1.57.0 #
- Released on: 2 December, 2021
- Branched from master on: 15 October, 2021
Language #
- Macro attributes may follow
#[derive]
and will see the original (pre-cfg
) input. - Accept curly-brace macros in expressions, like
m!{ .. }.method()
andm!{ .. }?
. - Allow panicking in constant evaluation.
- Ignore derived
Clone
andDebug
implementations during dead code analysis.
Compiler #
- Create more accurate debuginfo for vtables.
- Add
armv6k-nintendo-3ds
at Tier 3*. - Add
armv7-unknown-linux-uclibceabihf
at Tier 3*. - Add
m68k-unknown-linux-gnu
at Tier 3*. - Add SOLID targets at Tier 3*:
aarch64-kmc-solid_asp3
,armv7a-kmc-solid_asp3-eabi
,armv7a-kmc-solid_asp3-eabihf
* Refer to Rust’s [platform support page][platform-support-doc] for more information on Rust’s tiered platform support.
Libraries #
- Avoid allocations and copying in
Vec::leak
- Add
#[repr(i8)]
toOrdering
- Optimize
File::read_to_end
andread_to_string
- Update to Unicode 14.0
- Many more functions are marked
#[must_use]
, producing a warning when ignoring their return value. This helps catch mistakes such as expecting a function to mutate a value in place rather than return a new value.
Stabilised APIs #
[T; N]::as_mut_slice
[T; N]::as_slice
collections::TryReserveError
HashMap::try_reserve
HashSet::try_reserve
String::try_reserve
String::try_reserve_exact
Vec::try_reserve
Vec::try_reserve_exact
VecDeque::try_reserve
VecDeque::try_reserve_exact
Iterator::map_while
iter::MapWhile
proc_macro::is_available
Command::get_program
Command::get_args
Command::get_envs
Command::get_current_dir
CommandArgs
CommandEnvs
These APIs are now usable in const contexts:
- [
hint::unreachable_unchecked
]
Cargo #
Compatibility notes #
- Ignore derived
Clone
andDebug
implementations during dead code analysis. This will break some builds that set#![deny(dead_code)]
.
Internal changes #
These changes provide no direct user facing benefits, but represent significant improvements to the internals and overall performance of rustc and related tools.