Document NonZeroXxx layout guarantees #94786

joshlf · 2022-03-09T21:53:25Z

Document that NonZeroXxx has the same layout and bit validity as Xxx with the exception of 0.

Document that `NonZeroXxx` has the same layout and bit validity as `Xxx` with the exception of `0`.

rust-highfive · 2022-03-09T21:53:28Z

(rust-highfive has picked a reviewer for you, use r? to override)

scottmcm · 2022-03-10T19:50:41Z

This seems fine to me, but I'm unsure whether procedurally it needs an FCP. (It might be "this was always the intention" and not need it, but it could be "this is a new thing" and thus need it.) So I'll assign it over to the libs-api member who commented on the zulip thread about this:

r? @joshtriplett

joshtriplett · 2022-03-10T23:08:31Z

I feel like this was always the commitment, but at the same time, better to confirm that consensus rather than assuming it.

@rust-lang/libs-api, are we comfortable committing to the guarantee that NonZeroX is compatible with X?

joshtriplett · 2022-03-10T23:09:23Z

@rfcbot merge

rfcbot · 2022-03-10T23:09:24Z

Team member @joshtriplett has proposed to merge this. The next step is review by the rest of the tagged team members:

Concerns:

~~implications~~ resolved by Document NonZeroXxx layout guarantees #94786 (comment)

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.

dtolnay · 2022-03-11T02:06:04Z

Seems okay but do we further want to guarantee that it has the same ABI as X, for example that extern "C" fn() -> NonZeroU8 is bindable to/from C uint8_t(void)? That isn't covered by what's written in the PR.

joshlf · 2022-03-11T02:16:01Z

Seems okay but do we further want to guarantee that it has the same ABI as X, for example that extern "C" fn() -> NonZeroU8 is bindable to/from C uint8_t(void)? That isn't covered by what's written in the PR.

Presumably we'd need to clarify that 0 is an exception? It's not safe in the general case to use uint8_t(void) as extern "C" fn() -> NonZeroU8 (since the uint8_t(void) might return 0), nor is it safe in the general case to use extern "C" fn(NonZeroU8) as void(uint8_t) (since the void(uint8_t) might be passed 0).

dtolnay · 2022-03-11T02:47:00Z

Committing to the ABI being the same isn't about saying it's safe/correct to arbitrarily interchange the two signatures. It's just about whether the registers involved in the calling convention are guaranteed to line up, e.g. that if fn() -> u8 returns its result in a particular register then fn() -> NonZeroU8 also returns in that same register. This is something you need to guarantee and is not the case in some "obvious" cases, for example that std::unique_ptr<T> () and T* () do not return the same way, even though unique_ptr is "just a pointer" and has the same layout as a pointer.

joshtriplett · 2022-03-11T07:31:12Z

Seems okay but do we further want to guarantee that it has the same ABI as X, for example that extern "C" fn() -> NonZeroU8 is bindable to/from C uint8_t(void)? That isn't covered by what's written in the PR.

I think it was intended to be, but making that more explicit would help. We should document that it is repr(transparent) and can be used in FFI.

m-ou-se · 2022-03-11T16:13:01Z

@rfcbot concern implications

I think it's important to also say that this doesn't mean that e.g. Option<NonZeroU8> and Option<u8> have the same layout. Saying that NonZeroU8 and u8 have the same layout might seem to imply that they always take the same amount of space, even when combined with other things.

scottmcm · 2022-03-11T17:27:02Z

@m-ou-se For Option<NonZeroU##> specifically, that has already been a guarantee since this FCP in 2018.

But perhaps it would be good to merge that text into this section, and say something like "As a special case, Option<NonZeroU##> is also guaranteed to have the same size, alignment, and ABI as U##. The compiler may also perform additional layout optimizations using this type, but those are not guaranteed."

workingjubilee · 2022-03-25T21:42:49Z

I agree that clarifying the differences between Option<u8>, Option<NZu8>, and u8 is important. In particular, while I believe that they have the same size, and I believe NZu8 has the same ABI as u8, Option<NZu8> and u8 would not necessarily be ABI interchangeable even if NZu8 and u8 are, even if they have the same layout.

