_already_uniquely_borrowed(
                         new_loan.span, "closure", &nl, &new_loan_msg, new_loan_str,
-                        old_loan.span, &old_loan_msg, previous_end_span, Origin::Ast)
+                        old_loan.span, &old_loan_msg, previous_end_span, "", Origin::Ast)
                 }
                 (..) =>
                     self.bccx.cannot_reborrow_already_borrowed(
diff --git a/src/librustc_data_structures/lib.rs b/src/librustc_data_structures/lib.rs
index 96cb235a93362..8e0ecb70c6896 100644
--- a/src/librustc_data_structures/lib.rs
+++ b/src/librustc_data_structures/lib.rs
@@ -81,7 +81,6 @@ pub mod sync;
 pub mod tiny_list;
 pub mod thin_vec;
 pub mod transitive_relation;
-pub mod tuple_slice;
 pub use ena::unify;
 pub mod vec_linked_list;
 pub mod work_queue;
diff --git a/src/librustc_data_structures/tuple_slice.rs b/src/librustc_data_structures/tuple_slice.rs
deleted file mode 100644
index b7c71dd366469..0000000000000
--- a/src/librustc_data_structures/tuple_slice.rs
+++ /dev/null
@@ -1,70 +0,0 @@
-// Copyright 2014 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.
-
-use std::slice;
-
-/// Allows to view uniform tuples as slices
-pub trait TupleSlice<T> {
-    fn as_slice(&self) -> &[T];
-    fn as_mut_slice(&mut self) -> &mut [T];
-}
-
-macro_rules! impl_tuple_slice {
-    ($tuple_type:ty, $size:expr) => {
-        impl<T> TupleSlice<T> for $tuple_type {
-            fn as_slice(&self) -> &[T] {
-                unsafe {
-                    let ptr = &self.0 as *const T;
-                    slice::from_raw_parts(ptr, $size)
-                }
-            }
-
-            fn as_mut_slice(&mut self) -> &mut [T] {
-                unsafe {
-                    let ptr = &mut self.0 as *mut T;
-                    slice::from_raw_parts_mut(ptr, $size)
-                }
-            }
-        }
-    }
-}
-
-impl_tuple_slice!((T, T), 2);
-impl_tuple_slice!((T, T, T), 3);
-impl_tuple_slice!((T, T, T, T), 4);
-impl_tuple_slice!((T, T, T, T, T), 5);
-impl_tuple_slice!((T, T, T, T, T, T), 6);
-impl_tuple_slice!((T, T, T, T, T, T, T), 7);
-impl_tuple_slice!((T, T, T, T, T, T, T, T), 8);
-
-#[test]
-fn test_sliced_tuples() {
-    let t2 = (100, 101);
-    assert_eq!(t2.as_slice(), &[100, 101]);
-
-    let t3 = (102, 103, 104);
-    assert_eq!(t3.as_slice(), &[102, 103, 104]);
-
-    let t4 = (105, 106, 107, 108);
-    assert_eq!(t4.as_slice(), &[105, 106, 107, 108]);
-
-    let t5 = (109, 110, 111, 112, 113);
-    assert_eq!(t5.as_slice(), &[109, 110, 111, 112, 113]);
-
-    let t6 = (114, 115, 116, 117, 118, 119);
-    assert_eq!(t6.as_slice(), &[114, 115, 116, 117, 118, 119]);
-
-    let t7 = (120, 121, 122, 123, 124, 125, 126);
-    assert_eq!(t7.as_slice(), &[120, 121, 122, 123, 124, 125, 126]);
-
-    let t8 = (127, 128, 129, 130, 131, 132, 133, 134);
-    assert_eq!(t8.as_slice(), &[127, 128, 129, 130, 131, 132, 133, 134]);
-
-}
diff --git a/src/librustc_incremental/persist/work_product.rs b/src/librustc_incremental/persist/work_product.rs
index cfe59b1f67262..ddd28eb5393ec 100644
--- a/src/librustc_incremental/persist/work_product.rs
+++ b/src/librustc_incremental/persist/work_product.rs
@@ -29,7 +29,7 @@ pub fn copy_cgu_workproducts_to_incr_comp_cache_dir(
         return None
     }
 
-    let saved_files: Option<Vec<_>> =
+    let saved_files =
         files.iter()
              .map(|&(kind, ref path)| {
                  let extension = match kind {
@@ -51,11 +51,7 @@ pub fn copy_cgu_workproducts_to_incr_comp_cache_dir(
                      }
                  }
              })
-             .collect();
-    let saved_files = match saved_files {
-        None => return None,
-        Some(v) => v,
-    };
+             .collect::<Option<Vec<_>>>()?;
 
     let work_product = WorkProduct {
         cgu_name: cgu_name.to_string(),
diff --git a/src/librustc_mir/borrow_check/borrow_set.rs b/src/librustc_mir/borrow_check/borrow_set.rs
index fd7dc7fc4bd3a..947c32df0f6a3 100644
--- a/src/librustc_mir/borrow_check/borrow_set.rs
+++ b/src/librustc_mir/borrow_check/borrow_set.rs
@@ -16,7 +16,7 @@ use rustc::mir::traversal;
 use rustc::mir::visit::{
     PlaceContext, Visitor, NonUseContext, MutatingUseContext, NonMutatingUseContext
 };
-use rustc::mir::{self, Location, Mir, Place, Local};
+use rustc::mir::{self, Location, Mir, Local};
 use rustc::ty::{RegionVid, TyCtxt};
 use rustc::util::nodemap::{FxHashMap, FxHashSet};
 use rustc_data_structures::indexed_vec::IndexVec;
@@ -41,10 +41,6 @@ crate struct BorrowSet<'tcx> {
     /// only need to store one borrow index
     crate activation_map: FxHashMap<Location, Vec<BorrowIndex>>,
 
-    /// Every borrow has a region; this maps each such regions back to
-    /// its borrow-indexes.
-    crate region_map: FxHashMap<RegionVid, FxHashSet<BorrowIndex>>,
-
     /// Map from local to all the borrows on that local
     crate local_map: FxHashMap<mir::Local, FxHashSet<BorrowIndex>>,
 
@@ -149,7 +145,6 @@ impl<'tcx> BorrowSet<'tcx> {
             idx_vec: IndexVec::new(),
             location_map: Default::default(),
             activation_map: Default::default(),
-            region_map: Default::default(),
             local_map: Default::default(),
             pending_activations: Default::default(),
             locals_state_at_exit:
@@ -164,7 +159,6 @@ impl<'tcx> BorrowSet<'tcx> {
             borrows: visitor.idx_vec,
             location_map: visitor.location_map,
             activation_map: visitor.activation_map,
-            region_map: visitor.region_map,
             local_map: visitor.local_map,
             locals_state_at_exit: visitor.locals_state_at_exit,
         }
@@ -184,7 +178,6 @@ struct GatherBorrows<'a, 'gcx: 'tcx, 'tcx: 'a> {
     idx_vec: IndexVec<BorrowIndex, BorrowData<'tcx>>,
     location_map: FxHashMap<Location, BorrowIndex>,
     activation_map: FxHashMap<Location, Vec<BorrowIndex>>,
-    region_map: FxHashMap<RegionVid, FxHashSet<BorrowIndex>>,
     local_map: FxHashMap<mir::Local, FxHashSet<BorrowIndex>>,
 
     /// When we encounter a 2-phase borrow statement, it will always
@@ -229,7 +222,6 @@ impl<'a, 'gcx, 'tcx> Visitor<'tcx> for GatherBorrows<'a, 'gcx, 'tcx> {
 
             self.insert_as_pending_if_two_phase(location, &assigned_place, kind, idx);
 
-            self.region_map.entry(region).or_default().insert(idx);
             if let Some(local) = borrowed_place.root_local() {
                 self.local_map.entry(local).or_default().insert(idx);
             }
@@ -238,68 +230,68 @@ impl<'a, 'gcx, 'tcx> Visitor<'tcx> for GatherBorrows<'a, 'gcx, 'tcx> {
         self.super_assign(block, assigned_place, rvalue, location)
     }
 
-    fn visit_place(
+    fn visit_local(
         &mut self,
-        place: &mir::Place<'tcx>,
+        temp: &Local,
         context: PlaceContext<'tcx>,
         location: Location,
     ) {
-        self.super_place(place, context, location);
-
-        // We found a use of some temporary TEMP...
-        if let Place::Local(temp) = place {
-            // ... check whether we (earlier) saw a 2-phase borrow like
-            //
-            //     TMP = &mut place
-            if let Some(&borrow_index) = self.pending_activations.get(temp) {
-                let borrow_data = &mut self.idx_vec[borrow_index];
-
-                // Watch out: the use of TMP in the borrow itself
-                // doesn't count as an activation. =)
-                if borrow_data.reserve_location == location &&
-                    context == PlaceContext::MutatingUse(MutatingUseContext::Store)
-                {
-                    return;
-                }
+        if !context.is_use() {
+            return;
+        }
 
-                if let TwoPhaseActivation::ActivatedAt(other_location) =
-                        borrow_data.activation_location {
-                    span_bug!(
-                        self.mir.source_info(location).span,
-                        "found two uses for 2-phase borrow temporary {:?}: \
-                         {:?} and {:?}",
-                        temp,
-                        location,
-                        other_location,
-                    );
-                }
+        // We found a use of some temporary TMP
+        // check whether we (earlier) saw a 2-phase borrow like
+        //
+        //     TMP = &mut place
+        if let Some(&borrow_index) = self.pending_activations.get(temp) {
+            let borrow_data = &mut self.idx_vec[borrow_index];
 
-                // Otherwise, this is the unique later use
-                // that we expect.
-                borrow_data.activation_location = match context {
-                    // The use of TMP in a shared borrow does not
-                    // count as an actual activation.
-                    PlaceContext::NonMutatingUse(NonMutatingUseContext::SharedBorrow(..)) |
-                    PlaceContext::NonMutatingUse(NonMutatingUseContext::ShallowBorrow(..)) =>
-                        TwoPhaseActivation::NotActivated,
-                    _ => {
-                        // Double check: This borrow is indeed a two-phase borrow (that is,
-                        // we are 'transitioning' from `NotActivated` to `ActivatedAt`) and
-                        // we've not found any other activations (checked above).
-                        assert_eq!(
-                            borrow_data.activation_location,
-                            TwoPhaseActivation::NotActivated,
-                            "never found an activation for this borrow!",
-                        );
-
-                        self.activation_map
-                            .entry(location)
-                            .or_default()
-                            .push(borrow_index);
-                        TwoPhaseActivation::ActivatedAt(location)
-                    }
-                };
+            // Watch out: the use of TMP in the borrow itself
+            // doesn't count as an activation. =)
+            if borrow_data.reserve_location == location &&
+                context == PlaceContext::MutatingUse(MutatingUseContext::Store)
+            {
+                return;
+            }
+
+            if let TwoPhaseActivation::ActivatedAt(other_location) =
+                    borrow_data.activation_location {
+                span_bug!(
+                    self.mir.source_info(location).span,
+                    "found two uses for 2-phase borrow temporary {:?}: \
+                     {:?} and {:?}",
+                    temp,
+                    location,
+                    other_location,
+                );
             }
+
+            // Otherwise, this is the unique later use
+            // that we expect.
+            borrow_data.activation_location = match context {
+                // The use of TMP in a shared borrow does not
+                // count as an actual activation.
+                PlaceContext::NonMutatingUse(NonMutatingUseContext::SharedBorrow(..)) |
+                PlaceContext::NonMutatingUse(NonMutatingUseContext::ShallowBorrow(..)) =>
+                    TwoPhaseActivation::NotActivated,
+                _ => {
+                    // Double check: This borrow is indeed a two-phase borrow (that is,
+                    // we are 'transitioning' from `NotActivated` to `ActivatedAt`) and
+                    // we've not found any other activations (checked above).
+                    assert_eq!(
+                        borrow_data.activation_location,
+                        TwoPhaseActivation::NotActivated,
+                        "never found an activation for this borrow!",
+                    );
+
+                    self.activation_map
+                        .entry(location)
+                        .or_default()
+                        .push(borrow_index);
+                    TwoPhaseActivation::ActivatedAt(location)
+                }
+            };
         }
     }
 
diff --git a/src/librustc_mir/borrow_check/error_reporting.rs b/src/librustc_mir/borrow_check/error_reporting.rs
index 4ccd26bee8b88..ba26ed36c20f4 100644
--- a/src/librustc_mir/borrow_check/error_reporting.rs
+++ b/src/librustc_mir/borrow_check/error_reporting.rs
@@ -344,6 +344,13 @@ impl<'cx, 'gcx, 'tcx> MirBorrowckCtxt<'cx, 'gcx, 'tcx> {
 
         let first_borrow_desc;
 
