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

Rust 1.65.0

Language

• Error on as casts of enums with #[non_exhaustive] variants
• Stabilize let else
• Stabilize generic associated types (GATs)
• Add lints let_underscore_drop and let_underscore_lock from Clippy
• Stabilize breaking from arbitrary labeled blocks ("label-break-value")
• Uninitialized integers, floats, and raw pointers are now considered immediate UB. Usage of MaybeUninit is the correct way to work with uninitialized memory.
• Stabilize raw-dylib for Windows x86_64, aarch64, and thumbv7a
• Do not allow Drop impl on foreign ADTs

Compiler

• Stabilize -Csplit-debuginfo on Linux
• Use niche-filling optimization even when multiple variants have data
• Associated type projections are now verified to be well-formed prior to resolving the underlying type
• Stringify non-shorthand visibility correctly
• Normalize struct field types when unsizing
• Update to LLVM 15
• Fix aarch64 call abi to correctly zeroext when needed
• debuginfo: Generalize C++-like encoding for enums
• Add special_module_name lint
• Add support for generating unique profraw files by default when using -C instrument-coverage
• Allow dynamic linking for iOS/tvOS targets

New targets:

• Add armv4t-none-eabi as a tier 3 target
• Add powerpc64-unknown-openbsd and riscv64-unknown-openbsd as tier 3 targets
  • Refer to Rust's platform support page for more information on Rust's tiered platform support.

Libraries

• Don't generate PartialEq::ne in derive(PartialEq)
• Windows RNG: Use BCRYPT_RNG_ALG_HANDLE by default
• Forbid mixing System with direct system allocator calls
• Document no support for writing to non-blocking stdio/stderr
• std::layout::Layout size must not overflow isize::MAX when rounded up to align This also changes the safety conditions on Layout::from_size_align_unchecked.

Stabilized APIs

• std::backtrace::Backtrace
• Bound::as_ref
• std::io::read_to_string
• <*const T>::cast_mut
• <*mut T>::cast_const

These APIs are now stable in const contexts:

• <*const T>::offset_from
• <*mut T>::offset_from

Cargo

• Apply GitHub fast path even for partial hashes
• Do not add home bin path to PATH if it's already there
• Take priority into account within the pending queue. This slightly optimizes job scheduling by Cargo, with typically small improvements on larger crate graph builds.

Compatibility Notes

• std::layout::Layout size must not overflow isize::MAX when rounded up to align. This also changes the safety conditions on Layout::from_size_align_unchecked.
• PollFn now only implements Unpin if the closure is Unpin. This is a possible breaking change if users were relying on the blanket unpin implementation. See discussion on the PR for details of why this change was made.
• Drop ExactSizeIterator impl from std::char::EscapeAscii This is a backwards-incompatible change to the standard library's surface area, but is unlikely to affect real world usage.
• Do not consider a single repeated lifetime eligible for elision in the return type This behavior was unintentionally changed in 1.64.0, and this release reverts that change by making this an error again.
• Reenable disabled early syntax gates as future-incompatibility lints
• Update the minimum external LLVM to 13
• Don't duplicate file descriptors into stdio fds
• Sunset RLS
• Deny usage of #![cfg_attr(..., crate_type = ...)] to set the crate type This strengthens the forward compatibility lint deprecated_cfg_attr_crate_type_name to deny.
• llvm-has-rust-patches allows setting the build system to treat the LLVM as having Rust-specific patches This option may need to be set for distributions that are building Rust with a patched LLVM via llvm-config, not the built-in LLVM.
• Combining three or more languages (e.g. Objective C, C++ and Rust) into one binary may hit linker limitations when using lld. For more information, see issue 102754.

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.

• Add x.sh and x.ps1 shell scripts
• compiletest: use target cfg instead of hard-coded tables
• Use object instead of LLVM for reading bitcode from rlibs
• Enable MIR inlining for optimized compilations This provides a 3-10% improvement in compiletimes for real world crates. See perf results.