Turn custom code classes in docs into warning
By habit, since it was a new feature gate, I added a check which emitted an error in case the new syntax was used. However, since rustdoc tags parser was accepting *everything*, using the "new" syntax should never ever emit errors. It now emits a warning.
Follow-up of #110800.
cc `@Manishearth`
r? `@notriddle`
repr(transparent): it's fine if the one non-1-ZST field is a ZST
This code currently gets rejected:
```rust
#[repr(transparent)]
struct MyType([u16; 0])
```
That clearly seems like a bug to me: `repr(transparent)` [got defined ](https://github.com/rust-lang/rust/issues/77841#issuecomment-716575747) as having any number of 1-ZST fields plus optionally one more field; `MyType` clearly satisfies that definition.
This PR changes the `repr(transparent)` logic to actually match that definition.
Rollup of 6 pull requests
Successful merges:
- #114965 (Remove Drop impl of mpsc Receiver and (Sync)Sender)
- #115434 (make `Debug` impl for `ascii::Char` match that of `char`)
- #115477 (Stabilize the `Saturating` type)
- #115611 (add diagnostic for raw identifiers in format string)
- #115654 (improve PassMode docs)
- #115862 (Migrate `compiler/rustc_hir_typeck/src/callee.rs` to translatable diagnostics)
r? `@ghost`
`@rustbot` modify labels: rollup
Make `.rmeta` file in `dep-info` have correct name (`lib` prefix)
Since `filename_for_metadata()` and
`OutputFilenames::path(OutputType::Metadata)` had different logic for the name of the metadata file, the `.d` file contained a file name different from the actual name used. Share the logic to fix the out-of-sync name.
Without this fix, the `.d` file contained
dash-separated_something-extra.rmeta: dash-separated.rs
instead of
libdash_separated_something-extra.rmeta: dash-separated.rs
which is the name of the file that is actually written by the compiler.
Worth noting: It took me several iterations to get all tests to pass, so I am relatively confident that this PR does not break anything.
Closes#68839
add diagnostic for raw identifiers in format string
Format strings don't support raw identifiers (e.g. `format!("{r#type}")`), but they do support keywords in the format string directly (e.g. `format!("{type}")`). This PR improves the error output when attempting to use a raw identifier in a format string and adds a machine-applicable suggestion to remove the `r#`.
fixes https://github.com/rust-lang/rust/issues/115466
`#[diagnostic::on_unimplemented]` without filters
This commit adds support for a `#[diagnostic::on_unimplemented]` attribute with the following options:
* `message` to customize the primary error message
* `note` to add a customized note message to an error message
* `label` to customize the label part of the error message
The relevant behavior is specified in [RFC-3366](https://rust-lang.github.io/rfcs/3366-diagnostic-attribute-namespace.html)
impl Step for IP addresses
ACP: rust-lang/libs-team#235
Note: since this is insta-stable, it requires an FCP.
Separating out from the bit operations PR since it feels logically disjoint, and so their FCPs can be separate.
Accept additional user-defined syntax classes in fenced code blocks
Part of #79483.
This is a re-opening of https://github.com/rust-lang/rust/pull/79454 after a big update/cleanup. I also converted the syntax to pandoc as suggested by `@notriddle:` the idea is to be as compatible as possible with the existing instead of having our own syntax.
## Motivation
From the original issue: https://github.com/rust-lang/rust/issues/78917
> The technique used by `inline-c-rs` can be ported to other languages. It's just super fun to see C code inside Rust documentation that is also tested by `cargo doc`. I'm sure this technique can be used by other languages in the future.
Having custom CSS classes for syntax highlighting will allow tools like `highlight.js` to be used in order to provide highlighting for languages other than Rust while not increasing technical burden on rustdoc.
## What is the feature about?
In short, this PR changes two things, both related to codeblocks in doc comments in Rust documentation:
* Allow to disable generation of `language-*` CSS classes with the `custom` attribute.
* Add your own CSS classes to a code block so that you can use other tools to highlight them.