+        let explanation = self.explain_why_borrow_contains_point(context, issued_borrow, None);
+        let second_borrow_desc = if explanation.is_explained() {
+            "second "
+        } else {
+            ""
+        };
+
         // FIXME: supply non-"" `opt_via` when appropriate
         let mut err = match (
             gen_borrow_kind,
@@ -454,6 +461,7 @@ impl<'cx, 'gcx, 'tcx> MirBorrowckCtxt<'cx, 'gcx, 'tcx> {
                     issued_span,
                     "",
                     None,
+                    second_borrow_desc,
                     Origin::Mir,
                 )
             }
@@ -469,6 +477,7 @@ impl<'cx, 'gcx, 'tcx> MirBorrowckCtxt<'cx, 'gcx, 'tcx> {
                     issued_span,
                     "",
                     None,
+                    second_borrow_desc,
                     Origin::Mir,
                 )
             }
@@ -513,7 +522,7 @@ impl<'cx, 'gcx, 'tcx> MirBorrowckCtxt<'cx, 'gcx, 'tcx> {
             );
         }
 
-        self.explain_why_borrow_contains_point(context, issued_borrow, None)
+        explanation
             .add_explanation_to_diagnostic(self.infcx.tcx, self.mir, &mut err, first_borrow_desc);
 
         err.buffer(&mut self.errors_buffer);
diff --git a/src/librustc_mir/borrow_check/nll/explain_borrow/mod.rs b/src/librustc_mir/borrow_check/nll/explain_borrow/mod.rs
index bb9a29b055b7f..477b78926084e 100644
--- a/src/librustc_mir/borrow_check/nll/explain_borrow/mod.rs
+++ b/src/librustc_mir/borrow_check/nll/explain_borrow/mod.rs
@@ -52,6 +52,12 @@ pub(in borrow_check) enum LaterUseKind {
 }
 
 impl BorrowExplanation {
+    pub(in borrow_check) fn is_explained(&self) -> bool {
+        match self {
+            BorrowExplanation::Unexplained => false,
+            _ => true,
+        }
+    }
     pub(in borrow_check) fn add_explanation_to_diagnostic<'cx, 'gcx, 'tcx>(
         &self,
         tcx: TyCtxt<'cx, 'gcx, 'tcx>,
diff --git a/src/librustc_mir/borrow_check/prefixes.rs b/src/librustc_mir/borrow_check/prefixes.rs
index f73e08eb13521..7d583b4f54191 100644
--- a/src/librustc_mir/borrow_check/prefixes.rs
+++ b/src/librustc_mir/borrow_check/prefixes.rs
@@ -87,10 +87,7 @@ impl<'cx, 'gcx, 'tcx> MirBorrowckCtxt<'cx, 'gcx, 'tcx> {
 impl<'cx, 'gcx, 'tcx> Iterator for Prefixes<'cx, 'gcx, 'tcx> {
     type Item = &'cx Place<'tcx>;
     fn next(&mut self) -> Option<Self::Item> {
-        let mut cursor = match self.next {
-            None => return None,
-            Some(place) => place,
-        };
+        let mut cursor = self.next?;
 
         // Post-processing `place`: Enqueue any remaining
         // work. Also, `place` may not be a prefix itself, but
diff --git a/src/librustc_mir/dataflow/impls/borrows.rs b/src/librustc_mir/dataflow/impls/borrows.rs
index 27bc28ac81d84..3a9e4fc9e4ab9 100644
--- a/src/librustc_mir/dataflow/impls/borrows.rs
+++ b/src/librustc_mir/dataflow/impls/borrows.rs
@@ -246,7 +246,7 @@ impl<'a, 'gcx, 'tcx> BitDenotation for Borrows<'a, 'gcx, 'tcx> {
                 // re-consider the current implementations of the
                 // propagate_call_return method.
 
-                if let mir::Rvalue::Ref(region, _, ref place) = **rhs {
+                if let mir::Rvalue::Ref(_, _, ref place) = **rhs {
                     if place.ignore_borrow(
                         self.tcx,
                         self.mir,
@@ -258,13 +258,6 @@ impl<'a, 'gcx, 'tcx> BitDenotation for Borrows<'a, 'gcx, 'tcx> {
                         panic!("could not find BorrowIndex for location {:?}", location);
                     });
 
-                    assert!(self.borrow_set.region_map
-                        .get(&region.to_region_vid())
-                        .unwrap_or_else(|| {
-                            panic!("could not find BorrowIndexs for RegionVid {:?}", region);
-                        })
-                        .contains(&index)
-                    );
                     sets.gen(*index);
 
                     // Issue #46746: Two-phase borrows handles
diff --git a/src/librustc_mir/monomorphize/partitioning.rs b/src/librustc_mir/monomorphize/partitioning.rs
index 3a6ee6da42215..528942df29fee 100644
--- a/src/librustc_mir/monomorphize/partitioning.rs
+++ b/src/librustc_mir/monomorphize/partitioning.rs
@@ -585,7 +585,7 @@ fn merge_codegen_units<'tcx>(tcx: TyCtxt<'_, 'tcx, 'tcx>,
     // smallest into each other) we're sure to start off with a deterministic
     // order (sorted by name). This'll mean that if two cgus have the same size
     // the stable sort below will keep everything nice and deterministic.
-    codegen_units.sort_by_key(|cgu| cgu.name().clone());
+    codegen_units.sort_by_key(|cgu| *cgu.name());
 
     // Merge the two smallest codegen units until the target size is reached.
     while codegen_units.len() > target_cgu_count {
@@ -985,7 +985,7 @@ fn collect_and_partition_mono_items<'a, 'tcx>(
                 output.push_str(" @@");
                 let mut empty = Vec::new();
                 let cgus = item_to_cgus.get_mut(i).unwrap_or(&mut empty);
-                cgus.as_mut_slice().sort_by_cached_key(|&(ref name, _)| name.clone());
+                cgus.sort_by_key(|(name, _)| *name);
                 cgus.dedup();
                 for &(ref cgu_name, (linkage, _)) in cgus.iter() {
                     output.push_str(" ");
diff --git a/src/librustc_mir/transform/cleanup_post_borrowck.rs b/src/librustc_mir/transform/cleanup_post_borrowck.rs
index c0edd3926d32d..6d7fc404edbb1 100644
--- a/src/librustc_mir/transform/cleanup_post_borrowck.rs
+++ b/src/librustc_mir/transform/cleanup_post_borrowck.rs
@@ -10,17 +10,25 @@
 
 //! This module provides two passes:
 //!
-//!   - [CleanAscribeUserType], that replaces all
-//!     [StatementKind::AscribeUserType] statements with [StatementKind::Nop].
-//!   - [CleanFakeReadsAndBorrows], that replaces all [FakeRead] statements and
-//!     borrows that are read by [FakeReadCause::ForMatchGuard] fake reads with
-//!     [StatementKind::Nop].
+//!   - [`CleanAscribeUserType`], that replaces all [`AscribeUserType`]
+//!     statements with [`Nop`].
+//!   - [`CleanFakeReadsAndBorrows`], that replaces all [`FakeRead`] statements
+//!     and borrows that are read by [`ForMatchGuard`] fake reads with [`Nop`].
 //!
-//! The [CleanFakeReadsAndBorrows] "pass" is actually implemented as two
+//! The `CleanFakeReadsAndBorrows` "pass" is actually implemented as two
 //! traversals (aka visits) of the input MIR. The first traversal,
-//! [DeleteAndRecordFakeReads], deletes the fake reads and finds the temporaries
-//! read by [ForMatchGuard] reads, and [DeleteFakeBorrows] deletes the
-//! initialization of those temporaries.
+//! [`DeleteAndRecordFakeReads`], deletes the fake reads and finds the
+//! temporaries read by [`ForMatchGuard`] reads, and [`DeleteFakeBorrows`]
+//! deletes the initialization of those temporaries.
+//!
+//! [`CleanAscribeUserType`]: cleanup_post_borrowck::CleanAscribeUserType
+//! [`CleanFakeReadsAndBorrows`]: cleanup_post_borrowck::CleanFakeReadsAndBorrows
+//! [`DeleteAndRecordFakeReads`]: cleanup_post_borrowck::DeleteAndRecordFakeReads
+//! [`DeleteFakeBorrows`]: cleanup_post_borrowck::DeleteFakeBorrows
+//! [`AscribeUserType`]: rustc::mir::StatementKind::AscribeUserType
+//! [`Nop`]: rustc::mir::StatementKind::Nop
+//! [`FakeRead`]: rustc::mir::StatementKind::FakeRead
+//! [`ForMatchGuard`]: rustc::mir::FakeReadCause::ForMatchGuard
 
 use rustc_data_structures::fx::FxHashSet;
 
diff --git a/src/librustc_mir/util/borrowck_errors.rs b/src/librustc_mir/util/borrowck_errors.rs
index ae0483e3c140c..8566f845f23e3 100644
--- a/src/librustc_mir/util/borrowck_errors.rs
+++ b/src/librustc_mir/util/borrowck_errors.rs
@@ -261,6 +261,7 @@ pub trait BorrowckErrors<'cx>: Sized + Copy {
         old_loan_span: Span,
         old_opt_via: &str,
         previous_end_span: Option<Span>,
+        second_borrow_desc: &str,
         o: Origin,
     ) -> DiagnosticBuilder<'cx> {
         let mut err = struct_span_err!(
@@ -274,7 +275,10 @@ pub trait BorrowckErrors<'cx>: Sized + Copy {
             kind_new,
             OGN = o
         );
-        err.span_label(new_loan_span, format!("borrow occurs here{}", opt_via));
+        err.span_label(
+            new_loan_span,
+            format!("{}borrow occurs here{}", second_borrow_desc, opt_via),
+        );
         err.span_label(
             old_loan_span,
             format!("{} construction occurs here{}", container_name, old_opt_via),
diff --git a/src/librustc_resolve/build_reduced_graph.rs b/src/librustc_resolve/build_reduced_graph.rs
index 0fa41cb484fc9..da4cd73923ede 100644
--- a/src/librustc_resolve/build_reduced_graph.rs
+++ b/src/librustc_resolve/build_reduced_graph.rs
@@ -318,7 +318,7 @@ impl<'a, 'cl> Resolver<'a, 'cl> {
                         // This particular use tree
                         &tree, id, &prefix, true,
                         // The whole `use` item
-                        parent_scope.clone(), item, ty::Visibility::Invisible, root_span,
+                        parent_scope, item, ty::Visibility::Invisible, root_span,
                     );
                 }
             }
diff --git a/src/librustdoc/clean/mod.rs b/src/librustdoc/clean/mod.rs
index fd8f70b19e7ec..b0f3dcbd72ebb 100644
--- a/src/librustdoc/clean/mod.rs
+++ b/src/librustdoc/clean/mod.rs
@@ -708,8 +708,6 @@ impl<I: IntoIterator<Item=ast::NestedMetaItem>> NestedAttributesExt for I {
 /// kept separate because of issue #42760.
 #[derive(Clone, RustcEncodable, RustcDecodable, PartialEq, Eq, Debug, Hash)]
 pub enum DocFragment {
-    // FIXME #44229 (misdreavus): sugared and raw doc comments can be brought back together once
-    // hoedown is completely removed from rustdoc.
     /// A doc fragment created from a `///` or `//!` doc comment.
     SugaredDoc(usize, syntax_pos::Span, String),
     /// A doc fragment created from a "raw" `#[doc=""]` attribute.
@@ -3948,10 +3946,7 @@ pub fn path_to_def_local(tcx: &TyCtxt, path: &[&str]) -> Option<DefId> {
     let mut path_it = path.iter().peekable();
 
     loop {
-        let segment = match path_it.next() {
-            Some(segment) => segment,
-            None => return None,
-        };
+        let segment = path_it.next()?;
 
         for item_id in mem::replace(&mut items, HirVec::new()).iter() {
             let item = tcx.hir.expect_item(item_id.id);
@@ -3986,10 +3981,7 @@ pub fn path_to_def(tcx: &TyCtxt, path: &[&str]) -> Option<DefId> {
         let mut path_it = path.iter().skip(1).peekable();
 
         loop {
-            let segment = match path_it.next() {
-                Some(segment) => segment,
-                None => return None,
-            };
+            let segment = path_it.next()?;
 