It is very, very plausible to me that someone gets this wrong as a result while trying to do FFI or such.

dtolnay · 2022-03-25T21:58:59Z

As far as I know:

Option<NonZeroU8> guarantees same layout as u8 since Make the size of Option<NonZero*> a documented guarantee. #51396.
NonZeroU8 guarantees same layout as u8 once the FCP here has gone through.
IMO NonZeroU8 should further guarantee same ABI as u8, but I wouldn't block on this and it can happen later. People are going to assume this no matter what.
Option<NonZeroU8> continues to not have a specific guaranteed ABI. Whether it's the same as C uint8_t or as C struct S { uint8_t x; }; (which are not the same as one another) has never been settled.

library/core/src/num/nonzero.rs

joshtriplett · 2022-05-25T19:35:19Z

@m-ou-se Does #94786 (comment) address your concern?

JohnCSimon · 2022-07-23T23:39:40Z

triage:
@m-ou-se ☝️ ?

m-ou-se · 2022-08-18T13:01:36Z

@rfcbot resolve implications

Co-authored-by: Josh Triplett <josh@joshtriplett.org>

rustbot · 2022-10-05T16:40:53Z

Hey! It looks like you've submitted a new PR for the library teams!

If this PR contains changes to any rust-lang/rust public library APIs then please comment with @rustbot label +T-libs-api -T-libs to tag it appropriately. If this PR contains changes to any unstable APIs please edit the PR description to add a link to the relevant API Change Proposal or create one if you haven't already. If you're unsure where your change falls no worries, just leave it as is and the reviewer will take a look and make a decision to forward on if necessary.

Examples of T-libs-api changes:

Stabilizing library features
Introducing insta-stable changes such as new implementations of existing stable traits on existing stable types
Introducing new or changing existing unstable library APIs (excluding permanently unstable features / features without a tracking issue)
Changing public documentation in ways that create new stability guarantees
Changing observable runtime behavior of library APIs

joshlf · 2022-10-05T16:42:57Z

Thanks, @JohnCSimon!

@rustbot ready

dtolnay · 2023-04-04T18:16:27Z

@bors r+ rollup

bors · 2023-04-04T18:16:31Z

📌 Commit 9a3346b has been approved by dtolnay

It is now in the queue for this repository.

bors · 2023-04-05T01:10:16Z

⌛ Testing commit 9a3346b with merge f98a271...

bors · 2023-04-05T03:26:31Z

☀️ Test successful - checks-actions
Approved by: dtolnay
Pushing f98a271 to master...

rust-timer · 2023-04-05T04:43:20Z

Finished benchmarking commit (f98a271): comparison URL.

Overall result: ✅ improvements - no action needed

@rustbot label: -perf-regression

Instruction count

This is a highly reliable metric that was used to determine the overall result at the top of this comment.

	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-1.7%	[-1.7%, -1.7%]	1
All ❌✅ (primary)	-	-	0

Max RSS (memory usage)

Results

This is a less reliable metric that may be of interest but was not used to determine the overall result at the top of this comment.

	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	2.8%	[1.5%, 4.0%]	2
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-2.7%	[-2.7%, -2.7%]	1
All ❌✅ (primary)	-	-	0

Cycles

This benchmark run did not return any relevant results for this metric.

joshlf · 2023-04-26T21:35:58Z

@joshtriplett I've realized that I may have prematurely accepted your suggested language that made it into the merge:

#[doc = concat!("`Option<", stringify!($Ty), ">` is guaranteed to be compatible with `", stringify!($Int), "`,")]
/// including in FFI.

Does "compatible with" have a technical definition? In #104082, there's discussion of using the language "layout and bit validity", although I'm not sure whether that implicitly provides the same guarantees as your "...including in FFI" language.

Sorry for only bringing this up after the merge! Whatever the outcome of this discussion is, I can include any proposed changes in #104082.

