Rust release · Jan 17, 2019

Rust 1.32: what's new, what was stabilized

Short answerRust 1.32 was released on Jan 17, 2019: 72 newly stable APIs (i8::to_be_bytes, i8::to_le_bytes, i8::to_ne_bytes, i8::from_be_bytes, ...); 1 compatibility note that can affect existing code.

Jan 17, 2019release date

0language stabilizations

72APIs stabilized

-new edition

← Rust 1.31 All versions Rust 1.33 →

72 APIs stabilized

i8::to_be_bytes, i8::to_le_bytes, i8::to_ne_bytes, i8::from_be_bytes, i8::from_le_bytes, i8::from_ne_bytes, i16::to_be_bytes, i16::to_le_bytes, i16::to_ne_bytes, i16::from_be_bytes, i16::from_le_bytes, i16::from_ne_bytes, i32::to_be_bytes, i32::to_le_bytes, i32::to_ne_bytes, i32::from_be_bytes, i32::from_le_bytes, i32::from_ne_bytes, i64::to_be_bytes, i64::to_le_bytes, i64::to_ne_bytes, i64::from_be_bytes, i64::from_le_bytes, i64::from_ne_bytes, i128::to_be_bytes, i128::to_le_bytes, i128::to_ne_bytes, i128::from_be_bytes, i128::from_le_bytes, i128::from_ne_bytes, isize::to_be_bytes, isize::to_le_bytes, isize::to_ne_bytes, isize::from_be_bytes, isize::from_le_bytes, isize::from_ne_bytes, u8::to_be_bytes, u8::to_le_bytes, u8::to_ne_bytes, u8::from_be_bytes, u8::from_le_bytes, u8::from_ne_bytes, u16::to_be_bytes, u16::to_le_bytes, u16::to_ne_bytes, u16::from_be_bytes, u16::from_le_bytes, u16::from_ne_bytes, u32::to_be_bytes, u32::to_le_bytes, u32::to_ne_bytes, u32::from_be_bytes, u32::from_le_bytes, u32::from_ne_bytes, u64::to_be_bytes, u64::to_le_bytes, u64::to_ne_bytes, u64::from_be_bytes, u64::from_le_bytes, u64::from_ne_bytes, u128::to_be_bytes, u128::to_le_bytes, u128::to_ne_bytes, u128::from_be_bytes, u128::from_le_bytes, u128::from_ne_bytes, usize::to_be_bytes, usize::to_le_bytes, usize::to_ne_bytes, usize::from_be_bytes, usize::from_le_bytes, usize::from_ne_bytes

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:

[The argument types for AVX's

Use it

rustup update stable        # get the newest release
rustup install 1.32          # or exactly this one
rustup override set 1.32     # pin a project to it

To require at least this version from users of your crate, set rust-version = "1.32" 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

2018 edition

[You can now use the ? operator in macro definitions.][56245] The ? operator allows you to specify zero or one repetitions similar to the * and + operators.
[Module paths with no leading keyword like super, self, or crate, will now always resolve to the item (enum, struct, etc.) available in the module if present, before resolving to a external crate or an item the prelude.][56759] E.g. ```rust enum Color { Red, Green, Blue }

use Color::*; ```

All editions

[You can now match against PhantomData<T> types.][55837]
[You can now match against literals in macros with the literal specifier.][56072] This will match against a literal of any type. E.g. 1, 'A', "Hello World"
[Self can now be used as a constructor and pattern for unit and tuple structs.][56365] E.g. ```rust struct Point(i32, i32);

impl Point { pub fn new(x: i32, y: i32) -> Self { Self(x, y) }

pub fn is_origin(&self) -> bool { match self { Self(0, 0) => true, _ => false, } } } ```

[Self can also now be used in type definitions.][56366] E.g. ``rust enum List<T> where Self: PartialOrd<Self> // can write Self instead of List<T> { Nil, Cons(T, Box<Self>) // likewise here } ``
[You can now mark traits with #[must_use].][55663] This provides a warning if a impl Trait or dyn Trait is returned and unused in the program.