             for item in mem::replace(&mut items, Lrc::new(vec![])).iter() {
                 if item.ident.name == *segment {
diff --git a/src/librustdoc/html/layout.rs b/src/librustdoc/html/layout.rs
index 5263cfe7b0e4f..fa5d015e5b72d 100644
--- a/src/librustdoc/html/layout.rs
+++ b/src/librustdoc/html/layout.rs
@@ -57,6 +57,9 @@ pub fn render<T: fmt::Display, S: fmt::Display>(
     {css_extension}\
     {favicon}\
     {in_header}\
+    <style type=\"text/css\">\
+    #crate-search{{background-image:url(\"{root_path}down-arrow{suffix}.svg\");}}\
+    </style>\
 </head>\
 <body class=\"rustdoc {css_class}\">\
     <!--[if lte IE 8]>\
@@ -81,11 +84,16 @@ pub fn render<T: fmt::Display, S: fmt::Display>(
     <nav class=\"sub\">\
         <form class=\"search-form js-only\">\
             <div class=\"search-container\">\
-                <input class=\"search-input\" name=\"search\" \
-                       autocomplete=\"off\" \
-                       spellcheck=\"false\" \
-                       placeholder=\"Click or press ‘S’ to search, ‘?’ for more options…\" \
-                       type=\"search\">\
+                <div>\
+                    <select id=\"crate-search\">\
+                        <option value=\"All crates\">All crates</option>\
+                    </select>\
+                    <input class=\"search-input\" name=\"search\" \
+                           autocomplete=\"off\" \
+                           spellcheck=\"false\" \
+                           placeholder=\"Click or press ‘S’ to search, ‘?’ for more options…\" \
+                           type=\"search\">\
+                </div>\
                 <a id=\"settings-menu\" href=\"{root_path}settings.html\">\
                     <img src=\"{root_path}wheel{suffix}.svg\" width=\"18\" alt=\"Change settings\">\
                 </a>\
diff --git a/src/librustdoc/html/render.rs b/src/librustdoc/html/render.rs
index 2c4ddf38e9868..3e4874a5001aa 100644
--- a/src/librustdoc/html/render.rs
+++ b/src/librustdoc/html/render.rs
@@ -793,6 +793,8 @@ fn write_shared(
           static_files::BRUSH_SVG)?;
     write(cx.dst.join(&format!("wheel{}.svg", cx.shared.resource_suffix)),
           static_files::WHEEL_SVG)?;
+    write(cx.dst.join(&format!("down-arrow{}.svg", cx.shared.resource_suffix)),
+          static_files::DOWN_ARROW_SVG)?;
     write_minify(cx.dst.join(&format!("light{}.css", cx.shared.resource_suffix)),
                  static_files::themes::LIGHT,
                  options.enable_minification)?;
@@ -1066,7 +1068,7 @@ themePicker.onblur = handleThemeButtonsBlur;
                                        &[(minifier::js::Keyword::Null, "N")]),
                  &dst);
     }
-    try_err!(writeln!(&mut w, "initSearch(searchIndex);"), &dst);
+    try_err!(writeln!(&mut w, "initSearch(searchIndex);addSearchOptions(searchIndex);"), &dst);
 
     if options.enable_index_page {
         if let Some(index_page) = options.index_page.clone() {
@@ -2220,13 +2222,13 @@ impl<'a> Item<'a> {
                 return None;
             }
         } else {
-            let (krate, src_root) = match cache.extern_locations.get(&self.item.def_id.krate) {
-                Some(&(ref name, ref src, Local)) => (name, src),
-                Some(&(ref name, ref src, Remote(ref s))) => {
+            let (krate, src_root) = match *cache.extern_locations.get(&self.item.def_id.krate)? {
+                (ref name, ref src, Local) => (name, src),
+                (ref name, ref src, Remote(ref s)) => {
                     root = s.to_string();
                     (name, src)
                 }
-                Some(&(_, _, Unknown)) | None => return None,
+                (_, _, Unknown) => return None,
             };
 
             clean_srcpath(&src_root, file, false, |component| {
diff --git a/src/librustdoc/html/static/.eslintrc.js b/src/librustdoc/html/static/.eslintrc.js
new file mode 100644
index 0000000000000..c7af41ac969ce
--- /dev/null
+++ b/src/librustdoc/html/static/.eslintrc.js
@@ -0,0 +1,21 @@
+module.exports = {
+    "env": {
+        "browser": true,
+        "es6": true
+    },
+    "extends": "eslint:recommended",
+    "parserOptions": {
+        "ecmaVersion": 2015,
+        "sourceType": "module"
+    },
+    "rules": {
+        "linebreak-style": [
+            "error",
+            "unix"
+        ],
+        "semi": [
+            "error",
+            "always"
+        ]
+    }
+};
diff --git a/src/librustdoc/html/static/down-arrow.svg b/src/librustdoc/html/static/down-arrow.svg
new file mode 100644
index 0000000000000..a2d9a37dde091
--- /dev/null
+++ b/src/librustdoc/html/static/down-arrow.svg
@@ -0,0 +1 @@
+<?xml version="1.0" ?><!DOCTYPE svg  PUBLIC '-//W3C//DTD SVG 1.1//EN'  'http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd'><svg height="128px" id="Layer_1" style="enable-background:new 0 0 128 128;" version="1.1" viewBox="0 0 128 128" width="128px" xml:space="preserve" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink"><g><line style="fill:none;stroke:#2F3435;stroke-width:12;stroke-linecap:square;stroke-miterlimit:10;" x1="111" x2="64" y1="40.5" y2="87.499"/><line style="fill:none;stroke:#2F3435;stroke-width:12;stroke-linecap:square;stroke-miterlimit:10;" x1="64" x2="17" y1="87.499" y2="40.5"/></g></svg>
\ No newline at end of file
diff --git a/src/librustdoc/html/static/main.js b/src/librustdoc/html/static/main.js
index 781f99cd6932f..1869969a53069 100644
--- a/src/librustdoc/html/static/main.js
+++ b/src/librustdoc/html/static/main.js
@@ -10,8 +10,12 @@
  * except according to those terms.
  */
 
-/*jslint browser: true, es5: true */
-/*globals $: true, rootPath: true */
+// From rust:
+/* global ALIASES, currentCrate, rootPath */
+
+// Local js definitions:
+/* global addClass, getCurrentValue, hasClass */
+/* global isHidden onEach, removeClass, updateLocalStorage */
 
 if (!String.prototype.startsWith) {
     String.prototype.startsWith = function(searchString, position) {
@@ -214,12 +218,14 @@ if (!String.prototype.endsWith) {
     //
     // So I guess you could say things are getting pretty interoperable.
     function getVirtualKey(ev) {
-        if ("key" in ev && typeof ev.key != "undefined")
+        if ("key" in ev && typeof ev.key != "undefined") {
             return ev.key;
+        }
 
         var c = ev.charCode || ev.keyCode;
-        if (c == 27)
+        if (c == 27) {
             return "Escape";
+        }
         return String.fromCharCode(c);
     }
 
@@ -427,12 +433,13 @@ if (!String.prototype.endsWith) {
 
         /**
          * Executes the query and builds an index of results
-         * @param  {[Object]} query     [The user query]
-         * @param  {[type]} searchWords [The list of search words to query
-         *                               against]
-         * @return {[type]}             [A search index of results]
+         * @param  {[Object]} query      [The user query]
+         * @param  {[type]} searchWords  [The list of search words to query
+         *                                against]
+         * @param  {[type]} filterCrates [Crate to search in if defined]
+         * @return {[type]}              [A search index of results]
          */
-        function execQuery(query, searchWords) {
+        function execQuery(query, searchWords, filterCrates) {
             function itemTypeFromName(typename) {
                 for (var i = 0; i < itemTypes.length; ++i) {
                     if (itemTypes[i] === typename) {
@@ -808,6 +815,9 @@ if (!String.prototype.endsWith) {
             {
                 val = extractGenerics(val.substr(1, val.length - 2));
                 for (var i = 0; i < nSearchWords; ++i) {
+                    if (filterCrates !== undefined && searchIndex[i].crate !== filterCrates) {
+                        continue;
+                    }
                     var in_args = findArg(searchIndex[i], val, true);
                     var returned = checkReturned(searchIndex[i], val, true);
                     var ty = searchIndex[i];
@@ -862,6 +872,9 @@ if (!String.prototype.endsWith) {
                 var output = extractGenerics(parts[1]);
 
                 for (var i = 0; i < nSearchWords; ++i) {
+                    if (filterCrates !== undefined && searchIndex[i].crate !== filterCrates) {
+                        continue;
+                    }
                     var type = searchIndex[i].type;
                     var ty = searchIndex[i];
                     if (!type) {
@@ -933,11 +946,11 @@ if (!String.prototype.endsWith) {
                 var contains = paths.slice(0, paths.length > 1 ? paths.length - 1 : 1);
 
                 for (j = 0; j < nSearchWords; ++j) {
-                    var lev_distance;
                     var ty = searchIndex[j];
-                    if (!ty) {
+                    if (!ty || (filterCrates !== undefined && ty.crate !== filterCrates)) {
                         continue;
                     }
+                    var lev_distance;
                     var lev_add = 0;
                     if (paths.length > 1) {
                         var lev = checkPath(contains, paths[paths.length - 1], ty);
@@ -1300,7 +1313,16 @@ if (!String.prototype.endsWith) {
                 output = '<div class="search-failed"' + extraStyle + '>No results :(<br/>' +
                     'Try on <a href="https://duckduckgo.com/?q=' +
                     encodeURIComponent('rust ' + query.query) +
-                    '">DuckDuckGo</a>?</div>';
+                    '">DuckDuckGo</a>?<br/><br/>' +
+                    'Or try looking in one of these:<ul><li>The <a ' +
+                    'href="https://doc.rust-lang.org/reference/index.html">Rust Reference</a> for' +
+                    ' technical details about the language.</li><li><a ' +
+                    'href="https://doc.rust-lang.org/rust-by-example/index.html">Rust By Example' +
+                    '</a> for expository code examples.</a></li><li>The <a ' +
+                    'href="https://doc.rust-lang.org/book/index.html">Rust Book</a> for ' +
+                    'introductions to language features and the language itself.</li><li><a ' +
+                    'href="https://docs.rs">Docs.rs</a> for documentation of crates released on ' +
+                    '<a href="https://crates.io/">crates.io</a>.</li></ul></div>';
             }
             return [output, length];
         }
@@ -1313,7 +1335,7 @@ if (!String.prototype.endsWith) {
             return '<div>' + text + ' <div class="count">(' + nbElems + ')</div></div>';
         }
 
-        function showResults(results) {
+        function showResults(results, filterCrates) {
             if (results['others'].length === 1 &&
                 getCurrentValue('rustdoc-go-to-only-result') === "true") {
                 var elem = document.createElement('a');
@@ -1331,8 +1353,13 @@ if (!String.prototype.endsWith) {
             var ret_in_args = addTab(results['in_args'], query, false);
             var ret_returned = addTab(results['returned'], query, false);
 
+            var filter = "";
+            if (filterCrates !== undefined) {
+                filter = " (in <b>" + filterCrates + "</b> crate)";
+            }
+
             var output = '<h1>Results for ' + escape(query.query) +
-                (query.type ? ' (type: ' + escape(query.type) + ')' : '') + '</h1>' +
+                (query.type ? ' (type: ' + escape(query.type) + ')' : '') + filter + '</h1>' +
                 '<div id="titles">' +
                 makeTabHeader(0, "In Names", ret_others[1]) +
                 makeTabHeader(1, "In Parameters", ret_in_args[1]) +
@@ -1361,7 +1388,7 @@ if (!String.prototype.endsWith) {
             printTab(currentTab);
         }
 
-        function execSearch(query, searchWords) {
+        function execSearch(query, searchWords, filterCrates) {
             var queries = query.raw.split(",");
             var results = {
                 'in_args': [],
@@ -1372,7 +1399,7 @@ if (!String.prototype.endsWith) {
             for (var i = 0; i < queries.length; ++i) {
                 var query = queries[i].trim();
                 if (query.length !== 0) {
-                    var tmp = execQuery(getQuery(query), searchWords);
+                    var tmp = execQuery(getQuery(query), searchWords, filterCrates);
 
                     results['in_args'].push(tmp['in_args']);
                     results['returned'].push(tmp['returned']);
@@ -1434,7 +1461,16 @@ if (!String.prototype.endsWith) {
             }
         }
 
-        function search(e) {
+        function getFilterCrates() {
+            var elem = document.getElementById("crate-search");
+
+            if (elem && elem.value !== "All crates" && rawSearchIndex.hasOwnProperty(elem.value)) {
+                return elem.value;
+            }
+            return undefined;
+        }
+
+        function search(e, forced) {
             var params = getQueryStringParams();
             var query = getQuery(search_input.value.trim());
 
@@ -1442,7 +1478,10 @@ if (!String.prototype.endsWith) {
                 e.preventDefault();
             }
 
-            if (query.query.length === 0 || query.id === currentResults) {
+            if (query.query.length === 0) {
+                return;
+            }
+            if (forced !== true && query.id === currentResults) {
                 if (query.query.length > 0) {
                     putBackSearch(search_input);
                 }
@@ -1462,7 +1501,8 @@ if (!String.prototype.endsWith) {
                 }
             }
 
-            showResults(execSearch(query, index));
+            var filterCrates = getFilterCrates();
+            showResults(execSearch(query, index, filterCrates), filterCrates);
         }
 
         function buildIndex(rawSearchIndex) {
@@ -1562,6 +1602,13 @@ if (!String.prototype.endsWith) {
             };
             search_input.onpaste = search_input.onchange;
 
+            var selectCrate = document.getElementById('crate-search');
+            if (selectCrate) {
+                selectCrate.onchange = function() {
+                    search(undefined, true);
+                };
+            }
+
             // Push and pop states are used to add search results to the browser
             // history.
             if (browserSupportsHistoryApi()) {
@@ -2310,6 +2357,39 @@ if (!String.prototype.endsWith) {
     if (window.location.hash && window.location.hash.length > 0) {
         expandSection(window.location.hash.replace(/^#/, ''));
     }
+
+    function addSearchOptions(crates) {
+        var elem = document.getElementById('crate-search');
+
+        if (!elem) {
+            return;
+        }
+        var crates_text = [];
+        for (var crate in crates) {
+            if (crates.hasOwnProperty(crate)) {
+                crates_text.push(crate);
+            }
+        }
+        crates_text.sort(function(a, b) {
+            var lower_a = a.toLowerCase();
+            var lower_b = b.toLowerCase();
+
+            if (lower_a < lower_b) {
+                return -1;
+            } else if (lower_a > lower_b) {
+                return 1;
+            }
+            return 0;
+        });
+        for (var i = 0; i < crates_text.length; ++i) {
+            var option = document.createElement("option");
+            option.value = crates_text[i];
+            option.innerText = crates_text[i];
+            elem.appendChild(option);
+        }
+    }
+
+    window.addSearchOptions = addSearchOptions;
 }());
 
