Auto merge of #45261 - kennytm:rollup, r=kennytm

Rollup of 14 pull requests

- Successful merges: #44855, #45110, #45122, #45133, #45173, #45178, #45189, #45203, #45209, #45221, #45236, #45240, #45245, #45253
- Failed merges:

src/bootstrap/check.rs

@@ -246,8 +246,11 @@ impl Step for Rls {
         let compiler = builder.compiler(stage, host);
 
         builder.ensure(tool::Rls { compiler, target: self.host });
-        let mut cargo = builder.cargo(compiler, Mode::Tool, host, "test");
-        cargo.arg("--manifest-path").arg(build.src.join("src/tools/rls/Cargo.toml"));
+        let mut cargo = tool::prepare_tool_cargo(builder,
+                                                 compiler,
+                                                 host,
+                                                 "test",
+                                                 "src/tools/rls");
 
         // Don't build tests dynamically, just a pain to work with
         cargo.env("RUSTC_NO_PREFER_DYNAMIC", "1");
@@ -291,8 +294,11 @@ impl Step for Rustfmt {
         let compiler = builder.compiler(stage, host);
 
         builder.ensure(tool::Rustfmt { compiler, target: self.host });
-        let mut cargo = builder.cargo(compiler, Mode::Tool, host, "test");
-        cargo.arg("--manifest-path").arg(build.src.join("src/tools/rustfmt/Cargo.toml"));
+        let mut cargo = tool::prepare_tool_cargo(builder,
+                                                 compiler,
+                                                 host,
+                                                 "test",
+                                                 "src/tools/rustfmt");
 
         // Don't build tests dynamically, just a pain to work with
         cargo.env("RUSTC_NO_PREFER_DYNAMIC", "1");

src/bootstrap/native.rs

@@ -352,34 +352,51 @@ impl Step for Openssl {
             // originally from https://www.openssl.org/source/...
             let url = format!("https://s3-us-west-1.amazonaws.com/rust-lang-ci2/rust-ci-mirror/{}",
                               name);
-            let mut ok = false;
+            let mut last_error = None;
             for _ in 0..3 {
                 let status = Command::new("curl")
                                 .arg("-o").arg(&tmp)
+                                .arg("-f")  // make curl fail if the URL does not return HTTP 200
                                 .arg(&url)
                                 .status()
                                 .expect("failed to spawn curl");
-                if status.success() {
-                    ok = true;
-                    break
+
+                // Retry if download failed.
+                if !status.success() {
+                    last_error = Some(status.to_string());
+                    continue;
                 }
+
+                // Ensure the hash is correct.
+                let mut shasum = if target.contains("apple") || build.build.contains("netbsd") {
+                    let mut cmd = Command::new("shasum");
+                    cmd.arg("-a").arg("256");
+                    cmd
+                } else {
+                    Command::new("sha256sum")
+                };
+                let output = output(&mut shasum.arg(&tmp));
+                let found = output.split_whitespace().next().unwrap();
+
+                // If the hash is wrong, probably the download is incomplete or S3 served an error
+                // page. In any case, retry.
+                if found != OPENSSL_SHA256 {
+                    last_error = Some(format!(
+                        "downloaded openssl sha256 different\n\
+                         expected: {}\n\
+                         found:    {}\n",
+                        OPENSSL_SHA256,
+                        found
+                    ));
+                    continue;
+                }
+
+                // Everything is fine, so exit the retry loop.
+                last_error = None;
+                break;
             }
-            if !ok {
-                panic!("failed to download openssl source")
-            }
-            let mut shasum = if target.contains("apple") || build.build.contains("netbsd") {
-                let mut cmd = Command::new("shasum");
-                cmd.arg("-a").arg("256");
-                cmd
-            } else {
-                Command::new("sha256sum")
-            };
-            let output = output(&mut shasum.arg(&tmp));
-            let found = output.split_whitespace().next().unwrap();
-            if found != OPENSSL_SHA256 {
-                panic!("downloaded openssl sha256 different\n\
-                        expected: {}\n\
-                        found:    {}\n", OPENSSL_SHA256, found);
+            if let Some(error) = last_error {
+                panic!("failed to download openssl source: {}", error);
             }
             t!(fs::rename(&tmp, &tarball));
         }

src/liballoc/lib.rs

@@ -121,6 +121,7 @@
 #![feature(unique)]
 #![feature(unsize)]
 #![feature(allocator_internals)]
+#![feature(on_unimplemented)]
 
