Auto merge of #66011 - Mark-Simulacrum:beta-backport, r=pietroalbini

[beta] backport rollup

* save-analysis: Account for async desugaring in async fn return types #65936
* resolve: Turn the "non-empty glob must import something" error into a lint #65539
* Updated RELEASES.md for 1.39.0 #64878 (squashed)

RELEASES.md

@@ -1,3 +1,127 @@
+Version 1.39.0 (2019-11-07)
+===========================
+
+Language
+--------
+- [You can now create `async` functions and blocks with `async fn`, `async move {}`, and
+  `async {}` respectively, and you can now call `.await` on async expressions.][63209]
+- [You can now use certain attributes on function, closure, and function pointer
+  parameters.][64010] These attributes include `cfg`, `cfg_attr`, `allow`, `warn`,
+  `deny`, `forbid` as well as inert helper attributes used by procedural macro
+  attributes applied to items. e.g.
+  ```rust
+  fn len(
+      #[cfg(windows)] slice: &[u16],
+      #[cfg(not(windows))] slice: &[u8],
+  ) -> usize {
+      slice.len()
+  }
+  ```
+- [You can now take shared references to bind-by-move patterns in the `if` guards
+  of `match` arms.][63118] e.g.
+  ```rust
+  fn main() {
+      let array: Box<[u8; 4]> = Box::new([1, 2, 3, 4]);
+
+      match array {
+          nums
+  //      ---- `nums` is bound by move.
+              if nums.iter().sum::<u8>() == 10
+  //                 ^------ `.iter()` implicitly takes a reference to `nums`.
+          => {
+              drop(nums);
+  //          ----------- Legal as `nums` was bound by move and so we have ownership.
+          }
+          _ => unreachable!(),
+      }
+  }
+  ```
+
+
+
+Compiler
+--------
+- [Added tier 3\* support for the `i686-unknown-uefi` target.][64334]
+- [Added tier 3 support for the `sparc64-unknown-openbsd` target.][63595]
+- [rustc will now trim code snippets in diagnostics to fit in your terminal.][63402]
+  **Note** Cargo currently doesn't use this feature. Refer to
+  [cargo#7315][cargo/7315] to track this feature's progress.
+- [You can now pass `--show-output` argument to test binaries to print the
+  output of successful tests.][62600]
+
+
+\* Refer to Rust's [platform support page][forge-platform-support] for more
+information on Rust's tiered platform support.
+
+Libraries
+---------
+- [`Vec::new` and `String::new` are now `const` functions.][64028]
+- [`LinkedList::new` is now a `const` function.][63684]
+- [`str::len`, `[T]::len` and `str::as_bytes` are now `const` functions.][63770]
+- [The `abs`, `wrapping_abs`, and `overflowing_abs` numeric functions are
+  now `const`.][63786]
+
+Stabilized APIs
+---------------
+- [`Pin::into_inner`]
+- [`Instant::checked_duration_since`]
+- [`Instant::saturating_duration_since`]
+
+Cargo
+-----
+- [You can now publish git dependencies if supplied with a `version`.][cargo/7237]
+- [The `--all` flag has been renamed to `--workspace`.][cargo/7241] Using
+  `--all` is now deprecated.
+
+Misc
+----
+- [You can now pass `-Clinker` to rustdoc to control the linker used
+  for compiling doctests.][63834]
+
+Compatibility Notes
+-------------------
+- [Code that was previously accepted by the old borrow checker, but rejected by
+  the NLL borrow checker is now a hard error in Rust 2018.][63565] This was
+  previously a warning, and will also become a hard error in the Rust 2015
+  edition in the 1.40.0 release.
+- [`rustdoc` now requires `rustc` to be installed and in the same directory to
+  run tests.][63827] This should improve performance when running a large
+  amount of doctests.
+- [The `try!` macro will now issue a deprecation warning.][62672] It is
+  recommended to use the `?` operator instead.
+- [`asinh(-0.0)` now correctly returns `-0.0`.][63698] Previously this
+  returned `0.0`.
+
+[62600]: https://github.com/rust-lang/rust/pull/62600/
+[62672]: https://github.com/rust-lang/rust/pull/62672/
+[63118]: https://github.com/rust-lang/rust/pull/63118/
+[63209]: https://github.com/rust-lang/rust/pull/63209/
+[63402]: https://github.com/rust-lang/rust/pull/63402/
+[63565]: https://github.com/rust-lang/rust/pull/63565/
+[63595]: https://github.com/rust-lang/rust/pull/63595/
+[63684]: https://github.com/rust-lang/rust/pull/63684/
+[63698]: https://github.com/rust-lang/rust/pull/63698/
+[63770]: https://github.com/rust-lang/rust/pull/63770/
+[63786]: https://github.com/rust-lang/rust/pull/63786/
+[63827]: https://github.com/rust-lang/rust/pull/63827/
+[63834]: https://github.com/rust-lang/rust/pull/63834/
+[63927]: https://github.com/rust-lang/rust/pull/63927/
+[63933]: https://github.com/rust-lang/rust/pull/63933/
+[63934]: https://github.com/rust-lang/rust/pull/63934/
+[63938]: https://github.com/rust-lang/rust/pull/63938/
+[63940]: https://github.com/rust-lang/rust/pull/63940/
+[63941]: https://github.com/rust-lang/rust/pull/63941/
+[63945]: https://github.com/rust-lang/rust/pull/63945/
+[64010]: https://github.com/rust-lang/rust/pull/64010/
+[64028]: https://github.com/rust-lang/rust/pull/64028/
+[64334]: https://github.com/rust-lang/rust/pull/64334/
+[cargo/7237]: https://github.com/rust-lang/cargo/pull/7237/
+[cargo/7241]: https://github.com/rust-lang/cargo/pull/7241/
+[cargo/7315]: https://github.com/rust-lang/cargo/pull/7315/
+[`Pin::into_inner`]: https://doc.rust-lang.org/std/pin/struct.Pin.html#method.into_inner
+[`Instant::checked_duration_since`]: https://doc.rust-lang.org/std/time/struct.Instant.html#method.checked_duration_since
+[`Instant::saturating_duration_since`]: https://doc.rust-lang.org/std/time/struct.Instant.html#method.saturating_duration_since
+
 Version 1.38.0 (2019-09-26)
 ==========================
 