Pkgsrc changes: * Adjust patches and cargo checksums to new versions. * Adjust to not cross-build to 8.0, due to LLVM using c++17, so adjust USE_LANGUAGES. Upstream changes: Version 1.70.0 (2023-06-01) ========================== Language -------- - [Relax ordering rules for `asm!` operands] (rust-lang/rust#105798) - [Properly allow macro expanded `format_args` invocations to uses captures] (rust-lang/rust#106505) - [Lint ambiguous glob re-exports] (rust-lang/rust#107880) - [Perform const and unsafe checking for expressions in `let _ = expr` position.] (rust-lang/rust#102256) Compiler -------- - [Extend -Cdebuginfo with new options and named aliases] (rust-lang/rust#109808) 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] (rust-lang/rust#104363) - [Detect uninhabited types early in const eval] (rust-lang/rust#109435) - [Switch to LLD as default linker for {arm,thumb}v4t-none-eabi] (rust-lang/rust#109721) - [Add tier 3 target `loongarch64-unknown-linux-gnu`] (rust-lang/rust#96971) - [Add tier 3 target for `i586-pc-nto-qnx700` (QNX Neutrino RTOS, version 7.0)] (rust-lang/rust#109173), - [Insert alignment checks for pointer dereferences as debug assertions] (rust-lang/rust#98112) This catches undefined behavior at runtime, and may cause existing code to fail. Refer to Rust's [platform support page][platform-support-doc] for more information on Rust's tiered platform support. Libraries --------- - [Document NonZeroXxx layout guarantees] (rust-lang/rust#94786) - [Windows: make `Command` prefer non-verbatim paths] (rust-lang/rust#96391) - [Implement Default for some alloc/core iterators] (rust-lang/rust#99929) - [Fix handling of trailing bare CR in str::lines] (rust-lang/rust#100311) - [allow negative numeric literals in `concat!`] (rust-lang/rust#106844) - [Add documentation about the memory layout of `Cell`] (rust-lang/rust#106921) - [Use `partial_cmp` to implement tuple `lt`/`le`/`ge`/`gt`] (rust-lang/rust#108157) - [Stabilize `atomic_as_ptr`] (rust-lang/rust#108419) - [Stabilize `nonnull_slice_from_raw_parts`] (rust-lang/rust#97506) - [Partial stabilization of `once_cell`] (rust-lang/rust#105587) - [Stabilize `nonzero_min_max`] (rust-lang/rust#106633) - [Flatten/inline format_args!() and (string and int) literal arguments into format_args!()] (rust-lang/rust#106824) - [Stabilize movbe target feature] (rust-lang/rust#107711) - [don't splice from files into pipes in io::copy] (rust-lang/rust#108283) - [Add a builtin unstable `FnPtr` trait that is implemented for all function pointers] (rust-lang/rust#108080) This extends `Debug`, `Pointer`, `Hash`, `PartialEq`, `Eq`, `PartialOrd`, and `Ord` implementations for function pointers with all ABIs. Stabilized APIs --------------- - [`NonZero*::MIN/MAX`] (https://doc.rust-lang.org/stable/std/num/struct.NonZeroI8.html#associatedconstant.MIN) - [`BinaryHeap::retain`] (https://doc.rust-lang.org/stable/std/collections/struct.BinaryHeap.html#method.retain) - [`Default for std::collections::binary_heap::IntoIter`] (https://doc.rust-lang.org/stable/std/collections/binary_heap/struct.IntoIter.html) - [`Default for std::collections::btree_map::{IntoIter, Iter, IterMut}`] (https://doc.rust-lang.org/stable/std/collections/btree_map/struct.IntoIter.html) - [`Default for std::collections::btree_map::{IntoKeys, Keys}`] (https://doc.rust-lang.org/stable/std/collections/btree_map/struct.IntoKeys.html) - [`Default for std::collections::btree_map::{IntoValues, Values}`] (https://doc.rust-lang.org/stable/std/collections/btree_map/struct.IntoKeys.html) - [`Default for std::collections::btree_map::Range`] (https://doc.rust-lang.org/stable/std/collections/btree_map/struct.Range.html) - [`Default for std::collections::btree_set::{IntoIter, Iter}`] (https://doc.rust-lang.org/stable/std/collections/btree_set/struct.IntoIter.html) - [`Default for std::collections::btree_set::Range`] (https://doc.rust-lang.org/stable/std/collections/btree_set/struct.Range.html) - [`Default for std::collections::linked_list::{IntoIter, Iter, IterMut}`] (https://doc.rust-lang.org/stable/alloc/collections/linked_list/struct.IntoIter.html) - [`Default