 #![cfg_attr(not(test), feature(fused, fn_traits, placement_new_protocol, swap_with_slice, i128))]
 #![cfg_attr(test, feature(test, box_heap))]

src/liballoc/vec.rs

@@ -1543,6 +1543,7 @@ impl<T: Hash> Hash for Vec<T> {
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
+#[rustc_on_unimplemented = "vector indices are of type `usize` or ranges of `usize`"]
 impl<T> Index<usize> for Vec<T> {
     type Output = T;
 
@@ -1554,6 +1555,7 @@ impl<T> Index<usize> for Vec<T> {
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
+#[rustc_on_unimplemented = "vector indices are of type `usize` or ranges of `usize`"]
 impl<T> IndexMut<usize> for Vec<T> {
     #[inline]
     fn index_mut(&mut self, index: usize) -> &mut T {
@@ -1562,8 +1564,8 @@ impl<T> IndexMut<usize> for Vec<T> {
     }
 }
 
-
 #[stable(feature = "rust1", since = "1.0.0")]
+#[rustc_on_unimplemented = "vector indices are of type `usize` or ranges of `usize`"]
 impl<T> ops::Index<ops::Range<usize>> for Vec<T> {
     type Output = [T];
 
@@ -1572,7 +1574,9 @@ impl<T> ops::Index<ops::Range<usize>> for Vec<T> {
         Index::index(&**self, index)
     }
 }
+
 #[stable(feature = "rust1", since = "1.0.0")]
+#[rustc_on_unimplemented = "vector indices are of type `usize` or ranges of `usize`"]
 impl<T> ops::Index<ops::RangeTo<usize>> for Vec<T> {
     type Output = [T];
 
@@ -1581,7 +1585,9 @@ impl<T> ops::Index<ops::RangeTo<usize>> for Vec<T> {
         Index::index(&**self, index)
     }
 }
+
 #[stable(feature = "rust1", since = "1.0.0")]
+#[rustc_on_unimplemented = "vector indices are of type `usize` or ranges of `usize`"]
 impl<T> ops::Index<ops::RangeFrom<usize>> for Vec<T> {
     type Output = [T];
 
@@ -1590,7 +1596,9 @@ impl<T> ops::Index<ops::RangeFrom<usize>> for Vec<T> {
         Index::index(&**self, index)
     }
 }
+
 #[stable(feature = "rust1", since = "1.0.0")]
+#[rustc_on_unimplemented = "vector indices are of type `usize` or ranges of `usize`"]
 impl<T> ops::Index<ops::RangeFull> for Vec<T> {
     type Output = [T];
 
@@ -1599,7 +1607,9 @@ impl<T> ops::Index<ops::RangeFull> for Vec<T> {
         self
     }
 }
+
 #[unstable(feature = "inclusive_range", reason = "recently added, follows RFC", issue = "28237")]
+#[rustc_on_unimplemented = "vector indices are of type `usize` or ranges of `usize`"]
 impl<T> ops::Index<ops::RangeInclusive<usize>> for Vec<T> {
     type Output = [T];
 
@@ -1608,7 +1618,9 @@ impl<T> ops::Index<ops::RangeInclusive<usize>> for Vec<T> {
         Index::index(&**self, index)
     }
 }
+
 #[unstable(feature = "inclusive_range", reason = "recently added, follows RFC", issue = "28237")]
+#[rustc_on_unimplemented = "vector indices are of type `usize` or ranges of `usize`"]
 impl<T> ops::Index<ops::RangeToInclusive<usize>> for Vec<T> {
     type Output = [T];
 
