Announcing Rust 1.74.0

posts/2023-11-16-Rust-1.74.0.md

@@ -0,0 +1,156 @@
+---
+layout: post
+title: "Announcing Rust 1.74.0"
+author: The Rust Release Team
+release: true
+---
+
+The Rust team is happy to announce a new version of Rust, 1.74.0. Rust is a programming language empowering everyone to build reliable and efficient software.
+
+If you have a previous version of Rust installed via rustup, you can get 1.74.0 with:
+
+```console
+rustup update stable
+```
+
+If you don't have it already, you can [get `rustup`](https://www.rust-lang.org/install.html) from the appropriate page on our website, and check out the [detailed release notes for 1.74.0](https://github.com/rust-lang/rust/releases/tag/1.74.0) on GitHub.
+
+If you'd like to help us out by testing future releases, you might consider updating locally to use the beta channel (`rustup default beta`) or the nightly channel (`rustup default nightly`). Please [report](https://github.com/rust-lang/rust/issues/new/choose) any bugs you might come across!
+
+## What's in 1.74.0 stable
+
+### Lint configuration through Cargo
+
+As proposed in [RFC 3389](https://rust-lang.github.io/rfcs/3389-manifest-lint.html),
+the `Cargo.toml` manifest now supports a `[lints]` table to configure the
+reporting level (forbid, deny, warn, allow) for lints from the compiler and
+other tools. So rather than setting `RUSTFLAGS` with `-F`/`-D`/`-W`/`-A`, which
+would affect the entire build, or using crate-level attributes like:
+
+```rust
+#![forbid(unsafe_code)]
+#![deny(clippy::enum_glob_use)]
+```
+
+You can now write those in your package manifest for Cargo to handle:
+
+```toml
+[lints.rust]
+unsafe_code = "forbid"
+
+[lints.clippy]
+enum_glob_use = "deny"
+```
+
+These can also be configured in a `[workspace.lints]` table, then inherited by
+`[lints] workspace = true` like many other workspace settings. Cargo will also
+track changes to these settings when deciding which crates need to be rebuilt.
+
+For more information, see the [`lints`] and [`workspace.lints`] sections of the
+Cargo reference manual.
+
+[`lints`]: https://doc.rust-lang.org/stable/cargo/reference/manifest.html#the-lints-section
+[`workspace.lints`]: https://doc.rust-lang.org/stable/cargo/reference/workspaces.html#the-lints-table
+
+### Cargo Registry Authentication
+
+Two more related Cargo features are included in this release: credential
+providers and authenticated private registries.
+
+Credential providers allow configuration of how Cargo gets credentials for a
+registry. Built-in providers are included for OS-specific secure secret storage
+on Linux, macOS, and Windows. Additionally, custom providers can be written to
+support arbitrary methods of storing or generating tokens. Using a secure
+credential provider reduces risk of registry tokens leaking.
+
+Registries can now optionally require authentication for all operations, not
+just publishing. This enables private Cargo registries to offer more secure
+hosting of crates. Use of private registries requires the configuration of a
+credential provider.
+
+For further information, see the
+[Cargo docs](https://doc.rust-lang.org/beta/cargo/reference/registry-authentication.html).
+
+### Projections in opaque return types
+
+If you have ever received the error that a "return type cannot contain a
+projection or `Self` that references lifetimes from a parent scope," you may
+now rest easy! The compiler now allows mentioning `Self` and
+associated types in opaque return types, like `async fn` and `-> impl Trait`.
+This is the kind of feature that gets Rust closer to how you might just
+_expect_ it to work, even if you have no idea about jargon like "projection".