for std::vec::IntoIter`] (https://doc.rust-lang.org/stable/alloc/vec/struct.IntoIter.html#impl-Default-for-IntoIter%3CT,+A%3E) - [`Default for std::iter::Chain`] (https://doc.rust-lang.org/stable/std/iter/struct.Chain.html) - [`Default for std::iter::Cloned`] (https://doc.rust-lang.org/stable/std/iter/struct.Cloned.html) - [`Default for std::iter::Copied`] (https://doc.rust-lang.org/stable/std/iter/struct.Copied.html) - [`Default for std::iter::Enumerate`] (https://doc.rust-lang.org/stable/std/iter/struct.Enumerate.html) - [`Default for std::iter::Flatten`] (https://doc.rust-lang.org/stable/std/iter/struct.Flatten.html) - [`Default for std::iter::Fuse`] (https://doc.rust-lang.org/stable/std/iter/struct.Fuse.html) - [`Default for std::iter::Rev`] (https://doc.rust-lang.org/stable/std/iter/struct.Rev.html) - [`Default for std::slice::Iter`] (https://doc.rust-lang.org/stable/std/slice/struct.Iter.html) - [`Default for std::slice::IterMut`] (https://doc.rust-lang.org/stable/std/slice/struct.IterMut.html) - [`Rc::into_inner`] (https://doc.rust-lang.org/stable/alloc/rc/struct.Rc.html#method.into_inner) - [`Arc::into_inner`] (https://doc.rust-lang.org/stable/alloc/sync/struct.Arc.html#method.into_inner) - [`std::cell::OnceCell`] (https://doc.rust-lang.org/stable/std/cell/struct.OnceCell.html) - [`Option::is_some_and`] (https://doc.rust-lang.org/stable/std/option/enum.Option.html#method.is_some_and) - [`NonNull::slice_from_raw_parts`] (https://doc.rust-lang.org/stable/std/ptr/struct.NonNull.html#method.slice_from_raw_parts) - [`Result::is_ok_and`] (https://doc.rust-lang.org/stable/std/result/enum.Result.html#method.is_ok_and) - [`Result::is_err_and`] (https://doc.rust-lang.org/stable/std/result/enum.Result.html#method.is_err_and) - [`std::sync::atomic::Atomic*::as_ptr`] (https://doc.rust-lang.org/stable/std/sync/atomic/struct.AtomicU8.html#method.as_ptr) - [`std::io::IsTerminal`] (https://doc.rust-lang.org/stable/std/io/trait.IsTerminal.html) - [`std::os::linux::net::SocketAddrExt`] (https://doc.rust-lang.org/stable/std/os/linux/net/trait.SocketAddrExt.html) - [`std::os::unix::net::UnixDatagram::bind_addr`] (https://doc.rust-lang.org/stable/std/os/unix/net/struct.UnixDatagram.html#method.bind_addr) - [`std::os::unix::net::UnixDatagram::connect_addr`] (https://doc.rust-lang.org/stable/std/os/unix/net/struct.UnixDatagram.html#method.connect_addr) - [`std::os::unix::net::UnixDatagram::send_to_addr`] (https://doc.rust-lang.org/stable/std/os/unix/net/struct.UnixDatagram.html#method.send_to_addr) - [`std::os::unix::net::UnixListener::bind_addr`] (https://doc.rust-lang.org/stable/std/os/unix/net/struct.UnixListener.html#method.bind_addr) - [`std::path::Path::as_mut_os_str`] (https://doc.rust-lang.org/stable/std/path/struct.Path.html#method.as_mut_os_str) - [`std::sync::OnceLock`] (https://doc.rust-lang.org/stable/std/sync/struct.OnceLock.html) Cargo ----- - [Add `CARGO_PKG_README`] (rust-lang/cargo#11645) - [Make `sparse` the default protocol for crates.io] (rust-lang/cargo#11791) - [Accurately show status when downgrading dependencies] (rust-lang/cargo#11839) - [Use registry.default for login/logout] (rust-lang/cargo#11949) - [Stabilize `cargo logout`] (rust-lang/cargo#11950) Misc ---- - [Stabilize rustdoc `--test-run-directory`] (rust-lang/rust#103682) Compatibility Notes ------------------- - [Prevent stable `libtest` from supporting `-Zunstable-options`] (rust-lang/rust#109044) - [Perform const and unsafe checking for expressions in `let _ = expr` position.] (rust-lang/rust#102256) - [WebAssembly targets enable `sign-ext` and `mutable-globals` features in codegen] (rust-lang/rust#109807) This may cause incompatibility with older execution environments. - [Insert alignment checks for pointer dereferences as debug assertions] (rust-lang/rust#98112) 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] (rust-lang/rust#109474) - [Use SipHash-1-3 instead of SipHash-2-4 for StableHasher] (rust-lang/rust#107925)