Compiler

[The default allocator has changed from jemalloc to the default allocator on your system.][55238] The compiler itself on Linux & macOS will still use jemalloc, but programs compiled with it will use the system allocator.
[Added the aarch64-pc-windows-msvc target.][55702]

Libraries

[PathBuf now implements FromStr.][55148]
[Box<[T]> now implements FromIterator<T>.][55843]
[The dbg! macro has been stabilized.][56395] This macro enables you to easily debug expressions in your rust program. E.g. ``rust let a = 2; let b = dbg!(a * 2) + 1; // ^-- prints: [src/main.rs:4] a * 2 = 4 assert_eq!(b, 5); ``

The following APIs are now const functions and can be used in a const context.

[Cell::as_ptr]
[UnsafeCell::get]
[char::is_ascii]
[iter::empty]
[ManuallyDrop::new]
[ManuallyDrop::into_inner]
[RangeInclusive::start]
[RangeInclusive::end]
[NonNull::as_ptr]
[slice::as_ptr]
[str::as_ptr]
[Duration::as_secs]
[Duration::subsec_millis]
[Duration::subsec_micros]
[Duration::subsec_nanos]
[CStr::as_ptr]
[Ipv4Addr::is_unspecified]
[Ipv6Addr::new]
[Ipv6Addr::octets]

Stabilized APIs

[i8::to_be_bytes]
[i8::to_le_bytes]
[i8::to_ne_bytes]
[i8::from_be_bytes]
[i8::from_le_bytes]
[i8::from_ne_bytes]
[i16::to_be_bytes]
[i16::to_le_bytes]
[i16::to_ne_bytes]
[i16::from_be_bytes]
[i16::from_le_bytes]
[i16::from_ne_bytes]
[i32::to_be_bytes]
[i32::to_le_bytes]
[i32::to_ne_bytes]
[i32::from_be_bytes]
[i32::from_le_bytes]
[i32::from_ne_bytes]
[i64::to_be_bytes]
[i64::to_le_bytes]
[i64::to_ne_bytes]
[i64::from_be_bytes]
[i64::from_le_bytes]
[i64::from_ne_bytes]
[i128::to_be_bytes]
[i128::to_le_bytes]
[i128::to_ne_bytes]
[i128::from_be_bytes]
[i128::from_le_bytes]
[i128::from_ne_bytes]
[isize::to_be_bytes]
[isize::to_le_bytes]
[isize::to_ne_bytes]
[isize::from_be_bytes]
[isize::from_le_bytes]
[isize::from_ne_bytes]
[u8::to_be_bytes]
[u8::to_le_bytes]
[u8::to_ne_bytes]
[u8::from_be_bytes]
[u8::from_le_bytes]
[u8::from_ne_bytes]
[u16::to_be_bytes]
[u16::to_le_bytes]
[u16::to_ne_bytes]
[u16::from_be_bytes]
[u16::from_le_bytes]
[u16::from_ne_bytes]
[u32::to_be_bytes]
[u32::to_le_bytes]
[u32::to_ne_bytes]
[u32::from_be_bytes]
[u32::from_le_bytes]
[u32::from_ne_bytes]
[u64::to_be_bytes]
[u64::to_le_bytes]
[u64::to_ne_bytes]
[u64::from_be_bytes]
[u64::from_le_bytes]
[u64::from_ne_bytes]
[u128::to_be_bytes]
[u128::to_le_bytes]
[u128::to_ne_bytes]
[u128::from_be_bytes]
[u128::from_le_bytes]
[u128::from_ne_bytes]
[usize::to_be_bytes]
[usize::to_le_bytes]
[usize::to_ne_bytes]
[usize::from_be_bytes]
[usize::from_le_bytes]
[usize::from_ne_bytes]

Cargo

[You can now run cargo c as an alias for cargo check.][cargo/6218]
[Usernames are now allowed in alt registry URLs.][cargo/6242]

Misc

[libproc_macro has been added to the rust-src distribution.][55280]

Compatibility Notes

The argument types for AVX's _mm256_stream_si256, _mm256_stream_pd, _mm256_stream_ps have been changed from *const to *mut as the previous implementation was unsound.

Release notes from the Rust project's RELEASES.md (MIT or Apache-2.0); summaries above are ours.