 // Sets the focus on the search bar at the top of the page
diff --git a/src/librustdoc/html/static/rustdoc.css b/src/librustdoc/html/static/rustdoc.css
index b6242457ae2b8..37d26a4cadc57 100644
--- a/src/librustdoc/html/static/rustdoc.css
+++ b/src/librustdoc/html/static/rustdoc.css
@@ -135,7 +135,6 @@ summary {
 
 code, pre {
 	font-family: "Source Code Pro", monospace;
-	white-space: pre-wrap;
 }
 .docblock code, .docblock-short code {
 	border-radius: 3px;
@@ -283,7 +282,7 @@ nav.sub {
 	padding-left: 0;
 }
 
-:not(.source) .example-wrap {
+.rustdoc:not(.source) .example-wrap {
 	display: inline-flex;
 	margin-bottom: 10px;
 }
@@ -301,8 +300,9 @@ nav.sub {
 	text-align: right;
 }
 
-:not(.source) .example-wrap > pre.rust {
+.rustdoc:not(.source) .example-wrap > pre.rust {
 	width: 100%;
+	overflow-x: auto;
 }
 
 body:not(.source) .example-wrap > pre {
@@ -620,13 +620,36 @@ a {
 .search-container {
 	position: relative;
 }
+.search-container > div {
+	display: inline-flex;
+	width: calc(100% - 34px);
+}
+#crate-search {
+	margin-top: 5px;
+	padding: 6px;
+	padding-right: 19px;
+	border: 0;
+	border-right: 0;
+	border-radius: 4px 0 0 4px;
+	outline: none;
+	cursor: pointer;
+	border-right: 1px solid;
+	-moz-appearance: none;
+	-webkit-appearance: none;
+	/* Removes default arrow from firefox */
+	text-indent: 0.01px;
+	text-overflow: "";
+	background-repeat: no-repeat;
+	background-color: transparent;
+	background-size: 16%;
+	background-position: calc(100% - 1px) 56%;
+}
 .search-container > .top-button {
 	position: absolute;
 	right: 0;
 	top: 10px;
 }
 .search-input {
-	width: calc(100% - 34px);
 	/* Override Normalize.css: we have margins and do
 	 not want to overflow - the `moz` attribute is necessary
 	 until Firefox 29, too early to drop at this point */
@@ -634,13 +657,14 @@ a {
 	box-sizing: border-box !important;
 	outline: none;
 	border: none;
-	border-radius: 1px;
+	border-radius: 0 1px 1px 0;
 	margin-top: 5px;
 	padding: 10px 16px;
 	font-size: 17px;
 	transition: border-color 300ms ease;
 	transition: border-radius 300ms ease-in-out;
 	transition: box-shadow 300ms ease-in-out;
+	width: 100%;
 }
 
 .search-input:focus {
@@ -1132,6 +1156,13 @@ pre.rust {
 	margin-top: 20px;
 }
 
+.search-failed > ul {
+	text-align: left;
+	max-width: 570px;
+	margin-left: auto;
+	margin-right: auto;
+}
+
 #titles {
 	height: 35px;
 }
diff --git a/src/librustdoc/html/static/source-script.js b/src/librustdoc/html/static/source-script.js
index 1db8218dae6f2..03b0955a34c31 100644
--- a/src/librustdoc/html/static/source-script.js
+++ b/src/librustdoc/html/static/source-script.js
@@ -10,6 +10,12 @@
  * except according to those terms.
  */
 
+// From rust:
+/* global sourcesIndex */
+
+// Local js definitions:
+/* global addClass, getCurrentValue, hasClass, removeClass, updateLocalStorage */
+
 function getCurrentFilePath() {
     var parts = window.location.pathname.split("/");
     var rootPathParts = window.rootPath.split("/");
diff --git a/src/librustdoc/html/static/storage.js b/src/librustdoc/html/static/storage.js
index 150001a751445..e8f0c03d91aa6 100644
--- a/src/librustdoc/html/static/storage.js
+++ b/src/librustdoc/html/static/storage.js
@@ -10,6 +10,9 @@
  * except according to those terms.
  */
 
+// From rust:
+/* global resourcesSuffix */
+
 var currentTheme = document.getElementById("themeStyle");
 var mainTheme = document.getElementById("mainThemeStyle");
 
diff --git a/src/librustdoc/html/static/themes/dark.css b/src/librustdoc/html/static/themes/dark.css
index acf9a8cca6447..2cd1a8580890c 100644
--- a/src/librustdoc/html/static/themes/dark.css
+++ b/src/librustdoc/html/static/themes/dark.css
@@ -182,9 +182,15 @@ a.test-arrow {
 	color: #999;
 }
 
+#crate-search {
+	color: #111;
+	background-color: #f0f0f0;
+	border-color: #000;
+}
+
 .search-input {
 	color: #111;
-	box-shadow: 0 0 0 1px #000, 0 0 0 2px transparent;
+	box-shadow: 1px 0 0 1px #000, 0 0 0 2px transparent;
 	background-color: #f0f0f0;
 }
 
@@ -285,7 +291,7 @@ pre.ignore:hover, .information:hover + pre.ignore {
 	color: rgba(255,142,0,1);
 }
 
-.search-failed > a {
+.search-failed a {
 	color: #0089ff;
 }
 
diff --git a/src/librustdoc/html/static/themes/light.css b/src/librustdoc/html/static/themes/light.css
index d98f1718a6ab7..4cf35f64d19a4 100644
--- a/src/librustdoc/html/static/themes/light.css
+++ b/src/librustdoc/html/static/themes/light.css
@@ -182,9 +182,16 @@ a.test-arrow {
 	color: #999;
 }
 
+#crate-search {
+	color: #555;
+	background-color: white;
+	border-color: #e0e0e0;
+	box-shadow: 0px 0 0 1px #e0e0e0, 0 0 0 2px transparent;
+}
+
 .search-input {
 	color: #555;
-	box-shadow: 0 0 0 1px #e0e0e0, 0 0 0 2px transparent;
+	box-shadow: 1px 0 0 1px #e0e0e0, 0 0 0 2px transparent;
 	background-color: white;
 }
 
@@ -279,7 +286,7 @@ pre.ignore:hover, .information:hover + pre.ignore {
 	color: rgba(255,142,0,1);
 }
 
-.search-failed > a {
+.search-failed a {
 	color: #0089ff;
 }
 
diff --git a/src/librustdoc/html/static_files.rs b/src/librustdoc/html/static_files.rs
index ee29f15d686c1..a485facfac2dc 100644
--- a/src/librustdoc/html/static_files.rs
+++ b/src/librustdoc/html/static_files.rs
@@ -45,6 +45,9 @@ pub static BRUSH_SVG: &'static [u8] = include_bytes!("static/brush.svg");
 /// The file contents of `wheel.svg`, the icon used for the settings button.
 pub static WHEEL_SVG: &'static [u8] = include_bytes!("static/wheel.svg");
 
+/// The file contents of `down-arrow.svg`, the icon used for the crate choice combobox.
+pub static DOWN_ARROW_SVG: &'static [u8] = include_bytes!("static/down-arrow.svg");
+
 /// The contents of `COPYRIGHT.txt`, the license listing for files distributed with documentation
 /// output.
 pub static COPYRIGHT: &'static [u8] = include_bytes!("static/COPYRIGHT.txt");
diff --git a/src/librustdoc/passes/collect_intra_doc_links.rs b/src/librustdoc/passes/collect_intra_doc_links.rs
index 7183cfe571192..3f6cf519b16d5 100644
--- a/src/librustdoc/passes/collect_intra_doc_links.rs
+++ b/src/librustdoc/passes/collect_intra_doc_links.rs
@@ -460,6 +460,19 @@ pub fn span_of_attrs(attrs: &Attributes) -> syntax_pos::Span {
     start.to(end)
 }
 
+/// Reports a resolution failure diagnostic.
+///
+/// Ideally we can report the diagnostic with the actual span in the source where the link failure
+/// occurred. However, there's a mismatch between the span in the source code and the span in the
+/// markdown, so we have to do a bit of work to figure out the correspondence.
+///
+/// It's not too hard to find the span for sugared doc comments (`///` and `/**`), because the
+/// source will match the markdown exactly, excluding the comment markers. However, it's much more
+/// difficult to calculate the spans for unsugared docs, because we have to deal with escaping and
+/// other source features. So, we attempt to find the exact source span of the resolution failure
+/// in sugared docs, but use the span of the documentation attributes themselves for unsugared
+/// docs. Because this span might be overly large, we display the markdown line containing the
+/// failure as a note.
 fn resolution_failure(
     cx: &DocContext,
     attrs: &Attributes,
@@ -470,34 +483,50 @@ fn resolution_failure(
     let sp = span_of_attrs(attrs);
     let msg = format!("`[{}]` cannot be resolved, ignoring it...", path_str);
 
-    let code_dox = sp.to_src(cx);
-
-    let doc_comment_padding = 3;
     let mut diag = if let Some(link_range) = link_range {
-        // blah blah blah\nblah\nblah [blah] blah blah\nblah blah
-        //                       ^    ~~~~~~
-        //                       |    link_range
-        //                       last_new_line_offset
-
         let mut diag;
-        if dox.lines().count() == code_dox.lines().count() {
-            let line_offset = dox[..link_range.start].lines().count();
-            // The span starts in the `///`, so we don't have to account for the leading whitespace
-            let code_dox_len = if line_offset <= 1 {
-                doc_comment_padding
-            } else {
-                // The first `///`
-                doc_comment_padding +
-                    // Each subsequent leading whitespace and `///`
-                    code_dox.lines().skip(1).take(line_offset - 1).fold(0, |sum, line| {
-                        sum + doc_comment_padding + line.len() - line.trim_start().len()
-                    })
-            };
 
-            // Extract the specific span
+        if attrs.doc_strings.iter().all(|frag| match frag {
+            DocFragment::SugaredDoc(..) => true,
+            _ => false,
+        }) {
+            let source_dox = sp.to_src(cx);
+            let mut source_lines = source_dox.lines().peekable();
+            let mut md_lines = dox.lines().peekable();
+
+            // The number of bytes from the start of the source span to the resolution failure that
+            // are *not* part of the markdown, like comment markers.
+            let mut source_offset = 0;
+
+            // Eat any source lines before the markdown starts (e.g., `/**` on its own line).
+            while let Some(source_line) = source_lines.peek() {
+                if source_line.contains(md_lines.peek().unwrap()) {
+                    break;
+                }
+
+                // Include the newline.
+                source_offset += source_line.len() + 1;
+                source_lines.next().unwrap();
+            }
+
+            // The number of lines up to and including the resolution failure.
+            let num_lines = dox[..link_range.start].lines().count();
+
+            // Consume inner comment markers (e.g., `///` or ` *`).
+            for (source_line, md_line) in source_lines.zip(md_lines).take(num_lines) {
+                source_offset += if md_line.is_empty() {
+                    // If there is no markdown on this line, then the whole line is a comment
+                    // marker. We don't have to count the newline here because it's in the markdown
+                    // too.
+                    source_line.len()
+                } else {
+                    source_line.find(md_line).unwrap()
+                };
+            }
+
             let sp = sp.from_inner_byte_pos(
-                link_range.start + code_dox_len,
-                link_range.end + code_dox_len,
+                link_range.start + source_offset,
+                link_range.end + source_offset,
             );
 
             diag = cx.tcx.struct_span_lint_node(lint::builtin::INTRA_DOC_LINK_RESOLUTION_FAILURE,
@@ -511,6 +540,10 @@ fn resolution_failure(
                                                 sp,
                                                 &msg);
 
+            // blah blah blah\nblah\nblah [blah] blah blah\nblah blah
+            //                       ^     ~~~~
+            //                       |     link_range
+            //                       last_new_line_offset
             let last_new_line_offset = dox[..link_range.start].rfind('\n').map_or(0, |n| n + 1);
             let line = dox[last_new_line_offset..].lines().next().unwrap_or("");
 
diff --git a/src/libstd/env.rs b/src/libstd/env.rs
index 9066c0b769479..d14efa2e3c76d 100644
--- a/src/libstd/env.rs
+++ b/src/libstd/env.rs
@@ -828,7 +828,7 @@ pub mod consts {
     /// - s390x
     /// - sparc64
     #[stable(feature = "env", since = "1.0.0")]
-    pub const ARCH: &'static str = super::arch::ARCH;
+    pub const ARCH: &str = super::arch::ARCH;
 
