safe transmute: support `Single` enums
Previously, the implementation of `Tree::from_enum` incorrectly treated enums with `Variants::Single` and `Variants::Multiple` identically. This is incorrect for `Variants::Single` enums, which delegate their layout to that of a variant with a particular index (or no variant at all if the enum is empty).
This flaw manifested first as an ICE. `Tree::from_enum` attempted to compute the tag of variants other than the one at `Variants::Single`'s `index`, and fell afoul of a sanity-checking assertion in `compiler/rustc_const_eval/src/interpret/discriminant.rs`. This assertion is non-load-bearing, and can be removed; the routine its in is well-behaved even without it.
With the assertion removed, the proximate issue becomes apparent: calling `Tree::from_variant` on a variant that does not exist is ill-defined. A sanity check the given variant has `FieldShapes::Arbitrary` fails, and the analysis is (correctly) aborted with `Err::NotYetSupported`.
This commit corrects this chain of failures by ensuring that `Tree::from_variant` is not called on variants that are, as far as layout is concerned, nonexistent. Specifically, the implementation of `Tree::from_enum` is now partitioned into three cases:
1. enums that are uninhabited
2. enums for which all but one variant is uninhabited
3. enums with multiple inhabited variants
`Tree::from_variant` is now only invoked in the third case. In the first case, `Tree::uninhabited()` is produced. In the second case, the layout is delegated to `Variants::Single`'s index.
Fixes#125811
docs(rustc): Improve discoverable of Cargo docs
In preparing Cargo's blog post for 1.80, I tried to find the documentation for the lint configuration and I couldn't. The link is only visible from the lint itself, which isn't where I started, and the side bar, which was collapsed for me.
The first place I went was the docs for `unexpected_cfgs` because this is configuration for that lint. If using lint configuration were a one off, I could see skipping it here. However, when we discussed this with at least one T-compiler member, there was interest in using this for other lints in the future. To that end, it seems like we should be exposing this with the lint itself.
The second place I checked was the `check-cfg` documentation. This now has a call out for the sub-page.
Add no_std Xtensa targets support
Adds no_std Xtensa targets. This enables using Rust on ESP32, ESP32-S2 and ESP32-S3 chips.
Tier 3 policy:
> A tier 3 target must have a designated developer or developers (the "target maintainers") on record to be CCed when issues arise regarding the target. (The mechanism to track and CC such developers may evolve over time.)
`@MabezDev` and I (`@SergioGasquez)` will maintain the targets.
> Targets must use naming consistent with any existing targets; for instance, a target for the same CPU or OS as an existing Rust target should use the same name for that CPU or OS. Targets should normally use the same names and naming conventions as used elsewhere in the broader ecosystem beyond Rust (such as in other toolchains), unless they have a very good reason to diverge. Changing the name of a target can be highly disruptive, especially once the target reaches a higher tier, so getting the name right is important even for a tier 3 target.
The target triple is consistent with other targets.
> Target names should not introduce undue confusion or ambiguity unless absolutely necessary to maintain ecosystem compatibility. For example, if the name of the target makes people extremely likely to form incorrect beliefs about what it targets, the name should be changed or augmented to disambiguate it.
> If possible, use only letters, numbers, dashes and underscores for the name. Periods (.) are known to cause issues in Cargo.
We follow the same naming convention as other targets.
> Tier 3 targets may have unusual requirements to build or use, but must not create legal issues or impose onerous legal terms for the Rust project or for Rust developers or users.
The target does not introduce any legal issues.
> The target must not introduce license incompatibilities.
There are no license incompatibilities
> Anything added to the Rust repository must be under the standard Rust license (MIT OR Apache-2.0).
Everything added is under that licenses
> The target must not cause the Rust tools or libraries built for any other host (even when supporting cross-compilation to the target) to depend on any new dependency less permissive than the Rust licensing policy. This applies whether the dependency is a Rust crate that would require adding new license exceptions (as specified by the tidy tool in the rust-lang/rust repository), or whether the dependency is a native library or binary. In other words, the introduction of the target must not cause a user installing or running a version of Rust or the Rust tools to be subject to any new license requirements.
