1.63.0 #

• Released on: 11 August, 2022
• Branched from master on: 24 June, 2022

Language #

• Remove migrate borrowck mode for pre-NLL errors.
• Modify MIR building to drop repeat expressions with length zero.
• Remove label/lifetime shadowing warnings.
• Allow explicit generic arguments in the presence of impl Trait args.
• Make cenum_impl_drop_cast warnings deny-by-default.
• Prevent unwinding when -C panic=abort is used regardless of declared ABI.
• lub: don’t bail out due to empty binders.

Compiler #

• Stabilize the bundle native library modifier, also removing the deprecated static-nobundle linking kind.
• Add Apple WatchOS compile targets*.
• Add a Windows application manifest to rustc-main.

* Refer to Rust’s [platform support page][platform-support-doc] for more information on Rust’s tiered platform support.

Libraries #

• Implement Copy, Clone, PartialEq and Eq for core::fmt::Alignment.
• Extend ptr::null and null_mut to all thin (including extern) types.
• impl Read and Write for VecDeque<u8>.
• STD support for the Nintendo 3DS.
• Use rounding in float to Duration conversion methods.
• Make write/print macros eagerly drop temporaries.
• Implement internal traits that enable [OsStr]::join.
• Implement Hash for core::alloc::Layout.
• Add capacity documentation for OsString.
• Put a bound on collection misbehavior.
• Make std::mem::needs_drop accept ?Sized.
• impl Termination for Infallible and then make the Result impls of Termination more generic.
• Document Rust’s stance on /proc/self/mem.

Stabilized APIs #

• array::from_fn
• Box::into_pin
• BinaryHeap::try_reserve
• BinaryHeap::try_reserve_exact
• OsString::try_reserve
• OsString::try_reserve_exact
• PathBuf::try_reserve
• PathBuf::try_reserve_exact
• Path::try_exists
• Ref::filter_map
• RefMut::filter_map
• NonNull::<[T]>::len
• ToOwned::clone_into
• Ipv6Addr::to_ipv4_mapped
• unix::io::AsFd
• unix::io::BorrowedFd<'fd>
• unix::io::OwnedFd
• windows::io::AsHandle
• windows::io::BorrowedHandle<'handle>
• windows::io::OwnedHandle
• windows::io::HandleOrInvalid
• windows::io::HandleOrNull
• windows::io::InvalidHandleError
• windows::io::NullHandleError
• windows::io::AsSocket
• windows::io::BorrowedSocket<'handle>
• windows::io::OwnedSocket
• thread::scope
• thread::Scope
• thread::ScopedJoinHandle

These APIs are now usable in const contexts:

• array::from_ref
• slice::from_ref
• intrinsics::copy
• intrinsics::copy_nonoverlapping
• <*const T>::copy_to
• <*const T>::copy_to_nonoverlapping
• <*mut T>::copy_to
• <*mut T>::copy_to_nonoverlapping
• <*mut T>::copy_from
• <*mut T>::copy_from_nonoverlapping
• str::from_utf8
• Utf8Error::error_len
• Utf8Error::valid_up_to
• Condvar::new
• Mutex::new
• RwLock::new

Cargo #

• Stabilize the --config path command-line argument.
• Expose rust-version in the environment as CARGO_PKG_RUST_VERSION.

Compatibility Notes #

• #[link] attributes are now checked more strictly, which may introduce errors for invalid attribute arguments that were previously ignored.
• Rounding is now used when converting a float to a Duration. The converted duration can differ slightly from what it was.

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.

• Prepare Rust for LLVM opaque pointers.