Pass Ident by reference in ast Visitor
`MutVisitor`'s version of `visit_ident` passes around `&Ident`, but `Visitor` copies `Ident`. This PR changes that
r? `@petrochenkov`
related to #128974
Fundamentally, we have *three* disjoint categories of functions:
1. const-stable functions
2. private/unstable functions that are meant to be callable from const-stable functions
3. functions that can make use of unstable const features
This PR implements the following system:
- `#[rustc_const_stable]` puts functions in the first category. It may only be applied to `#[stable]` functions.
- `#[rustc_const_unstable]` by default puts functions in the third category. The new attribute `#[rustc_const_stable_indirect]` can be added to such a function to move it into the second category.
- `const fn` without a const stability marker are in the second category if they are still unstable. They automatically inherit the feature gate for regular calls, it can now also be used for const-calls.
Also, several holes in recursive const stability checking are being closed.
There's still one potential hole that is hard to avoid, which is when MIR
building automatically inserts calls to a particular function in stable
functions -- which happens in the panic machinery. Those need to *not* be
`rustc_const_unstable` (or manually get a `rustc_const_stable_indirect`) to be
sure they follow recursive const stability. But that's a fairly rare and special
case so IMO it's fine.
The net effect of this is that a `#[unstable]` or unmarked function can be
constified simply by marking it as `const fn`, and it will then be
const-callable from stable `const fn` and subject to recursive const stability
requirements. If it is publicly reachable (which implies it cannot be unmarked),
it will be const-unstable under the same feature gate. Only if the function ever
becomes `#[stable]` does it need a `#[rustc_const_unstable]` or
`#[rustc_const_stable]` marker to decide if this should also imply
const-stability.
Adding `#[rustc_const_unstable]` is only needed for (a) functions that need to
use unstable const lang features (including intrinsics), or (b) `#[stable]`
functions that are not yet intended to be const-stable. Adding
`#[rustc_const_stable]` is only needed for functions that are actually meant to
be directly callable from stable const code. `#[rustc_const_stable_indirect]` is
used to mark intrinsics as const-callable and for `#[rustc_const_unstable]`
functions that are actually called from other, exposed-on-stable `const fn`. No
other attributes are required.
Because `note_obligation_cause_code` is recursive, if multiple types are too
long to print to the terminal, a `long_ty_file` will be created. Before, one was
created *per recursion*. Now, it is passed in so it gets printed only once.
Part of #132013.
When printing
```
= help: the trait `chumsky::private::ParserSealed<'_, &'a str, ((), ()), chumsky::extra::Full<EmptyErr, (), ()>>` is implemented for `Then<Ignored<chumsky::combinator::Filter<chumsky::primitive::Any<&str, chumsky::extra::Full<EmptyErr, (), ()>>, {closure@src/main.rs:9:17: 9:27}>, char>, chumsky::combinator::Map<impl CSTParser<'a, O>, O, {closure@src/main.rs:11:24: 11:27}>, (), (), chumsky::extra::Full<EmptyErr, (), ()>>`
= help: for that trait implementation, expected `((), ())`, found `()`
```
Highlight only the `expected` and `found` types, instead of the full type in the first `help`.
Emit future-incompatibility lint when calling/declaring functions with vectors that require missing target feature
On some architectures, vector types may have a different ABI depending on whether the relevant target features are enabled. (The ABI when the feature is disabled is often not specified, but LLVM implements some de-facto ABI.)
As discussed in https://github.com/rust-lang/lang-team/issues/235, this turns out to very easily lead to unsound code.
This commit makes it a post-monomorphization error to declare or call functions using those vector types in a context in which the corresponding target features are disabled, if using an ABI for which the difference is relevant. This ensures that these functions are always called with a consistent ABI.
See the [nomination comment](https://github.com/rust-lang/rust/pull/127731#issuecomment-2288558187) for more discussion.
r? RalfJung
Part of https://github.com/rust-lang/rust/issues/116558
ci: aarch64-gnu-debug job
- Adds a new CI job which checks that the compiler builds with `--enable-debug` and tests that `needs-force-clang-based-tests` pass (where cross-language LTO is tested).
- Add a test confirming that `-Zbranch-protection=pac-ret` and cross-language LTO work together.
r? `@Mark-Simulacrum`
try-job: aarch64-gnu-debug
On some architectures, vector types may have a different ABI when
relevant target features are enabled.
As discussed in https://github.com/rust-lang/lang-team/issues/235, this
turns out to very easily lead to unsound code.
This commit makes it an error to declare or call functions using those
vector types in a context in which the corresponding target features are
disabled, if using an ABI for which the difference is relevant.
coverage: Emit LLVM intrinsics using the normal helper method
Codegen already has convenient ways to declare and emit LLVM intrinsics, so there's no need for coverage instrumentation to jump through hoops to emit them manually.
