allow unions with mutable references and tuples of allowed types #97995
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RalfJung
commented
Jun 11, 2022
| ) -> bool { | ||
| // We don't just accept all !needs_drop fields, due to semver concerns. | ||
| match ty.kind() { | ||
| ty::TyKind::Ref(..) => true, // references never drop (even mutable refs, which are non-Copy and hence fail the later check) |
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I noticed that is_trivially_pure_clone_copy is, for some reason, careful around references and raw pointers:
rust/compiler/rustc_middle/src/ty/sty.rs
Line 2340 in 90db033
Not sure if that should be a concern here.
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at least mutable references can't be cloned or copied, so it makes sense.
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Hm, the comment on that calls out custom metadata ("Thin pointers & thin shared references are pure-clone-copy, but for anything with custom metadata it might be more complicated."), which I think makes sense for Copy/Clone -- we might eventually support having metadata be !Copy, I guess. But here we really care about !Drop, not !Copy, and I can't ever see &T/&mut T/*const/*mut gaining any kind of drop impl, so I think we're OK here.
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That check is just an optimization though. It could be adjusted once we do have custom metadata.
We already guarantee on stable that all raw ptrs can be duplicated.
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we might eventually support having metadata be
!Copy, I guess
Not to my understanding, at least not for simply ?Sized (you would need even more opt-outs).
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Could we allow also to place unions inside unions? For example this code doesn't compile, because union U1 {
a: (),
}
union U2 {
b: U1,
} |
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unions can implement Drop like all other types, so there is no good reason to special-case them.
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Good point, and what about arrays? They are a special case of a tuple ( We could also allow slices, so that we don't print E0658 (!Copy types in unions are unstable), |
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Arrays are a bit tricky because of the size 0 case. So I figured I'd start with what is simple an obvious. |
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@rfcbot merge |
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Team member @joshtriplett has proposed to merge this. The next step is review by the rest of the tagged team members: No concerns currently listed. Once a majority of reviewers approve (and at most 2 approvals are outstanding), this will enter its final comment period. If you spot a major issue that hasn't been raised at any point in this process, please speak up! See this document for info about what commands tagged team members can give me. |
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Easy +1 on It's not clear to me that tuples are quite so obvious -- especially if zero-length arrays are non-obvious (#97995 (comment)) then wouldn't zero-length tuples also be non-obvious? |
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@rfcbot reviewed |
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Hey @RalfJung -- we were discussing in the @rust-lang/lang meeting today and we had a question. It seems like we could trivially permit |
My concern was that I am not sure whether |
I have now implemented this. |
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@rfcbot reviewed |
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🔔 This is now entering its final comment period, as per the review above. 🔔 |
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Some changes occurred in src/tools/clippy cc @rust-lang/clippy |
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@bors r=Mark-Simulacrum rollup=never |
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📌 Commit e43a0de62a6dbe0fab34b59baa0da0453dc29ac3 has been approved by It is now in the queue for this repository. |
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@bors r=Mark-Simulacrum |
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☀️ Test successful - checks-actions |
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Jul 14, 2022
Tested on commit rust-lang/rust@cbb07c2. Direct link to PR: <rust-lang/rust#97995> 💔 miri on windows: test-pass → test-fail (cc @RalfJung @oli-obk). 💔 miri on linux: test-pass → test-fail (cc @RalfJung @oli-obk).
