Auto merge of #77462 - jonas-schievink:rollup-m0rqdh5, r=jonas-schievink

Rollup of 12 pull requests

Successful merges:

 - #76101 (Update RELEASES.md for 1.47.0)
 - #76739 (resolve: prohibit anon const non-static lifetimes)
 - #76811 (Doc alias name restriction)
 - #77405 (Add tracking issue of iter_advance_by feature)
 - #77409 (Add example for iter chain struct)
 - #77415 (Better error message for `async` blocks in a const-context)
 - #77423 (Add `-Zprecise-enum-drop-elaboration`)
 - #77432 (Use posix_spawn on musl targets)
 - #77441 (Fix AVR stack corruption bug)
 - #77442 (Clean up on example doc fixes for ptr::copy)
 - #77444 (Fix span for incorrect pattern field and add label)
 - #77453 (Stop running macOS builds on Azure Pipelines)

Failed merges:

r? `@ghost`

32 files changed, 408 insertions, 211 deletions

diff --git a/RELEASES.md b/RELEASES.md
index 0f59d72bd16..62d30842b23 100644
--- a/RELEASES.md
+++ b/RELEASES.md
@@ -1,3 +1,138 @@
+Version 1.47.0 (2020-10-08)
+==========================
+
+Language
+--------
+- [Closures will now warn when not used.][74869]
+
+Compiler
+--------
+- [Stabilized the `-C control-flow-guard` codegen option][73893], which enables
+  [Control Flow Guard][1.47.0-cfg] for Windows platforms, and is ignored on other
+  platforms.
+- [Upgraded to LLVM 11.][73526]
+- [Added tier 3\* support for the `thumbv4t-none-eabi` target.][74419]
+- [Upgrade the FreeBSD toolchain to version 11.4][75204]
+- [`RUST_BACKTRACE`'s output is now more compact.][75048]
+
+\* Refer to Rust's [platform support page][forge-platform-support] for more
+information on Rust's tiered platform support.
+
+Libraries
+---------
+- [`CStr` now implements `Index<RangeFrom<usize>>`.][74021]
+- [Traits in `std`/`core` are now implemented for arrays of any length, not just
+  those of length less than 33.][74060]
+- [`ops::RangeFull` and `ops::Range` now implement Default.][73197]
+- [`panic::Location` now implements `Copy`, `Clone`, `Eq`, `Hash`, `Ord`,
+  `PartialEq`, and `PartialOrd`.][73583]
+
+Stabilized APIs
+---------------
+- [`Ident::new_raw`]
+- [`Range::is_empty`]
+- [`RangeInclusive::is_empty`]
+- [`Result::as_deref`]
+- [`Result::as_deref_mut`]
+- [`Vec::leak`]
+- [`pointer::offset_from`]
+- [`f32::TAU`]
+- [`f64::TAU`]
+
+The following previously stable APIs have now been made const.
+
+- [The `new` method for all `NonZero` integers.][73858]
+- [The `checked_add`,`checked_sub`,`checked_mul`,`checked_neg`, `checked_shl`,
+  `checked_shr`, `saturating_add`, `saturating_sub`, and `saturating_mul`
+  methods for all integers.][73858]
+- [The `checked_abs`, `saturating_abs`, `saturating_neg`, and `signum`  for all
+  signed integers.][73858]
+- [The `is_ascii_alphabetic`, `is_ascii_uppercase`, `is_ascii_lowercase`,
+  `is_ascii_alphanumeric`, `is_ascii_digit`, `is_ascii_hexdigit`,
+  `is_ascii_punctuation`, `is_ascii_graphic`, `is_ascii_whitespace`, and
+  `is_ascii_control` methods for `char` and `u8`.][73858]
+
+Cargo
+-----
+- [`build-dependencies` are now built with opt-level 0 by default.][cargo/8500]
+  You can override this by setting the following in your `Cargo.toml`.
+  ```toml
+  [profile.release.build-override]
+  opt-level = 3
+  ```
+- [`cargo-help` will now display man pages for commands rather just the
+  `--help` text.][cargo/8456]
+- [`cargo-metadata` now emits a `test` field indicating if a target has
+  tests enabled.][cargo/8478]
+- [`workspace.default-members` now respects `workspace.exclude`.][cargo/8485]
+- [`cargo-publish` will now use an alternative registry by default if it's the
+  only registry specified in `package.publish`.][cargo/8571]
+
+Misc
+----
+- [Added a help button beside Rustdoc's searchbar that explains rustdoc's
+  type based search.][75366]
+- [Added the Ayu theme to rustdoc.][71237]
+
+Compatibility Notes
+-------------------
+- [Bumped the minimum supported Emscripten version to 1.39.20.][75716]
+- [Fixed a regression parsing `{} && false` in tail expressions.][74650]
+- [Added changes to how proc-macros are expanded in `macro_rules!` that should
+  help to preserve more span information.][73084] These changes may cause
+  compiliation errors if your macro was unhygenic or didn't correctly handle
+  `Delimiter::None`.
+- [Moved support for the CloudABI target to tier 3.][75568]
+- [`linux-gnu` targets now require minimum kernel 2.6.32 and glibc 2.11.][74163]
+- [Added the `rustc-docs` component.][75560] This allows you to install
+  and read the documentation for the compiler internal APIs. (Currently only
+  available for `x86_64-unknown-linux-gnu`.)
+
+Internal Only
+--------
+- [Improved default settings for bootstrapping in `x.py`.][73964] You can read details about this change in the ["Changes To `x.py` Defaults"](https://blog.rust-lang.org/inside-rust/2020/08/30/changes-to-x-py-defaults.html) post on the Inside Rust blog.
+
+[1.47.0-cfg]: https://docs.microsoft.com/en-us/windows/win32/secbp/control-flow-guard
+[75048]: https://github.com/rust-lang/rust/pull/75048/
+[74163]: https://github.com/rust-lang/rust/pull/74163/
+[71237]: https://github.com/rust-lang/rust/pull/71237/
+[74869]: https://github.com/rust-lang/rust/pull/74869/
+[73858]: https://github.com/rust-lang/rust/pull/73858/
+[75716]: https://github.com/rust-lang/rust/pull/75716/
+[75908]: https://github.com/rust-lang/rust/pull/75908/
+[75516]: https://github.com/rust-lang/rust/pull/75516/
+[75560]: https://github.com/rust-lang/rust/pull/75560/
+[75568]: https://github.com/rust-lang/rust/pull/75568/
+[75366]: https://github.com/rust-lang/rust/pull/75366/
+[75204]: https://github.com/rust-lang/rust/pull/75204/
+[74650]: https://github.com/rust-lang/rust/pull/74650/
+[74419]: https://github.com/rust-lang/rust/pull/74419/
+[73964]: https://github.com/rust-lang/rust/pull/73964/
+[74021]: https://github.com/rust-lang/rust/pull/74021/
+[74060]: https://github.com/rust-lang/rust/pull/74060/
+[73893]: https://github.com/rust-lang/rust/pull/73893/
+[73526]: https://github.com/rust-lang/rust/pull/73526/
+[73583]: https://github.com/rust-lang/rust/pull/73583/
+[73084]: https://github.com/rust-lang/rust/pull/73084/
+[73197]: https://github.com/rust-lang/rust/pull/73197/
+[72488]: https://github.com/rust-lang/rust/pull/72488/
+[cargo/8456]: https://github.com/rust-lang/cargo/pull/8456/
+[cargo/8478]: https://github.com/rust-lang/cargo/pull/8478/
+[cargo/8485]: https://github.com/rust-lang/cargo/pull/8485/
+[cargo/8500]: https://github.com/rust-lang/cargo/pull/8500/
+[cargo/8571]: https://github.com/rust-lang/cargo/pull/8571/
+[`Ident::new_raw`]:  https://doc.rust-lang.org/nightly/proc_macro/struct.Ident.html#method.new_raw
+[`Range::is_empty`]: https://doc.rust-lang.org/nightly/std/ops/struct.Range.html#method.is_empty
+[`RangeInclusive::is_empty`]: https://doc.rust-lang.org/nightly/std/ops/struct.RangeInclusive.html#method.is_empty
+[`Result::as_deref_mut`]: https://doc.rust-lang.org/nightly/std/result/enum.Result.html#method.as_deref_mut
+[`Result::as_deref`]: https://doc.rust-lang.org/nightly/std/result/enum.Result.html#method.as_deref
+[`TypeId::of`]: https://doc.rust-lang.org/nightly/std/any/struct.TypeId.html#method.of
+[`Vec::leak`]: https://doc.rust-lang.org/nightly/std/vec/struct.Vec.html#method.leak
+[`f32::TAU`]: https://doc.rust-lang.org/nightly/std/f32/consts/constant.TAU.html
+[`f64::TAU`]: https://doc.rust-lang.org/nightly/std/f64/consts/constant.TAU.html
+[`pointer::offset_from`]: https://doc.rust-lang.org/nightly/std/primitive.pointer.html#method.offset_from
+
+
 Version 1.46.0 (2020-08-27)
 ==========================
 