Requirements are not changed for any other target.
> Compiling, linking, and emitting functional binaries, libraries, or other code for the target (whether hosted on the target itself or cross-compiling from another target) must not depend on proprietary (non-FOSS) libraries. Host tools built for the target itself may depend on the ordinary runtime libraries supplied by the platform and commonly used by other applications built for the target, but those libraries must not be required for code generation for the target; cross-compilation to the target must not require such libraries at all. For instance, rustc built for the target may depend on a common proprietary C runtime library or console output library, but must not depend on a proprietary code generation library or code optimization library. Rust's license permits such combinations, but the Rust project has no interest in maintaining such combinations within the scope of Rust itself, even at tier 3.
The linker used by the targets is the GCC linker from the GCC toolchain cross-compiled for Xtensa. GNU GPL.
> "onerous" here is an intentionally subjective term. At a minimum, "onerous" legal/licensing terms include but are not limited to: non-disclosure requirements, non-compete requirements, contributor license agreements (CLAs) or equivalent, "non-commercial"/"research-only"/etc terms, requirements conditional on the employer or employment of any particular Rust developers, revocable terms, any requirements that create liability for the Rust project or its developers or users, or any requirements that adversely affect the livelihood or prospects of the Rust project or its developers or users.
No such terms exist for this target
> Neither this policy nor any decisions made regarding targets shall create any binding agreement or estoppel by any party. If any member of an approving Rust team serves as one of the maintainers of a target, or has any legal or employment requirement (explicit or implicit) that might affect their decisions regarding a target, they must recuse themselves from any approval decisions regarding the target's tier status, though they may otherwise participate in discussions.
> This requirement does not prevent part or all of this policy from being cited in an explicit contract or work agreement (e.g. to implement or maintain support for a target). This requirement exists to ensure that a developer or team responsible for reviewing and approving a target does not face any legal threats or obligations that would prevent them from freely exercising their judgment in such approval, even if such judgment involves subjective matters or goes beyond the letter of these requirements.
Understood
> Tier 3 targets should attempt to implement as much of the standard libraries as possible and appropriate (core for most targets, alloc for targets that can support dynamic memory allocation, std for targets with an operating system or equivalent layer of system-provided functionality), but may leave some code unimplemented (either unavailable or stubbed out as appropriate), whether because the target makes it impossible to implement or challenging to implement. The authors of pull requests are not obligated to avoid calling any portions of the standard library on the basis of a tier 3 target not implementing those portions.
The target already implements core.
> The target must provide documentation for the Rust community explaining how to build for the target, using cross-compilation if possible. If the target supports running binaries, or running tests (even if they do not pass), the documentation must explain how to run such binaries or tests for the target, using emulation if possible or dedicated hardware if necessary.
Here is how to build for the target https://docs.esp-rs.org/book/installation/riscv-and-xtensa.html and it also covers how to run binaries on the target.
> Tier 3 targets must not impose burden on the authors of pull requests, or other developers in the community, to maintain the target. In particular, do not post comments (automated or manual) on a PR that derail or suggest a block on the PR based on a tier 3 target. Do not send automated messages or notifications (via any medium, including via `@)` to a PR author or others involved with a PR regarding a tier 3 target, unless they have opted into such messages.
> Backlinks such as those generated by the issue/PR tracker when linking to an issue or PR are not considered a violation of this policy, within reason. However, such messages (even on a separate repository) must not generate notifications to anyone involved with a PR who has not requested such notifications.
Understood
> Patches adding or updating tier 3 targets must not break any existing tier 2 or tier 1 target, and must not knowingly break another tier 3 target without approval of either the compiler team or the maintainers of the other tier 3 target.
> In particular, this may come up when working on closely related targets, such as variations of the same architecture with different features. Avoid introducing unconditional uses of features that another variation of the target may not have; use conditional compilation or runtime detection, as appropriate, to let each target run code supported by that target.
No other targets should be affected
> Tier 3 targets must be able to produce assembly using at least one of rustc's supported backends from any host target.