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Finished benchmarking commit (cbb07c2): comparison url. Instruction countThis benchmark run did not return any relevant results for this metric. Max RSS (memory usage)Results
CyclesResults
If you disagree with this performance assessment, please file an issue in rust-lang/rustc-perf. @rustbot label: -perf-regression Footnotes |
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@RalfJung Would you mind posting a PR to the reference to update it for this change? IIUC, this expands the list of allowed fields to Copy, ManuallyDrop, &mut, and tuples containing any combination of those? I'm not sure if there is a term to succinctly refer to what those types are, but there are severally places that could use updating I think:
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yvt
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Aug 13, 2022
Unions with `impl Copy` and `ManuallyDrop` fields have been stabilized by [rust-lang/rust#77547][1] back in 2020, making enabling the feature already unnecessary for us. A few more field types have been added to the allowlist later by [rust-lang/rust#97995][2], which also removed the feature as there was no intent to stabilize more field types. [1]: rust-lang/rust#77547 [2]: rust-lang/rust#97995
wip-sync
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Oct 11, 2022
Pkgsrc changes: * Add patch to fix vendor/kqueue issue (on 32-bit hosts) * Adjust other patches & line numbers * Version bumps & checksum changes. Upstream changes: Version 1.64.0 (2022-09-22) =========================== Language -------- - [Unions with mutable references or tuples of allowed types are now allowed](rust-lang/rust#97995) - It is now considered valid to deallocate memory pointed to by a shared reference `&T` [if every byte in `T` is inside an `UnsafeCell`](rust-lang/rust#98017) - Unused tuple struct fields are now warned against in an allow-by-default lint, [`unused_tuple_struct_fields`] (rust-lang/rust#95977), similar to the existing warning for unused struct fields. This lint will become warn-by-default in the future. Compiler -------- - [Add Nintendo Switch as tier 3 target] (rust-lang/rust#88991) - Refer to Rust's [platform support page][platform-support-doc] for more information on Rust's tiered platform support. - [Only compile `#[used]` as llvm.compiler.used for ELF targets] (rust-lang/rust#93718) - [Add the `--diagnostic-width` compiler flag to define the terminal width.] (rust-lang/rust#95635) - [Add support for link-flavor `rust-lld` for iOS, tvOS and watchOS] (rust-lang/rust#98771) Libraries --------- - [Remove restrictions on compare-exchange memory ordering.] (rust-lang/rust#98383) - You can now `write!` or `writeln!` into an `OsString`: [Implement `fmt::Write` for `OsString`](rust-lang/rust#97915) - [Make RwLockReadGuard covariant] (rust-lang/rust#96820) - [Implement `FusedIterator` for `std::net::[Into]Incoming`] (rust-lang/rust#97300) - [`impl<T: AsRawFd> AsRawFd for {Arc,Box}<T>`] (rust-lang/rust#97437) - [`ptr::copy` and `ptr::swap` are doing untyped copies] (rust-lang/rust#97712) - [Add cgroupv1 support to `available_parallelism`] (rust-lang/rust#97925) - [Mitigate many incorrect uses of `mem::uninitialized`] (rust-lang/rust#99182) Stabilized APIs --------------- - [`future::IntoFuture`] (https://doc.rust-lang.org/stable/std/future/trait.IntoFuture.html) - [`future::poll_fn`] (https://doc.rust-lang.org/stable/std/future/fn.poll_fn.html) - [`task::ready!