Add `cast_init` and `cast_uninit` methods for pointers
ACP: rust-lang/libs-team#627
Tracking issue: rust-lang/rust#145036
This includes an incredibly low-effort search to find uses that could be switched to using these methods. I only searched for `cast::<\w>` and `cast::<MaybeUninit` because there would otherwise be way too much to look through, and I also didn't modify anything inside submodules/subtrees.
Adjust documentation of `dangling`
I believe the current doc of `dangling` is slightly off as it indicates:
`Note that the pointer value may potentially represent a valid pointer to a T`
The returned pointer has no provenance, so it may not be a valid pointer (except in the case of ZSTs, but I don't think this is what the documentation is trying to warn about).
See: https://rust-lang.zulipchat.com/#narrow/channel/136281-t-opsem/topic/Dangling.20pointers.3A.20definition
The value returned by dangling may never be used to dereference a value that isn't a ZST, even if address equality is detected with that of a valid pointer.
This is a minor fix, but this doc still got me confused for a second
Deprecate RUST_TEST_* env variables
Like with rust-lang/rust#139224, this is a documentation-only deprecation for now. Over time, we can
- warn and then remove on use of unstable environment variables
- warn on use of stable environment variables (no plan to remove due to compatibility)
Longer term, we expect test runners, like `cargo test`, to provide the necessary mechanisms for environmental or persistent configuration (e.g. using cargo config which supports `.cargo/config.toml` as well as environment variables).
This would include:
- `RUST_TEST_THREADS`
- `RUST_TEST_NOCAPTURE`
- `RUST_TEST_SHUFFLE` (unstable)
- `RUST_TEST_SHUFFLE_SEED` (unstable)
The primary outcomes for this change are
- Reducing the scope of what is expected for custom test harnesses to implement
- Reduce the mechanisms that test runners, like `cargo test`, are expected to track when they are being bypassed to protect against negative interactions, e.g. `RUST_TEST_NOCAPTURE=1` when json output is being read.
For testing-devex FCP, see rust-lang/testing-devex-team#10Fixesrust-lang/testing-devex-team#10
History
-------
At each step, I could not find evidence of design discussions on whether to support CLI, env, or both. The first env variable seems to come from the fact that it was being forked out of an existing env variable that had a much wider scope.
At best, this seems like a way to offer a more persistent configuration for these flags but environment variables hidden away in libtest is a bit clunky and this seems like the wrong layer to handle this problem.
**Originally:** `RUST_THREADS` was respected by the Rust runtime and libextra/test got this for free
**2013:** rust-lang/rust#7335 suggested splitting `RUST_TEST_TASKS` out of `RUST_THREADS`. In that issue and the implementation (rust-lang/rust#8823).
**2014:** rust-lang/rust#13374 ask for support to disable capturing of stdout/stderr. `--nocapture` and `RUST_TEST_NOCAPTURE` were added together.
**2015:** rust-lang/rust#23525 renamed `RUST_TEST_TASKS` to `RUST_TEST_THREADS`
**2016:** rust-lang/rust#25636 asked to configure `RUST_TEST_THREADS` via `--test-threads` which was implemented in rust-lang/rust#35414
**2021:** rust-lang/rust#85440 asked for test randomization which was implemented in rust-lang/rust#89082, adding `--shuffle` / RUST_TEST_SHUFFLE` and `--shuffle-seed SEED` / `RUST_TEST_SHUFFLE_SEED`
Potentially relevant issues
---------------------------
- rust-lang/rust#74845
Constify `SystemTime` methods
This is separated out from rust-lang/rust#143949 due to the fact that it touches nontrivial system code. While the same arithmetic methods on `Instant` could be made const, since that type explicitly cannot be constructed at const-time, we don't bother. However, due to the fact that `SystemTime::UNIX_EPOCH` exists, it can be useful to create other anchors at other points in time, and thus these methods should be possible to use in const context.
> Side comment: I would honestly like to just move every single implementation which is a thin wrapper over `Duration` or some integer clock into their own module which is tested on all targets, so that we don't have to worry about code for lower-tier targets not being tested. However, the comments in `std::sys_common` pointing out the desire to move things to `std::sys::common` confused me, particularly due to the fact that `std::sys::common` is taken from the hellish asterisk-import of `std::sys::pal::common` and others.
>
> I think that, for trivial types like this, we should just have a platform-independent module that can be tested on all platforms, to both ensure that the code is properly tested regardless of whether higher-tier platforms needed, and to avoid the extreme mental gymnastics required to determine where in the code it lies.