+
+This functionality had an unstable feature gate because its implementation
+originally didn't properly deal with captured lifetimes, and once that was
+fixed it was given time to make sure it was sound. For more technical details,
+see the [stabilization pull request][115659], which describes the following
+examples that are all now allowed:
+
+```rust
+struct Wrapper<'a, T>(&'a T);
+
+// Opaque return types that mention `Self`:
+impl Wrapper<'_, ()> {
+    async fn async_fn() -> Self { /* ... */ }
+    fn impl_trait() -> impl Iterator<Item = Self> { /* ... */ }
+}
+
+trait Trait<'a> {
+    type Assoc;
+    fn new() -> Self::Assoc;
+}
+impl Trait<'_> for () {
+    type Assoc = ();
+    fn new() {}
+}
+
+// Opaque return types that mention an associated type:
+impl<'a, T: Trait<'a>> Wrapper<'a, T> {
+    async fn mk_assoc() -> T::Assoc { /* ... */ }
+    fn a_few_assocs() -> impl Iterator<Item = T::Assoc> { /* ... */ }
+}
+```
+
+[115659]: https://github.com/rust-lang/rust/pull/115659
+
+### Stabilized APIs
+
+- [`core::num::Saturating`](https://doc.rust-lang.org/stable/std/num/struct.Saturating.html)
+- [`impl From<io::Stdout> for std::process::Stdio`](https://doc.rust-lang.org/stable/std/process/struct.Stdio.html#impl-From%3CStdout%3E-for-Stdio)
+- [`impl From<io::Stderr> for std::process::Stdio`](https://doc.rust-lang.org/stable/std/process/struct.Stdio.html#impl-From%3CStderr%3E-for-Stdio)
+- [`impl From<OwnedHandle> for std::process::Child{Stdin, Stdout, Stderr}`](https://doc.rust-lang.org/stable/std/process/struct.Stdio.html#impl-From%3CStderr%3E-for-Stdio)
+- [`impl From<OwnedFd> for std::process::Child{Stdin, Stdout, Stderr}`](https://doc.rust-lang.org/stable/std/process/struct.Stdio.html#impl-From%3CStderr%3E-for-Stdio)
+- [`std::ffi::OsString::from_encoded_bytes_unchecked`](https://doc.rust-lang.org/stable/std/ffi/struct.OsString.html#method.from_encoded_bytes_unchecked)
+- [`std::ffi::OsString::into_encoded_bytes`](https://doc.rust-lang.org/stable/std/ffi/struct.OsString.html#method.into_encoded_bytes)
+- [`std::ffi::OsStr::from_encoded_bytes_unchecked`](https://doc.rust-lang.org/stable/std/ffi/struct.OsStr.html#method.from_encoded_bytes_unchecked)
+- [`std::ffi::OsStr::as_encoded_bytes`](https://doc.rust-lang.org/stable/std/ffi/struct.OsStr.html#method.as_encoded_bytes)
+- [`std::io::Error::other`](https://doc.rust-lang.org/stable/std/io/struct.Error.html#method.other)
+- [`impl TryFrom<char> for u16`](https://doc.rust-lang.org/stable/std/primitive.u16.html#impl-TryFrom%3Cchar%3E-for-u16)
+- [`impl<T: Clone, const N: usize> From<&[T; N]> for Vec<T>`](https://doc.rust-lang.org/stable/std/vec/struct.Vec.html#impl-From%3C%26%5BT;+N%5D%3E-for-Vec%3CT,+Global%3E)
+- [`impl<T: Clone, const N: usize> From<&mut [T; N]> for Vec<T>`](https://doc.rust-lang.org/stable/std/vec/struct.Vec.html#impl-From%3C%26mut+%5BT;+N%5D%3E-for-Vec%3CT,+Global%3E)
+- [`impl<T, const N: usize> From<[T; N]> for Arc<[T]>`](https://doc.rust-lang.org/stable/std/sync/struct.Arc.html#impl-From%3C%5BT;+N%5D%3E-for-Arc%3C%5BT%5D,+Global%3E)
+- [`impl<T, const N: usize> From<[T; N]> for Rc<[T]>`](https://doc.rust-lang.org/stable/std/rc/struct.Rc.html#impl-From%3C%5BT;+N%5D%3E-for-Rc%3C%5BT%5D,+Global%3E)
+
+These APIs are now stable in const contexts:
+
+- [`core::mem::transmute_copy`](https://doc.rust-lang.org/stable/std/mem/fn.transmute_copy.html)
+- [`str::is_ascii`](https://doc.rust-lang.org/stable/std/primitive.str.html#method.is_ascii)
+- [`[u8]::is_ascii`](https://doc.rust-lang.org/stable/std/primitive.slice.html#method.is_ascii)
+
+### Compatibility notes
+
+* As [previously announced][apple-min], Rust 1.74 has increased its
+  requirements on Apple platforms. The minimum versions are now:
+    - macOS: 10.12 Sierra (First released 2016)
+    - iOS: 10 (First released 2016)
+    - tvOS: 10 (First released 2016)
+
+[apple-min]: https://blog.rust-lang.org/2023/09/25/Increasing-Apple-Version-Requirements.html
+
+### Other changes
+
+Check out everything that changed in [Rust](https://github.com/rust-lang/rust/releases/tag/1.74.0), [Cargo](https://github.com/rust-lang/cargo/blob/master/CHANGELOG.md#cargo-174-2023-11-16), and [Clippy](https://github.com/rust-lang/rust-clippy/blob/master/CHANGELOG.md#rust-174).
+
+## Contributors to 1.74.0
+
+Many people came together to create Rust 1.74.0. We couldn't have done it without all of you. [Thanks!](https://thanks.rust-lang.org/rust/1.74.0/)