src/ci/azure-pipelines/auto.yml

@@ -124,8 +124,6 @@ jobs:
         IMAGE: dist-x86_64-netbsd
         DEPLOY: 1
 
-      asmjs:
-        IMAGE: asmjs
       i686-gnu:
         IMAGE: i686-gnu
       i686-gnu-nopt:

src/librustc_resolve/resolve_imports.rs

@@ -972,8 +972,9 @@ impl<'a, 'b> ImportResolver<'a, 'b> {
                 if !is_prelude &&
                    max_vis.get() != ty::Visibility::Invisible && // Allow empty globs.
                    !max_vis.get().is_at_least(directive.vis.get(), &*self) {
-                    let msg = "A non-empty glob must import something with the glob's visibility";
-                    self.r.session.span_err(directive.span, msg);
+                    let msg =
+                    "glob import doesn't reexport anything because no candidate is public enough";
+                    self.r.session.buffer_lint(UNUSED_IMPORTS, directive.id, directive.span, msg);
                 }
                 return None;
             }

src/librustc_save_analysis/dump_visitor.rs

@@ -300,7 +300,16 @@ impl<'l, 'tcx> DumpVisitor<'l, 'tcx> {
             }
 
             if let ast::FunctionRetTy::Ty(ref ret_ty) = sig.decl.output {
-                v.visit_ty(ret_ty);
+                // In async functions, return types are desugared and redefined
+                // as an `impl Trait` existential type. Because of this, to match
+                // the definition paths when resolving nested types we need to
+                // start walking from the newly-created definition.
+                match sig.header.asyncness.node {
+                    ast::IsAsync::Async { return_impl_trait_id, .. } => {
+                        v.nest_tables(return_impl_trait_id, |v| v.visit_ty(ret_ty))
+                    }
+                    _ => v.visit_ty(ret_ty)
+                }
             }
 