>
> However, since I'm not on any of the teams maintaining this code and am not involved, I'll settle for just copy-pasting like everyone else has been doing. I just want to express how I'm not happy about that.
**Reviewer note: please only pay attention to the last commit of this PR, until its blocker is merged.**
Since this depends on the previous PR:
`@rustbot` blocked
Add ASCII-related methods from `u8` and `MIN`/`MAX` to `core::ascii::Char`
* Add ASCII-related methods from `u8` to `core::ascii::Char`.
* Add `core::ascii::Char::MIN` and `core::ascii::Char::MAX`.
Make explicit guarantees about `Vec`’s allocator
This commit amends the documentation of `Vec::as_mut_ptr` and `Vec::into_raw_parts` to make it explicit that such calls may be paired with calls to `dealloc` with a suitable layout. This guarantee was effectively already provided by the docs of `Vec::from_raw_parts` mentioning `alloc`.
Additionally, we copy-paste and adjust the “Memory layout” section from the documentation of `std::boxed` to `std::vec`. This explains the allocator guarantees in more detail.
This is a documentation-only deprecation for now.
Over time, we can
- warn and then remove on use of unstable environment variables
- warn on use of stable environment variables (no plan to remove due to
compatibility)
Longer term, we expect test runners, like `cargo test`, to provide the
necessary mechanisms for environmental or persistent configuration (e.g.
using cargo config which supports `.cargo/config.toml` as well as
environment variables).
This would include:
- `RUST_TEST_THREADS`
- `RUST_TEST_NOCAPTURE`
- `RUST_TEST_SHUFFLE` (unstable)
- `RUST_TEST_SHUFFLE_SEED` (unstable)
The primary outcomes for this change are
- Reducing the scope of what is expected for custom test harnesses to
implement
- Reduce the mechanisms that test runners, like `cargo test`, are
expected to track when they are being bypassed to protect against
negative interactions, e.g. `RUST_TEST_NOCAPTURE=1` when json output
is being read.
This commit amends the documentation of `Vec::as_mut_ptr` and
`Vec::into_raw_parts` to make it explicit that such calls may be paired
with calls to `dealloc` with a suitable layout. This guarantee was
effectively already provided by the docs of `Vec::from_raw_parts`
mentioning `alloc`.
Additionally, we copy-paste and adjust the “Memory layout” section from
the documentation of `std::boxed` to `std::vec`. This explains the allocator
guarantees in more detail.
Use a time representation with 1900-01-01-00:00:00 at timezone -1440 min as
anchor. This is the earliest time supported in UEFI.
Signed-off-by: Ayush Singh <ayush@beagleboard.org>
std: sys: io: io_slice: Add UEFI types
UEFI networking APIs do support vectored read/write. While the types for UDP4, UDP6, TCP4 and TCP6 are defined separately, they are essentially the same C struct. So we can map IoSlice and IoSliceMut to have the same binary representation.
Since all UEFI networking types for read/write are DSTs, `IoSlice` and `IoSliceMut` will need to be copied to the end of the transmit/receive structures. So having the same binary representation just allows us to do a single memcpy instead of having to loop and set the DST.
cc ``@nicholasbishop``
document assumptions about `Clone` and `Eq` traits
Most standard library collections break if `Clone` has a non-standard implementation which violates `x.clone() == x`. [Here](https://play.rust-lang.org/?version=stable&mode=debug&edition=2024&gist=b7fc6dfa8410cbb673eb8d38393d81de) the resulting broken behaviour of different collections is shown. I originally created an issue at https://github.com/rust-lang/hashbrown/issues/629, but the conclusion there was that `x.clone()` resulting in an object that compares equal to the original one is probably a very universal assumption. However, this assumption is (to my knowledge) not documented anywhere.
I propose to make this assumption explicit in the `Clone` trait documentation. The property that seems the most reasonable to me is the following: When implementing both `Clone` and `PartialEq`, then
```text
x == x -> x.clone() == x
```
is expected to hold. This way, when also implementing `Eq`, it automatically follows that `x.clone() == x` has to hold, which should be enough for the collections to not break. At the same time, the property also works for the "normal" elements of a type with `PartialEq`. For the wording, I tried to follow the [`Hash` and `Eq`](https://doc.rust-lang.org/std/hash/trait.Hash.html#hash-and-eq) documentation.
As I am fairly new to Rust, it might well be that this property cannot be generally expected – it seems reasonable to me, but any counter-examples or critique, both content- and wording-wise, would be very welcome. If the property turns out to be too general, I would suggest to at least document the assumption of `x.clone() == x` for the collections somehow.