     /// The family of the operating system. Example value is `unix`.
     ///
@@ -837,7 +837,7 @@ pub mod consts {
     /// - unix
     /// - windows
     #[stable(feature = "env", since = "1.0.0")]
-    pub const FAMILY: &'static str = os::FAMILY;
+    pub const FAMILY: &str = os::FAMILY;
 
     /// A string describing the specific operating system in use.
     /// Example value is `linux`.
@@ -856,7 +856,7 @@ pub mod consts {
     /// - android
     /// - windows
     #[stable(feature = "env", since = "1.0.0")]
-    pub const OS: &'static str = os::OS;
+    pub const OS: &str = os::OS;
 
     /// Specifies the filename prefix used for shared libraries on this
     /// platform. Example value is `lib`.
@@ -866,7 +866,7 @@ pub mod consts {
     /// - lib
     /// - `""` (an empty string)
     #[stable(feature = "env", since = "1.0.0")]
-    pub const DLL_PREFIX: &'static str = os::DLL_PREFIX;
+    pub const DLL_PREFIX: &str = os::DLL_PREFIX;
 
     /// Specifies the filename suffix used for shared libraries on this
     /// platform. Example value is `.so`.
@@ -877,7 +877,7 @@ pub mod consts {
     /// - .dylib
     /// - .dll
     #[stable(feature = "env", since = "1.0.0")]
-    pub const DLL_SUFFIX: &'static str = os::DLL_SUFFIX;
+    pub const DLL_SUFFIX: &str = os::DLL_SUFFIX;
 
     /// Specifies the file extension used for shared libraries on this
     /// platform that goes after the dot. Example value is `so`.
@@ -888,7 +888,7 @@ pub mod consts {
     /// - dylib
     /// - dll
     #[stable(feature = "env", since = "1.0.0")]
-    pub const DLL_EXTENSION: &'static str = os::DLL_EXTENSION;
+    pub const DLL_EXTENSION: &str = os::DLL_EXTENSION;
 
     /// Specifies the filename suffix used for executable binaries on this
     /// platform. Example value is `.exe`.
@@ -900,7 +900,7 @@ pub mod consts {
     /// - .pexe
     /// - `""` (an empty string)
     #[stable(feature = "env", since = "1.0.0")]
-    pub const EXE_SUFFIX: &'static str = os::EXE_SUFFIX;
+    pub const EXE_SUFFIX: &str = os::EXE_SUFFIX;
 
     /// Specifies the file extension, if any, used for executable binaries
     /// on this platform. Example value is `exe`.
@@ -910,72 +910,72 @@ pub mod consts {
     /// - exe
     /// - `""` (an empty string)
     #[stable(feature = "env", since = "1.0.0")]
-    pub const EXE_EXTENSION: &'static str = os::EXE_EXTENSION;
+    pub const EXE_EXTENSION: &str = os::EXE_EXTENSION;
 }
 
 #[cfg(target_arch = "x86")]
 mod arch {
-    pub const ARCH: &'static str = "x86";
+    pub const ARCH: &str = "x86";
 }
 
 #[cfg(target_arch = "x86_64")]
 mod arch {
-    pub const ARCH: &'static str = "x86_64";
+    pub const ARCH: &str = "x86_64";
 }
 
 #[cfg(target_arch = "arm")]
 mod arch {
-    pub const ARCH: &'static str = "arm";
+    pub const ARCH: &str = "arm";
 }
 
 #[cfg(target_arch = "aarch64")]
 mod arch {
-    pub const ARCH: &'static str = "aarch64";
+    pub const ARCH: &str = "aarch64";
 }
 
 #[cfg(target_arch = "mips")]
 mod arch {
-    pub const ARCH: &'static str = "mips";
+    pub const ARCH: &str = "mips";
 }
 
 #[cfg(target_arch = "mips64")]
 mod arch {
-    pub const ARCH: &'static str = "mips64";
+    pub const ARCH: &str = "mips64";
 }
 
 #[cfg(target_arch = "powerpc")]
 mod arch {
-    pub const ARCH: &'static str = "powerpc";
+    pub const ARCH: &str = "powerpc";
 }
 
 #[cfg(target_arch = "powerpc64")]
 mod arch {
-    pub const ARCH: &'static str = "powerpc64";
+    pub const ARCH: &str = "powerpc64";
 }
 
 #[cfg(target_arch = "s390x")]
 mod arch {
-    pub const ARCH: &'static str = "s390x";
+    pub const ARCH: &str = "s390x";
 }
 
 #[cfg(target_arch = "sparc64")]
 mod arch {
-    pub const ARCH: &'static str = "sparc64";
+    pub const ARCH: &str = "sparc64";
 }
 
 #[cfg(target_arch = "le32")]
 mod arch {
-    pub const ARCH: &'static str = "le32";
+    pub const ARCH: &str = "le32";
 }
 
 #[cfg(target_arch = "asmjs")]
 mod arch {
-    pub const ARCH: &'static str = "asmjs";
+    pub const ARCH: &str = "asmjs";
 }
 
 #[cfg(target_arch = "wasm32")]
 mod arch {
-    pub const ARCH: &'static str = "wasm32";
+    pub const ARCH: &str = "wasm32";
 }
 
 #[cfg(test)]
diff --git a/src/libstd/ffi/c_str.rs b/src/libstd/ffi/c_str.rs
index 66718b95408ca..7c7f83967e051 100644
--- a/src/libstd/ffi/c_str.rs
+++ b/src/libstd/ffi/c_str.rs
@@ -671,7 +671,7 @@ impl fmt::Debug for CStr {
 #[stable(feature = "cstr_default", since = "1.10.0")]
 impl<'a> Default for &'a CStr {
     fn default() -> &'a CStr {
-        const SLICE: &'static [c_char] = &[0];
+        const SLICE: &[c_char] = &[0];
         unsafe { CStr::from_ptr(SLICE.as_ptr()) }
     }
 }
@@ -1475,7 +1475,7 @@ mod tests {
 
     #[test]
     fn cstr_const_constructor() {
-        const CSTR: &'static CStr = unsafe {
+        const CSTR: &CStr = unsafe {
             CStr::from_bytes_with_nul_unchecked(b"Hello, world!\0")
         };
 
diff --git a/src/libstd/keyword_docs.rs b/src/libstd/keyword_docs.rs
index 13cf3133dcd12..c1eaf29bb4407 100644
--- a/src/libstd/keyword_docs.rs
+++ b/src/libstd/keyword_docs.rs
@@ -65,7 +65,7 @@ mod as_keyword { }
 /// look like this:
 ///
 /// ```rust
-/// const WORDS: &'static str = "hello rust!";
+/// const WORDS: &str = "hello rust!";
 /// ```
 ///
 /// Thanks to static lifetime elision, you usually don't have to explicitly use 'static:
diff --git a/src/libstd/path.rs b/src/libstd/path.rs
index a153456370c6f..9fad40c564944 100644
--- a/src/libstd/path.rs
+++ b/src/libstd/path.rs
@@ -1397,6 +1397,9 @@ impl<'a> From<&'a Path> for Box<Path> {
 
 #[stable(feature = "path_buf_from_box", since = "1.18.0")]
 impl From<Box<Path>> for PathBuf {
+    /// Converts a `Box<Path>` into a `PathBuf`
+    ///
+    /// This conversion does not allocate or copy memory.
     fn from(boxed: Box<Path>) -> PathBuf {
         boxed.into_path_buf()
     }
@@ -1404,6 +1407,10 @@ impl From<Box<Path>> for PathBuf {
 
 #[stable(feature = "box_from_path_buf", since = "1.20.0")]
 impl From<PathBuf> for Box<Path> {
+    /// Converts a `PathBuf` into a `Box<Path>`
+    ///
+    /// This conversion currently should not allocate memory,
+    /// but this behavior is not guaranteed on all platforms or in all future versions.
     fn from(p: PathBuf) -> Box<Path> {
         p.into_boxed_path()
     }
@@ -1426,6 +1433,9 @@ impl<'a, T: ?Sized + AsRef<OsStr>> From<&'a T> for PathBuf {
 
 #[stable(feature = "rust1", since = "1.0.0")]
 impl From<OsString> for PathBuf {
+    /// Converts a `OsString` into a `PathBuf`
+    ///
+    /// This conversion does not allocate or copy memory.
     fn from(s: OsString) -> PathBuf {
         PathBuf { inner: s }
     }
@@ -1433,6 +1443,9 @@ impl From<OsString> for PathBuf {
 
 #[stable(feature = "from_path_buf_for_os_string", since = "1.14.0")]
 impl From<PathBuf> for OsString {
+    /// Converts a `PathBuf` into a `OsString`
+    ///
+    /// This conversion does not allocate or copy memory.
     fn from(path_buf : PathBuf) -> OsString {
         path_buf.inner
     }
@@ -1440,6 +1453,9 @@ impl From<PathBuf> for OsString {
 
 #[stable(feature = "rust1", since = "1.0.0")]
 impl From<String> for PathBuf {
+    /// Converts a `String` into a `PathBuf`
+    ///
+    /// This conversion does not allocate or copy memory.
     fn from(s: String) -> PathBuf {
         PathBuf::from(OsString::from(s))
     }
@@ -1536,6 +1552,7 @@ impl<'a> From<Cow<'a, Path>> for PathBuf {
 
 #[stable(feature = "shared_from_slice2", since = "1.24.0")]
 impl From<PathBuf> for Arc<Path> {
+    /// Converts a Path into a Rc by copying the Path data into a new Rc buffer.
     #[inline]
     fn from(s: PathBuf) -> Arc<Path> {
         let arc: Arc<OsStr> = Arc::from(s.into_os_string());
@@ -1545,6 +1562,7 @@ impl From<PathBuf> for Arc<Path> {
 
 #[stable(feature = "shared_from_slice2", since = "1.24.0")]
 impl<'a> From<&'a Path> for Arc<Path> {
+    /// Converts a Path into a Rc by copying the Path data into a new Rc buffer.
     #[inline]
     fn from(s: &Path) -> Arc<Path> {
         let arc: Arc<OsStr> = Arc::from(s.as_os_str());
@@ -1554,6 +1572,7 @@ impl<'a> From<&'a Path> for Arc<Path> {
 
 #[stable(feature = "shared_from_slice2", since = "1.24.0")]
 impl From<PathBuf> for Rc<Path> {
+    /// Converts a Path into a Rc by copying the Path data into a new Rc buffer.
     #[inline]
     fn from(s: PathBuf) -> Rc<Path> {
         let rc: Rc<OsStr> = Rc::from(s.into_os_string());
@@ -1563,6 +1582,7 @@ impl From<PathBuf> for Rc<Path> {
 
 #[stable(feature = "shared_from_slice2", since = "1.24.0")]
 impl<'a> From<&'a Path> for Rc<Path> {
+    /// Converts a Path into a Rc by copying the Path data into a new Rc buffer.
     #[inline]
     fn from(s: &Path) -> Rc<Path> {
         let rc: Rc<OsStr> = Rc::from(s.as_os_str());
diff --git a/src/libstd/sys/cloudabi/shims/env.rs b/src/libstd/sys/cloudabi/shims/env.rs
index 31777aa94bcd4..c7691e3b2df29 100644
--- a/src/libstd/sys/cloudabi/shims/env.rs
+++ b/src/libstd/sys/cloudabi/shims/env.rs
@@ -9,11 +9,11 @@
 // except according to those terms.
 
 pub mod os {
-    pub const FAMILY: &'static str = "cloudabi";
-    pub const OS: &'static str = "cloudabi";
-    pub const DLL_PREFIX: &'static str = "lib";
-    pub const DLL_SUFFIX: &'static str = ".so";
-    pub const DLL_EXTENSION: &'static str = "so";
-    pub const EXE_SUFFIX: &'static str = "";
-    pub const EXE_EXTENSION: &'static str = "";
+    pub const FAMILY: &str = "cloudabi";
+    pub const OS: &str = "cloudabi";
+    pub const DLL_PREFIX: &str = "lib";
+    pub const DLL_SUFFIX: &str = ".so";
+    pub const DLL_EXTENSION: &str = "so";
+    pub const EXE_SUFFIX: &str = "";
+    pub const EXE_EXTENSION: &str = "";
 }
diff --git a/src/libstd/sys/redox/env.rs b/src/libstd/sys/redox/env.rs
index 669b7520df846..75e35046fb725 100644
--- a/src/libstd/sys/redox/env.rs
+++ b/src/libstd/sys/redox/env.rs
@@ -9,11 +9,11 @@
 // except according to those terms.
 
 pub mod os {
-    pub const FAMILY: &'static str = "redox";
-    pub const OS: &'static str = "redox";
-    pub const DLL_PREFIX: &'static str = "lib";
-    pub const DLL_SUFFIX: &'static str = ".so";
-    pub const DLL_EXTENSION: &'static str = "so";
-    pub const EXE_SUFFIX: &'static str = "";
-    pub const EXE_EXTENSION: &'static str = "";
+    pub const FAMILY: &str = "redox";
+    pub const OS: &str = "redox";
+    pub const DLL_PREFIX: &str = "lib";
+    pub const DLL_SUFFIX: &str = ".so";
+    pub const DLL_EXTENSION: &str = "so";
+    pub const EXE_SUFFIX: &str = "";
+    pub const EXE_EXTENSION: &str = "";
 }
diff --git a/src/libstd/sys/redox/path.rs b/src/libstd/sys/redox/path.rs
index e6a267dd5d913..b1a4ed30404c0 100644
--- a/src/libstd/sys/redox/path.rs
+++ b/src/libstd/sys/redox/path.rs
@@ -35,5 +35,5 @@ pub fn parse_prefix(path: &OsStr) -> Option<Prefix> {
     }
 }
 