Add support for `~const` item bounds
Supports the only missing capability of `~const` associated types that I can think of now (this is obviously excluding `~const` opaques, which I see as an extension to this; I'll probably do that next).
r? ``@lcnr`` mostly b/c it changes candidate assembly, or reassign
cc ``@fee1-dead``
Expand `ptr::fn_addr_eq()` documentation.
* Describe more clearly what is (not) guaranteed, and de-emphasize the description of rustc implementation details.
* Explain what you *can* reliably use it for.
Tracking issue for `ptr_fn_addr_eq`: #129322
The motivation for this PR is that I just learned that `ptr::fn_addr_eq()` exists, read the documentation, and thought: “*I* know what this means, but someone not already familiar with how `rustc` works could be left wondering whether this is even good for anything.” Fixing that seems especially important if we’re going to recommend people use it instead of `==` (as per #118833).
[rustdoc] Do not consider nested functions as main function even if named `main` in doctests
Fixes#131893.
If a nested function is called `main`, it is not considered as the entry point of the program. Therefore, doctests should not consider such functions as such either.
r? `@notriddle`
Adding an extra `OnceCell` to `CrateCoverageContext` is much nicer than trying
to thread this string through multiple layers of function calls that already
have access to the context.
Rollup of 6 pull requests
Successful merges:
- #131851 ([musl] use posix_spawn if a directory change was requested)
- #132048 (AIX: use /dev/urandom for random implementation )
- #132093 (compiletest: suppress Windows Error Reporting (WER) for `run-make` tests)
- #132101 (Avoid using imports in thread_local_inner! in static)
- #132113 (Provide a default impl for Pattern::as_utf8_pattern)
- #132115 (rustdoc: Extend fake_variadic to "wrapped" tuples)
r? `@ghost`
`@rustbot` modify labels: rollup
Provide a default impl for Pattern::as_utf8_pattern
Newly added ```Pattern::as_utf8_pattern()``` causes needless breakage for crates that implement Pattern. This provides a default implementation instead.
r? `@BurntSushi`
Avoid using imports in thread_local_inner! in static
Fixes#131863 for wasm targets
All other macros were done in #131866, but this sub module is missed.
r? `@jieyouxu`
compiletest: suppress Windows Error Reporting (WER) for `run-make` tests
WER by default will show a *bunch* of error dialogues for missing DLLs on Windows for `run-make` tests. We address that by:
1. Guarding `run-make` test process spawning with `disable_error_reporting`.
2. Fixing `disable_error_reporting` to also add the [`SEM_FAILCRITICALERRORS` flag to `SetErrorMode`][SetErrorMode]. Just `SEM_NOGPFAULTERRORBOX` was not sufficient to suppress error dialogues for e.g. missing DLLs.
Fixes#132092. In particular, refer to that issue for the necessary conditions to observe these dialogues from popping up in the first place.
I was only able to manually test this locally in my "native" Windows msvc environment and it prevents the WER dialogues from popping up, I don't think it's possible to really test this automatically.
[SetErrorMode]: https://learn.microsoft.com/en-us/windows/win32/api/errhandlingapi/nf-errhandlingapi-seterrormode?redirectedfrom=MSDN#parameters
AIX: use /dev/urandom for random implementation
On AIX, we can poll `/dev/urandom` for cryptographically secure random output to implement `fill_bytes` because we don't have equivalent syscalls like other platforms. https://www.ibm.com/docs/en/aix/7.3?topic=files-random-urandom-devices
[musl] use posix_spawn if a directory change was requested
Currently, not all libcs have the `posix_spawn_file_actions_addchdir_np` symbol available to them. So we attempt to do a weak symbol lookup for that function. But that only works if libc is a dynamic library -- with statically linked musl binaries the symbol lookup would never work, so we would never be able to use it even if the musl in use supported the symbol.
Now that Rust has a minimum musl version of 1.2.3, all supported musl versions now include this symbol, so we can unconditionally expect it to be there. This symbol was added to libc in https://github.com/rust-lang/libc/pull/3949 -- use it here.
I couldn't find any tests for whether the posix_spawn path is used, but I've verified with cargo-nextest that this change works. This is a substantial improvement to nextest's performance with musl. On my workstation with a Ryzen 7950x, against https://github.com/clap-rs/clap at
61f5ee514f8f60ed8f04c6494bdf36c19e7a8126:
Before:
```
Summary [ 1.071s] 879 tests run: 879 passed, 0 skipped
```
After:
```
Summary [ 0.392s] 879 tests run: 879 passed, 0 skipped
```
Fixes#99740.
try-job: dist-various-1
try-job: dist-various-2
