Rust 1.70.0

Language

• Relax ordering rules for asm! operands
• Properly allow macro expanded format_args invocations to uses captures
• Lint ambiguous glob re-exports
• Perform const and unsafe checking for expressions in let _ = expr position.

Compiler

• Extend -Cdebuginfo with new options and named aliases This provides a smaller version of debuginfo for cases that only need line number information (-Cdebuginfo=line-tables-only), which may eventually become the default for -Cdebuginfo=1.
• Make unused_allocation lint against Box::new too
• Detect uninhabited types early in const eval
• Switch to LLD as default linker for {arm,thumb}v4t-none-eabi
• Add tier 3 target loongarch64-unknown-linux-gnu
• Add tier 3 target for i586-pc-nto-qnx700 (QNX Neutrino RTOS, version 7.0),
• Insert alignment checks for pointer dereferences as debug assertions This catches undefined behavior at runtime, and may cause existing code to fail.

Refer to Rust's platform support page for more information on Rust's tiered platform support.

Libraries

• Document NonZeroXxx layout guarantees
• Windows: make Command prefer non-verbatim paths
• Implement Default for some alloc/core iterators
• Fix handling of trailing bare CR in str::lines
• allow negative numeric literals in concat!
• Add documentation about the memory layout of Cell
• Use partial_cmp to implement tuple lt/le/ge/gt
• Stabilize atomic_as_ptr
• Stabilize nonnull_slice_from_raw_parts
• Partial stabilization of once_cell
• Stabilize nonzero_min_max
• Flatten/inline format_args!() and (string and int) literal arguments into format_args!()
• Stabilize movbe target feature
• don't splice from files into pipes in io::copy
• Add a builtin unstable FnPtr trait that is implemented for all function pointers This extends Debug, Pointer, Hash, PartialEq, Eq, PartialOrd, and Ord implementations for function pointers with all ABIs.

Stabilized APIs

• NonZero*::MIN/MAX
• BinaryHeap::retain
• Default for std::collections::binary_heap::IntoIter
• Default for std::collections::btree_map::{IntoIter, Iter, IterMut}
• Default for std::collections::btree_map::{IntoKeys, Keys}
• Default for std::collections::btree_map::{IntoValues, Values}
• Default for std::collections::btree_map::Range
• Default for std::collections::btree_set::{IntoIter, Iter}
• Default for std::collections::btree_set::Range
• Default for std::collections::linked_list::{IntoIter, Iter, IterMut}
• Default for std::vec::IntoIter
• Default for std::iter::Chain
• Default for std::iter::Cloned
• Default for std::iter::Copied
• Default for std::iter::Enumerate
• Default for std::iter::Flatten
• Default for std::iter::Fuse
• Default for std::iter::Rev
• Default for std::slice::Iter
• Default for std::slice::IterMut
• Rc::into_inner
• Arc::into_inner
• std::cell::OnceCell
• Option::is_some_and
• NonNull::slice_from_raw_parts
• Result::is_ok_and
• Result::is_err_and
• std::sync::atomic::Atomic*::as_ptr
• std::io::IsTerminal
• std::os::linux::net::SocketAddrExt
• std::os::unix::net::UnixDatagram::bind_addr
• std::os::unix::net::UnixDatagram::connect_addr
• std::os::unix::net::UnixDatagram::send_to_addr
• std::os::unix::net::UnixListener::bind_addr
• std::path::Path::as_mut_os_str
• std::sync::OnceLock

Cargo

• Add CARGO_PKG_README
• Make sparse the default protocol for crates.io
• Accurately show status when downgrading dependencies
• Use registry.default for login/logout
• Stabilize cargo logout

Misc

• Stabilize rustdoc --test-run-directory

Compatibility Notes

• Prevent stable libtest from supporting -Zunstable-options
• Perform const and unsafe checking for expressions in let _ = expr position.
• WebAssembly targets enable sign-ext and mutable-globals features in codegen This may cause incompatibility with older execution environments.
• Insert alignment checks for pointer dereferences as debug assertions This catches undefined behavior at runtime, and may cause existing code to fail.

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.

• Upgrade to LLVM 16
• Use SipHash-1-3 instead of SipHash-2-4 for StableHasher

Rust 1.69.0

Language

• Deriving built-in traits on packed structs works with Copy fields.
• Stabilize the cmpxchg16b target feature on x86 and x86_64.
• Improve analysis of trait bounds for associated types.
• Allow associated types to be used as union fields.
• Allow Self: Autotrait bounds on dyn-safe trait methods.
• Treat str as containing [u8] for auto trait purposes.

Compiler

• Upgrade *-pc-windows-gnu on CI to mingw-w64 v10 and GCC 12.2.
• Rework min_choice algorithm of member constraints.
• Support true and false as boolean flags in compiler arguments.
• Default repr(C) enums to c_int size.

Libraries

• Implement the unstable DispatchFromDyn for cell types, allowing downstream experimentation with custom method receivers.
• Document that fmt::Arguments::as_str() may return Some(_) in more cases after optimization, subject to change.
• Implement AsFd and AsRawFd for Rc.