-pub const MAIN_SEP_STR: &'static str = "/";
+pub const MAIN_SEP_STR: &str = "/";
 pub const MAIN_SEP: char = '/';
diff --git a/src/libstd/sys/redox/process.rs b/src/libstd/sys/redox/process.rs
index 4370c1e05027b..8f6d83c544a54 100644
--- a/src/libstd/sys/redox/process.rs
+++ b/src/libstd/sys/redox/process.rs
@@ -143,7 +143,7 @@ impl Command {
 
     pub fn spawn(&mut self, default: Stdio, needs_stdin: bool)
                  -> io::Result<(Process, StdioPipes)> {
-         const CLOEXEC_MSG_FOOTER: &'static [u8] = b"NOEX";
+         const CLOEXEC_MSG_FOOTER: &[u8] = b"NOEX";
 
          if self.saw_nul {
              return Err(io::Error::new(ErrorKind::InvalidInput,
diff --git a/src/libstd/sys/unix/env.rs b/src/libstd/sys/unix/env.rs
index ad116c57f557e..1b6838f0295ef 100644
--- a/src/libstd/sys/unix/env.rs
+++ b/src/libstd/sys/unix/env.rs
@@ -10,176 +10,176 @@
 
 #[cfg(target_os = "linux")]
 pub mod os {
-    pub const FAMILY: &'static str = "unix";
-    pub const OS: &'static str = "linux";
-    pub const DLL_PREFIX: &'static str = "lib";
-    pub const DLL_SUFFIX: &'static str = ".so";
-    pub const DLL_EXTENSION: &'static str = "so";
-    pub const EXE_SUFFIX: &'static str = "";
-    pub const EXE_EXTENSION: &'static str = "";
+    pub const FAMILY: &str = "unix";
+    pub const OS: &str = "linux";
+    pub const DLL_PREFIX: &str = "lib";
+    pub const DLL_SUFFIX: &str = ".so";
+    pub const DLL_EXTENSION: &str = "so";
+    pub const EXE_SUFFIX: &str = "";
+    pub const EXE_EXTENSION: &str = "";
 }
 
 #[cfg(target_os = "macos")]
 pub mod os {
-    pub const FAMILY: &'static str = "unix";
-    pub const OS: &'static str = "macos";
-    pub const DLL_PREFIX: &'static str = "lib";
-    pub const DLL_SUFFIX: &'static str = ".dylib";
-    pub const DLL_EXTENSION: &'static str = "dylib";
-    pub const EXE_SUFFIX: &'static str = "";
-    pub const EXE_EXTENSION: &'static str = "";
+    pub const FAMILY: &str = "unix";
+    pub const OS: &str = "macos";
+    pub const DLL_PREFIX: &str = "lib";
+    pub const DLL_SUFFIX: &str = ".dylib";
+    pub const DLL_EXTENSION: &str = "dylib";
+    pub const EXE_SUFFIX: &str = "";
+    pub const EXE_EXTENSION: &str = "";
 }
 
 #[cfg(target_os = "ios")]
 pub mod os {
-    pub const FAMILY: &'static str = "unix";
-    pub const OS: &'static str = "ios";
-    pub const DLL_PREFIX: &'static str = "lib";
-    pub const DLL_SUFFIX: &'static str = ".dylib";
-    pub const DLL_EXTENSION: &'static str = "dylib";
-    pub const EXE_SUFFIX: &'static str = "";
-    pub const EXE_EXTENSION: &'static str = "";
+    pub const FAMILY: &str = "unix";
+    pub const OS: &str = "ios";
+    pub const DLL_PREFIX: &str = "lib";
+    pub const DLL_SUFFIX: &str = ".dylib";
+    pub const DLL_EXTENSION: &str = "dylib";
+    pub const EXE_SUFFIX: &str = "";
+    pub const EXE_EXTENSION: &str = "";
 }
 
 #[cfg(target_os = "freebsd")]
 pub mod os {
-    pub const FAMILY: &'static str = "unix";
-    pub const OS: &'static str = "freebsd";
-    pub const DLL_PREFIX: &'static str = "lib";
-    pub const DLL_SUFFIX: &'static str = ".so";
-    pub const DLL_EXTENSION: &'static str = "so";
-    pub const EXE_SUFFIX: &'static str = "";
-    pub const EXE_EXTENSION: &'static str = "";
+    pub const FAMILY: &str = "unix";
+    pub const OS: &str = "freebsd";
+    pub const DLL_PREFIX: &str = "lib";
+    pub const DLL_SUFFIX: &str = ".so";
+    pub const DLL_EXTENSION: &str = "so";
+    pub const EXE_SUFFIX: &str = "";
+    pub const EXE_EXTENSION: &str = "";
 }
 
 #[cfg(target_os = "dragonfly")]
 pub mod os {
-    pub const FAMILY: &'static str = "unix";
-    pub const OS: &'static str = "dragonfly";
-    pub const DLL_PREFIX: &'static str = "lib";
-    pub const DLL_SUFFIX: &'static str = ".so";
-    pub const DLL_EXTENSION: &'static str = "so";
-    pub const EXE_SUFFIX: &'static str = "";
-    pub const EXE_EXTENSION: &'static str = "";
+    pub const FAMILY: &str = "unix";
+    pub const OS: &str = "dragonfly";
+    pub const DLL_PREFIX: &str = "lib";
+    pub const DLL_SUFFIX: &str = ".so";
+    pub const DLL_EXTENSION: &str = "so";
+    pub const EXE_SUFFIX: &str = "";
+    pub const EXE_EXTENSION: &str = "";
 }
 
 #[cfg(target_os = "bitrig")]
 pub mod os {
-    pub const FAMILY: &'static str = "unix";
-    pub const OS: &'static str = "bitrig";
-    pub const DLL_PREFIX: &'static str = "lib";
-    pub const DLL_SUFFIX: &'static str = ".so";
-    pub const DLL_EXTENSION: &'static str = "so";
-    pub const EXE_SUFFIX: &'static str = "";
-    pub const EXE_EXTENSION: &'static str = "";
+    pub const FAMILY: &str = "unix";
+    pub const OS: &str = "bitrig";
+    pub const DLL_PREFIX: &str = "lib";
+    pub const DLL_SUFFIX: &str = ".so";
+    pub const DLL_EXTENSION: &str = "so";
+    pub const EXE_SUFFIX: &str = "";
+    pub const EXE_EXTENSION: &str = "";
 }
 
 #[cfg(target_os = "netbsd")]
 pub mod os {
-    pub const FAMILY: &'static str = "unix";
-    pub const OS: &'static str = "netbsd";
-    pub const DLL_PREFIX: &'static str = "lib";
-    pub const DLL_SUFFIX: &'static str = ".so";
-    pub const DLL_EXTENSION: &'static str = "so";
-    pub const EXE_SUFFIX: &'static str = "";
-    pub const EXE_EXTENSION: &'static str = "";
+    pub const FAMILY: &str = "unix";
+    pub const OS: &str = "netbsd";
+    pub const DLL_PREFIX: &str = "lib";
+    pub const DLL_SUFFIX: &str = ".so";
+    pub const DLL_EXTENSION: &str = "so";
+    pub const EXE_SUFFIX: &str = "";
+    pub const EXE_EXTENSION: &str = "";
 }
 
 #[cfg(target_os = "openbsd")]
 pub mod os {
-    pub const FAMILY: &'static str = "unix";
-    pub const OS: &'static str = "openbsd";
-    pub const DLL_PREFIX: &'static str = "lib";
-    pub const DLL_SUFFIX: &'static str = ".so";
-    pub const DLL_EXTENSION: &'static str = "so";
-    pub const EXE_SUFFIX: &'static str = "";
-    pub const EXE_EXTENSION: &'static str = "";
+    pub const FAMILY: &str = "unix";
+    pub const OS: &str = "openbsd";
+    pub const DLL_PREFIX: &str = "lib";
+    pub const DLL_SUFFIX: &str = ".so";
+    pub const DLL_EXTENSION: &str = "so";
+    pub const EXE_SUFFIX: &str = "";
+    pub const EXE_EXTENSION: &str = "";
 }
 
 #[cfg(target_os = "android")]
 pub mod os {
-    pub const FAMILY: &'static str = "unix";
-    pub const OS: &'static str = "android";
-    pub const DLL_PREFIX: &'static str = "lib";
-    pub const DLL_SUFFIX: &'static str = ".so";
-    pub const DLL_EXTENSION: &'static str = "so";
-    pub const EXE_SUFFIX: &'static str = "";
-    pub const EXE_EXTENSION: &'static str = "";
+    pub const FAMILY: &str = "unix";
+    pub const OS: &str = "android";
+    pub const DLL_PREFIX: &str = "lib";
+    pub const DLL_SUFFIX: &str = ".so";
+    pub const DLL_EXTENSION: &str = "so";
+    pub const EXE_SUFFIX: &str = "";
+    pub const EXE_EXTENSION: &str = "";
 }
 
 #[cfg(target_os = "solaris")]
 pub mod os {
-    pub const FAMILY: &'static str = "unix";
-    pub const OS: &'static str = "solaris";
-    pub const DLL_PREFIX: &'static str = "lib";
-    pub const DLL_SUFFIX: &'static str = ".so";
-    pub const DLL_EXTENSION: &'static str = "so";
-    pub const EXE_SUFFIX: &'static str = "";
-    pub const EXE_EXTENSION: &'static str = "";
+    pub const FAMILY: &str = "unix";
+    pub const OS: &str = "solaris";
+    pub const DLL_PREFIX: &str = "lib";
+    pub const DLL_SUFFIX: &str = ".so";
+    pub const DLL_EXTENSION: &str = "so";
+    pub const EXE_SUFFIX: &str = "";
+    pub const EXE_EXTENSION: &str = "";
 }
 
 #[cfg(target_os = "haiku")]
 pub mod os {
-    pub const FAMILY: &'static str = "unix";
-    pub const OS: &'static str = "haiku";
-    pub const DLL_PREFIX: &'static str = "lib";
-    pub const DLL_SUFFIX: &'static str = ".so";
-    pub const DLL_EXTENSION: &'static str = "so";
-    pub const EXE_SUFFIX: &'static str = "";
-    pub const EXE_EXTENSION: &'static str = "";
+    pub const FAMILY: &str = "unix";
+    pub const OS: &str = "haiku";
+    pub const DLL_PREFIX: &str = "lib";
+    pub const DLL_SUFFIX: &str = ".so";
+    pub const DLL_EXTENSION: &str = "so";
+    pub const EXE_SUFFIX: &str = "";
+    pub const EXE_EXTENSION: &str = "";
 }
 
 #[cfg(all(target_os = "emscripten", target_arch = "asmjs"))]
 pub mod os {
-    pub const FAMILY: &'static str = "unix";
-    pub const OS: &'static str = "emscripten";
-    pub const DLL_PREFIX: &'static str = "lib";
-    pub const DLL_SUFFIX: &'static str = ".so";
-    pub const DLL_EXTENSION: &'static str = "so";
-    pub const EXE_SUFFIX: &'static str = ".js";
-    pub const EXE_EXTENSION: &'static str = "js";
+    pub const FAMILY: &str = "unix";
+    pub const OS: &str = "emscripten";
+    pub const DLL_PREFIX: &str = "lib";
+    pub const DLL_SUFFIX: &str = ".so";
+    pub const DLL_EXTENSION: &str = "so";
+    pub const EXE_SUFFIX: &str = ".js";
+    pub const EXE_EXTENSION: &str = "js";
 }
 
 #[cfg(all(target_os = "emscripten", target_arch = "wasm32"))]
 pub mod os {
-    pub const FAMILY: &'static str = "unix";
-    pub const OS: &'static str = "emscripten";
-    pub const DLL_PREFIX: &'static str = "lib";
-    pub const DLL_SUFFIX: &'static str = ".so";
-    pub const DLL_EXTENSION: &'static str = "so";
-    pub const EXE_SUFFIX: &'static str = ".js";
-    pub const EXE_EXTENSION: &'static str = "js";
+    pub const FAMILY: &str = "unix";
+    pub const OS: &str = "emscripten";
+    pub const DLL_PREFIX: &str = "lib";
+    pub const DLL_SUFFIX: &str = ".so";
+    pub const DLL_EXTENSION: &str = "so";
+    pub const EXE_SUFFIX: &str = ".js";
+    pub const EXE_EXTENSION: &str = "js";
 }
 