Pkgsrc changes: * Adjust patches and cargo checksums to new versions. * Add support for NetBSD/riscv64. Upstream changes: Version 1.70.0 (2023-06-01) ========================== Language -------- - [Relax ordering rules for `asm!` operands] (rust-lang/rust#105798) - [Properly allow macro expanded `format_args` invocations to uses captures] (rust-lang/rust#106505) - [Lint ambiguous glob re-exports] (rust-lang/rust#107880) - [Perform const and unsafe checking for expressions in `let _ = expr` position.] (rust-lang/rust#102256) Compiler -------- - [Extend -Cdebuginfo with new options and named aliases] (rust-lang/rust#109808) 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] (rust-lang/rust#104363) - [Detect uninhabited types early in const eval] (rust-lang/rust#109435) - [Switch to LLD as default linker for {arm,thumb}v4t-none-eabi] (rust-lang/rust#109721) - [Add tier 3 target `loongarch64-unknown-linux-gnu`] (rust-lang/rust#96971) - [Add tier 3 target for `i586-pc-nto-qnx700`(QNX Neutrino RTOS, version 7.0)] (rust-lang/rust#109173), - [Insert alignment checks for pointer dereferences as debug assertions] (rust-lang/rust#98112) This catches undefined behavior at runtime, and may cause existing code to fail. Refer to Rust's [platform support page][platform-support-doc] for more information on Rust's tiered platform support. Libraries --------- - [Document NonZeroXxx layout guarantees] (rust-lang/rust#94786) - [Windows: make `Command` prefer non-verbatim paths] (rust-lang/rust#96391) - [Implement Default for some alloc/core iterators] (rust-lang/rust#99929) - [Fix handling of trailing bare CR in str::lines] (rust-lang/rust#100311) - [allow negative numeric literals in `concat!`] (rust-lang/rust#106844) - [Add documentation about the memory layout of `Cell`] (rust-lang/rust#106921) - [Use `partial_cmp` to implement tuple `lt`/`le`/`ge`/`gt`] (rust-lang/rust#108157) - [Stabilize `atomic_as_ptr`] (rust-lang/rust#108419) - [Stabilize `nonnull_slice_from_raw_parts`] (rust-lang/rust#97506) - [Partial stabilization of `once_cell`] (rust-lang/rust#105587) - [Stabilize `nonzero_min_max`] (rust-lang/rust#106633) - [Flatten/inline format_args!() and (string and int) literal arguments into format_args!()] (rust-lang/rust#106824) - [Stabilize movbe target feature] (rust-lang/rust#107711) - [don't splice from files into pipes in io::copy] (rust-lang/rust#108283) - [Add a builtin unstable `FnPtr` trait that is implemented for all function pointers] (rust-lang/rust#108080) This extends `Debug`, `Pointer`, `Hash`, `PartialEq`, `Eq`, `PartialOrd`, and `Ord` implementations for function pointers with all ABIs. Stabilized APIs --------------- - [`NonZero*::MIN/MAX`] (https://doc.rust-lang.org/stable/std/num/struct.NonZeroI8.html#associatedconstant.MIN) - [`BinaryHeap::retain`] (https://doc.rust-lang.org/stable/std/collections/struct.BinaryHeap.html#method.retain) - [`Default for std::collections::binary_heap::IntoIter`] (https://doc.rust-lang.org/stable/std/collections/binary_heap/struct.IntoIter.html) - [`Default for std::collections::btree_map::{IntoIter, Iter, IterMut}`] (https://doc.rust-lang.org/stable/std/collections/btree_map/struct.IntoIter.html) - [`Default for std::collections::btree_map::{IntoKeys, Keys}`] (https://doc.rust-lang.org/stable/std/collections/btree_map/struct.IntoKeys.html) - [`Default for std::collections::btree_map::{IntoValues, Values}`] (https://doc.rust-lang.org/stable/std/collections/btree_map/struct.IntoKeys.html) - [`Default for std::collections::btree_map::Range`] (https://doc.rust-lang.org/stable/std/collections/btree_map/struct.Range.html) - [`Default for std::collections::btree_set::{IntoIter, Iter}`] (https://doc.rust-lang.org/stable/std/collections/btree_set/struct.IntoIter.html) - [`Default for std::collections::btree_set::Range`] (https://doc.rust-lang.org/stable/std/collections/btree_set/struct.Range.html) - [`Default for std::collections::linked_list::{IntoIter, Iter, IterMut}`] (https://doc.rust-lang.org/stable/alloc/collections/linked_list/struct.IntoIter.html) - [`Default