             // walk the fn body
@@ -369,6 +378,7 @@ impl<'l, 'tcx> DumpVisitor<'l, 'tcx> {
         &mut self,
         item: &'l ast::Item,
         decl: &'l ast::FnDecl,
+        header: &'l ast::FnHeader,
         ty_params: &'l ast::Generics,
         body: &'l ast::Block,
     ) {
@@ -391,7 +401,16 @@ impl<'l, 'tcx> DumpVisitor<'l, 'tcx> {
                     // FIXME: Opaque type desugaring prevents us from easily
                     // processing trait bounds. See `visit_ty` for more details.
                 } else {
-                    v.visit_ty(&ret_ty);
+                    // In async functions, return types are desugared and redefined
+                    // as an `impl Trait` existential type. Because of this, to match
+                    // the definition paths when resolving nested types we need to
+                    // start walking from the newly-created definition.
+                    match header.asyncness.node {
+                        ast::IsAsync::Async { return_impl_trait_id, .. } => {
+                            v.nest_tables(return_impl_trait_id, |v| v.visit_ty(ret_ty))
+                        }
+                        _ => v.visit_ty(ret_ty)
+                    }
                 }
             }
 
@@ -1315,8 +1334,8 @@ impl<'l, 'tcx> Visitor<'l> for DumpVisitor<'l, 'tcx> {
                     );
                 }
             }
-            Fn(ref decl, .., ref ty_params, ref body) => {
-                self.process_fn(item, &decl, ty_params, &body)
+            Fn(ref decl, ref header, ref ty_params, ref body) => {
+                self.process_fn(item, &decl, &header, ty_params, &body)
             }
             Static(ref typ, _, ref expr) => self.process_static_or_const_item(item, typ, expr),
             Const(ref typ, ref expr) => self.process_static_or_const_item(item, &typ, &expr),

src/test/ui/imports/reexports.rs

@@ -1,16 +1,21 @@
+#![warn(unused_imports)]
+
 mod a {
     fn foo() {}
     mod foo {}
 
     mod a {
         pub use super::foo; //~ ERROR cannot be re-exported
-        pub use super::*; //~ ERROR must import something with the glob's visibility
+        pub use super::*;
+        //~^ WARNING glob import doesn't reexport anything because no candidate is public enough
     }
 }
 
 mod b {
     pub fn foo() {}
-    mod foo { pub struct S; }
+    mod foo {
+        pub struct S;
+    }
 
     pub mod a {
         pub use super::foo; // This is OK since the value `foo` is visible enough.

src/test/ui/imports/reexports.stderr

@@ -1,34 +1,40 @@
 error[E0364]: `foo` is private, and cannot be re-exported
-  --> $DIR/reexports.rs:6:17
+  --> $DIR/reexports.rs:8:17
    |
 LL |         pub use super::foo;
    |                 ^^^^^^^^^^
    |
 note: consider marking `foo` as `pub` in the imported module
-  --> $DIR/reexports.rs:6:17
+  --> $DIR/reexports.rs:8:17
    |
 LL |         pub use super::foo;
    |                 ^^^^^^^^^^
 
-error: A non-empty glob must import something with the glob's visibility
-  --> $DIR/reexports.rs:7:17
-   |
-LL |         pub use super::*;
-   |                 ^^^^^^^^
-
 error[E0603]: module `foo` is private
-  --> $DIR/reexports.rs:28:15
+  --> $DIR/reexports.rs:33:15
    |
 LL |     use b::a::foo::S;
    |               ^^^
 
 error[E0603]: module `foo` is private
-  --> $DIR/reexports.rs:29:15
+  --> $DIR/reexports.rs:34:15
    |
 LL |     use b::b::foo::S as T;
    |               ^^^
 
-error: aborting due to 4 previous errors
+warning: glob import doesn't reexport anything because no candidate is public enough
+  --> $DIR/reexports.rs:9:17
+   |
+LL |         pub use super::*;
+   |                 ^^^^^^^^
+   |
+note: lint level defined here
+  --> $DIR/reexports.rs:1:9
+   |
+LL | #![warn(unused_imports)]
+   |         ^^^^^^^^^^^^^^
+
+error: aborting due to 3 previous errors
 
 Some errors have detailed explanations: E0364, E0603.
 For more information about an error, try `rustc --explain E0364`.

src/test/ui/save-analysis/issue-65590.rs

@@ -0,0 +1,21 @@
+// check-pass
+// compile-flags: -Zsave-analysis
+// edition:2018
+
+// Async desugaring for return types in (associated) functions introduces a
+// separate definition internally, which we need to take into account
+// (or else we ICE).
+trait Trait { type Assoc; }
+struct Struct;
+
+async fn foobar<T: Trait>() -> T::Assoc {
+    unimplemented!()
+}
+
+impl Struct {
+    async fn foo<T: Trait>(&self) -> T::Assoc {
+        unimplemented!()
+    }
+}
+
+fn main() {}