 #[cfg(target_os = "fuchsia")]
 pub mod os {
-    pub const FAMILY: &'static str = "unix";
-    pub const OS: &'static str = "fuchsia";
-    pub const DLL_PREFIX: &'static str = "lib";
-    pub const DLL_SUFFIX: &'static str = ".so";
-    pub const DLL_EXTENSION: &'static str = "so";
-    pub const EXE_SUFFIX: &'static str = "";
-    pub const EXE_EXTENSION: &'static str = "";
+    pub const FAMILY: &str = "unix";
+    pub const OS: &str = "fuchsia";
+    pub const DLL_PREFIX: &str = "lib";
+    pub const DLL_SUFFIX: &str = ".so";
+    pub const DLL_EXTENSION: &str = "so";
+    pub const EXE_SUFFIX: &str = "";
+    pub const EXE_EXTENSION: &str = "";
 }
 
 #[cfg(target_os = "l4re")]
 pub mod os {
-    pub const FAMILY: &'static str = "unix";
-    pub const OS: &'static str = "l4re";
-    pub const DLL_PREFIX: &'static str = "lib";
-    pub const DLL_SUFFIX: &'static str = ".so";
-    pub const DLL_EXTENSION: &'static str = "so";
-    pub const EXE_SUFFIX: &'static str = "";
-    pub const EXE_EXTENSION: &'static str = "";
+    pub const FAMILY: &str = "unix";
+    pub const OS: &str = "l4re";
+    pub const DLL_PREFIX: &str = "lib";
+    pub const DLL_SUFFIX: &str = ".so";
+    pub const DLL_EXTENSION: &str = "so";
+    pub const EXE_SUFFIX: &str = "";
+    pub const EXE_EXTENSION: &str = "";
 }
 
 #[cfg(target_os = "hermit")]
 pub mod os {
-    pub const FAMILY: &'static str = "unix";
-    pub const OS: &'static str = "hermit";
-    pub const DLL_PREFIX: &'static str = "lib";
-    pub const DLL_SUFFIX: &'static str = ".so";
-    pub const DLL_EXTENSION: &'static str = "so";
-    pub const EXE_SUFFIX: &'static str = "";
-    pub const EXE_EXTENSION: &'static str = "";
+    pub const FAMILY: &str = "unix";
+    pub const OS: &str = "hermit";
+    pub const DLL_PREFIX: &str = "lib";
+    pub const DLL_SUFFIX: &str = ".so";
+    pub const DLL_EXTENSION: &str = "so";
+    pub const EXE_SUFFIX: &str = "";
+    pub const EXE_EXTENSION: &str = "";
 }
diff --git a/src/libstd/sys/unix/os.rs b/src/libstd/sys/unix/os.rs
index b387a8d59a56d..03e81a720dc64 100644
--- a/src/libstd/sys/unix/os.rs
+++ b/src/libstd/sys/unix/os.rs
@@ -283,11 +283,14 @@ pub fn current_exe() -> io::Result<PathBuf> {
 
 #[cfg(any(target_os = "linux", target_os = "android", target_os = "emscripten"))]
 pub fn current_exe() -> io::Result<PathBuf> {
-    let selfexe = PathBuf::from("/proc/self/exe");
-    if selfexe.exists() {
-        ::fs::read_link(selfexe)
-    } else {
-        Err(io::Error::new(io::ErrorKind::Other, "no /proc/self/exe available. Is /proc mounted?"))
+    match ::fs::read_link("/proc/self/exe") {
+        Err(ref e) if e.kind() == io::ErrorKind::NotFound => {
+            Err(io::Error::new(
+                io::ErrorKind::Other,
+                "no /proc/self/exe available. Is /proc mounted?"
+            ))
+        },
+        other => other,
     }
 }
 
diff --git a/src/libstd/sys/unix/path.rs b/src/libstd/sys/unix/path.rs
index bf9af7a4353a8..834b4b448dc8a 100644
--- a/src/libstd/sys/unix/path.rs
+++ b/src/libstd/sys/unix/path.rs
@@ -25,5 +25,5 @@ pub fn parse_prefix(_: &OsStr) -> Option<Prefix> {
     None
 }
 
-pub const MAIN_SEP_STR: &'static str = "/";
+pub const MAIN_SEP_STR: &str = "/";
 pub const MAIN_SEP: char = '/';
diff --git a/src/libstd/sys/unix/process/process_unix.rs b/src/libstd/sys/unix/process/process_unix.rs
index bfbf12f34ee37..3248f42446071 100644
--- a/src/libstd/sys/unix/process/process_unix.rs
+++ b/src/libstd/sys/unix/process/process_unix.rs
@@ -22,7 +22,7 @@ use sys;
 impl Command {
     pub fn spawn(&mut self, default: Stdio, needs_stdin: bool)
                  -> io::Result<(Process, StdioPipes)> {
-        const CLOEXEC_MSG_FOOTER: &'static [u8] = b"NOEX";
+        const CLOEXEC_MSG_FOOTER: &[u8] = b"NOEX";
 
         let envp = self.capture_env();
 
diff --git a/src/libstd/sys/wasm/env.rs b/src/libstd/sys/wasm/env.rs
index 1422042bd0228..09235a944eec0 100644
--- a/src/libstd/sys/wasm/env.rs
+++ b/src/libstd/sys/wasm/env.rs
@@ -9,11 +9,11 @@
 // except according to those terms.
 
 pub mod os {
-    pub const FAMILY: &'static str = "";
-    pub const OS: &'static str = "";
-    pub const DLL_PREFIX: &'static str = "";
-    pub const DLL_SUFFIX: &'static str = ".wasm";
-    pub const DLL_EXTENSION: &'static str = "wasm";
-    pub const EXE_SUFFIX: &'static str = ".wasm";
-    pub const EXE_EXTENSION: &'static str = "wasm";
+    pub const FAMILY: &str = "";
+    pub const OS: &str = "";
+    pub const DLL_PREFIX: &str = "";
+    pub const DLL_SUFFIX: &str = ".wasm";
+    pub const DLL_EXTENSION: &str = "wasm";
+    pub const EXE_SUFFIX: &str = ".wasm";
+    pub const EXE_EXTENSION: &str = "wasm";
 }
diff --git a/src/libstd/sys/wasm/path.rs b/src/libstd/sys/wasm/path.rs
index 395b8c1e40e98..fcc9d617a876a 100644
--- a/src/libstd/sys/wasm/path.rs
+++ b/src/libstd/sys/wasm/path.rs
@@ -25,5 +25,5 @@ pub fn parse_prefix(_: &OsStr) -> Option<Prefix> {
     None
 }
 
-pub const MAIN_SEP_STR: &'static str = "/";
+pub const MAIN_SEP_STR: &str = "/";
 pub const MAIN_SEP: char = '/';
diff --git a/src/libstd/sys/windows/env.rs b/src/libstd/sys/windows/env.rs
index e6d74895774ce..4523df04f247d 100644
--- a/src/libstd/sys/windows/env.rs
+++ b/src/libstd/sys/windows/env.rs
@@ -9,11 +9,11 @@
 // except according to those terms.
 
 pub mod os {
-    pub const FAMILY: &'static str = "windows";
-    pub const OS: &'static str = "windows";
-    pub const DLL_PREFIX: &'static str = "";
-    pub const DLL_SUFFIX: &'static str = ".dll";
-    pub const DLL_EXTENSION: &'static str = "dll";
-    pub const EXE_SUFFIX: &'static str = ".exe";
-    pub const EXE_EXTENSION: &'static str = "exe";
+    pub const FAMILY: &str = "windows";
+    pub const OS: &str = "windows";
+    pub const DLL_PREFIX: &str = "";
+    pub const DLL_SUFFIX: &str = ".dll";
+    pub const DLL_EXTENSION: &str = "dll";
+    pub const EXE_SUFFIX: &str = ".exe";
+    pub const EXE_EXTENSION: &str = "exe";
 }
diff --git a/src/libstd/sys/windows/os.rs b/src/libstd/sys/windows/os.rs
index 29ea82c2053cd..4d7b7236c59c6 100644
--- a/src/libstd/sys/windows/os.rs
+++ b/src/libstd/sys/windows/os.rs
@@ -48,8 +48,8 @@ pub fn error_string(mut errnum: i32) -> String {
         // `[MS-ERREF]`: https://msdn.microsoft.com/en-us/library/cc231198.aspx
         if (errnum & c::FACILITY_NT_BIT as i32) != 0 {
             // format according to https://support.microsoft.com/en-us/help/259693
-            const NTDLL_DLL: &'static [u16] = &['N' as _, 'T' as _, 'D' as _, 'L' as _, 'L' as _,
-                                                '.' as _, 'D' as _, 'L' as _, 'L' as _, 0];
+            const NTDLL_DLL: &[u16] = &['N' as _, 'T' as _, 'D' as _, 'L' as _, 'L' as _,
+                                        '.' as _, 'D' as _, 'L' as _, 'L' as _, 0];
             module = c::GetModuleHandleW(NTDLL_DLL.as_ptr());
 
             if module != ptr::null_mut() {
diff --git a/src/libstd/sys/windows/path.rs b/src/libstd/sys/windows/path.rs
index 98d62a0c953a6..385ea8e053167 100644
--- a/src/libstd/sys/windows/path.rs
+++ b/src/libstd/sys/windows/path.rs
@@ -91,10 +91,7 @@ pub fn parse_prefix<'a>(path: &'a OsStr) -> Option<Prefix> {
     }
 
     fn parse_two_comps(mut path: &[u8], f: fn(u8) -> bool) -> Option<(&[u8], &[u8])> {
-        let first = match path.iter().position(|x| f(*x)) {
-            None => return None,
-            Some(x) => &path[..x],
-        };
+        let first = &path[..path.iter().position(|x| f(*x))?];
         path = &path[(first.len() + 1)..];
         let idx = path.iter().position(|x| f(*x));
         let second = &path[..idx.unwrap_or(path.len())];
@@ -102,5 +99,5 @@ pub fn parse_prefix<'a>(path: &'a OsStr) -> Option<Prefix> {
     }
 }
 
-pub const MAIN_SEP_STR: &'static str = "\\";
+pub const MAIN_SEP_STR: &str = "\\";
 pub const MAIN_SEP: char = '\\';
diff --git a/src/libstd/sys_common/wtf8.rs b/src/libstd/sys_common/wtf8.rs
index 19ce932aa1233..3530b7af9ad05 100644
--- a/src/libstd/sys_common/wtf8.rs
+++ b/src/libstd/sys_common/wtf8.rs
@@ -40,7 +40,7 @@ use str;
 use sync::Arc;
 use sys_common::AsInner;
 
-const UTF8_REPLACEMENT_CHARACTER: &'static str = "\u{FFFD}";
+const UTF8_REPLACEMENT_CHARACTER: &str = "\u{FFFD}";
 
 /// A Unicode code point: from U+0000 to U+10FFFF.
 ///
diff --git a/src/libsyntax/ext/tt/macro_parser.rs b/src/libsyntax/ext/tt/macro_parser.rs
index 8fd9590a66415..68d94b43dba2c 100644
--- a/src/libsyntax/ext/tt/macro_parser.rs
+++ b/src/libsyntax/ext/tt/macro_parser.rs
@@ -309,7 +309,7 @@ fn create_matches(len: usize) -> Box<[Rc<NamedMatchVec>]> {
         vec![]
     } else {
         let empty_matches = Rc::new(SmallVec::new());
-        vec![empty_matches.clone(); len]
+        vec![empty_matches; len]
     }.into_boxed_slice()
 }
 
diff --git a/src/test/run-pass/impl-trait/example-calendar.rs b/src/test/run-pass/impl-trait/example-calendar.rs
index e6dd421f48f51..7373828427e98 100644
--- a/src/test/run-pass/impl-trait/example-calendar.rs
+++ b/src/test/run-pass/impl-trait/example-calendar.rs
@@ -753,10 +753,7 @@ where It: Iterator {
     type Item = Vec<It::Item>;
 
     fn next(&mut self) -> Option<Vec<It::Item>> {
-        let first = match self.it.next() {
-            Some(e) => e,
-            None => return None
-        };
+        let first = self.it.next()?;
 
         let mut result = Vec::with_capacity(self.n);
         result.push(first);
diff --git a/src/test/rustdoc-js/filter-crate.js b/src/test/rustdoc-js/filter-crate.js
new file mode 100644
index 0000000000000..97ecc607f4764
--- /dev/null
+++ b/src/test/rustdoc-js/filter-crate.js
@@ -0,0 +1,19 @@
+// 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.
+
+// exact-check
+
+const QUERY = 'hashmap';
+const FILTER_CRATE = 'core';
+
+const EXPECTED = {
+    'others': [
+    ],
+};
diff --git a/src/test/rustdoc-ui/intra-links-warning.rs b/src/test/rustdoc-ui/intra-links-warning.rs
index d6bc275b57a6a..3051bec88d24d 100644
--- a/src/test/rustdoc-ui/intra-links-warning.rs
+++ b/src/test/rustdoc-ui/intra-links-warning.rs
@@ -55,3 +55,26 @@ macro_rules! f {
     }
 }
 f!("Foo\nbar [BarF] bar\nbaz");
+
+/** # for example,
+ *
+ * time to introduce a link [error]*/
+pub struct A;
+
+/**
+ * # for example,
+ *
+ * time to introduce a link [error]
+ */
+pub struct B;
+
+#[doc = "single line [error]"]
+pub struct C;
+
+#[doc = "single line with \"escaping\" [error]"]
+pub struct D;
+
+/// Item docs.
+#[doc="Hello there!"]
+/// [error]
+pub struct E;
diff --git a/src/test/rustdoc-ui/intra-links-warning.stderr b/src/test/rustdoc-ui/intra-links-warning.stderr
index c05f99fadc9e4..543919938cea7 100644
--- a/src/test/rustdoc-ui/intra-links-warning.stderr
+++ b/src/test/rustdoc-ui/intra-links-warning.stderr
@@ -55,6 +55,60 @@ LL |        /// [Qux:Y]
    |
    = help: to escape `[` and `]` characters, just add '/' before them like `/[` or `/]`
 