for std::vec::IntoIter`] (https://doc.rust-lang.org/stable/alloc/vec/struct.IntoIter.html#impl-Default-for-IntoIter%3CT,+A%3E) - [`Default for std::iter::Chain`] (https://doc.rust-lang.org/stable/std/iter/struct.Chain.html) - [`Default for std::iter::Cloned`] (https://doc.rust-lang.org/stable/std/iter/struct.Cloned.html) - [`Default for std::iter::Copied`] (https://doc.rust-lang.org/stable/std/iter/struct.Copied.html) - [`Default for std::iter::Enumerate`] (https://doc.rust-lang.org/stable/std/iter/struct.Enumerate.html) - [`Default for std::iter::Flatten`] (https://doc.rust-lang.org/stable/std/iter/struct.Flatten.html) - [`Default for std::iter::Fuse`] (https://doc.rust-lang.org/stable/std/iter/struct.Fuse.html) - [`Default for std::iter::Rev`] (https://doc.rust-lang.org/stable/std/iter/struct.Rev.html) - [`Default for std::slice::Iter`] (https://doc.rust-lang.org/stable/std/slice/struct.Iter.html) - [`Default for std::slice::IterMut`] (https://doc.rust-lang.org/stable/std/slice/struct.IterMut.html) - [`Rc::into_inner`] (https://doc.rust-lang.org/stable/alloc/rc/struct.Rc.html#method.into_inner) - [`Arc::into_inner`] (https://doc.rust-lang.org/stable/alloc/sync/struct.Arc.html#method.into_inner) - [`std::cell::OnceCell`] (https://doc.rust-lang.org/stable/std/cell/struct.OnceCell.html) - [`Option::is_some_and`] (https://doc.rust-lang.org/stable/std/option/enum.Option.html#method.is_some_and) - [`NonNull::slice_from_raw_parts`] (https://doc.rust-lang.org/stable/std/ptr/struct.NonNull.html#method.slice_from_raw_parts) - [`Result::is_ok_and`] (https://doc.rust-lang.org/stable/std/result/enum.Result.html#method.is_ok_and) - [`Result::is_err_and`] (https://doc.rust-lang.org/stable/std/result/enum.Result.html#method.is_err_and) - [`std::sync::atomic::Atomic*::as_ptr`] (https://doc.rust-lang.org/stable/std/sync/atomic/struct.AtomicU8.html#method.as_ptr) - [`std::io::IsTerminal`] (https://doc.rust-lang.org/stable/std/io/trait.IsTerminal.html) - [`std::os::linux::net::SocketAddrExt`] (https://doc.rust-lang.org/stable/std/os/linux/net/trait.SocketAddrExt.html) - [`std::os::unix::net::UnixDatagram::bind_addr`] (https://doc.rust-lang.org/stable/std/os/unix/net/struct.UnixDatagram.html#method.bind_addr) - [`std::os::unix::net::UnixDatagram::connect_addr`] (https://doc.rust-lang.org/stable/std/os/unix/net/struct.UnixDatagram.html#method.connect_addr) - [`std::os::unix::net::UnixDatagram::send_to_addr`] (https://doc.rust-lang.org/stable/std/os/unix/net/struct.UnixDatagram.html#method.send_to_addr) - [`std::os::unix::net::UnixListener::bind_addr`] (https://doc.rust-lang.org/stable/std/os/unix/net/struct.UnixListener.html#method.bind_addr) - [`std::path::Path::as_mut_os_str`] (https://doc.rust-lang.org/stable/std/path/struct.Path.html#method.as_mut_os_str) - [`std::sync::OnceLock`] (https://doc.rust-lang.org/stable/std/sync/struct.OnceLock.html) Cargo ----- - [Add `CARGO_PKG_README`] (rust-lang/cargo#11645) - [Make `sparse` the default protocol for crates.io] (rust-lang/cargo#11791) - [Accurately show status when downgrading dependencies] (rust-lang/cargo#11839) - [Use registry.default for login/logout] (rust-lang/cargo#11949) - [Stabilize `cargo logout`] (rust-lang/cargo#11950) Misc ---- - [Stabilize rustdoc `--test-run-directory`] (rust-lang/rust#103682) Compatibility Notes ------------------- - [Prevent stable `libtest` from supporting `-Zunstable-options`] (rust-lang/rust#109044) - [Perform const and unsafe checking for expressions in `let _ = expr` position.] (rust-lang/rust#102256) - [WebAssembly targets enable `sign-ext` and `mutable-globals` features in codegen] (rust-lang/rust#109807) This may cause incompatibility with older execution environments. - [Insert alignment checks for pointer dereferences as debug assertions] (rust-lang/rust#98112) 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] (rust-lang/rust#109474) - [Use SipHash-1-3 instead of SipHash-2-4 for StableHasher] (rust-lang/rust#107925)