Stabilized APIs

• CStr::from_bytes_until_nul
• core::ffi::FromBytesUntilNulError

These APIs are now stable in const contexts:

• SocketAddr::new
• SocketAddr::ip
• SocketAddr::port
• SocketAddr::is_ipv4
• SocketAddr::is_ipv6
• SocketAddrV4::new
• SocketAddrV4::ip
• SocketAddrV4::port
• SocketAddrV6::new
• SocketAddrV6::ip
• SocketAddrV6::port
• SocketAddrV6::flowinfo
• SocketAddrV6::scope_id

Cargo

• Cargo now suggests cargo fix or cargo clippy --fix when compilation warnings are auto-fixable.
• Cargo now suggests cargo add if you try to install a library crate.
• Cargo now sets the CARGO_BIN_NAME environment variable also for binary examples.

Rustdoc

• Vertically compact trait bound formatting.
• Only include stable lints in rustdoc::all group.
• Compute maximum Levenshtein distance based on the query.
• Remove inconsistently-present sidebar tooltips.
• Search by macro when query ends with !.

Compatibility Notes

• The rust-analysis component from rustup now only contains a warning placeholder. This was primarily intended for RLS, and the corresponding -Zsave-analysis flag has been removed from the compiler as well.
• Unaligned references to packed fields are now a hard error. This has been a warning since 1.53, and denied by default with a future-compatibility warning since 1.62.
• Update the minimum external LLVM to 14.
• Cargo now emits errors on invalid characters in a registry token.
• When default-features is set to false of a workspace dependency, and an inherited dependency of a member has default-features = true, Cargo will enable default features of that dependency.
• Cargo denies CARGO_HOME in the [env] configuration table. Cargo itself doesn't pick up this value, but recursive calls to cargo would, which was not intended.
• Debuginfo for build dependencies is now off if not explicitly set. This is expected to improve the overall build time.
• The Rust distribution no longer always includes rustdoc If tools = [...] is set in bootstrap.toml, we will respect a missing rustdoc in that list. By default rustdoc remains included. To retain the prior behavior explicitly add "rustdoc" to the list.

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.

• Move format_args!() into AST (and expand it during AST lowering)

Rust 1.68.2

• Update the GitHub RSA host key bundled within Cargo. The key was rotated by GitHub on 2023-03-24 after the old one leaked.
• Mark the old GitHub RSA host key as revoked. This will prevent Cargo from accepting the leaked key even when trusted by the system.
• Add support for @revoked and a better error message for @cert-authority in Cargo's SSH host key verification

Rust 1.68.1

• Fix miscompilation in produced Windows MSVC artifacts This was introduced by enabling ThinLTO for the distributed rustc which led to miscompilations in the resulting binary. Currently this is believed to be limited to the -Zdylib-lto flag used for rustc compilation, rather than a general bug in ThinLTO, so only rustc artifacts should be affected.
• Fix --enable-local-rust builds
• Treat $prefix-clang as clang in linker detection code
• Fix panic in compiler code

Rust 1.68.0

Language

• Stabilize default_alloc_error_handler This allows usage of alloc on stable without requiring the definition of a handler for allocation failure. Defining custom handlers is still unstable.
• Stabilize efiapi calling convention.
• Remove implicit promotion for types with drop glue

Compiler

• Change bindings_with_variant_name to deny-by-default
• Allow .. to be parsed as let initializer
• Add armv7-sony-vita-newlibeabihf as a tier 3 target
• Always check alignment during compile-time const evaluation
• Disable "split dwarf inlining" by default.
• Add vendor to Fuchsia's target triple
• Enable sanitizers for s390x-linux

Libraries

• Loosen the bound on the Debug implementation of Weak.
• Make std::task::Context !Send and !Sync
• PhantomData layout guarantees
• Don't derive Debug for OnceWith & RepeatWith
• Implement DerefMut for PathBuf
• Add O(1) Vec -> VecDeque conversion guarantee
• Leak amplification for peek_mut() to ensure BinaryHeap's invariant is always met

Stabilized APIs

• {core,std}::pin::pin!
• impl From<bool> for {f32,f64}
• std::path::MAIN_SEPARATOR_STR
• impl DerefMut for PathBuf

These APIs are now stable in const contexts:

• VecDeque::new

Cargo

• Stabilize sparse registry support for crates.io
• cargo build --verbose tells you more about why it recompiles.
• Show progress of crates.io index update even net.git-fetch-with-cli option enabled

Misc

Compatibility Notes

• Only support Android NDK 25 or newer
• Add SEMICOLON_IN_EXPRESSIONS_FROM_MACROS to future-incompat report
• Only specify --target by default for -Zgcc-ld=lld on wasm
• Bump IMPLIED_BOUNDS_ENTAILMENT to Deny + ReportNow
• std::task::Context no longer implements Send and Sync

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.