diff --git a/compiler/rustc_interface/src/tests.rs b/compiler/rustc_interface/src/tests.rs
index 72e10bc4304..07ce9d0cd94 100644
--- a/compiler/rustc_interface/src/tests.rs
+++ b/compiler/rustc_interface/src/tests.rs
@@ -568,6 +568,7 @@ fn test_debugging_options_tracking_hash() {
     tracked!(osx_rpath_install_name, true);
     tracked!(panic_abort_tests, true);
     tracked!(plt, Some(true));
+    tracked!(precise_enum_drop_elaboration, false);
     tracked!(print_fuel, Some("abc".to_string()));
     tracked!(profile, true);
     tracked!(profile_emit, Some(PathBuf::from("abc")));
diff --git a/compiler/rustc_mir/src/dataflow/impls/mod.rs b/compiler/rustc_mir/src/dataflow/impls/mod.rs
index d4b9600f766..185f0edfeb6 100644
--- a/compiler/rustc_mir/src/dataflow/impls/mod.rs
+++ b/compiler/rustc_mir/src/dataflow/impls/mod.rs
@@ -358,6 +358,10 @@ impl<'tcx> GenKillAnalysis<'tcx> for MaybeInitializedPlaces<'_, 'tcx> {
         discr: &mir::Operand<'tcx>,
         edge_effects: &mut impl SwitchIntEdgeEffects<G>,
     ) {
+        if !self.tcx.sess.opts.debugging_opts.precise_enum_drop_elaboration {
+            return;
+        }
+
         let enum_ = discr.place().and_then(|discr| {
             switch_on_enum_discriminant(self.tcx, &self.body, &self.body[block], discr)
         });
@@ -469,6 +473,10 @@ impl<'tcx> GenKillAnalysis<'tcx> for MaybeUninitializedPlaces<'_, 'tcx> {
         discr: &mir::Operand<'tcx>,
         edge_effects: &mut impl SwitchIntEdgeEffects<G>,
     ) {
+        if !self.tcx.sess.opts.debugging_opts.precise_enum_drop_elaboration {
+            return;
+        }
+
         if !self.mark_inactive_variants_as_uninit {
             return;
         }
diff --git a/compiler/rustc_mir/src/transform/check_consts/ops.rs b/compiler/rustc_mir/src/transform/check_consts/ops.rs
index 25ed7859d21..32e233e337d 100644
--- a/compiler/rustc_mir/src/transform/check_consts/ops.rs
+++ b/compiler/rustc_mir/src/transform/check_consts/ops.rs
@@ -151,14 +151,15 @@ impl NonConstOp for FnPtrCast {
 }
 
 #[derive(Debug)]
-pub struct Generator;
+pub struct Generator(pub hir::GeneratorKind);
 impl NonConstOp for Generator {
     fn status_in_item(&self, _: &ConstCx<'_, '_>) -> Status {
         Status::Forbidden
     }
 
     fn build_error(&self, ccx: &ConstCx<'_, 'tcx>, span: Span) -> DiagnosticBuilder<'tcx> {
-        ccx.tcx.sess.struct_span_err(span, "Generators and `async` functions cannot be `const`")
+        let msg = format!("{}s are not allowed in {}s", self.0, ccx.const_kind());
+        ccx.tcx.sess.struct_span_err(span, &msg)
     }
 }
 
diff --git a/compiler/rustc_mir/src/transform/check_consts/validation.rs b/compiler/rustc_mir/src/transform/check_consts/validation.rs
index ab63fd03a33..4e714bfeed3 100644
--- a/compiler/rustc_mir/src/transform/check_consts/validation.rs
+++ b/compiler/rustc_mir/src/transform/check_consts/validation.rs
@@ -770,6 +770,14 @@ impl Visitor<'tcx> for Validator<'mir, 'tcx> {
                     return;
                 }
 