The layout was documented as guaranteed in 1.70.0 rust-lang/rust#94786

Document NonZeroXxx layout guarantees

b142720

Document that `NonZeroXxx` has the same layout and bit validity as `Xxx` with the exception of `0`.

rust-highfive assigned scottmcm Mar 9, 2022

rust-highfive added the S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. label Mar 9, 2022

Add missing closing parenthesis

7f88cd2

rust-highfive assigned joshtriplett and unassigned scottmcm Mar 10, 2022

joshtriplett added the T-libs-api Relevant to the library API team, which will review and decide on the PR/issue. label Mar 10, 2022

rfcbot added proposed-final-comment-period Proposed to merge/close by relevant subteam, see T-<team> label. Will enter FCP once signed off. disposition-merge This issue / PR is in PFCP or FCP with a disposition to merge it. labels Mar 10, 2022

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joshtriplett reviewed May 25, 2022

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library/core/src/num/nonzero.rs Show resolved Hide resolved

Update library/core/src/num/nonzero.rs

7d4e9b3

Co-authored-by: Josh Triplett <josh@joshtriplett.org>

Fix typo (missing >)

8323d6a

rustbot added S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. and removed S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. labels Oct 5, 2022

Add missing trailing )]

9a3346b

dtolnay approved these changes Apr 4, 2023

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bors added S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Apr 4, 2023

dtolnay assigned dtolnay and unassigned joshtriplett Apr 4, 2023

bors added the merged-by-bors This PR was explicitly merged by bors. label Apr 5, 2023

bors merged commit f98a271 into rust-lang:master Apr 5, 2023
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rustbot added this to the 1.70.0 milestone Apr 5, 2023

bors mentioned this pull request Apr 5, 2023

Specify NonZero and Option<NonZero> layout #104082

Closed

joshlf deleted the patch-5 branch April 11, 2023 22:20

pravic mentioned this pull request May 29, 2023

Github rejects rendering of RELEASES.md #112058

Closed

zachs18 added a commit to zachs18/bytemuck that referenced this pull request Jul 17, 2023

Remove FIXME and checks about NonZero[int] layout.