#### The `custom` attribute
Let's start with the new `custom` attribute: it will disable the generation of the `language-*` CSS class on the generated HTML code block. For example:
```rust
/// ```custom,c
/// int main(void) {
/// return 0;
/// }
/// ```
```
The generated HTML code block will not have `class="language-c"` because the `custom` attribute has been set. The `custom` attribute becomes especially useful with the other thing added by this feature: adding your own CSS classes.
#### Adding your own CSS classes
The second part of this feature is to allow users to add CSS classes themselves so that they can then add a JS library which will do it (like `highlight.js` or `prism.js`), allowing to support highlighting for other languages than Rust without increasing burden on rustdoc. To disable the automatic `language-*` CSS class generation, you need to use the `custom` attribute as well.
This allow users to write the following:
```rust
/// Some code block with `{class=language-c}` as the language string.
///
/// ```custom,{class=language-c}
/// int main(void) {
/// return 0;
/// }
/// ```
fn main() {}
```
This will notably produce the following HTML:
```html
<pre class="language-c">
int main(void) {
return 0;
}</pre>
```
Instead of:
```html
<pre class="rust rust-example-rendered">
<span class="ident">int</span> <span class="ident">main</span>(<span class="ident">void</span>) {
<span class="kw">return</span> <span class="number">0</span>;
}
</pre>
```
To be noted, we could have written `{.language-c}` to achieve the same result. `.` and `class=` have the same effect.
One last syntax point: content between parens (`(like this)`) is now considered as comment and is not taken into account at all.
In addition to this, I added an `unknown` field into `LangString` (the parsed code block "attribute") because of cases like this:
```rust
/// ```custom,class:language-c
/// main;
/// ```
pub fn foo() {}
```
Without this `unknown` field, it would generate in the DOM: `<pre class="language-class:language-c language-c">`, which is quite bad. So instead, it now stores all unknown tags into the `unknown` field and use the first one as "language". So in this case, since there is no unknown tag, it'll simply generate `<pre class="language-c">`. I added tests to cover this.
Finally, I added a parser for the codeblock attributes to make it much easier to maintain. It'll be pretty easy to extend.
As to why this syntax for adding attributes was picked: it's [Pandoc's syntax](https://pandoc.org/MANUAL.html#extension-fenced_code_attributes). Even if it seems clunkier in some cases, it's extensible, and most third-party Markdown renderers are smart enough to ignore Pandoc's brace-delimited attributes (from [this comment](https://github.com/rust-lang/rust/pull/110800#issuecomment-1522044456)).
## Raised concerns
#### It's not obvious when the `language-*` attribute generation will be added or not.
It is added by default. If you want to disable it, you will need to use the `custom` attribute.
#### Why not using HTML in markdown directly then?
Code examples in most languages are likely to contain `<`, `>`, `&` and `"` characters. These characters [require escaping](https://developer.mozilla.org/en-US/docs/Web/HTML/Element/pre) when written inside the `<pre>` element. Using the \`\`\` code blocks allows rustdoc to take care of escaping, which means doc authors can paste code samples directly without manually converting them to HTML.
cc `@poliorcetics`
r? `@notriddle`
closure field capturing: don't depend on alignment of packed fields
This fixes the closure field capture part of https://github.com/rust-lang/rust/issues/115305: field capturing always stops at projections into packed structs, no matter the alignment of the field. This means changing a private field type from `u8` to `u64` can never change how closures capture fields, which is probably what we want.
Here's an example where, before this PR, changing the type of a private field in a repr(Rust) struct can change the output of a program:
```rust
#![allow(dead_code)]
mod m {
// before patch
#[derive(Default)]
pub struct S1(u8);
// after patch
#[derive(Default)]
pub struct S2(u64);
}
struct NoisyDrop;
impl Drop for NoisyDrop {
fn drop(&mut self) {
eprintln!("dropped!");
}
}
#[repr(packed)]
struct MyType {
field: m::S1, // output changes when this becomes S2
other_field: NoisyDrop,
third_field: Vec<()>,
}
fn test(r: MyType) {
let c = || {
let _val = std::ptr::addr_of!(r.field);
let _val = r.third_field;
};
drop(c);
eprintln!("before dropping");
}
fn main() {
test(MyType {
field: Default::default(),
other_field: NoisyDrop,
third_field: Vec::new(),
});
}
```
Of course this is a breaking change for the same reason that doing field capturing in the first place was a breaking change. Packed fields are relatively rare and depending on drop order is relatively rare, so I don't expect this to have much impact, but it's hard to be sure and even a crater run will only tell us so much.