It can produce assembly, but it requires a custom LLVM with Xtensa support (https://github.com/espressif/llvm-project/). The patches are trying to be upstreamed (https://github.com/espressif/llvm-project/issues/4)
Edition 2024: Make `!` fall back to `!`
This PR changes never type fallback to be `!` (the never type itself) in the next, 2024, edition.
This makes the never type's behavior more intuitive (in 2024 edition) and is the first step of the path to stabilize it.
r? `@compiler-errors`
Allow rust-project.json to include arbitrary shell commands for runnables
This is a follow-up on #16135, resolving the feedback raised :)
Allow rust-project.json to include shell runnables, of the form:
```
{
"build_info": {
"label": "//project/foo:my-crate",
"target_kind": "bin",
"shell_runnables": [
{
"kind": "run",
"program": "buck2",
"args": ["run", "//project/foo:my-crate"]
},
{
"kind": "test_one",
"program": "test_runner",
"args": ["--name=$$TEST_NAME$$"]
}
]
}
}
```
If these runnable configs are present for the current crate in rust-project.json, offer them as runnables in VS Code.
This PR required some boring changes to APIs that previously only handled cargo situations. I've split out these changes as commits labelled 'refactor', so it's easy to see the interesting changes.
feat: show type bounds from containers when hovering on functions
fix#12917.
### Changes
1. Added Support for displaying the container and type bounds from it when hovering on functions with generic types.
2. Added a user config to determine whether to display container bounds (enabled by default).
3. Added regression tests.
4. Simplified and refactored `hir/display.rs` to improve readability.
Chore(deps-dev): Bump braces from 3.0.2 to 3.0.3 in /editors/code
Bumps [braces](https://github.com/micromatch/braces) from 3.0.2 to 3.0.3.
<details>
<summary>Commits</summary>
<ul>
<li><a href="74b2db2938"><code>74b2db2</code></a> 3.0.3</li>
<li><a href="88f1429a0f"><code>88f1429</code></a> update eslint. lint, fix unit tests.</li>
<li><a href="415d660c30"><code>415d660</code></a> Snyk js braces 6838727 (<a href="https://redirect.github.com/micromatch/braces/issues/40">#40</a>)</li>
<li><a href="190510f79d"><code>190510f</code></a> fix tests, skip 1 test in test/braces.expand</li>
<li><a href="716eb9f12d"><code>716eb9f</code></a> readme bump</li>
<li><a href="a5851e57f4"><code>a5851e5</code></a> Merge pull request <a href="https://redirect.github.com/micromatch/braces/issues/37">#37</a> from coderaiser/fix/vulnerability</li>
<li><a href="2092bd1fb1"><code>2092bd1</code></a> feature: braces: add maxSymbols (<a href="https://github.com/micromatch/braces/issues/">https://github.com/micromatch/braces/issues/</a>...</li>
<li><a href="9f5b4cf473"><code>9f5b4cf</code></a> fix: vulnerability (<a href="https://security.snyk.io/vuln/SNYK-JS-BRACES-6838727">https://security.snyk.io/vuln/SNYK-JS-BRACES-6838727</a>)</li>
<li><a href="98414f9f1f"><code>98414f9</code></a> remove funding file</li>
<li><a href="665ab5d561"><code>665ab5d</code></a> update keepEscaping doc (<a href="https://redirect.github.com/micromatch/braces/issues/27">#27</a>)</li>
<li>Additional commits viewable in <a href="https://github.com/micromatch/braces/compare/3.0.2...3.0.3">compare view</a></li>
</ul>
</details>
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fix: ensure that the parent of a SourceRoot cannot be itself
fix#17378.
In `FileSetConfig.map`, different roots might be mapped to the same `root_id` due to deduplication in `ProjectFolders::new`:
```rust
// Example from rustup
/Users/roife/code/rustup/target/debug/build/rustup-863a063426b56c51/out
/Users/roife/code/rustup
```
In `source_root_parent_map`, r-a might encounter paths where their SourceRootId (i.e. `root_id`) is identical, yet one the them is the parent of the another. This situation can cause the `root_id` to be its own parent, potentially leading to an infinite loop.
This PR resolves such cases by adding a check.