+                // `async` blocks get lowered to `std::future::from_generator(/* a closure */)`.
+                let is_async_block = Some(callee) == tcx.lang_items().from_generator_fn();
+                if is_async_block {
+                    let kind = hir::GeneratorKind::Async(hir::AsyncGeneratorKind::Block);
+                    self.check_op(ops::Generator(kind));
+                    return;
+                }
+
                 // HACK: This is to "unstabilize" the `transmute` intrinsic
                 // within const fns. `transmute` is allowed in all other const contexts.
                 // This won't really scale to more intrinsics or functions. Let's allow const
@@ -869,7 +877,7 @@ impl Visitor<'tcx> for Validator<'mir, 'tcx> {
             TerminatorKind::Abort => self.check_op(ops::Abort),
 
             TerminatorKind::GeneratorDrop | TerminatorKind::Yield { .. } => {
-                self.check_op(ops::Generator)
+                self.check_op(ops::Generator(hir::GeneratorKind::Gen))
             }
 
             TerminatorKind::Assert { .. }
diff --git a/compiler/rustc_parse/src/parser/pat.rs b/compiler/rustc_parse/src/parser/pat.rs
index 2c0133a24dc..5aced9dc37c 100644
--- a/compiler/rustc_parse/src/parser/pat.rs
+++ b/compiler/rustc_parse/src/parser/pat.rs
@@ -795,6 +795,7 @@ impl<'a> Parser<'a> {
         }
         self.bump();
         let (fields, etc) = self.parse_pat_fields().unwrap_or_else(|mut e| {
+            e.span_label(path.span, "while parsing the fields for this pattern");
             e.emit();
             self.recover_stmt();
             (vec![], true)
@@ -844,7 +845,7 @@ impl<'a> Parser<'a> {
 
             // check that a comma comes after every field
             if !ate_comma {
-                let err = self.struct_span_err(self.prev_token.span, "expected `,`");
+                let err = self.struct_span_err(self.token.span, "expected `,`");
                 if let Some(mut delayed) = delayed_err {
                     delayed.emit();
                 }
diff --git a/compiler/rustc_passes/src/check_attr.rs b/compiler/rustc_passes/src/check_attr.rs
index 1ec251326a8..b52216c45ce 100644
--- a/compiler/rustc_passes/src/check_attr.rs
+++ b/compiler/rustc_passes/src/check_attr.rs
@@ -260,23 +260,42 @@ impl CheckAttrVisitor<'tcx> {
         }
     }
 
