Rust versions / 1.66
Rust release · Dec 15, 2022
Rust 1.66: what's new, what was stabilized
Short answerRust 1.66 was released on Dec 15, 2022: 1 language stabilization (Stabilize sym operands in inline assembly); 12 newly stable APIs (proc_macro::Span::source_text, uX::{checked_add_signed, overflowing_add_signed, saturating_add_signed, wrapping_add_signed}, iX::{checked_add_unsigned, overflowing_add_unsigned, saturating_add_unsigned, wrapping_add_unsigned}, iX::{checked_sub_unsigned, overflowing_sub_unsigned, saturating_sub_unsigned, wrapping_sub_unsigned}, ...); 9 compatibility notes that can affect existing code. Point release: 1.66.1 (Jan 10, 2023).
← Rust 1.65All versionsRust 1.67 →
Language features stabilized
- Stabilize sym operands in inline assembly
12 APIs stabilized
proc_macro::Span::source_text, uX::{checked_add_signed, overflowing_add_signed, saturating_add_signed, wrapping_add_signed}, iX::{checked_add_unsigned, overflowing_add_unsigned, saturating_add_unsigned, wrapping_add_unsigned}, iX::{checked_sub_unsigned, overflowing_sub_unsigned, saturating_sub_unsigned, wrapping_sub_unsigned}, BTreeSet::{first, last, pop_first, pop_last}, BTreeMap::{first_key_value, last_key_value, first_entry, last_entry, pop_first, pop_last}, AsFd, impl TryFrom<Vec<T>> for Box<[T; N]>, core::hint::black_box, Duration::try_from_secs_{f32,f64}, Option::unzip, std::os::fd
Can it break my build?
The release lists these compatibility notes. Most only affect rare code, but read them before you raise your toolchain in CI:
- Only apply
ProceduralMasqueradehack to older versions ofrental - Don't export
__heap_baseand__data_endon wasm32-wasi. - Don't export
__wasm_init_memoryon WebAssembly. - Only export
__tls_*on wasm32-unknown-unknown. - Don't link to
libresolvin libstd on Darwin - Update libstd's libc to 0.2.135 (to make
libstdno longer pull inlibiconv.dylibon Darwin) - Opaque types no longer imply lifetime bounds
- Make
order_dependent_trait_objectsshow up in future-breakage reports - Change std::process::Command spawning to default to inheriting the parent's signal mask
Use it
rustup update stable # get the newest release
rustup install 1.66 # or exactly this one
rustup override set 1.66 # pin a project to itTo require at least this version from users of your crate, set rust-version = "1.66" under [package] in Cargo.toml. Cargo then refuses to build it on older compilers with a clear message, and with resolver 3 (the default on the 2024 edition, Rust 1.85+) it also prefers dependency versions that support it.
Full release notes
Language
- Permit specifying explicit discriminants on all
repr(Int)enums ``rust #[repr(u8)] enum Foo { A(u8) = 0, B(i8) = 1, C(bool) = 42, }`` - Allow transmutes between the same type differing only in lifetimes
- Change constant evaluation errors from a deny-by-default lint to a hard error
- Trigger
must_useonimpl Traitfor supertraits This makesimpl ExactSizeIteratorrespect the existing#[must_use]annotation onIterator. - Allow
..=Xin patterns - Uplift
clippy::for_loops_over_fallibleslint into rustc - Stabilize
symoperands in inline assembly - Update to Unicode 15
- Opaque types no longer imply lifetime bounds This is a soundness fix which may break code that was erroneously relying on this behavior.
Compiler
- Add armv5te-none-eabi and thumbv5te-none-eabi tier 3 targets
- Refer to Rust's [platform support page][platform-support-doc] for more information on Rust's tiered platform support.
- Add support for linking against macOS universal libraries
Libraries
- [Fix
#[derive(Default)]on a generic#[default]enum adding unnecessaryDefaultbounds](https://github.com/rust-lang/rust/pull/101040/) - Update to Unicode 15
Stabilized APIs
proc_macro::Span::source_textuX::{checked_add_signed, overflowing_add_signed, saturating_add_signed, wrapping_add_signed}iX::{checked_add_unsigned, overflowing_add_unsigned, saturating_add_unsigned, wrapping_add_unsigned}iX::{checked_sub_unsigned, overflowing_sub_unsigned, saturating_sub_unsigned, wrapping_sub_unsigned}BTreeSet::{first, last, pop_first, pop_last}BTreeMap::{first_key_value, last_key_value, first_entry, last_entry, pop_first, pop_last}- Add
AsFdimplementations for stdio lock types on WASI. - [
impl TryFrom<Vec<T>> for Box<[T; N]>](https://doc.rust-lang.org/stable/std/boxed/struct.Box.html#impl-TryFrom%3CVec%3CT%2C%20Global%3E%3E-for-Box%3C%5BT%3B%20N%5D%2C%20Global%3E) core::hint::black_boxDuration::try_from_secs_{f32,f64}Option::unzipstd::os::fd
Rustdoc
Cargo
- Added
cargo removeto remove dependencies from Cargo.toml cargo publishnow waits for the new version to be downloadable before exiting
See detailed release notes for more.
Compatibility Notes
- Only apply
ProceduralMasqueradehack to older versions ofrental - Don't export
__heap_baseand__data_endon wasm32-wasi. - Don't export
__wasm_init_memoryon WebAssembly. - Only export
__tls_*on wasm32-unknown-unknown. - Don't link to
libresolvin libstd on Darwin - Update libstd's libc to 0.2.135 (to make
libstdno longer pull inlibiconv.dylibon Darwin) - Opaque types no longer imply lifetime bounds This is a soundness fix which may break code that was erroneously relying on this behavior.
- Make
order_dependent_trait_objectsshow up in future-breakage reports - Change std::process::Command spawning to default to inheriting the parent's signal mask
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.
1.66.1 (Jan 10, 2023)
- Added validation of SSH host keys for git URLs in Cargo (CVE-2022-46176)
Release notes from the Rust project's RELEASES.md (MIT or Apache-2.0); summaries above are ours.
Up next
Next releaseRust 1.67Released Jan 26, 2023.Read it next →Also worth your time
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