7423d74

The layout was documented as guaranteed in 1.70.0 rust-lang/rust#94786

zachs18 mentioned this pull request Jul 17, 2023

Remove note and checks about NonZero[int] layout. Lokathor/bytemuck#199

Merged

Lokathor pushed a commit to Lokathor/bytemuck that referenced this pull request Jul 17, 2023

Remove FIXME and checks about NonZero[int] layout. (#199)

1ed1aae

The layout was documented as guaranteed in 1.70.0 rust-lang/rust#94786

joshlf mentioned this pull request Aug 19, 2023

Specify bit validity and padding of some types rust-lang/reference#1392

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Document NonZeroXxx layout guarantees #94786

Document NonZeroXxx layout guarantees #94786

joshlf commented Mar 9, 2022

rust-highfive commented Mar 9, 2022

scottmcm commented Mar 10, 2022 •

edited

joshtriplett commented Mar 10, 2022

joshtriplett commented Mar 10, 2022

rfcbot commented Mar 10, 2022 •

edited by BurntSushi

dtolnay commented Mar 11, 2022 •

edited

joshlf commented Mar 11, 2022

dtolnay commented Mar 11, 2022

joshtriplett commented Mar 11, 2022

m-ou-se commented Mar 11, 2022

scottmcm commented Mar 11, 2022

workingjubilee commented Mar 25, 2022 •

edited

dtolnay commented Mar 25, 2022 •

edited

joshtriplett commented May 25, 2022

JohnCSimon commented Jul 23, 2022

m-ou-se commented Aug 18, 2022

rustbot commented Oct 5, 2022

joshlf commented Oct 5, 2022

dtolnay commented Apr 4, 2023

bors commented Apr 4, 2023

bors commented Apr 5, 2023

bors commented Apr 5, 2023

rust-timer commented Apr 5, 2023

joshlf commented Apr 26, 2023

Document NonZeroXxx layout guarantees #94786

Document NonZeroXxx layout guarantees #94786

Conversation

joshlf commented Mar 9, 2022

rust-highfive commented Mar 9, 2022

scottmcm commented Mar 10, 2022 • edited

joshtriplett commented Mar 10, 2022

joshtriplett commented Mar 10, 2022

rfcbot commented Mar 10, 2022 • edited by BurntSushi

dtolnay commented Mar 11, 2022 • edited

joshlf commented Mar 11, 2022

dtolnay commented Mar 11, 2022

joshtriplett commented Mar 11, 2022

m-ou-se commented Mar 11, 2022

scottmcm commented Mar 11, 2022

workingjubilee commented Mar 25, 2022 • edited

dtolnay commented Mar 25, 2022 • edited

joshtriplett commented May 25, 2022

JohnCSimon commented Jul 23, 2022

m-ou-se commented Aug 18, 2022

rustbot commented Oct 5, 2022

joshlf commented Oct 5, 2022

dtolnay commented Apr 4, 2023

bors commented Apr 4, 2023

bors commented Apr 5, 2023

bors commented Apr 5, 2023

rust-timer commented Apr 5, 2023

Overall result: ✅ improvements - no action needed

Instruction count

Max RSS (memory usage)

Cycles

joshlf commented Apr 26, 2023

scottmcm commented Mar 10, 2022 •

edited

rfcbot commented Mar 10, 2022 •

edited by BurntSushi

dtolnay commented Mar 11, 2022 •

edited

workingjubilee commented Mar 25, 2022 •

edited

dtolnay commented Mar 25, 2022 •

edited