`] (https://doc.rust-lang.org/stable/std/task/macro.ready.html) - [`num::NonZero*::checked_mul`] (https://doc.rust-lang.org/stable/std/num/struct.NonZeroUsize.html#method.checked_mul) - [`num::NonZero*::checked_pow`] (https://doc.rust-lang.org/stable/std/num/struct.NonZeroUsize.html#method.checked_pow) - [`num::NonZero*::saturating_mul`] (https://doc.rust-lang.org/stable/std/num/struct.NonZeroUsize.html#method.saturating_mul) - [`num::NonZero*::saturating_pow`] (https://doc.rust-lang.org/stable/std/num/struct.NonZeroUsize.html#method.saturating_pow) - [`num::NonZeroI*::abs`] (https://doc.rust-lang.org/stable/std/num/struct.NonZeroIsize.html#method.abs) - [`num::NonZeroI*::checked_abs`] (https://doc.rust-lang.org/stable/std/num/struct.NonZeroIsize.html#method.checked_abs) - [`num::NonZeroI*::overflowing_abs`] (https://doc.rust-lang.org/stable/std/num/struct.NonZeroIsize.html#method.overflowing_abs) - [`num::NonZeroI*::saturating_abs`] (https://doc.rust-lang.org/stable/std/num/struct.NonZeroIsize.html#method.saturating_abs) - [`num::NonZeroI*::unsigned_abs`] (https://doc.rust-lang.org/stable/std/num/struct.NonZeroIsize.html#method.unsigned_abs) - [`num::NonZeroI*::wrapping_abs`] (https://doc.rust-lang.org/stable/std/num/struct.NonZeroIsize.html#method.wrapping_abs) - [`num::NonZeroU*::checked_add`] (https://doc.rust-lang.org/stable/std/num/struct.NonZeroUsize.html#method.checked_add) - [`num::NonZeroU*::checked_next_power_of_two`] (https://doc.rust-lang.org/stable/std/num/struct.NonZeroUsize.html#method.checked_next_power_of_two) - [`num::NonZeroU*::saturating_add`] (https://doc.rust-lang.org/stable/std/num/struct.NonZeroUsize.html#method.saturating_add) - [`os::unix::process::CommandExt::process_group`] (https://doc.rust-lang.org/stable/std/os/unix/process/trait.CommandExt.html#tymethod.process_group) - [`os::windows::fs::FileTypeExt::is_symlink_dir`] (https://doc.rust-lang.org/stable/std/os/windows/fs/trait.FileTypeExt.html#tymethod.is_symlink_dir) - [`os::windows::fs::FileTypeExt::is_symlink_file`] (https://doc.rust-lang.org/stable/std/os/windows/fs/trait.FileTypeExt.html#tymethod.is_symlink_file) These types were previously stable in `std::ffi`, but are now also available in `core` and `alloc`: - [`core::ffi::CStr`] (https://doc.rust-lang.org/stable/core/ffi/struct.CStr.html) - [`core::ffi::FromBytesWithNulError`] (https://doc.rust-lang.org/stable/core/ffi/struct.FromBytesWithNulError.html) - [`alloc::ffi::CString`] (https://doc.rust-lang.org/stable/alloc/ffi/struct.CString.html) - [`alloc::ffi::FromVecWithNulError`] (https://doc.rust-lang.org/stable/alloc/ffi/struct.FromVecWithNulError.html) - [`alloc::ffi::IntoStringError`] (https://doc.rust-lang.org/stable/alloc/ffi/struct.IntoStringError.html) - [`alloc::ffi::NulError`] (https://doc.rust-lang.org/stable/alloc/ffi/struct.NulError.html) These types were previously stable in `std::os::raw`, but are now also available in `core::ffi` and `std::ffi`: - [`ffi::c_char`] (https://doc.rust-lang.org/stable/std/ffi/type.c_char.html) - [`ffi::c_double`] (https://doc.rust-lang.org/stable/std/ffi/type.c_double.html) - [`ffi::c_float`] (https://doc.rust-lang.org/stable/std/ffi/type.c_float.html) - [`ffi::c_int`] (https://doc.rust-lang.org/stable/std/ffi/type.c_int.html) - [`ffi::c_long`] (https://doc.rust-lang.org/stable/std/ffi/type.c_long.html) - [`ffi::c_longlong`] (https://doc.rust-lang.org/stable/std/ffi/type.c_longlong.html) - [`ffi::c_schar`] (https://doc.rust-lang.org/stable/std/ffi/type.c_schar.html) - [`ffi::c_short`] (https://doc.rust-lang.org/stable/std/ffi/type.c_short.html) - [`ffi::c_uchar`] (https://doc.rust-lang.org/stable/std/ffi/type.c_uchar.html) - [`ffi::c_uint`] (https://doc.rust-lang.org/stable/std/ffi/type.c_uint.html) - [`ffi::c_ulong`] (https://doc.rust-lang.org/stable/std/ffi/type.c_ulong.html) - [`ffi::c_ulonglong`] (https://doc.rust-lang.org/stable/std/ffi/type.c_ulonglong.html) - [`ffi::c_ushort`] (https://doc.rust-lang.org/stable/std/ffi/type.c_ushort.html) These APIs are now usable in const contexts: - [`slice::from_raw_parts`] (https://doc.rust-lang.org/stable/core/slice/fn.from_raw_parts.html) Cargo ----- - [Packages can now inherit settings from the workspace so that the settings can be centralized in one place.] (rust-lang/cargo#10859) See [`workspace.package`](https://doc.rust-lang.org/nightly/cargo/reference/workspaces.html#the-workspacepackage-table) and [`workspace.dependencies`](https://doc.rust-lang.org/nightly/cargo/reference/workspaces.html#the-workspacedependencies-table) for more details on how to define these common settings. - [Cargo commands can now accept multiple `--target` flags to build for multiple targets at once] (rust-lang/cargo#10766), and the [`build.target`](https://doc.rust-lang.org/nightly/cargo/reference/config.html#buildtarget) config option may now take an array of multiple targets. - [The `--jobs` argument can now take a negative number to count backwards from the max CPUs.] (rust-lang/cargo#10844) - [`cargo add` will now update `Cargo.lock`.] (rust-lang/cargo#10902) - [Added](rust-lang/cargo#10838) the [`--crate-type`](https://doc.rust-lang.org/nightly/cargo/commands/cargo-rustc.html#option-cargo-rustc---crate-type) flag to `cargo rustc` to override the crate type. - [Significantly improved the performance fetching git dependencies from GitHub when using a hash in the `rev` field.] (rust-lang/cargo#10079) Misc ---- - [The `rust-analyzer` rustup component is now available on the stable channel.] (rust-lang/rust#98640) Compatibility Notes ------------------- - The minimum required versions for all `-linux-gnu` targets are now at least kernel 3.2 and glibc 2.17, for targets that previously supported older versions: [Increase the minimum linux-gnu versions](rust-lang/rust#95026) - [Network primitives are now implemented with the ideal Rust layout, not the C system layout] (rust-lang/rust#78802). This can cause problems when transmuting the types. - [Add assertion that `transmute_copy`'s `U` is not larger than `T`] (rust-lang/rust#98839) - [A soundness bug in `BTreeMap` was fixed] (rust-lang/rust#99413) that allowed data it was borrowing to be dropped before the container. - [The Drop behavior of C-like enums cast to ints has changed] (rust-lang/rust#96862). These are already discouraged by a compiler warning. - [Relate late-bound closure lifetimes to parent fn in NLL] (rust-lang/rust#98835) - [Errors at const-eval time are now in future incompatibility reports] (rust-lang/rust#97743) - On the `thumbv6m-none-eabi` target, some incorrect `asm!` statements were erroneously accepted if they used the high registers (r8 to r14) as an input/output operand. [This is no longer accepted] (rust-lang/rust#99155). - [`impl Trait` was accidentally accepted as the associated type value of return-position `impl Trait`] (rust-lang/rust#97346), without fulfilling all the trait bounds of that associated type, as long as the hidden type satisfies said bounds. This has been fixed. 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. - Windows builds now use profile-guided optimization, providing 10-20% improvements to compiler performance: [Utilize PGO for windows x64 rustc dist builds] (rust-lang/rust#96978) - [Stop keeping metadata in memory before writing it to disk] (rust-lang/rust#96544) - [compiletest: strip debuginfo by default for mode=ui] (rust-lang/rust#98140) - Many improvements to generated code for derives, including performance improvements: - [Don't use match-destructuring for derived ops on structs.] (rust-lang/rust#98446) - [Many small deriving cleanups] (rust-lang/rust#98741) - [More derive output improvements] (rust-lang/rust#98758) - [Clarify deriving code](rust-lang/rust#98915) - [Final derive output improvements] (rust-lang/rust#99046) - [Stop injecting `#[allow(unused_qualifications)]` in generated `derive` implementations](rust-lang/rust#99485) - [Improve `derive(Debug)`](rust-lang/rust#98190) - [Bump to clap 3](rust-lang/rust#98213) - [fully move dropck to mir](rust-lang/rust#98641) - [Optimize `Vec::insert` for the case where `index == len`.] (rust-lang/rust#98755) - [Convert rust-analyzer to an in-tree tool] (rust-lang/rust#99603)
