Fri Sep 23 00:08:21 UTC 2022 - William Brown <william.brown@suse.com>
Version 1.64.0 (2022-09-22)
===========================
Language
--------
- [Unions with mutable references or tuples of allowed types are now allowed](https://github.com/rust-lang/rust/pull/97995/)
- It is now considered valid to deallocate memory pointed to by a shared reference `&T` [if every byte in `T` is inside an `UnsafeCell`](https://github.com/rust-lang/rust/pull/98017/)
- Unused tuple struct fields are now warned against in an allow-by-default lint, [`unused_tuple_struct_fields`](https://github.com/rust-lang/rust/pull/95977/), similar to the existing warning for unused struct fields. This lint will become warn-by-default in the future.
Compiler
--------
- [Add Nintendo Switch as tier 3 target](https://github.com/rust-lang/rust/pull/88991/)
- Refer to Rust's [platform support page][platform-support-doc] for more
information on Rust's tiered platform support.
- [Only compile `#[used]` as llvm.compiler.used for ELF targets](https://github.com/rust-lang/rust/pull/93718/)
- [Add the `--diagnostic-width` compiler flag to define the terminal width.](https://github.com/rust-lang/rust/pull/95635/)
- [Add support for link-flavor `rust-lld` for iOS, tvOS and watchOS](https://github.com/rust-lang/rust/pull/98771/)
Libraries
---------
- [Remove restrictions on compare-exchange memory ordering.](https://github.com/rust-lang/rust/pull/98383/)
- You can now `write!` or `writeln!` into an `OsString`: [Implement `fmt::Write` for `OsString`](https://github.com/rust-lang/rust/pull/97915/)
- [Significantly improved the performance fetching git dependencies from GitHub
when using a hash in the `rev` field.](https://github.com/rust-lang/cargo/pull/10079)
Misc
----
- [The `rust-analyzer` rustup component is now available on the stable channel.](https://github.com/rust-lang/rust/pull/98640/)
Compatibility Notes
-------------------
- The minimum required versions for all `-linux-gnu` targets are now at least kernel 3.2 and glibc 2.17, for targets that previously supported older versions: [Increase the minimum linux-gnu versions](https://github.com/rust-lang/rust/pull/95026/)
- [Network primitives are now implemented with the ideal Rust layout, not the C system layout](https://github.com/rust-lang/rust/pull/78802/). This can cause problems when transmuting the types.
- [Add assertion that `transmute_copy`'s `U` is not larger than `T`](https://github.com/rust-lang/rust/pull/98839/)
- [A soundness bug in `BTreeMap` was fixed](https://github.com/rust-lang/rust/pull/99413/) that allowed data it was borrowing to be dropped before the container.
- [The Drop behavior of C-like enums cast to ints has changed](https://github.com/rust-lang/rust/pull/96862/). These are already discouraged by a compiler warning.
- [Relate late-bound closure lifetimes to parent fn in NLL](https://github.com/rust-lang/rust/pull/98835/)
- [Errors at const-eval time are now in future incompatibility reports](https://github.com/rust-lang/rust/pull/97743/)
- On the `thumbv6m-none-eabi` target, some incorrect `asm!` statements were erroneously accepted if they used the high registers (r8 to r14) as an input/output operand. [This is no longer accepted](https://github.com/rust-lang/rust/pull/99155/).
- [`impl Trait` was accidentally accepted as the associated type value of return-position `impl Trait`](https://github.com/rust-lang/rust/pull/97346/), without fulfilling all the trait bounds of that associated type, as long as the hidden type satisfies said bounds. This has been fixed.