Auto merge of #108041 - Mark-Simulacrum:relnotes, r=Mark-Simulacrum

Add 1.68.0 release notes

r? `@cuviper`

RELEASES.md

@@ -1,3 +1,99 @@
+Version 1.68.0 (2023-03-09)
+==========================
+
+<a id="1.68.0-Language"></a>
+
+Language
+--------
+
+- [Stabilize default_alloc_error_handler](https://github.com/rust-lang/rust/pull/102318/)
+  This allows usage of `alloc` on stable without requiring the 
+  definition of a handler for allocation failure. Defining custom handlers is still unstable.
+- [Stabilize `efiapi` calling convention.](https://github.com/rust-lang/rust/pull/105795/)
+- [Remove implicit promotion for types with drop glue](https://github.com/rust-lang/rust/pull/105085/)
+
+<a id="1.68.0-Compiler"></a>
+
+Compiler
+--------
+
+- [Change `bindings_with_variant_name` to deny-by-default](https://github.com/rust-lang/rust/pull/104154/)
+- [Allow .. to be parsed as let initializer](https://github.com/rust-lang/rust/pull/105701/)
+- [Add `armv7-sony-vita-newlibeabihf` as a tier 3 target](https://github.com/rust-lang/rust/pull/105712/)
+- [Always check alignment during compile-time const evaluation](https://github.com/rust-lang/rust/pull/104616/)
+- [Disable "split dwarf inlining" by default.](https://github.com/rust-lang/rust/pull/106709/)
+- [Add vendor to Fuchsia's target triple](https://github.com/rust-lang/rust/pull/106429/)
+- [Enable sanitizers for s390x-linux](https://github.com/rust-lang/rust/pull/107127/)
+
+<a id="1.68.0-Libraries"></a>
+
+Libraries
+---------
+
+- [Loosen the bound on the Debug implementation of Weak.](https://github.com/rust-lang/rust/pull/90291/)
+- [Make `std::task::Context` !Send and !Sync](https://github.com/rust-lang/rust/pull/95985/)
+- [PhantomData layout guarantees](https://github.com/rust-lang/rust/pull/104081/)
+- [Don't derive Debug for `OnceWith` & `RepeatWith`](https://github.com/rust-lang/rust/pull/104163/)
+- [Implement DerefMut for PathBuf](https://github.com/rust-lang/rust/pull/105018/)
+- [Add O(1) `Vec -> VecDeque` conversion guarantee](https://github.com/rust-lang/rust/pull/105128/)
+- [Leak amplification for peek_mut() to ensure BinaryHeap's invariant is always met](https://github.com/rust-lang/rust/pull/105851/)
+
+<a id="1.68.0-Stabilized-APIs"></a>
+
+Stabilized APIs
+---------------
+
+- [`{core,std}::pin::pin!`](https://doc.rust-lang.org/stable/std/pin/macro.pin.html)
+- [`impl From<bool> for {f32,f64}`](https://doc.rust-lang.org/stable/std/primitive.f32.html#impl-From%3Cbool%3E-for-f32)
+- [`std::path::MAIN_SEPARATOR_STR`](https://doc.rust-lang.org/stable/std/path/constant.MAIN_SEPARATOR_STR.html)
+- [`impl DerefMut for PathBuf`](https://doc.rust-lang.org/stable/std/path/struct.PathBuf.html#impl-DerefMut-for-PathBuf)
+
+These APIs are now stable in const contexts:
+
+- [`VecDeque::new`](https://doc.rust-lang.org/stable/std/collections/struct.VecDeque.html#method.new)
+
+<a id="1.68.0-Cargo"></a>
+
+Cargo
+-----
+
+- [Stabilize sparse registry support for crates.io](https://github.com/rust-lang/cargo/pull/11224/)
+- [`cargo build --verbose` tells you more about why it recompiles.](https://github.com/rust-lang/cargo/pull/11407/)
+- [Show progress of crates.io index update even `net.git-fetch-with-cli` option enabled](https://github.com/rust-lang/cargo/pull/11579/)
+
+<a id="1.68.0-Misc"></a>
+
+Misc
+----
+
+<a id="1.68.0-Compatibility-Notes"></a>
+
+Compatibility Notes
+-------------------
+
+- [Add `SEMICOLON_IN_EXPRESSIONS_FROM_MACROS` to future-incompat report](https://github.com/rust-lang/rust/pull/103418/)
+- [Only specify `--target` by default for `-Zgcc-ld=lld` on wasm](https://github.com/rust-lang/rust/pull/101792/)
+- [Bump `IMPLIED_BOUNDS_ENTAILMENT` to Deny + ReportNow](https://github.com/rust-lang/rust/pull/106465/)
+- [`std::task::Context` no longer implements Send and Sync](https://github.com/rust-lang/rust/pull/95985)
+
+<a id="1.68.0-Internal-Changes"></a>
+
+Internal Changes
+----------------
+
+These changes do not affect any public interfaces of Rust, but they represent
+significant improvements to the performance or internals of rustc and related
+tools.
+
+- [Encode spans relative to the enclosing item](https://github.com/rust-lang/rust/pull/84762/)
+- [Don't normalize in AstConv](https://github.com/rust-lang/rust/pull/101947/)
+- [Find the right lower bound region in the scenario of partial order relations](https://github.com/rust-lang/rust/pull/104765/)
+- [Fix impl block in const expr](https://github.com/rust-lang/rust/pull/104889/)
+- [Check ADT fields for copy implementations considering regions](https://github.com/rust-lang/rust/pull/105102/)
+- [rustdoc: simplify JS search routine by not messing with lev distance](https://github.com/rust-lang/rust/pull/105796/)
+- [Enable ThinLTO for rustc on `x86_64-pc-windows-msvc`](https://github.com/rust-lang/rust/pull/103591/)
+- [Enable ThinLTO for rustc on `x86_64-apple-darwin`](https://github.com/rust-lang/rust/pull/103647/)
+
 Version 1.67.1 (2023-02-09)
 ===========================