+    fn doc_alias_str_error(&self, meta: &NestedMetaItem) {
+        self.tcx
+            .sess
+            .struct_span_err(
+                meta.span(),
+                "doc alias attribute expects a string: #[doc(alias = \"0\")]",
+            )
+            .emit();
+    }
+
     fn check_doc_alias(&self, attr: &Attribute, hir_id: HirId, target: Target) -> bool {
         if let Some(mi) = attr.meta() {
             if let Some(list) = mi.meta_item_list() {
                 for meta in list {
                     if meta.has_name(sym::alias) {
-                        if !meta.is_value_str()
-                            || meta
-                                .value_str()
-                                .map(|s| s.to_string())
-                                .unwrap_or_else(String::new)
-                                .is_empty()
+                        if !meta.is_value_str() {
+                            self.doc_alias_str_error(meta);
+                            return false;
+                        }
+                        let doc_alias =
+                            meta.value_str().map(|s| s.to_string()).unwrap_or_else(String::new);
+                        if doc_alias.is_empty() {
+                            self.doc_alias_str_error(meta);
+                            return false;
+                        }
+                        if let Some(c) =
+                            doc_alias.chars().find(|&c| c == '"' || c == '\'' || c.is_whitespace())
                         {
                             self.tcx
                                 .sess
                                 .struct_span_err(
                                     meta.span(),
-                                    "doc alias attribute expects a string: #[doc(alias = \"0\")]",
+                                    &format!(
+                                        "{:?} character isn't allowed in `#[doc(alias = \"...\")]`",
+                                        c,
+                                    ),
                                 )
                                 .emit();
                             return false;
@@ -312,6 +331,7 @@ impl CheckAttrVisitor<'tcx> {
                                     &format!("`#[doc(alias = \"...\")]` isn't allowed on {}", err),
                                 )
                                 .emit();
+                            return false;
                         }
                     }
                 }
diff --git a/compiler/rustc_resolve/src/late/diagnostics.rs b/compiler/rustc_resolve/src/late/diagnostics.rs
index ced272e474d..521ea7ad184 100644
--- a/compiler/rustc_resolve/src/late/diagnostics.rs
+++ b/compiler/rustc_resolve/src/late/diagnostics.rs
@@ -16,6 +16,7 @@ use rustc_hir::def::{self, CtorKind, DefKind};
 use rustc_hir::def_id::{DefId, CRATE_DEF_INDEX, LOCAL_CRATE};
 use rustc_hir::PrimTy;
 use rustc_session::config::nightly_options;
+use rustc_session::parse::feature_err;
 use rustc_span::hygiene::MacroKind;
 use rustc_span::symbol::{kw, sym, Ident, Symbol};
 use rustc_span::{BytePos, Span, DUMMY_SP};
@@ -1599,4 +1600,32 @@ impl<'tcx> LifetimeContext<'_, 'tcx> {
             _ => {}
         }
     }
+
+    /// Non-static lifetimes are prohibited in anonymous constants under `min_const_generics` so
+    /// this function will emit an error if `min_const_generics` is enabled, the body identified by
+    /// `body_id` is an anonymous constant and `lifetime_ref` is non-static.
+    crate fn maybe_emit_forbidden_non_static_lifetime_error(
+        &self,
+        body_id: hir::BodyId,
+        lifetime_ref: &'tcx hir::Lifetime,
+    ) {
+        let is_anon_const = matches!(
+            self.tcx.def_kind(self.tcx.hir().body_owner_def_id(body_id)),
+            hir::def::DefKind::AnonConst
+        );
+        let is_allowed_lifetime = matches!(
+            lifetime_ref.name,
+            hir::LifetimeName::Implicit | hir::LifetimeName::Static | hir::LifetimeName::Underscore
+        );
+
+        if self.tcx.features().min_const_generics && is_anon_const && !is_allowed_lifetime {
+            feature_err(
+                &self.tcx.sess.parse_sess,
+                sym::const_generics,
+                lifetime_ref.span,
+                "a non-static lifetime is not allowed in a `const`",
+            )
+            .emit();
+        }
+    }
 }
diff --git a/compiler/rustc_resolve/src/late/lifetimes.rs b/compiler/rustc_resolve/src/late/lifetimes.rs
index 31360d47473..072fb509b19 100644
--- a/compiler/rustc_resolve/src/late/lifetimes.rs
+++ b/compiler/rustc_resolve/src/late/lifetimes.rs
@@ -1777,6 +1777,10 @@ impl<'a, 'tcx> LifetimeContext<'a, 'tcx> {
         let result = loop {
             match *scope {
                 Scope::Body { id, s } => {
+                    // Non-static lifetimes are prohibited in anonymous constants under
+                    // `min_const_generics`.
+                    self.maybe_emit_forbidden_non_static_lifetime_error(id, lifetime_ref);
+
                     outermost_body = Some(id);
