Rust 1.45.0

Language

--------

- [Out of range float to int conversions using as has been defined as a saturating

conversion.][71269] This was previously undefined behaviour, but you can use the

{f64, f32}::to_int_unchecked methods to continue using the current behaviour, which

may be desirable in rare performance sensitive situations.

- [mem::Discriminant now uses T's discriminant type instead of always

using u64.][70705]

- [Function like procedural macros can now be used in expression, pattern, and statement

positions.][68717] This means you can now use a function-like procedural macro

anywhere you can use a declarative (macro_rules!) macro.

Compiler

--------

- [You can now override individual target features through the target-feature

flag.][72094] E.g. -C target-feature=+avx2 -C target-feature=+fma is now

equivalent to -C target-feature=+avx2,+fma.

- [Added the force-unwind-tables flag.][69984] This option allows

rustc to always generate unwind tables regardless of panic strategy.

- [Added the embed-bitcode flag.][71716] This codegen flag allows rustc

to include LLVM bitcode into generated rlibs (this is on by default).

- [Added the tiny value to the code-model codegen flag.][72397]

- [Added tier 3 support\* for the mipsel-sony-psp target.][72062]

- [Added tier 3 support for the thumbv7a-uwp-windows-msvc target.][72133]

- [Upgraded to LLVM 10.][67759]

\* Refer to Rust's [platform support page][platform-support-doc] for more

information on Rust's tiered platform support.

Libraries

---------

- [net::{SocketAddr, SocketAddrV4, SocketAddrV6} now implements PartialOrd

and Ord.][72239]

- [proc_macro::TokenStream now implements Default.][72234]

- [You can now use char with

ops::{Range, RangeFrom, RangeFull, RangeInclusive, RangeTo} to iterate over

a range of codepoints.][72413] E.g.

you can now write the following;

  for ch in 'a'..='z' {
print!("{}", ch);
}
println!();
// Prints "abcdefghijklmnopqrstuvwxyz"

- [OsString now implements FromStr.][71662]

- [The saturating_neg method has been added to all signed integer primitive

types, and the saturating_abs method has been added for all integer

primitive types.][71886]

- [Arc, Rc now implement From>, and Box now

implements From when T is [T: Copy], str, CStr, OsStr,

or Path.][71447]

- [Box<[T]> now implements From<[T; N]>.][71095]

- [BitOr and BitOrAssign are implemented for all NonZero

integer types.][69813]

- [The fetch_min, and fetch_max methods have been added to all atomic

integer types.][72324]

- [The fetch_update method has been added to all atomic integer types.][71843]

Stabilized APIs

---------------

- [Arc::as_ptr]

- [BTreeMap::remove_entry]

- [Rc::as_ptr]

- [rc::Weak::as_ptr]

- [rc::Weak::from_raw]

- [rc::Weak::into_raw]

- [str::strip_prefix]

- [str::strip_suffix]

- [sync::Weak::as_ptr]

- [sync::Weak::from_raw]

- [sync::Weak::into_raw]

- [char::UNICODE_VERSION]

- [Span::resolved_at]

- [Span::located_at]

- [Span::mixed_site]

- [unix::process::CommandExt::arg0]

Cargo

-----

- [Cargo uses the embed-bitcode flag to optimize disk usage and build

time.][cargo/8066]

Misc

----

- [Rustdoc now supports strikethrough text in Markdown.][71928] E.g.

~~outdated information~~ becomes "~~outdated information~~".

- [Added an emoji to Rustdoc's deprecated API message.][72014]

Compatibility Notes

-------------------

- [Trying to self initialize a static value (that is creating a value using

itself) is unsound and now causes a compile error.][71140]

- [{f32, f64}::powi now returns a slightly different value on Windows.][73420]

This is due to changes in LLVM's intrinsics which {f32, f64}::powi uses.

- [Rustdoc's CLI's extra error exit codes have been removed.][71900] These were

previously undocumented and not intended for public use. Rustdoc still provides

a non-zero exit code on errors.

- [Rustc's lto flag is incompatible with the new embed-bitcode=no.][71848]

This may cause issues if LTO is enabled through RUSTFLAGS or cargo rustc

flags while cargo is adding embed-bitcode itself. The recommended way to

control LTO is with Cargo profiles, either in Cargo.toml or .cargo/config,

or by setting CARGO_PROFILE__LTO in the environment.