+warning: `[error]` cannot be resolved, ignoring it...
+  --> $DIR/intra-links-warning.rs:61:30
+   |
+LL |  * time to introduce a link [error]*/
+   |                              ^^^^^ cannot be resolved, ignoring
+   |
+   = help: to escape `[` and `]` characters, just add '/' before them like `/[` or `/]`
+
+warning: `[error]` cannot be resolved, ignoring it...
+  --> $DIR/intra-links-warning.rs:67:30
+   |
+LL |  * time to introduce a link [error]
+   |                              ^^^^^ cannot be resolved, ignoring
+   |
+   = help: to escape `[` and `]` characters, just add '/' before them like `/[` or `/]`
+
+warning: `[error]` cannot be resolved, ignoring it...
+  --> $DIR/intra-links-warning.rs:71:1
+   |
+LL | #[doc = "single line [error]"]
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: the link appears in this line:
+           
+           single line [error]
+                        ^^^^^
+   = help: to escape `[` and `]` characters, just add '/' before them like `/[` or `/]`
+
+warning: `[error]` cannot be resolved, ignoring it...
+  --> $DIR/intra-links-warning.rs:74:1
+   |
+LL | #[doc = "single line with /"escaping/" [error]"]
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: the link appears in this line:
+           
+           single line with "escaping" [error]
+                                        ^^^^^
+   = help: to escape `[` and `]` characters, just add '/' before them like `/[` or `/]`
+
+warning: `[error]` cannot be resolved, ignoring it...
+  --> $DIR/intra-links-warning.rs:77:1
+   |
+LL | / /// Item docs.
+LL | | #[doc="Hello there!"]
+LL | | /// [error]
+   | |___________^
+   |
+   = note: the link appears in this line:
+           
+            [error]
+             ^^^^^
+   = help: to escape `[` and `]` characters, just add '/' before them like `/[` or `/]`
+
 warning: `[BarA]` cannot be resolved, ignoring it...
   --> $DIR/intra-links-warning.rs:24:10
    |
@@ -64,37 +118,19 @@ LL | /// bar [BarA] bar
    = help: to escape `[` and `]` characters, just add '/' before them like `/[` or `/]`
 
 warning: `[BarB]` cannot be resolved, ignoring it...
-  --> $DIR/intra-links-warning.rs:28:1
+  --> $DIR/intra-links-warning.rs:30:9
    |
-LL | / /**
-LL | |  * Foo
-LL | |  * bar [BarB] bar
-LL | |  * baz
-LL | |  */
-   | |___^
+LL |  * bar [BarB] bar
+   |         ^^^^ cannot be resolved, ignoring
    |
-   = note: the link appears in this line:
-           
-            bar [BarB] bar
-                 ^^^^
    = help: to escape `[` and `]` characters, just add '/' before them like `/[` or `/]`
 
 warning: `[BarC]` cannot be resolved, ignoring it...
-  --> $DIR/intra-links-warning.rs:35:1
+  --> $DIR/intra-links-warning.rs:37:6
    |
-LL | / /** Foo
-LL | |
-LL | | bar [BarC] bar
-LL | | baz
-...  |
-LL | |
-LL | | */
-   | |__^
+LL | bar [BarC] bar
+   |      ^^^^ cannot be resolved, ignoring
    |
-   = note: the link appears in this line:
-           
-           bar [BarC] bar
-                ^^^^
    = help: to escape `[` and `]` characters, just add '/' before them like `/[` or `/]`
 
 warning: `[BarD]` cannot be resolved, ignoring it...
diff --git a/src/test/ui/E0501.ast.nll.stderr b/src/test/ui/E0501.ast.nll.stderr
index 72fda9079d636..8a3fce3a554eb 100644
--- a/src/test/ui/E0501.ast.nll.stderr
+++ b/src/test/ui/E0501.ast.nll.stderr
@@ -7,7 +7,7 @@ LL |         inside_closure(a)
    |                        - first borrow occurs due to use of `a` in closure
 LL |     };
 LL |     outside_closure_1(a); //[ast]~ ERROR cannot borrow `*a` as mutable because previous closure requires unique access
-   |                       ^ borrow occurs here
+   |                       ^ second borrow occurs here
 ...
 LL |     drop(bar);
    |          --- first borrow later used here
@@ -21,7 +21,7 @@ LL |         inside_closure(a)
    |                        - first borrow occurs due to use of `a` in closure
 ...
 LL |     outside_closure_2(a); //[ast]~ ERROR cannot borrow `*a` as immutable because previous closure requires unique access
-   |                       ^ borrow occurs here
+   |                       ^ second borrow occurs here
 ...
 LL |     drop(bar);
    |          --- first borrow later used here
diff --git a/src/test/ui/E0501.mir.stderr b/src/test/ui/E0501.mir.stderr
index 72fda9079d636..8a3fce3a554eb 100644
--- a/src/test/ui/E0501.mir.stderr
+++ b/src/test/ui/E0501.mir.stderr
@@ -7,7 +7,7 @@ LL |         inside_closure(a)
    |                        - first borrow occurs due to use of `a` in closure
 LL |     };
 LL |     outside_closure_1(a); //[ast]~ ERROR cannot borrow `*a` as mutable because previous closure requires unique access
-   |                       ^ borrow occurs here
+   |                       ^ second borrow occurs here
 ...
 LL |     drop(bar);
    |          --- first borrow later used here
@@ -21,7 +21,7 @@ LL |         inside_closure(a)
    |                        - first borrow occurs due to use of `a` in closure
 ...
 LL |     outside_closure_2(a); //[ast]~ ERROR cannot borrow `*a` as immutable because previous closure requires unique access
-   |                       ^ borrow occurs here
+   |                       ^ second borrow occurs here
 ...
 LL |     drop(bar);
    |          --- first borrow later used here
diff --git a/src/test/ui/borrowck/borrowck-insert-during-each.nll.stderr b/src/test/ui/borrowck/borrowck-insert-during-each.nll.stderr
index 123d475f1c09f..84fc69465cb4a 100644
--- a/src/test/ui/borrowck/borrowck-insert-during-each.nll.stderr
+++ b/src/test/ui/borrowck/borrowck-insert-during-each.nll.stderr
@@ -10,7 +10,7 @@ LL | |         |a| { //~ ERROR closure requires unique access to `f`
 LL | |             f.n.insert(*a);
    | |             - first borrow occurs due to use of `f` in closure
 LL | |         })
-   | |__________^ borrow occurs here
+   | |__________^ second borrow occurs here
 
 error[E0500]: closure requires unique access to `f` but it is already borrowed
   --> $DIR/borrowck-insert-during-each.rs:27:9
diff --git a/src/test/ui/existential_types/private_unused.rs b/src/test/ui/existential_types/private_unused.rs
new file mode 100644
index 0000000000000..736d812bc0aff
--- /dev/null
+++ b/src/test/ui/existential_types/private_unused.rs
@@ -0,0 +1,13 @@
+// compile-pass
+
+#[deny(warnings)]
+
+enum Empty { }
+trait Bar<T> {}
+impl Bar<Empty> for () {}
+
+fn boo() -> impl Bar<Empty> {}
+
+fn main() {
+    boo();
+}
diff --git a/src/test/ui/generator/yield-while-ref-reborrowed.nll.stderr b/src/test/ui/generator/yield-while-ref-reborrowed.nll.stderr
index 8dabb3c2505b6..60163d78e78f9 100644
--- a/src/test/ui/generator/yield-while-ref-reborrowed.nll.stderr
+++ b/src/test/ui/generator/yield-while-ref-reborrowed.nll.stderr
@@ -7,7 +7,7 @@ LL |         let a = &mut *x;
    |                       - first borrow occurs due to use of `x` in generator
 ...
 LL |     println!("{}", x); //~ ERROR
-   |                    ^ borrow occurs here
+   |                    ^ second borrow occurs here
 LL |     b.resume();
    |     - first borrow later used here
 
diff --git a/src/test/ui/nll/closure-borrow-spans.stderr b/src/test/ui/nll/closure-borrow-spans.stderr
index 3e423dadd192c..98a261657b1e7 100644
--- a/src/test/ui/nll/closure-borrow-spans.stderr
+++ b/src/test/ui/nll/closure-borrow-spans.stderr
@@ -126,7 +126,7 @@ LL |     let f = || *x = 0;
    |             |
    |             closure construction occurs here
 LL |     let y = &x; //~ ERROR
-   |             ^^ borrow occurs here
+   |             ^^ second borrow occurs here
 LL |     f.use_ref();
    |     - first borrow later used here
 
@@ -138,7 +138,7 @@ LL |     let f = || *x = 0;
    |             |
    |             closure construction occurs here
 LL |     let y = &mut x; //~ ERROR
-   |             ^^^^^^ borrow occurs here
+   |             ^^^^^^ second borrow occurs here
 LL |     f.use_ref();
    |     - first borrow later used here
 
diff --git a/src/tools/compiletest/src/errors.rs b/src/tools/compiletest/src/errors.rs
index dd2e5557c16d4..8d20a9e271705 100644
--- a/src/tools/compiletest/src/errors.rs
+++ b/src/tools/compiletest/src/errors.rs
@@ -119,10 +119,7 @@ fn parse_expected(
     line: &str,
     tag: &str,
 ) -> Option<(WhichLine, Error)> {
-    let start = match line.find(tag) {
-        Some(i) => i,
-        None => return None,
-    };
+    let start = line.find(tag)?;
     let (follow, adjusts) = if line[start + tag.len()..].chars().next().unwrap() == '|' {
         (true, 0)
     } else {
diff --git a/src/tools/compiletest/src/header.rs b/src/tools/compiletest/src/header.rs
index ed2114b653015..f4a82aeb307dc 100644
--- a/src/tools/compiletest/src/header.rs
+++ b/src/tools/compiletest/src/header.rs
@@ -707,14 +707,8 @@ impl Config {
 
     fn parse_custom_normalization(&self, mut line: &str, prefix: &str) -> Option<(String, String)> {
         if self.parse_cfg_name_directive(line, prefix) == ParsedNameDirective::Match {
-            let from = match parse_normalization_string(&mut line) {
-                Some(s) => s,
-                None => return None,
-            };
-            let to = match parse_normalization_string(&mut line) {
-                Some(s) => s,
-                None => return None,
-            };
+            let from = parse_normalization_string(&mut line)?;
+            let to = parse_normalization_string(&mut line)?;
             Some((from, to))
         } else {
             None
@@ -873,14 +867,8 @@ fn expand_variables(mut value: String, config: &Config) -> String {
 /// ```
 fn parse_normalization_string(line: &mut &str) -> Option<String> {
     // FIXME support escapes in strings.
-    let begin = match line.find('"') {
-        Some(i) => i + 1,
-        None => return None,
-    };
-    let end = match line[begin..].find('"') {
-        Some(i) => i + begin,
-        None => return None,
-    };
+    let begin = line.find('"')? + 1;
+    let end = line[begin..].find('"')? + begin;
     let result = line[begin..end].to_owned();
     *line = &line[end + 1..];
     Some(result)
diff --git a/src/tools/linkchecker/main.rs b/src/tools/linkchecker/main.rs
index 11c83819eaa93..e6bf9a285723b 100644
--- a/src/tools/linkchecker/main.rs
+++ b/src/tools/linkchecker/main.rs
@@ -332,10 +332,7 @@ fn maybe_redirect(source: &str) -> Option<String> {
     const REDIRECT: &'static str = "<p>Redirecting to <a href=";
 
     let mut lines = source.lines();
-    let redirect_line = match lines.nth(6) {
-        Some(l) => l,
-        None => return None,
-    };
+    let redirect_line = lines.nth(6)?;
 
     redirect_line.find(REDIRECT).map(|i| {
         let rest = &redirect_line[(i + REDIRECT.len() + 1)..];
diff --git a/src/tools/rustdoc-js/tester.js b/src/tools/rustdoc-js/tester.js
index c8ce4cf8bb5be..f7c30df9f3ebb 100644
--- a/src/tools/rustdoc-js/tester.js
+++ b/src/tools/rustdoc-js/tester.js
@@ -259,6 +259,7 @@ function main(argv) {
                                'exports.QUERY = QUERY;exports.EXPECTED = EXPECTED;');
         const expected = loadedFile.EXPECTED;
         const query = loadedFile.QUERY;
+        const filter_crate = loadedFile.FILTER_CRATE;
         const ignore_order = loadedFile.ignore_order;
         const exact_check = loadedFile.exact_check;
         const should_fail = loadedFile.should_fail;