                     scope = s;
                 }
diff --git a/compiler/rustc_session/src/options.rs b/compiler/rustc_session/src/options.rs
index 712c9cb87c9..b705ab6d931 100644
--- a/compiler/rustc_session/src/options.rs
+++ b/compiler/rustc_session/src/options.rs
@@ -1008,6 +1008,10 @@ options! {DebuggingOptions, DebuggingSetter, basic_debugging_options,
         "a single extra argument to prepend the linker invocation (can be used several times)"),
     pre_link_args: Vec<String> = (Vec::new(), parse_list, [UNTRACKED],
         "extra arguments to prepend to the linker invocation (space separated)"),
+    precise_enum_drop_elaboration: bool = (true, parse_bool, [TRACKED],
+        "use a more precise version of drop elaboration for matches on enums (default: yes). \
+        This results in better codegen, but has caused miscompilations on some tier 2 platforms. \
+        See #77382 and #74551."),
     print_fuel: Option<String> = (None, parse_opt_string, [TRACKED],
         "make rustc print the total optimization fuel used by a crate"),
     print_link_args: bool = (false, parse_bool, [UNTRACKED],
diff --git a/library/core/src/intrinsics.rs b/library/core/src/intrinsics.rs
index 4e4b31c0cb4..426cdb12ec4 100644
--- a/library/core/src/intrinsics.rs
+++ b/library/core/src/intrinsics.rs
@@ -1901,9 +1901,10 @@ pub unsafe fn copy_nonoverlapping<T>(src: *const T, dst: *mut T, count: usize) {
 /// ```
 /// use std::ptr;
 ///
-/// /// # Safety:
+/// /// # Safety
+/// ///
 /// /// * `ptr` must be correctly aligned for its type and non-zero.
-/// /// * `ptr` must be valid for reads of `elts` contiguous objects of type `T`.
+/// /// * `ptr` must be valid for reads of `elts` contiguous elements of type `T`.
 /// /// * Those elements must not be used after calling this function unless `T: Copy`.
 /// # #[allow(dead_code)]
 /// unsafe fn from_buf_raw<T>(ptr: *const T, elts: usize) -> Vec<T> {
diff --git a/library/core/src/iter/adapters/chain.rs b/library/core/src/iter/adapters/chain.rs
index 13c6a75d58b..ac27ec19b36 100644
--- a/library/core/src/iter/adapters/chain.rs
+++ b/library/core/src/iter/adapters/chain.rs
@@ -6,6 +6,17 @@ use crate::usize;
 ///
 /// This `struct` is created by [`Iterator::chain`]. See its documentation
 /// for more.
+///
+/// # Examples
+///
+/// ```
+/// use std::iter::Chain;
+/// use std::slice::Iter;
+///
+/// let a1 = [1, 2, 3];
+/// let a2 = [4, 5, 6];
+/// let iter: Chain<Iter<_>, Iter<_>> = a1.iter().chain(a2.iter());
+/// ```
 #[derive(Clone, Debug)]
 #[must_use = "iterators are lazy and do nothing unless consumed"]
 #[stable(feature = "rust1", since = "1.0.0")]
diff --git a/library/core/src/iter/traits/double_ended.rs b/library/core/src/iter/traits/double_ended.rs
index d370c16ea5a..16bee0e2eee 100644
--- a/library/core/src/iter/traits/double_ended.rs
+++ b/library/core/src/iter/traits/double_ended.rs
@@ -123,7 +123,7 @@ pub trait DoubleEndedIterator: Iterator {
     /// assert_eq!(iter.advance_back_by(100), Err(1)); // only `&3` was skipped
     /// ```
     #[inline]
-    #[unstable(feature = "iter_advance_by", reason = "recently added", issue = "none")]
+    #[unstable(feature = "iter_advance_by", reason = "recently added", issue = "77404")]
     fn advance_back_by(&mut self, n: usize) -> Result<(), usize> {
         for i in 0..n {
             self.next_back().ok_or(i)?;
diff --git a/library/core/src/iter/traits/iterator.rs b/library/core/src/iter/traits/iterator.rs
index 36d4a50856f..813afcc0ec6 100644
--- a/library/core/src/iter/traits/iterator.rs
+++ b/library/core/src/iter/traits/iterator.rs
@@ -314,7 +314,7 @@ pub trait Iterator {
     /// assert_eq!(iter.advance_by(100), Err(1)); // only `&4` was skipped
     /// ```
     #[inline]
-    #[unstable(feature = "iter_advance_by", reason = "recently added", issue = "none")]
+    #[unstable(feature = "iter_advance_by", reason = "recently added", issue = "77404")]
     fn advance_by(&mut self, n: usize) -> Result<(), usize> {
         for i in 0..n {
             self.next().ok_or(i)?;
diff --git a/library/std/src/sys/unix/process/process_unix.rs b/library/std/src/sys/unix/process/process_unix.rs
index ea7ea6f067c..32f456266c9 100644
--- a/library/std/src/sys/unix/process/process_unix.rs
+++ b/library/std/src/sys/unix/process/process_unix.rs
@@ -252,7 +252,8 @@ impl Command {
     #[cfg(not(any(
         target_os = "macos",
         target_os = "freebsd",
-        all(target_os = "linux", target_env = "gnu")
+        all(target_os = "linux", target_env = "gnu"),
+        all(target_os = "linux", target_env = "musl"),
     )))]
     fn posix_spawn(
         &mut self,
@@ -267,7 +268,8 @@ impl Command {
     #[cfg(any(
         target_os = "macos",
         target_os = "freebsd",
-        all(target_os = "linux", target_env = "gnu")
+        all(target_os = "linux", target_env = "gnu"),
+        all(target_os = "linux", target_env = "musl"),
     ))]
     fn posix_spawn(
         &mut self,
@@ -297,10 +299,10 @@ impl Command {
             }
         }
 