An additional thought of mine:
If it is indeed generally expected that `x == x -> x.clone() == x`, then, for the sake of completeness, one could also define that `x != x -> y != y for y = x.clone()` should hold, i.e., that an object that did not compare equal to itself before cloning, should also not compare equal to itself afterwards.
Constify remaining traits/impls for `const_ops`
Tracking issue: rust-lang/rust#143802
This is split into two commits for ease of reviewability:
1. Updates the `forward_ref_*` macros to accept multiple attributes (in anticipation of needing `rust_const_unstable` attributes) and also *require* attributes in these macros. Since the default attribute only helps for the initial implementations, it means it's easy to get wrong for future implementations, as shown for the saturating implementations which were incorrect before.
2. Actually constify the traits/impls.
A few random other notes on the implementation specifically:
* I unindented the attributes that were passed to the `forward_ref_*` macro calls because in some places rustfmt wanted them to be unindented, and in others it was allowed because they were themselves inside of macro bodies. I chose the consistent indenting even though I (personally) think it looks worse.
----
As far as the actual changes go, this constifies the following additional traits:
* `Neg`
* `Not`
* `BitAnd`
* `BitOr`
* `BitXor`
* `Shl`
* `Shr`
* `AddAssign`
* `SubAssign`
* `MulAssign`
* `DivAssign`
* `RemAssign`
* `BitAndAssign`
* `BitOrAssign`
* `BitXorAssign`
* `ShlAssign`
* `ShrAssign`
In terms of constified implementations of these traits, it adds the reference-forwarded versions of all the arithmetic operators, which are defined by the macros in `library/core/src/internal_macros.rs`. I'm not going to fully enumerate these because we'd be here all day, but sufficed to say, it effectively allows adding an `&` to one or both sides of an operator for primitives.
Additionally, I constified the implementations for `Wrapping`, `Saturating`, and `NonZero` as well, since all of them forward to already-const-stable methods. (potentially via intrinsics, to avoid extra overhead)
There are three "non-primitive" types which implement these traits, listed below. Note that I put "non-primitive" in quotes since I'm including `Wrapping`, `Saturating`, and `NonZero`, which are just wrappers over primitives.
* `Duration` (arithmetic operations)
* `SystemTime` (arithmetic operations)
* `Ipv4Addr` (bit operations)
* `Ipv6Addr` (bit operations)
Additionally, because the methods on `SystemTime` needed to make these operations const were not marked const, a separate tracking issue for const-stabilising those methods is rust-lang/rust#144517.
Stuff left out of this PR:
* `Assume` (this could trivially be made const, but since the docs indicate this is still under heavy design, I figured I'd leave it out)
* `Instant` (this could be made const, but cannot reasonably be constructed at constant time, so, isn't useful)
* `SystemTime` (will submit separate PR)
* SIMD types (I'm tackling these all at once later; see rust-lang/portable-simd#467)
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> [!NOTE]
> # Concerns (0 active)
>
> - ~~[May break Clippy](https://github.com/rust-lang/rust/pull/143949#issuecomment-3081466077)~~ resolved in [this comment](https://github.com/rust-lang/rust/pull/143949#issuecomment-3083628215)
>
> *Managed by ```@rustbot`—see`` [help](https://forge.rust-lang.org/triagebot/concern.html) for details.*
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Replace unsafe `security_attributes` function with safe `inherit_handle` alternative
The `security_attributes` function is marked as safe despite taking a raw pointer which will later be used. Fortunately this function is only used internally and only in one place that has been basically the same for a decade now. However, we only ever set one bool so it's easy enough to replace with something that's actually safe.
In the future we might want to expose the ability for users to set security attributes. But that should be properly designed (and safe!).
`{BTree,Hash}Map`: add "`Entry` API" section heading
I wanted to link to an introduction of the `Entry` API to the help message of `clippy::map_entry` (see https://github.com/rust-lang/rust-clippy/issues/11598 for motivation), but I found the documentation on the `Entry` enum itself a bit short. On the other hand, `{BTree,Hash}Map` both have sections in their docs introducing the whole API and giving usage examples, and so I would like to link to that instead. For that, I introduce the "`Entry` API" section heading to both of them.
Do let me know whether you think this is the right approach.
The `security_attributes` function is marked as safe despite taking a raw pointer which will later be used. Fortunately this function is only used internally and only in one place that has been basically the same for a decade now.
However, we only ever set one bool so it's easy enough to replace with something that's actually safe.