• Encode spans relative to the enclosing item
• Don't normalize in AstConv
• Find the right lower bound region in the scenario of partial order relations
• Fix impl block in const expr
• Check ADT fields for copy implementations considering regions
• rustdoc: simplify JS search routine by not messing with lev distance
• Enable ThinLTO for rustc on x86_64-pc-windows-msvc
• Enable ThinLTO for rustc on x86_64-apple-darwin

Rust 1.67.1

• Fix interoperability with thin archives.
• Fix an internal error in the compiler build process.
• Downgrade clippy::uninlined_format_args to pedantic.

Rust 1.67.0

Language

• Make Sized predicates coinductive, allowing cycles.
• #[must_use] annotations on async fn also affect the Future::Output.
• Elaborate supertrait obligations when deducing closure signatures.
• Invalid literals are no longer an error under cfg(FALSE).
• Unreserve braced enum variants in value namespace.

Compiler

• Enable varargs support for calling conventions other than C or cdecl.
• Add new MIR constant propagation based on dataflow analysis.
• Optimize field ordering by grouping m*2^n-sized fields with equivalently aligned ones.
• Stabilize native library modifier verbatim.

Added, updated, and removed targets:

• Add a tier 3 target for PowerPC on AIX, powerpc64-ibm-aix.
• Add a tier 3 target for the Sony PlayStation 1, mipsel-sony-psx.
• Add tier 3 no_std targets for the QNX Neutrino RTOS, aarch64-unknown-nto-qnx710 and x86_64-pc-nto-qnx710.
• Promote UEFI targets to tier 2, aarch64-unknown-uefi, i686-unknown-uefi, and x86_64-unknown-uefi.
• Remove tier 3 linuxkernel targets (not used by the actual kernel).

Refer to Rust's platform support page for more information on Rust's tiered platform support.

Libraries

• Merge crossbeam-channel into std::sync::mpsc.
• Fix inconsistent rounding of 0.5 when formatted to 0 decimal places.
• Derive Eq and Hash for ControlFlow.
• Don't build compiler_builtins with -C panic=abort.

Stabilized APIs

• {integer}::checked_ilog
• {integer}::checked_ilog2
• {integer}::checked_ilog10
• {integer}::ilog
• {integer}::ilog2
• {integer}::ilog10
• NonZeroU*::ilog2
• NonZeroU*::ilog10
• NonZero*::BITS

These APIs are now stable in const contexts:

• char::from_u32
• char::from_digit
• char::to_digit
• core::char::from_u32
• core::char::from_digit

Compatibility Notes

• The layout of repr(Rust) types now groups m*2^n-sized fields with equivalently aligned ones. This is intended to be an optimization, but it is also known to increase type sizes in a few cases for the placement of enum tags. As a reminder, the layout of repr(Rust) types is an implementation detail, subject to change.
• 0.5 now rounds to 0 when formatted to 0 decimal places. This makes it consistent with the rest of floating point formatting that rounds ties toward even digits.
• Chains of && and || will now drop temporaries from their sub-expressions in evaluation order, left-to-right. Previously, it was "twisted" such that the first expression dropped its temporaries last, after all of the other expressions dropped in order.
• Underscore suffixes on string literals are now a hard error. This has been a future-compatibility warning since 1.20.0.
• Stop passing -export-dynamic to wasm-ld.
• main is now mangled as __main_void on wasm32-wasi.
• Cargo now emits an error if there are multiple registries in the configuration with the same index URL.

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.

• Rewrite LLVM's archive writer in Rust.

Rust 1.66.1

• Added validation of SSH host keys for git URLs in Cargo (CVE-2022-46176)

Rust 1.66.1

• Added validation of SSH host keys for git URLs in Cargo (CVE-2022-46176)

Rust 1.66.0

Language

• Permit specifying explicit discriminants on all repr(Int) enums

  #[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_use on impl Trait for supertraits This makes impl ExactSizeIterator respect the existing #[must_use] annotation on Iterator.
• Allow ..=X in patterns
• Uplift clippy::for_loops_over_fallibles lint into rustc
• Stabilize sym operands 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 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 unnecessary Default bounds
• Update to Unicode 15

Stabilized 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}
• BTreeSet::{first, last, pop_first, pop_last}
• BTreeMap::{first_key_value, last_key_value, first_entry, last_entry, pop_first, pop_last}
• Add AsFd implementations for stdio lock types on WASI.
• impl TryFrom<Vec<T>> for Box<[T; N]>
• core::hint::black_box
• Duration::try_from_secs_{f32,f64}
• Option::unzip
• std::os::fd

Rustdoc

• Add Rustdoc warning for invalid HTML tags in the documentation

Cargo

• Added cargo remove to remove dependencies from Cargo.toml
• cargo publish now waits for the new version to be downloadable before exiting

See detailed release notes for more.

Compatibility Notes

• Only apply ProceduralMasquerade hack to older versions of rental
• Don't export __heap_base and __data_end on wasm32-wasi.
• Don't export __wasm_init_memory on WebAssembly.
• Only export __tls_* on wasm32-unknown-unknown.
• Don't link to libresolv in libstd on Darwin
• Update libstd's libc to 0.2.135 (to make libstd no longer pull in libiconv.dylib on 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_objects show 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.

• Enable BOLT for LLVM compilation
• Enable LTO for rustc_driver.so