Auto merge of #75722 - Mark-Simulacrum:beta-next, r=Mark-Simulacrum

[beta] backports

* Fix regionck failure when converting Index to IndexMut #74960
* Update RELEASES.md for 1.46.0 #74744
* allow escaping bound vars when normalizing `ty::Opaque` #75443

r? @ghost

Author: bors

RELEASES.md

@@ -1,3 +1,128 @@
+Version 1.46.0 (2020-08-27)
+==========================
+
+Language
+--------
+- [`if`, `match`, and `loop` expressions can now be used in const functions.][72437]
+- [Additionally you are now also able to coerce and cast to slices (`&[T]`) in
+  const functions.][73862]
+- [The `#[track_caller]` attribute can now be added to functions to use the
+  function's caller's location information for panic messages.][72445]
+- [Recursively indexing into tuples no longer needs parentheses.][71322] E.g.
+  `x.0.0` over `(x.0).0`.
+- [`mem::transmute` can now be used in static and constants.][72920] **Note**
+  You currently can't use `mem::transmute` in constant functions.
+
+Compiler
+--------
+- [You can now use the `cdylib` target on Apple iOS and tvOS platforms.][73516]
+- [Enabled static "Position Independent Executables" by default
+  for `x86_64-unknown-linux-musl`.][70740]
+
+Libraries
+---------
+- [`mem::forget` is now a `const fn`.][73887]
+- [`String` now implements `From<char>`.][73466]
+- [The `leading_ones`, and `trailing_ones` methods have been stabilised for all
+  integer types.][73032]
+- [`vec::IntoIter<T>` now implements `AsRef<[T]>`.][72583]
+- [All non-zero integer types (`NonZeroU8`) now implement `TryFrom` for their
+  zero-able equivalent (e.g. `TryFrom<u8>`).][72717]
+- [`&[T]` and `&mut [T]` now implement `PartialEq<Vec<T>>`.][71660]
+- [`(String, u16)` now implements `ToSocketAddrs`.][73007]
+- [`vec::Drain<'_, T>` now implements `AsRef<[T]>`.][72584]
+
+Stabilized APIs
+---------------
+- [`Option::zip`]
+- [`vec::Drain::as_slice`]
+
+Cargo
+-----
+Added a number of new environment variables that are now available when
+compiling your crate.
+
+- [`CARGO_BIN_NAME` and `CARGO_CRATE_NAME`][cargo/8270] Providing the name of
+  the specific binary being compiled and the name of the crate.
+- [`CARGO_PKG_LICENSE`][cargo/8325] The license from the manifest of the package.
+- [`CARGO_PKG_LICENSE_FILE`][cargo/8387] The path to the license file.
+
+Compatibility Notes
+-------------------
+- [The target configuration option `abi_blacklist` has been renamed
+  to `unsupported_abis`.][74150] The old name will still continue to work.
+- [Rustc will now warn if you have a C-like enum that implements `Drop`.][72331]
+  This was previously accepted but will become a hard error in a future release.
+- [Rustc will fail to compile if you have a struct with
+  `#[repr(i128)]` or `#[repr(u128)]`.][74109] This representation is currently only
+  allowed on `enum`s.
+- [Tokens passed to `macro_rules!` are now always captured.][73293] This helps
+  ensure that spans have the correct information, and may cause breakage if you
+  were relying on receiving spans with dummy information.
+- [The InnoSetup installer for Windows is no longer available.][72569] This was
+  a legacy installer that was replaced by a MSI installer a few years ago but
+  was still being built.
+- [`{f32, f64}::asinh` now returns the correct values for negative numbers.][72486]
+- [Rustc will no longer accept overlapping trait implementations that only
+  differ in how the lifetime was bound.][72493]
+- [Rustc now correctly relates the lifetime of an existential associated
+  type.][71896] This fixes some edge cases where `rustc` would erroneously allow
+  you to pass a shorter lifetime than expected.
+
+[74109]: https://github.com/rust-lang/rust/pull/74109/
+[74150]: https://github.com/rust-lang/rust/pull/74150/
+[73862]: https://github.com/rust-lang/rust/pull/73862/
+[73887]: https://github.com/rust-lang/rust/pull/73887/
+[73466]: https://github.com/rust-lang/rust/pull/73466/
+[73516]: https://github.com/rust-lang/rust/pull/73516/
+[73293]: https://github.com/rust-lang/rust/pull/73293/
+[73007]: https://github.com/rust-lang/rust/pull/73007/
+[73032]: https://github.com/rust-lang/rust/pull/73032/
+[72920]: https://github.com/rust-lang/rust/pull/72920/
+[72569]: https://github.com/rust-lang/rust/pull/72569/
+[72583]: https://github.com/rust-lang/rust/pull/72583/
+[72584]: https://github.com/rust-lang/rust/pull/72584/
+[72717]: https://github.com/rust-lang/rust/pull/72717/
+[72437]: https://github.com/rust-lang/rust/pull/72437/
+[72445]: https://github.com/rust-lang/rust/pull/72445/
+[72486]: https://github.com/rust-lang/rust/pull/72486/
+[72493]: https://github.com/rust-lang/rust/pull/72493/
+[72331]: https://github.com/rust-lang/rust/pull/72331/
+[71896]: https://github.com/rust-lang/rust/pull/71896/
+[71660]: https://github.com/rust-lang/rust/pull/71660/
+[71322]: https://github.com/rust-lang/rust/pull/71322/
+[70740]: https://github.com/rust-lang/rust/pull/70740/
+[cargo/8270]: https://github.com/rust-lang/cargo/pull/8270/
+[cargo/8325]: https://github.com/rust-lang/cargo/pull/8325/
+[cargo/8387]: https://github.com/rust-lang/cargo/pull/8387/
+[`Option::zip`]: https://doc.rust-lang.org/stable/std/option/enum.Option.html#method.zip
+[`vec::Drain::as_slice`]: https://doc.rust-lang.org/stable/std/vec/struct.Drain.html#method.as_slice
+
+
+Version 1.45.2 (2020-08-03)
+==========================
+
+* [Fix bindings in tuple struct patterns][74954]
+* [Fix track_caller integration with trait objects][74784]
+
+[74954]: https://github.com/rust-lang/rust/issues/74954
+[74784]: https://github.com/rust-lang/rust/issues/74784
+
+
+Version 1.45.1 (2020-07-30)
+==========================
+
+* [Fix const propagation with references.][73613]
+* [rustfmt accepts rustfmt_skip in cfg_attr again.][73078]
+* [Avoid spurious implicit region bound.][74509]
+* [Install clippy on x.py install][74457]
+
+[73613]: https://github.com/rust-lang/rust/pull/73613
+[73078]: https://github.com/rust-lang/rust/issues/73078
+[74509]: https://github.com/rust-lang/rust/pull/74509
+[74457]: https://github.com/rust-lang/rust/pull/74457
+
+
 Version 1.45.0 (2020-07-16)
 ==========================
 