@@ -1619,41 +1631,52 @@ impl<T> ops::Index<ops::RangeToInclusive<usize>> for Vec<T> {
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
+#[rustc_on_unimplemented = "vector indices are of type `usize` or ranges of `usize`"]
 impl<T> ops::IndexMut<ops::Range<usize>> for Vec<T> {
     #[inline]
     fn index_mut(&mut self, index: ops::Range<usize>) -> &mut [T] {
         IndexMut::index_mut(&mut **self, index)
     }
 }
+
 #[stable(feature = "rust1", since = "1.0.0")]
+#[rustc_on_unimplemented = "vector indices are of type `usize` or ranges of `usize`"]
 impl<T> ops::IndexMut<ops::RangeTo<usize>> for Vec<T> {
     #[inline]
     fn index_mut(&mut self, index: ops::RangeTo<usize>) -> &mut [T] {
         IndexMut::index_mut(&mut **self, index)
     }
 }
+
 #[stable(feature = "rust1", since = "1.0.0")]
+#[rustc_on_unimplemented = "vector indices are of type `usize` or ranges of `usize`"]
 impl<T> ops::IndexMut<ops::RangeFrom<usize>> for Vec<T> {
     #[inline]
     fn index_mut(&mut self, index: ops::RangeFrom<usize>) -> &mut [T] {
         IndexMut::index_mut(&mut **self, index)
     }
 }
+
 #[stable(feature = "rust1", since = "1.0.0")]
+#[rustc_on_unimplemented = "vector indices are of type `usize` or ranges of `usize`"]
 impl<T> ops::IndexMut<ops::RangeFull> for Vec<T> {
     #[inline]
     fn index_mut(&mut self, _index: ops::RangeFull) -> &mut [T] {
         self
     }
 }
+
 #[unstable(feature = "inclusive_range", reason = "recently added, follows RFC", issue = "28237")]
+#[rustc_on_unimplemented = "vector indices are of type `usize` or ranges of `usize`"]
 impl<T> ops::IndexMut<ops::RangeInclusive<usize>> for Vec<T> {
     #[inline]
     fn index_mut(&mut self, index: ops::RangeInclusive<usize>) -> &mut [T] {
         IndexMut::index_mut(&mut **self, index)
     }
 }
+
 #[unstable(feature = "inclusive_range", reason = "recently added, follows RFC", issue = "28237")]
+#[rustc_on_unimplemented = "vector indices are of type `usize` or ranges of `usize`"]
 impl<T> ops::IndexMut<ops::RangeToInclusive<usize>> for Vec<T> {
     #[inline]
     fn index_mut(&mut self, index: ops::RangeToInclusive<usize>) -> &mut [T] {

src/libcore/mem.rs

@@ -429,9 +429,11 @@ pub fn align_of_val<T: ?Sized>(val: &T) -> usize {
 
 /// Returns whether dropping values of type `T` matters.
 ///
-/// This is purely an optimization hint, and may be implemented conservatively.
-/// For instance, always returning `true` would be a valid implementation of
-/// this function.
+/// This is purely an optimization hint, and may be implemented conservatively:
+/// it may return `true` for types that don't actually need to be dropped.
+/// As such always returning `true` would be a valid implementation of
+/// this function. However if this function actually returns `false`, then you
+/// can be certain dropping `T` has no side effect.
 ///
 /// Low level implementations of things like collections, which need to manually
 /// drop their data, should use this function to avoid unnecessarily

src/librustc/middle/reachable.rs

@@ -336,6 +336,12 @@ struct CollectPrivateImplItemsVisitor<'a, 'tcx: 'a> {
 
 impl<'a, 'tcx: 'a> ItemLikeVisitor<'tcx> for CollectPrivateImplItemsVisitor<'a, 'tcx> {
     fn visit_item(&mut self, item: &hir::Item) {
+        // Anything which has custom linkage gets thrown on the worklist no
+        // matter where it is in the crate.
+        if attr::contains_name(&item.attrs, "linkage") {
+            self.worklist.push(item.id);
+        }
+
         // We need only trait impls here, not inherent impls, and only non-exported ones
         if let hir::ItemImpl(.., Some(ref trait_ref), _, ref impl_item_refs) = item.node {
             if !self.access_levels.is_reachable(item.id) {

src/librustc/mir/mod.rs

@@ -415,9 +415,11 @@ pub enum BorrowKind {
 ///////////////////////////////////////////////////////////////////////////
 // Variables and temps
 