Internals Only

--------------

- [Make clippy a git subtree instead of a git submodule][70655]

- [Unify the undo log of all snapshot types][69464]

[71848]: https://github.com/rust-lang/rust/issues/71848/

[73420]: https://github.com/rust-lang/rust/issues/73420/

[72324]: https://github.com/rust-lang/rust/pull/72324/

[71843]: https://github.com/rust-lang/rust/pull/71843/

[71886]: https://github.com/rust-lang/rust/pull/71886/

[72234]: https://github.com/rust-lang/rust/pull/72234/

[72239]: https://github.com/rust-lang/rust/pull/72239/

[72397]: https://github.com/rust-lang/rust/pull/72397/

[72413]: https://github.com/rust-lang/rust/pull/72413/

[72014]: https://github.com/rust-lang/rust/pull/72014/

[72062]: https://github.com/rust-lang/rust/pull/72062/

[72094]: https://github.com/rust-lang/rust/pull/72094/

[72133]: https://github.com/rust-lang/rust/pull/72133/

[67759]: https://github.com/rust-lang/rust/pull/67759/

[71900]: https://github.com/rust-lang/rust/pull/71900/

[71928]: https://github.com/rust-lang/rust/pull/71928/

[71662]: https://github.com/rust-lang/rust/pull/71662/

[71716]: https://github.com/rust-lang/rust/pull/71716/

[71447]: https://github.com/rust-lang/rust/pull/71447/

[71269]: https://github.com/rust-lang/rust/pull/71269/

[71095]: https://github.com/rust-lang/rust/pull/71095/

[71140]: https://github.com/rust-lang/rust/pull/71140/

[70655]: https://github.com/rust-lang/rust/pull/70655/

[70705]: https://github.com/rust-lang/rust/pull/70705/

[69984]: https://github.com/rust-lang/rust/pull/69984/

[69813]: https://github.com/rust-lang/rust/pull/69813/

[69464]: https://github.com/rust-lang/rust/pull/69464/

[68717]: https://github.com/rust-lang/rust/pull/68717/

[cargo/8066]: https://github.com/rust-lang/cargo/pull/8066

[Arc::as_ptr]: https://doc.rust-lang.org/stable/std/sync/struct.Arc.html#method.as_ptr

[BTreeMap::remove_entry]: https://doc.rust-lang.org/stable/std/collections/struct.BTreeMap.html#method.remove_entry

[Rc::as_ptr]: https://doc.rust-lang.org/stable/std/rc/struct.Rc.html#method.as_ptr

[rc::Weak::as_ptr]: https://doc.rust-lang.org/stable/std/rc/struct.Weak.html#method.as_ptr

[rc::Weak::from_raw]: https://doc.rust-lang.org/stable/std/rc/struct.Weak.html#method.from_raw

[rc::Weak::into_raw]: https://doc.rust-lang.org/stable/std/rc/struct.Weak.html#method.into_raw

[sync::Weak::as_ptr]: https://doc.rust-lang.org/stable/std/sync/struct.Weak.html#method.as_ptr

[sync::Weak::from_raw]: https://doc.rust-lang.org/stable/std/sync/struct.Weak.html#method.from_raw

[sync::Weak::into_raw]: https://doc.rust-lang.org/stable/std/sync/struct.Weak.html#method.into_raw

[str::strip_prefix]: https://doc.rust-lang.org/stable/std/primitive.str.html#method.strip_prefix

[str::strip_suffix]: https://doc.rust-lang.org/stable/std/primitive.str.html#method.strip_suffix

[char::UNICODE_VERSION]: https://doc.rust-lang.org/stable/std/char/constant.UNICODE_VERSION.html

[Span::resolved_at]: https://doc.rust-lang.org/stable/proc_macro/struct.Span.html#method.resolved_at

[Span::located_at]: https://doc.rust-lang.org/stable/proc_macro/struct.Span.html#method.located_at

[Span::mixed_site]: https://doc.rust-lang.org/stable/proc_macro/struct.Span.html#method.mixed_site

[unix::process::CommandExt::arg0]: https://doc.rust-lang.org/std/os/unix/process/trait.CommandExt.html#tymethod.arg0