netbsd-srcmastr
pushed a commit
to NetBSD/pkgsrc
that referenced
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Nov 16, 2022
Pkgsrc changes: * This package now contains rust-analyzer, so implicitly conflicts with that pkgsrc package. The same goes for the rust-src package. * Add NetBSD/arm6 port * Add unfinished NetBSD/mipsel port * Revert the use of the internal LLVM, should now build with the new pkgsrc LLVM (15). * Add depndence on compat80 for sparc64 to fix the build * Adapt patches * Add CHECK_INTERPRETER_SKIP for a few (mostly unused) files. (A proper fix may come later.) Upstream changes: Version 1.64.0 (2022-09-22) =========================== Language -------- - [Unions with mutable references or tuples of allowed types are now allowed](rust-lang/rust#97995) - It is now considered valid to deallocate memory pointed to by a shared reference `&T` [if every byte in `T` is inside an `UnsafeCell`](rust-lang/rust#98017) - Unused tuple struct fields are now warned against in an allow-by-default lint, [`unused_tuple_struct_fields`] (rust-lang/rust#95977), similar to the existing warning for unused struct fields. This lint will become warn-by-default in the future. Compiler -------- - [Add Nintendo Switch as tier 3 target] (rust-lang/rust#88991) - Refer to Rust's [platform support page][platform-support-doc] for more information on Rust's tiered platform support. - [Only compile `#[used]` as llvm.compiler.used for ELF targets] (rust-lang/rust#93718) - [Add the `--diagnostic-width` compiler flag to define the terminal width.] (rust-lang/rust#95635) - [Add support for link-flavor `rust-lld` for iOS, tvOS and watchOS] (rust-lang/rust#98771) Libraries --------- - [Remove restrictions on compare-exchange memory ordering.] (rust-lang/rust#98383) - You can now `write!` or `writeln!` into an `OsString`: [Implement `fmt::Write` for `OsString`](rust-lang/rust#97915) - [Make RwLockReadGuard covariant] (rust-lang/rust#96820) - [Implement `FusedIterator` for `std::net::[Into]Incoming`] (rust-lang/rust#97300) - [`impl<T: AsRawFd> AsRawFd for {Arc,Box}<T>`] (rust-lang/rust#97437) - [`ptr::copy` and `ptr::swap` are doing untyped copies] (rust-lang/rust#97712) - [Add cgroupv1 support to `available_parallelism`] (rust-lang/rust#97925) - [Mitigate many incorrect uses of `mem::uninitialized`] (rust-lang/rust#99182) Stabilized APIs --------------- - [`future::IntoFuture`] (https://doc.rust-lang.org/stable/std/future/trait.IntoFuture.html) - [`future::poll_fn`] (https://doc.rust-lang.org/stable/std/future/fn.poll_fn.html) - [`task::ready!`] (https://doc.rust-lang.org/stable/std/task/macro.ready.html) - [`num::NonZero*::checked_mul`] (https://doc.rust-lang.org/stable/std/num/struct.NonZeroUsize.html#method.checked_mul) - [`num::NonZero*::checked_pow`] (https://doc.rust-lang.org/stable/std/num/struct.NonZeroUsize.html#method.checked_pow) - [`num::NonZero*::saturating_mul`] (https://doc.rust-lang.org/stable/std/num/struct.NonZeroUsize.html#method.saturating_mul) - [`num::NonZero*::saturating_pow`] (https://doc.rust-lang.org/stable/std/num/struct.NonZeroUsize.html#method.saturating_pow) - [`num::NonZeroI*::abs`] (https://doc.rust-lang.org/stable/std/num/struct.NonZeroIsize.html#method.abs) - [`num::NonZeroI*::checked_abs`] (https://doc.rust-lang.org/stable/std/num/struct.NonZeroIsize.html#method.checked_abs) - [`num::NonZeroI*::overflowing_abs`] (https://doc.rust-lang.org/stable/std/num/struct.NonZeroIsize.html#method.overflowing_abs) - [`num::NonZeroI*::saturating_abs`] (https://doc.rust-lang.org/stable/std/num