@@ -47,7 +172,7 @@ Libraries
   // Prints "abcdefghijklmnopqrstuvwxyz"
   ```
 - [`OsString` now implements `FromStr`.][71662]
-- [The `saturating_neg` method as been added to all signed integer primitive
+- [The `saturating_neg` method has been added to all signed integer primitive
   types, and the `saturating_abs` method has been added for all integer
   primitive types.][71886]
 - [`Arc<T>`, `Rc<T>` now implement  `From<Cow<'_, T>>`, and `Box` now
@@ -82,6 +207,9 @@ Stabilized APIs
 Cargo
 -----
 
+- [Cargo uses the `embed-bitcode` flag to optimize disk usage and build
+  time.][cargo/8066]
+
 Misc
 ----
 - [Rustdoc now supports strikethrough text in Markdown.][71928] E.g.
@@ -97,12 +225,18 @@ Compatibility Notes
 - [Rustdoc's CLI's extra error exit codes have been removed.][71900] These were
   previously undocumented and not intended for public use. Rustdoc still provides
   a non-zero exit code on errors.
+- [Rustc's `lto` flag is incompatible with the new `embed-bitcode=no`.][71848]
+  This may cause issues if LTO is enabled through `RUSTFLAGS` or `cargo rustc`
+  flags while cargo is adding `embed-bitcode` itself. The recommended way to
+  control LTO is with Cargo profiles, either in `Cargo.toml` or `.cargo/config`,
+  or by setting `CARGO_PROFILE_<name>_LTO` in the environment.
 
 Internals Only
 --------------
 - [Make clippy a git subtree instead of a git submodule][70655]
 - [Unify the undo log of all snapshot types][69464]
 
+[71848]: https://github.com/rust-lang/rust/issues/71848/
 [73420]: https://github.com/rust-lang/rust/issues/73420/
 [72324]: https://github.com/rust-lang/rust/pull/72324/
 [71843]: https://github.com/rust-lang/rust/pull/71843/
@@ -129,6 +263,7 @@ Internals Only
 [69813]: https://github.com/rust-lang/rust/pull/69813/
 [69464]: https://github.com/rust-lang/rust/pull/69464/
 [68717]: https://github.com/rust-lang/rust/pull/68717/
+[cargo/8066]: https://github.com/rust-lang/cargo/pull/8066
 [`Arc::as_ptr`]: https://doc.rust-lang.org/stable/std/sync/struct.Arc.html#method.as_ptr
 [`BTreeMap::remove_entry`]: https://doc.rust-lang.org/stable/std/collections/struct.BTreeMap.html#method.remove_entry
 [`Rc::as_ptr`]: https://doc.rust-lang.org/stable/std/rc/struct.Rc.html#method.as_ptr

src/ci/docker/host-x86_64/dist-various-2/build-x86_64-fortanix-unknown-sgx-toolchain.sh

@@ -7,7 +7,7 @@ target="x86_64-fortanix-unknown-sgx"
 
 install_prereq() {
     curl https://apt.llvm.org/llvm-snapshot.gpg.key|apt-key add -
-    add-apt-repository -y 'deb http://apt.llvm.org/bionic/ llvm-toolchain-bionic main'
+    add-apt-repository -y 'deb http://apt.llvm.org/bionic/ llvm-toolchain-bionic-11 main'
     apt-get update
     apt-get install -y --no-install-recommends \
             build-essential \

src/librustc_trait_selection/traits/auto_trait.rs

@@ -729,7 +729,7 @@ impl AutoTraitFinder<'tcx> {
                     // and turn them into an explicit negative impl for our type.
                     debug!("Projecting and unifying projection predicate {:?}", predicate);
 
-                    match poly_project_and_unify_type(select, &obligation.with(p)) {
+                    match project::poly_project_and_unify_type(select, &obligation.with(p)) {
                         Err(e) => {
                             debug!(
                                 "evaluate_nested_obligations: Unable to unify predicate \
@@ -738,7 +738,11 @@ impl AutoTraitFinder<'tcx> {
                             );
                             return false;