Move several more float tests to floats/mod.rs
This PR moves several tests to `floats/mod.rs`, as discussed in https://github.com/rust-lang/rust/issues/141726. The tests moved are:
* `test_abs`
* `test_signum`
* `test_is_sign_positive`
* `test_is_sign_negative`
* `test_next_up`
* `test_next_down`
* `test_sqrt_domain`
* `test_clamp_min_greater_than_max`
* `test_clamp_min_is_nan`
* `test_clamp_max_is_nan`
* `test_total_cmp`
This covers all the "easy" tests: the ones that don't have a lot of precision-specific constants. It's not clear to me that it's worth migrating the others.
Each test is its own commit (with the exception of the clamp tests), so it may be easiest to review each commit individually.
r? tgross35
Rollup of 8 pull requests
Successful merges:
- rust-lang/rust#139451 (Add `target_env = "macabi"` and `target_env = "sim"`)
- rust-lang/rust#144039 (Use `tcx.short_string()` in more diagnostics)
- rust-lang/rust#144192 (atomicrmw on pointers: move integer-pointer cast hacks into backend)
- rust-lang/rust#144545 (In rustc_pattern_analysis, put `true` witnesses before `false` witnesses)
- rust-lang/rust#144579 (Implement declarative (`macro_rules!`) attribute macros (RFC 3697))
- rust-lang/rust#144649 (Account for bare tuples and `Pin` methods in field searching logic)
- rust-lang/rust#144775 (more strongly dissuade use of `skip_binder`)
- rust-lang/rust#144987 (Enable f16 and f128 on targets that were fixed in LLVM21)
r? `@ghost`
`@rustbot` modify labels: rollup
atomicrmw on pointers: move integer-pointer cast hacks into backend
Conceptually, we want to have atomic operations on pointers of the form `fn atomic_add(ptr: *mut T, offset: usize, ...)`. However, LLVM does not directly support such operations (https://github.com/llvm/llvm-project/issues/120837), so we have to cast the `offset` to a pointer somewhere.
This PR moves that hack into the LLVM backend, so that the standard library, intrinsic, and Miri all work with the conceptual operation we actually want. Hopefully, one day LLVM will gain a way to represent these operations without integer-pointer casts, and then the hack will disappear entirely.
Cc ```@nikic``` -- this is the best we can do right now, right?
Fixes https://github.com/rust-lang/rust/issues/134617
Rollup of 19 pull requests
Successful merges:
- rust-lang/rust#144400 (`tests/ui/issues/`: The Issues Strike Back [3/N])
- rust-lang/rust#144764 ([codegen] assume the tag, not the relative discriminant)
- rust-lang/rust#144807 (Streamline config in bootstrap)
- rust-lang/rust#144899 (Print CGU reuse statistics in `-Zprint-mono-items`)
- rust-lang/rust#144909 (Add new `test::print_merged_doctests_times` used by rustdoc to display more detailed time information)
- rust-lang/rust#144912 (Resolver: introduce a conditionally mutable Resolver for (non-)speculative resolution.)
- rust-lang/rust#144914 (Add support for `ty::Instance` path shortening in diagnostics)
- rust-lang/rust#144931 ([win][arm64ec] Fix msvc-wholearchive for Arm64EC)
- rust-lang/rust#144999 (coverage: Remove all unstable support for MC/DC instrumentation)
- rust-lang/rust#145009 (A couple small changes for rust-analyzer next-solver work)
- rust-lang/rust#145030 (GVN: Do not flatten derefs with ProjectionElem::Index. )
- rust-lang/rust#145042 (stdarch subtree update)
- rust-lang/rust#145047 (move `type_check` out of `compute_regions`)
- rust-lang/rust#145051 (Prevent name collisions with internal implementation details)
- rust-lang/rust#145053 (Add a lot of NLL `known-bug` tests)
- rust-lang/rust#145055 (Move metadata symbol export from exported_non_generic_symbols to exported_symbols)
- rust-lang/rust#145057 (Clean up some resolved test regressions of const trait removals in std)
- rust-lang/rust#145068 (Readd myself to review queue)
- rust-lang/rust#145070 (Add minimal `armv7a-vex-v5` tier three target)
r? `@ghost`
`@rustbot` modify labels: rollup
Add new `test::print_merged_doctests_times` used by rustdoc to display more detailed time information
This PR is the first commit of https://github.com/rust-lang/rust/pull/144908. Sadly, it seems like we can't do all of it at once...
r? ``@Amanieu``
This standardizes how max and min subnormals are generated. Since the
new method doesn't use powf, it also enables some of the tests for f128
that were previously disabled due to issues with powf (although it looks
like those issues were already fixed anyway). f16 signalling nan tests
previously disabled are not re-enabled, since the underlying LLVM issue
has not been closed.