/struct.NonZeroIsize.html#method.saturating_abs) - [`num::NonZeroI*::unsigned_abs`] (https://doc.rust-lang.org/stable/std/num/struct.NonZeroIsize.html#method.unsigned_abs) - [`num::NonZeroI*::wrapping_abs`] (https://doc.rust-lang.org/stable/std/num/struct.NonZeroIsize.html#method.wrapping_abs) - [`num::NonZeroU*::checked_add`] (https://doc.rust-lang.org/stable/std/num/struct.NonZeroUsize.html#method.checked_add) - [`num::NonZeroU*::checked_next_power_of_two`] (https://doc.rust-lang.org/stable/std/num/struct.NonZeroUsize.html#method.checked_next_power_of_two) - [`num::NonZeroU*::saturating_add`] (https://doc.rust-lang.org/stable/std/num/struct.NonZeroUsize.html#method.saturating_add) - [`os::unix::process::CommandExt::process_group`] (https://doc.rust-lang.org/stable/std/os/unix/process/trait.CommandExt.html#tymethod.process_group) - [`os::windows::fs::FileTypeExt::is_symlink_dir`] (https://doc.rust-lang.org/stable/std/os/windows/fs/trait.FileTypeExt.html#tymethod.is_symlink_dir) - [`os::windows::fs::FileTypeExt::is_symlink_file`] (https://doc.rust-lang.org/stable/std/os/windows/fs/trait.FileTypeExt.html#tymethod.is_symlink_file) These types were previously stable in `std::ffi`, but are now also available in `core` and `alloc`: - [`core::ffi::CStr`] (https://doc.rust-lang.org/stable/core/ffi/struct.CStr.html) - [`core::ffi::FromBytesWithNulError`] (https://doc.rust-lang.org/stable/core/ffi/struct.FromBytesWithNulError.html) - [`alloc::ffi::CString`] (https://doc.rust-lang.org/stable/alloc/ffi/struct.CString.html) - [`alloc::ffi::FromVecWithNulError`] (https://doc.rust-lang.org/stable/alloc/ffi/struct.FromVecWithNulError.html) - [`alloc::ffi::IntoStringError`] (https://doc.rust-lang.org/stable/alloc/ffi/struct.IntoStringError.html) - [`alloc::ffi::NulError`] (https://doc.rust-lang.org/stable/alloc/ffi/struct.NulError.html) These types were previously stable in `std::os::raw`, but are now also available in `core::ffi` and `std::ffi`: - [`ffi::c_char`] (https://doc.rust-lang.org/stable/std/ffi/type.c_char.html) - [`ffi::c_double`] (https://doc.rust-lang.org/stable/std/ffi/type.c_double.html) - [`ffi::c_float`] (https://doc.rust-lang.org/stable/std/ffi/type.c_float.html) - [`ffi::c_int`] (https://doc.rust-lang.org/stable/std/ffi/type.c_int.html) - [`ffi::c_long`] (https://doc.rust-lang.org/stable/std/ffi/type.c_long.html) - [`ffi::c_longlong`] (https://doc.rust-lang.org/stable/std/ffi/type.c_longlong.html) - [`ffi::c_schar`] (https://doc.rust-lang.org/stable/std/ffi/type.c_schar.html) - [`ffi::c_short`] (https://doc.rust-lang.org/stable/std/ffi/type.c_short.html) - [`ffi::c_uchar`] (https://doc.rust-lang.org/stable/std/ffi/type.c_uchar.html) - [`ffi::c_uint`] (https://doc.rust-lang.org/stable/std/ffi/type.c_uint.html) - [`ffi::c_ulong`] (https://doc.rust-lang.org/stable/std/ffi/type.c_ulong.html) - [`ffi::c_ulonglong`] (https://doc.rust-lang.org/stable/std/ffi/type.c_ulonglong.html) - [`ffi::c_ushort`] (https://doc.rust-lang.org/stable/std/ffi/type.c_ushort.html) These APIs are now usable in const contexts: - [`slice::from_raw_parts`] (https://doc.rust-lang.org/stable/core/slice/fn.from_raw_parts.html) Cargo ----- - [Packages can now inherit settings from the workspace so that the settings can be centralized in one place.] (rust-lang/cargo#10859) See [`workspace.package`](https://doc.rust-lang.org/nightly/cargo/reference/workspaces.html#the-workspacepackage-table) and [`workspace.dependencies`](https://doc.rust-lang.org/nightly/cargo/reference/workspaces.html#the-workspacedependencies-table) for more details on how to define these common settings. - [Cargo commands can now accept multiple `--target` flags to build for multiple targets at once] (rust-lang/cargo#10766), and the [`build.target`](https://doc.rust-lang.org/nightly/cargo/reference/config.html#buildtarget) config