-        // Solaris and glibc 2.29+ can set a new working directory, and maybe
-        // others will gain this non-POSIX function too. We'll check for this
-        // weak symbol as soon as it's needed, so we can return early otherwise
-        // to do a manual chdir before exec.
+        // Solaris, glibc 2.29+, and musl 1.24+ can set a new working directory,
+        // and maybe others will gain this non-POSIX function too. We'll check
+        // for this weak symbol as soon as it's needed, so we can return early
+        // otherwise to do a manual chdir before exec.
         weak! {
             fn posix_spawn_file_actions_addchdir_np(
                 *mut libc::posix_spawn_file_actions_t,
diff --git a/src/ci/azure-pipelines/auto.yml b/src/ci/azure-pipelines/auto.yml
index 05177e517d0..37c2e9bc35a 100644
--- a/src/ci/azure-pipelines/auto.yml
+++ b/src/ci/azure-pipelines/auto.yml
@@ -18,45 +18,9 @@ trigger:
   - auto
 
 jobs:
-- job: macOS
+- job: Dummy
   timeoutInMinutes: 600
   pool:
-    vmImage: macos-10.15
+    vmImage: ubuntu-16.04
   steps:
-  - template: steps/run.yml
-  variables:
-    # We're still uploading macOS builds from Azure Pipelines.
-    - group: prod-credentials
-  strategy:
-    matrix:
-      # OSX builders running tests, these run the full test suite.
-      # NO_DEBUG_ASSERTIONS=1 to make them go faster, but also do have some
-      # runners that run `//ignore-debug` tests.
-      #
-      # Note that the compiler is compiled to target 10.8 here because the Xcode
-      # version that we're using, 8.2, cannot compile LLVM for OSX 10.7.
-      x86_64-apple:
-        SCRIPT: ./x.py --stage 2 test
-        INITIAL_RUST_CONFIGURE_ARGS: --build=x86_64-apple-darwin --enable-sanitizers --enable-profiler --set rust.jemalloc --set llvm.ninja=false
-        RUSTC_RETRY_LINKER_ON_SEGFAULT: 1
-        MACOSX_DEPLOYMENT_TARGET: 10.8
-        MACOSX_STD_DEPLOYMENT_TARGET: 10.7
-        NO_LLVM_ASSERTIONS: 1
-        NO_DEBUG_ASSERTIONS: 1
-
-      dist-x86_64-apple:
-        SCRIPT: ./x.py dist
-        INITIAL_RUST_CONFIGURE_ARGS: --host=x86_64-apple-darwin --target=x86_64-apple-darwin,aarch64-apple-ios,x86_64-apple-ios --enable-full-tools --enable-sanitizers --enable-profiler --set rust.jemalloc --set llvm.ninja=false
-        RUSTC_RETRY_LINKER_ON_SEGFAULT: 1
-        MACOSX_DEPLOYMENT_TARGET: 10.7
-        NO_LLVM_ASSERTIONS: 1
-        NO_DEBUG_ASSERTIONS: 1
-        DIST_REQUIRE_ALL_TOOLS: 1
-
-      dist-x86_64-apple-alt:
-        SCRIPT: ./x.py dist
-        INITIAL_RUST_CONFIGURE_ARGS: --enable-extended --enable-profiler --set rust.jemalloc --set llvm.ninja=false
-        RUSTC_RETRY_LINKER_ON_SEGFAULT: 1
-        MACOSX_DEPLOYMENT_TARGET: 10.7
-        NO_LLVM_ASSERTIONS: 1
-        NO_DEBUG_ASSERTIONS: 1
+  - bash: echo "We're running this job since bors is still gating on Azure"
diff --git a/src/ci/azure-pipelines/steps/run.yml b/src/ci/azure-pipelines/steps/run.yml
deleted file mode 100644
index 34fc4d76fa2..00000000000
--- a/src/ci/azure-pipelines/steps/run.yml
+++ /dev/null
@@ -1,142 +0,0 @@
-#####################################
-##    READ BEFORE CHANGING THIS    ##
-#####################################
-
-# We're in the process of evaluating GitHub Actions as a possible replacement
-# for Azure Pipelines, and at the moment the configuration is duplicated
-# between the two CI providers. Be sure to also change the configuration in
-# src/ci/github-actions when changing this file.
-
-#####################################
-
-# FIXME(linux): need to configure core dumps, enable them, and then dump
-# backtraces on failure from all core dumps:
-#
-# - bash: sudo apt install gdb
-# - bash: sudo sh -c 'echo "/checkout/obj/cores/core.%p.%E" > /proc/sys/kernel/core_pattern'
-#
-# Check travis config for `gdb --batch` command to print all crash logs
-
-steps:
-
-# Configure our CI_JOB_NAME variable which log analyzers can use for the main
-# step to see what's going on.
-- bash: |
-    builder=$(echo $AGENT_JOBNAME | cut -d ' ' -f 2)
-    echo "##vso[task.setvariable variable=CI_JOB_NAME]$builder"
-  displayName: Configure Job Name
-
-# Disable automatic line ending conversion, which is enabled by default on
-# Azure's Windows image. Having the conversion enabled caused regressions both
-# in our test suite (it broke miri tests) and in the ecosystem, since we
-# started shipping install scripts with CRLF endings instead of the old LF.
-#
-# Note that we do this a couple times during the build as the PATH and current
-# user/directory change, e.g. when mingw is enabled.
-- bash: git config --global core.autocrlf false
-  displayName: "Disable git automatic line ending conversion"
-
-- checkout: self
-  fetchDepth: 2
-
-- bash: src/ci/scripts/setup-environment.sh
-  displayName: Setup environment
-
-- bash: src/ci/scripts/clean-disk.sh
-  displayName: Clean disk
-
-- bash: src/ci/scripts/should-skip-this.sh
-  displayName: Decide whether to run this job
-
-- bash: src/ci/scripts/collect-cpu-stats.sh
-  displayName: Collect CPU-usage statistics in the background
-
-- bash: src/ci/scripts/dump-environment.sh
-  displayName: Show the current environment
-
-- bash: src/ci/scripts/install-sccache.sh
-  displayName: Install sccache
-  condition: and(succeeded(), not(variables.SKIP_JOB))
-
-- bash: src/ci/scripts/install-clang.sh
-  displayName: Install clang
-  condition: and(succeeded(), not(variables.SKIP_JOB))
-
-- bash: src/ci/scripts/install-wix.sh
-  displayName: Install wix
-  condition: and(succeeded(), not(variables.SKIP_JOB))
-
-- bash: src/ci/scripts/symlink-build-dir.sh
-  displayName: Ensure the build happens on a partition with enough space
-  condition: and(succeeded(), not(variables.SKIP_JOB))
-
-- bash: src/ci/scripts/disable-git-crlf-conversion.sh
-  displayName: "Disable git automatic line ending conversion (on C:/)"
-  condition: and(succeeded(), not(variables.SKIP_JOB))
-
-- bash: src/ci/scripts/install-msys2.sh
-  displayName: Install msys2
-  condition: and(succeeded(), not(variables.SKIP_JOB))
-
-- bash: src/ci/scripts/install-mingw.sh
-  displayName: Install MinGW
-  condition: and(succeeded(), not(variables.SKIP_JOB))
-
-- bash: src/ci/scripts/install-ninja.sh
-  displayName: Install ninja
-  condition: and(succeeded(), not(variables.SKIP_JOB))
-
-- bash: src/ci/scripts/enable-docker-ipv6.sh
-  displayName: Enable IPv6 on Docker
-  condition: and(succeeded(), not(variables.SKIP_JOB))
-
-# Disable automatic line ending conversion (again). On Windows, when we're
-# installing dependencies, something switches the git configuration directory or
-# re-enables autocrlf. We've not tracked down the exact cause -- and there may
-# be multiple -- but this should ensure submodules are checked out with the
-# appropriate line endings.
-- bash: src/ci/scripts/disable-git-crlf-conversion.sh
-  displayName: Disable git automatic line ending conversion
-  condition: and(succeeded(), not(variables.SKIP_JOB))
-
-- bash: src/ci/scripts/checkout-submodules.sh
-  displayName: Checkout submodules
-  condition: and(succeeded(), not(variables.SKIP_JOB))
-
-- bash: src/ci/scripts/verify-line-endings.sh
-  displayName: Verify line endings
-  condition: and(succeeded(), not(variables.SKIP_JOB))
-
-# Ensure the `aws` CLI is installed so we can deploy later on, cache docker
-# images, etc.
-- bash: src/ci/scripts/install-awscli.sh
-  condition: and(succeeded(), not(variables.SKIP_JOB))
-  displayName: Install awscli
-
-- bash: src/ci/scripts/run-build-from-ci.sh
-  timeoutInMinutes: 600
-  env:
-    AWS_ACCESS_KEY_ID: $(SCCACHE_AWS_ACCESS_KEY_ID)
-    AWS_SECRET_ACCESS_KEY: $(SCCACHE_AWS_SECRET_ACCESS_KEY)
-    TOOLSTATE_REPO_ACCESS_TOKEN: $(TOOLSTATE_REPO_ACCESS_TOKEN)
-  condition: and(succeeded(), not(variables.SKIP_JOB))
-  displayName: Run build
-
-- bash: src/ci/scripts/upload-artifacts.sh
-  env:
-    AWS_ACCESS_KEY_ID: $(UPLOAD_AWS_ACCESS_KEY_ID)
-    AWS_SECRET_ACCESS_KEY: $(UPLOAD_AWS_SECRET_ACCESS_KEY)
-  displayName: Upload artifacts
-  # Adding a condition on DEPLOY=1 or DEPLOY_ALT=1 is not needed as all deploy
-  # builders *should* have the AWS credentials available. Still, explicitly
-  # adding the condition is helpful as this way CI will not silently skip
-  # deploying artifacts from a dist builder if the variables are misconfigured,
-  # erroring about invalid credentials instead.
-  condition: |
-    and(
-      succeeded(), not(variables.SKIP_JOB),
-      or(
-        variables.UPLOAD_AWS_SECRET_ACCESS_KEY,
-        eq(variables.DEPLOY, '1'), eq(variables.DEPLOY_ALT, '1')
-      )
-    )
diff --git a/src/doc/rustdoc/src/advanced-features.md b/src/doc/rustdoc/src/advanced-features.md
index c9a0dff5ab3..8c7926f116b 100644
--- a/src/doc/rustdoc/src/advanced-features.md
+++ b/src/doc/rustdoc/src/advanced-features.md
@@ -46,3 +46,5 @@ pub struct BigX;
 