                         }
-                        Ok(Some(v)) => {
+                        Ok(Err(project::InProgress)) => {
+                            debug!("evaluate_nested_obligations: recursive projection predicate");
+                            return false;
+                        }
+                        Ok(Ok(Some(v))) => {
                             // We only care about sub-obligations
                             // when we started out trying to unify
                             // some inference variables. See the comment above
@@ -757,8 +761,8 @@ impl AutoTraitFinder<'tcx> {
                                 }
                             }
                         }
-                        Ok(None) => {
-                            // It's ok not to make progress when hvave no inference variables -
+                        Ok(Ok(None)) => {
+                            // It's ok not to make progress when have no inference variables -
                             // in that case, we were only performing unifcation to check if an
                             // error occurred (which would indicate that it's impossible for our
                             // type to implement the auto trait).

src/librustc_trait_selection/traits/fulfill.rs

@@ -426,14 +426,20 @@ impl<'a, 'b, 'tcx> ObligationProcessor for FulfillProcessor<'a, 'b, 'tcx> {
 
             ty::PredicateKind::Projection(ref data) => {
                 let project_obligation = obligation.with(*data);
+                let tcx = self.selcx.tcx();
                 match project::poly_project_and_unify_type(self.selcx, &project_obligation) {
-                    Ok(None) => {
-                        let tcx = self.selcx.tcx();
-                        pending_obligation.stalled_on =
-                            trait_ref_infer_vars(self.selcx, data.to_poly_trait_ref(tcx));
+                    Ok(Ok(Some(os))) => ProcessResult::Changed(mk_pending(os)),
+                    Ok(Ok(None)) => {
+                        pending_obligation.stalled_on = trait_ref_infer_vars(
+                            self.selcx,
+                            project_obligation.predicate.to_poly_trait_ref(tcx),
+                        );
                         ProcessResult::Unchanged
                     }
-                    Ok(Some(os)) => ProcessResult::Changed(mk_pending(os)),
+                    // Let the caller handle the recursion
+                    Ok(Err(project::InProgress)) => ProcessResult::Changed(mk_pending(vec![
+                        pending_obligation.obligation.clone(),
+                    ])),
                     Err(e) => ProcessResult::Error(CodeProjectionError(e)),
                 }
             }

src/librustc_trait_selection/traits/mod.rs

@@ -51,9 +51,7 @@ pub use self::object_safety::is_vtable_safe_method;
 pub use self::object_safety::MethodViolationCode;
 pub use self::object_safety::ObjectSafetyViolation;
 pub use self::on_unimplemented::{OnUnimplementedDirective, OnUnimplementedNote};
-pub use self::project::{
-    normalize, normalize_projection_type, normalize_to, poly_project_and_unify_type,
-};
+pub use self::project::{normalize, normalize_projection_type, normalize_to};
 pub use self::select::{EvaluationCache, SelectionCache, SelectionContext};
 pub use self::select::{EvaluationResult, IntercrateAmbiguityCause, OverflowError};
 pub use self::specialize::specialization_graph::FutureCompatOverlapError;