Also see the [nomination comment](https://github.com/rust-lang/rust/pull/115315#issuecomment-1702807825).
Cc `@rust-lang/wg-rfc-2229` `@ehuss`
Make useless_ptr_null_checks smarter about some std functions
This teaches the `useless_ptr_null_checks` lint that some std functions can't ever return null pointers, because they need to point to valid data, get references as input, etc.
This is achieved by introducing an `#[rustc_never_returns_null_ptr]` attribute and adding it to these std functions (gated behind bootstrap `cfg_attr`).
Later on, the attribute could maybe be used to tell LLVM that the returned pointer is never null. I don't expect much impact of that though, as the functions are pretty shallow and usually the input data is already never null.
Follow-up of PR #113657Fixes#114442
Fallback effects even if types also fallback
`||` is short circuiting, so if we do ty/int var fallback, we *don't* do effect fallback 😸
r? `@fee1-dead` or `@oli-obk`
Fixes#115791Fixes#115842
Improve invalid let expression handling
- Move all of the checks for valid let expression positions to parsing.
- Add a field to ExprKind::Let in AST/HIR to mark whether it's in a valid location.
- Suppress some later errors and MIR construction for invalid let expressions.
- Fix a (drop) scope issue that was also responsible for #104172.
Fixes#104172Fixes#104868
Paper over an accidental regression
r? types
cc https://github.com/rust-lang/rust/issues/115781 (do not close issue until beta backport has been performed)
The PR reasons are explained with comments in the source.
In order to keep the diff simple, this PR effectively reverts https://github.com/rust-lang/rust/pull/113661, but only for RPITs. I will submit a follow up PR that fixes this correctly instead of just disabling the newly added check for RPITs. This PR should be significantly easier to review for beta backport
Properly consider binder vars in `HasTypeFlagsVisitor`
Given a PolyTraitRef like `for<'a> Ty: Trait` (where neither `Ty` nor `Trait` mention `'a`), we do *not* return true for `.has_type_flags(TypeFlags::HAS_LATE_BOUND)`, even though binders are supposed to act as if they have late-bound vars even if they don't mention them in their bound value: 31ae3b2bdb. This is because we use `HasTypeFlagsVisitor`, which only computes the type flags for `Ty`, `Const` and `Region` and `Predicates`, and we consequently skip any binders (and setting flags for their vars) that are not contained in one of these types.
This ends up causing a problem, because when we call `TyCtxt::erase_regions` (which both erases regions *and* anonymizes bound vars), we will skip such a PolyTraitRef, not anonymizing it, and therefore not making it structurally equal to other binders. This breaks vtable computations.
This PR computes the flags for all binders we enter in `HasTypeFlagsVisitor` if we're looking for `TypeFlags::HAS_LATE_BOUND` (or `TypeFlags::HAS_{RE,TY,CT}_LATE_BOUND`).
Fixes#115807
Fix the error message for `#![feature(no_coverage)]`
When #114656 was written, the feature flag to replace `no_coverage` was originally spelled `coverage`, but it was eventually changed to `coverage_attribute` instead.
That update happened to miss this error message in `removed.rs`, and unfortunately I only noticed just *after* the original PR was approved and merged.
cc ``@bossmc`` (original author) ``@oli-obk`` (original reviewer)
``@rustbot`` label +A-code-coverage
some ConstValue refactoring
In particular, use AllocId instead of Allocation in ConstValue::ByRef. This helps avoid redundant AllocIds when a `ByRef` constant gets put back into the interpreter.
r? `@oli-obk`
Fixes https://github.com/rust-lang/rust/issues/105536
Rework `no_coverage` to `coverage(off)`
As discussed at the tail of https://github.com/rust-lang/rust/issues/84605 this replaces the `no_coverage` attribute with a `coverage` attribute that takes sub-parameters (currently `off` and `on`) to control the coverage instrumentation.
Allows future-proofing for things like `coverage(off, reason="Tested live", issue="#12345")` or similar.