 Then, when looking for it through the `rustdoc` search, if you enter "x" or
 "big", search will show the `BigX` struct first.
+
+There are some limitations on the doc alias names though: you can't use `"` or whitespace.
diff --git a/src/librustdoc/clean/types.rs b/src/librustdoc/clean/types.rs
index 223fda84871..8fbfb04bac3 100644
--- a/src/librustdoc/clean/types.rs
+++ b/src/librustdoc/clean/types.rs
@@ -695,7 +695,7 @@ impl Attributes {
         self.other_attrs
             .lists(sym::doc)
             .filter(|a| a.has_name(sym::alias))
-            .filter_map(|a| a.value_str().map(|s| s.to_string().replace("\"", "")))
+            .filter_map(|a| a.value_str().map(|s| s.to_string()))
             .filter(|v| !v.is_empty())
             .collect::<FxHashSet<_>>()
     }
diff --git a/src/llvm-project b/src/llvm-project
-Subproject 2c56ba7db75b536b0432228b4760ed79174eca3
+Subproject e8b556b6a8836147429abe391d6ed18806867b4
diff --git a/src/test/rustdoc-ui/check-doc-alias-attr.rs b/src/test/rustdoc-ui/check-doc-alias-attr.rs
index b02cc1a4545..c8bec39fad6 100644
--- a/src/test/rustdoc-ui/check-doc-alias-attr.rs
+++ b/src/test/rustdoc-ui/check-doc-alias-attr.rs
@@ -7,4 +7,10 @@ pub struct Bar;
 #[doc(alias)] //~ ERROR
 #[doc(alias = 0)] //~ ERROR
 #[doc(alias("bar"))] //~ ERROR
+#[doc(alias = "\"")] //~ ERROR
+#[doc(alias = "\n")] //~ ERROR
+#[doc(alias = "
+")] //~^ ERROR
+#[doc(alias = " ")] //~ ERROR
+#[doc(alias = "\t")] //~ ERROR
 pub struct Foo;
diff --git a/src/test/rustdoc-ui/check-doc-alias-attr.stderr b/src/test/rustdoc-ui/check-doc-alias-attr.stderr
index 268230ab44a..be7d7b3dbea 100644
--- a/src/test/rustdoc-ui/check-doc-alias-attr.stderr
+++ b/src/test/rustdoc-ui/check-doc-alias-attr.stderr
@@ -16,5 +16,37 @@ error: doc alias attribute expects a string: #[doc(alias = "0")]
 LL | #[doc(alias("bar"))]
    |       ^^^^^^^^^^^^
 
-error: aborting due to 3 previous errors
+error: '\"' character isn't allowed in `#[doc(alias = "...")]`
+  --> $DIR/check-doc-alias-attr.rs:10:7
+   |
+LL | #[doc(alias = "\"")]
+   |       ^^^^^^^^^^^^
+
+error: '\n' character isn't allowed in `#[doc(alias = "...")]`
+  --> $DIR/check-doc-alias-attr.rs:11:7
+   |
+LL | #[doc(alias = "\n")]
+   |       ^^^^^^^^^^^^
+
+error: '\n' character isn't allowed in `#[doc(alias = "...")]`
+  --> $DIR/check-doc-alias-attr.rs:12:7
+   |
+LL |   #[doc(alias = "
+   |  _______^
+LL | | ")]
+   | |_^
+
+error: ' ' character isn't allowed in `#[doc(alias = "...")]`
+  --> $DIR/check-doc-alias-attr.rs:14:7
+   |
+LL | #[doc(alias = " ")]
+   |       ^^^^^^^^^^^
+
+error: '\t' character isn't allowed in `#[doc(alias = "...")]`
+  --> $DIR/check-doc-alias-attr.rs:15:7
+   |
+LL | #[doc(alias = "\t")]
+   |       ^^^^^^^^^^^^
+
+error: aborting due to 8 previous errors
 
diff --git a/src/test/ui/check-doc-alias-attr.rs b/src/test/ui/check-doc-alias-attr.rs
index b02cc1a4545..c8bec39fad6 100644
--- a/src/test/ui/check-doc-alias-attr.rs
+++ b/src/test/ui/check-doc-alias-attr.rs
@@ -7,4 +7,10 @@ pub struct Bar;
 #[doc(alias)] //~ ERROR
 #[doc(alias = 0)] //~ ERROR
 #[doc(alias("bar"))] //~ ERROR
+#[doc(alias = "\"")] //~ ERROR
+#[doc(alias = "\n")] //~ ERROR
+#[doc(alias = "
+")] //~^ ERROR
+#[doc(alias = " ")] //~ ERROR
+#[doc(alias = "\t")] //~ ERROR
 pub struct Foo;
diff --git a/src/test/ui/check-doc-alias-attr.stderr b/src/test/ui/check-doc-alias-attr.stderr
index 268230ab44a..be7d7b3dbea 100644
--- a/src/test/ui/check-doc-alias-attr.stderr
+++ b/src/test/ui/check-doc-alias-attr.stderr
@@ -16,5 +16,37 @@ error: doc alias attribute expects a string: #[doc(alias = "0")]
 LL | #[doc(alias("bar"))]
    |       ^^^^^^^^^^^^
 
-error: aborting due to 3 previous errors
+error: '\"' character isn't allowed in `#[doc(alias = "...")]`
+  --> $DIR/check-doc-alias-attr.rs:10:7
+   |
+LL | #[doc(alias = "\"")]
+   |       ^^^^^^^^^^^^
+
+error: '\n' character isn't allowed in `#[doc(alias = "...")]`
+  --> $DIR/check-doc-alias-attr.rs:11:7
+   |
+LL | #[doc(alias = "\n")]
+   |       ^^^^^^^^^^^^
+
+error: '\n' character isn't allowed in `#[doc(alias = "...")]`
+  --> $DIR/check-doc-alias-attr.rs:12:7
+   |
+LL |   #[doc(alias = "
+   |  _______^
+LL | | ")]
+   | |_^
+
+error: ' ' character isn't allowed in `#[doc(alias = "...")]`
+  --> $DIR/check-doc-alias-attr.rs:14:7
+   |
+LL | #[doc(alias = " ")]
+   |       ^^^^^^^^^^^
+
+error: '\t' character isn't allowed in `#[doc(alias = "...")]`
+  --> $DIR/check-doc-alias-attr.rs:15:7
+   |
+LL | #[doc(alias = "\t")]
+   |       ^^^^^^^^^^^^
+
+error: aborting due to 8 previous errors
 