-newtype_index!(Local, "_");
-
-pub const RETURN_POINTER: Local = Local(0);
+newtype_index!(Local
+    {
+        DEBUG_NAME = "_",
+        const RETURN_POINTER = 0,
+    });
 
 /// Classifies locals into categories. See `Mir::local_kind`.
 #[derive(PartialEq, Eq, Debug)]
@@ -551,7 +553,7 @@ pub struct UpvarDecl {
 ///////////////////////////////////////////////////////////////////////////
 // BasicBlock
 
-newtype_index!(BasicBlock, "bb");
+newtype_index!(BasicBlock { DEBUG_NAME = "bb" });
 
 ///////////////////////////////////////////////////////////////////////////
 // BasicBlockData and Terminator
@@ -1131,7 +1133,7 @@ pub type LvalueProjection<'tcx> = Projection<'tcx, Lvalue<'tcx>, Local, Ty<'tcx>
 /// and the index is a local.
 pub type LvalueElem<'tcx> = ProjectionElem<'tcx, Local, Ty<'tcx>>;
 
-newtype_index!(Field, "field");
+newtype_index!(Field { DEBUG_NAME = "field" });
 
 impl<'tcx> Lvalue<'tcx> {
     pub fn field(self, f: Field, ty: Ty<'tcx>) -> Lvalue<'tcx> {
@@ -1196,8 +1198,11 @@ impl<'tcx> Debug for Lvalue<'tcx> {
 ///////////////////////////////////////////////////////////////////////////
 // Scopes
 
-newtype_index!(VisibilityScope, "scope");
-pub const ARGUMENT_VISIBILITY_SCOPE : VisibilityScope = VisibilityScope(0);
+newtype_index!(VisibilityScope
+    {
+        DEBUG_NAME = "scope",
+        const ARGUMENT_VISIBILITY_SCOPE = 0,
+    });
 
 #[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
 pub struct VisibilityScopeData {
@@ -1522,7 +1527,7 @@ pub struct Constant<'tcx> {
     pub literal: Literal<'tcx>,
 }
 
-newtype_index!(Promoted, "promoted");
+newtype_index!(Promoted { DEBUG_NAME = "promoted" });
 
 #[derive(Clone, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
 pub enum Literal<'tcx> {

src/librustc_borrowck/borrowck/mod.rs

@@ -759,7 +759,21 @@ impl<'a, 'tcx> BorrowckCtxt<'a, 'tcx> {
 
                 let mut db = match err.cause {
                     MutabilityViolation => {
-                        self.cannot_assign(error_span, &descr, Origin::Ast)
+                        let mut db = self.cannot_assign(error_span, &descr, Origin::Ast);
+                        if let mc::NoteClosureEnv(upvar_id) = err.cmt.note {
+                            let node_id = self.tcx.hir.hir_to_node_id(upvar_id.var_id);
+                            let sp = self.tcx.hir.span(node_id);
+                            match self.tcx.sess.codemap().span_to_snippet(sp) {
+                                Ok(snippet) => {
+                                    let msg = &format!("consider making `{}` mutable", snippet);
+                                    db.span_suggestion(sp, msg, format!("mut {}", snippet));
+                                }
+                                _ => {
+                                    db.span_help(sp, "consider making this binding mutable");
+                                }
+                            }
+                        }
+                        db
                     }
                     BorrowViolation(euv::ClosureCapture(_)) => {
                         struct_span_err!(self.tcx.sess, error_span, E0595,