option may now take an array of multiple targets. - [The `--jobs` argument can now take a negative number to count backwards from the max CPUs.] (rust-lang/cargo#10844) - [`cargo add` will now update `Cargo.lock`.] (rust-lang/cargo#10902) - [Added](rust-lang/cargo#10838) the [`--crate-type`](https://doc.rust-lang.org/nightly/cargo/commands/cargo-rustc.html#option-cargo-rustc---crate-type) flag to `cargo rustc` to override the crate type. - [Significantly improved the performance fetching git dependencies from GitHub when using a hash in the `rev` field.] (rust-lang/cargo#10079) Misc ---- - [The `rust-analyzer` rustup component is now available on the stable channel.] (rust-lang/rust#98640) Compatibility Notes ------------------- - The minimum required versions for all `-linux-gnu` targets are now at least kernel 3.2 and glibc 2.17, for targets that previously supported older versions: [Increase the minimum linux-gnu versions](rust-lang/rust#95026) - [Network primitives are now implemented with the ideal Rust layout, not the C system layout] (rust-lang/rust#78802). This can cause problems when transmuting the types. - [Add assertion that `transmute_copy`'s `U` is not larger than `T`] (rust-lang/rust#98839) - [A soundness bug in `BTreeMap` was fixed] (rust-lang/rust#99413) that allowed data it was borrowing to be dropped before the container. - [The Drop behavior of C-like enums cast to ints has changed] (rust-lang/rust#96862). These are already discouraged by a compiler warning. - [Relate late-bound closure lifetimes to parent fn in NLL] (rust-lang/rust#98835) - [Errors at const-eval time are now in future incompatibility reports] (rust-lang/rust#97743) - On the `thumbv6m-none-eabi` target, some incorrect `asm!` statements were erroneously accepted if they used the high registers (r8 to r14) as an input/output operand. [This is no longer accepted] (rust-lang/rust#99155). - [`impl Trait` was accidentally accepted as the associated type value of return-position `impl Trait`] (rust-lang/rust#97346), without fulfilling all the trait bounds of that associated type, as long as the hidden type satisfies said bounds. This has been fixed. 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. - Windows builds now use profile-guided optimization, providing 10-20% improvements to compiler performance: [Utilize PGO for windows x64 rustc dist builds] (rust-lang/rust#96978) - [Stop keeping metadata in memory before writing it to disk] (rust-lang/rust#96544) - [compiletest: strip debuginfo by default for mode=ui] (rust-lang/rust#98140) - Many improvements to generated code for derives, including performance improvements: - [Don't use match-destructuring for derived ops on structs.] (rust-lang/rust#98446) - [Many small deriving cleanups] (rust-lang/rust#98741) - [More derive output improvements] (rust-lang/rust#98758) - [Clarify deriving code](rust-lang/rust#98915) - [Final derive output improvements] (rust-lang/rust#99046) - [Stop injecting `#[allow(unused_qualifications)]` in generated `derive` implementations](rust-lang/rust#99485) - [Improve `derive(Debug)`](rust-lang/rust#98190) - [Bump to clap 3](rust-lang/rust#98213) - [fully move dropck to mir](rust-lang/rust#98641) - [Optimize `Vec::insert` for the case where `index == len`.] (rust-lang/rust#98755) - [Convert rust-analyzer to an in-tree tool] (rust-lang/rust#99603)
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We currently allow shared references in unions, but not mutable references. That seems somewhat inconsistent. So let's allow all references, and while we are at it, let's make sure the set of allowed types is closed under tuples.
This will need T-lang FCP (at least).
Then remove the
tagged_unionsfeature, since we do not plan to stabilize any more of it.Closes #55149