diff --git a/src/test/ui/const-generics/min_const_generics/forbid-non-static-lifetimes.rs b/src/test/ui/const-generics/min_const_generics/forbid-non-static-lifetimes.rs
new file mode 100644
index 00000000000..02944e2bff2
--- /dev/null
+++ b/src/test/ui/const-generics/min_const_generics/forbid-non-static-lifetimes.rs
@@ -0,0 +1,27 @@
+#![feature(min_const_generics)]
+
+// This test checks that non-static lifetimes are prohibited under `min_const_generics`. It
+// currently emits an error with `min_const_generics`. This will ICE under `const_generics`.
+
+fn test<const N: usize>() {}
+
+fn issue_75323_and_74447_1<'a>() -> &'a () {
+    test::<{ let _: &'a (); 3 },>();
+   //~^ ERROR a non-static lifetime is not allowed in a `const`
+    &()
+}
+
+fn issue_75323_and_74447_2() {
+    test::<{ let _: &(); 3 },>();
+}
+
+fn issue_75323_and_74447_3() {
+    test::<{ let _: &'static (); 3 },>();
+}
+
+fn issue_73375<'a>() {
+    [(); (|_: &'a u8| (), 0).1];
+    //~^ ERROR a non-static lifetime is not allowed in a `const`
+}
+
+fn main() {}
diff --git a/src/test/ui/const-generics/min_const_generics/forbid-non-static-lifetimes.stderr b/src/test/ui/const-generics/min_const_generics/forbid-non-static-lifetimes.stderr
new file mode 100644
index 00000000000..cdfd491e395
--- /dev/null
+++ b/src/test/ui/const-generics/min_const_generics/forbid-non-static-lifetimes.stderr
@@ -0,0 +1,21 @@
+error[E0658]: a non-static lifetime is not allowed in a `const`
+  --> $DIR/forbid-non-static-lifetimes.rs:9:22
+   |
+LL |     test::<{ let _: &'a (); 3 },>();
+   |                      ^^
+   |
+   = note: see issue #44580 <https://github.com/rust-lang/rust/issues/44580> for more information
+   = help: add `#![feature(const_generics)]` to the crate attributes to enable
+
+error[E0658]: a non-static lifetime is not allowed in a `const`
+  --> $DIR/forbid-non-static-lifetimes.rs:23:16
+   |
+LL |     [(); (|_: &'a u8| (), 0).1];
+   |                ^^
+   |
+   = note: see issue #44580 <https://github.com/rust-lang/rust/issues/44580> for more information
+   = help: add `#![feature(const_generics)]` to the crate attributes to enable
+
+error: aborting due to 2 previous errors
+
+For more information about this error, try `rustc --explain E0658`.
diff --git a/src/test/ui/consts/async-block.rs b/src/test/ui/consts/async-block.rs
new file mode 100644
index 00000000000..1fa2a616091
--- /dev/null
+++ b/src/test/ui/consts/async-block.rs
@@ -0,0 +1,8 @@
+// From <https://github.com/rust-lang/rust/issues/77361>
+
+// edition:2018
+
+const _: i32 = { core::mem::ManuallyDrop::new(async { 0 }); 4 };
+//~^ `async` block
+
+fn main() {}
diff --git a/src/test/ui/consts/async-block.stderr b/src/test/ui/consts/async-block.stderr
new file mode 100644
index 00000000000..99f470623ac
--- /dev/null
+++ b/src/test/ui/consts/async-block.stderr
@@ -0,0 +1,8 @@
+error: `async` blocks are not allowed in constants
+  --> $DIR/async-block.rs:5:47
+   |
+LL | const _: i32 = { core::mem::ManuallyDrop::new(async { 0 }); 4 };
+   |                                               ^^^^^^^^^^^
+
+error: aborting due to previous error
+
diff --git a/src/test/ui/parser/bind-struct-early-modifiers.stderr b/src/test/ui/parser/bind-struct-early-modifiers.stderr
index 03482a41f54..b35762a887c 100644
--- a/src/test/ui/parser/bind-struct-early-modifiers.stderr
+++ b/src/test/ui/parser/bind-struct-early-modifiers.stderr
@@ -1,8 +1,10 @@
 error: expected `,`
-  --> $DIR/bind-struct-early-modifiers.rs:4:19
+  --> $DIR/bind-struct-early-modifiers.rs:4:20
    |
 LL |         Foo { ref x: ref x } => {},
-   |                   ^
+   |         ---        ^
+   |         |
+   |         while parsing the fields for this pattern
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/parser/issue-10392.stderr b/src/test/ui/parser/issue-10392.stderr
index 34991151c1e..438ea67d33c 100644
--- a/src/test/ui/parser/issue-10392.stderr
+++ b/src/test/ui/parser/issue-10392.stderr
@@ -2,7 +2,9 @@ error: expected identifier, found `,`
   --> $DIR/issue-10392.rs:6:13
    |
 LL |     let A { , } = a();
-   |             ^ expected identifier
+   |         -   ^ expected identifier
+   |         |
+   |         while parsing the fields for this pattern
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/parser/issue-63135.stderr b/src/test/ui/parser/issue-63135.stderr
index 396aec8335d..80e9ac5bedf 100644
--- a/src/test/ui/parser/issue-63135.stderr
+++ b/src/test/ui/parser/issue-63135.stderr
@@ -35,7 +35,9 @@ error: expected one of `!` or `[`, found `}`
   --> $DIR/issue-63135.rs:3:16
    |
 LL | fn i(n{...,f #
-   |                ^ expected one of `!` or `[`
+   |      -         ^ expected one of `!` or `[`
+   |      |
+   |      while parsing the fields for this pattern
 
 error: aborting due to 5 previous errors
 
diff --git a/src/test/ui/resolve/issue-54379.stderr b/src/test/ui/resolve/issue-54379.stderr
index 2a6b54572de..750727273eb 100644
--- a/src/test/ui/resolve/issue-54379.stderr
+++ b/src/test/ui/resolve/issue-54379.stderr
@@ -8,10 +8,12 @@ LL |         MyStruct { .., Some(_) } => {},
    |                    `..` must be at the end and cannot have a trailing comma
 
 error: expected `,`
-  --> $DIR/issue-54379.rs:9:24
+  --> $DIR/issue-54379.rs:9:28
    |
 LL |         MyStruct { .., Some(_) } => {},
-   |                        ^^^^
+   |         --------           ^
+   |         |
+   |         while parsing the fields for this pattern
 
 error: aborting due to 2 previous errors