Add tracking issue and unstable book page for `"vectorcall"` ABI
Originally added in 2015 by #30567, the Windows `"vectorcall"` ABI didn't have a tracking issue until now.
Tracking issue: #124485
Make `WHERE_CLAUSES_OBJECT_SAFETY` a regular object safety violation
#### The issue
In #50781, we have known about unsound `where` clauses in function arguments:
```rust
trait Impossible {}
trait Foo {
fn impossible(&self)
where
Self: Impossible;
}
impl Foo for &() {
fn impossible(&self)
where
Self: Impossible,
{}
}
// `where` clause satisfied for the object, meaning that the function now *looks* callable.
impl Impossible for dyn Foo {}
fn main() {
let x: &dyn Foo = &&();
x.impossible();
}
```
... which currently segfaults at runtime because we try to call a method in the vtable that doesn't exist. :(
#### What did u change
This PR removes the `WHERE_CLAUSES_OBJECT_SAFETY` lint and instead makes it a regular object safety violation. I choose to make this into a hard error immediately rather than a `deny` because of the time that has passed since this lint was authored, and the single (1) regression (see below).
That means that it's OK to mention `where Self: Trait` where clauses in your trait, but making such a trait into a `dyn Trait` object will report an object safety violation just like `where Self: Sized`, etc.
```rust
trait Impossible {}
trait Foo {
fn impossible(&self)
where
Self: Impossible; // <~ This definition is valid, just not object-safe.
}
impl Foo for &() {
fn impossible(&self)
where
Self: Impossible,
{}
}
fn main() {
let x: &dyn Foo = &&(); // <~ THIS is where we emit an error.
}
```
#### Regressions
From a recent crater run, there's only one crate that relies on this behavior: https://github.com/rust-lang/rust/pull/124305#issuecomment-2122381740. The crate looks unmaintained and there seems to be no dependents.
#### Further
We may later choose to relax this (e.g. when the where clause is implied by the supertraits of the trait or something), but this is not something I propose to do in this FCP.
For example, given:
```
trait Tr {
fn f(&self) where Self: Blanket;
}
impl<T: ?Sized> Blanket for T {}
```
Proving that some placeholder `S` implements `S: Blanket` would be sufficient to prove that the same (blanket) impl applies for both `Concerete: Blanket` and `dyn Trait: Blanket`.
Repeating here that I don't think we need to implement this behavior right now.
----
r? lcnr
Show files produced by `--emit foo` in json artifact notifications
Right now it is possible to ask `rustc` to save some intermediate representation into one or more files with `--emit=foo`, but figuring out what exactly was produced is difficult. This pull request adds information about `llvm_ir` and `asm` intermediate files into notifications produced by `--json=artifacts`.
Related discussion: https://internals.rust-lang.org/t/easier-access-to-files-generated-by-emit-foo/20477
Motivation - `cargo-show-asm` parses those intermediate files and presents them in a user friendly way, but right now I have to apply some dirty hacks. Hacks make behavior confusing: https://github.com/hintron/computer-enhance/issues/35
This pull request introduces a new behavior: now `rustc` will emit a new artifact notification for every artifact type user asked to `--emit`, for example for `--emit asm` those will include all the `.s` files.
Most users won't notice this behavior, to be affected by it all of the following must hold:
- user must use `rustc` binary directly (when `cargo` invokes `rustc` - it consumes artifact notifications and doesn't emit anything)
- user must specify both `--emit xxx` and `--json artifacts`
- user must refuse to handle unknown artifact types
- user must disable incremental compilation (or deal with it better than cargo does, or use a workaround like `save-temps`) in order not to hit #88829 / #89149
Use parenthetical notation for `Fn` traits
Always use the `Fn(T) -> R` format when printing closure traits instead of `Fn<(T,), Output = R>`.
Address #67100:
```
error[E0277]: expected a `Fn()` closure, found `F`
--> file.rs:6:13
|
6 | call_fn(f)
| ------- ^ expected an `Fn()` closure, found `F`
| |
| required by a bound introduced by this call
|
= note: wrap the `F` in a closure with no arguments: `|| { /* code */ }`
note: required by a bound in `call_fn`
--> file.rs:1:15
|
1 | fn call_fn<F: Fn() -> ()>(f: &F) {
| ^^^^^^^^^^ required by this bound in `call_fn`
help: consider further restricting this bound
|
5 | fn call_any<F: std::any::Any + Fn()>(f: &F) {
| ++++++
```
The `mir!` macro has multiple parts:
- An optional return type annotation.
- A sequence of zero or more local declarations.
- A mandatory starting anonymous basic block, which is brace-delimited.
- A sequence of zero of more additional named basic blocks.
Some `mir!` invocations use braces with a "block" style, like so:
```
mir! {
let _unit: ();
{
let non_copy = S(42);
let ptr = std::ptr::addr_of_mut!(non_copy);
// Inside `callee`, the first argument and `*ptr` are basically
// aliasing places!
Call(_unit = callee(Move(*ptr), ptr), ReturnTo(after_call), UnwindContinue())
}
after_call = {
Return()
}
}
```
Some invocations use parens with a "block" style, like so:
```
mir!(
let x: [i32; 2];
let one: i32;
{
x = [42, 43];
one = 1;
x = [one, 2];
RET = Move(x);
Return()
}
)
```
And some invocations uses parens with a "tighter" style, like so:
```
mir!({
SetDiscriminant(*b, 0);
Return()
})
```
This last style is generally used for cases where just the mandatory
starting basic block is present. Its braces are placed next to the
parens.
This commit changes all `mir!` invocations to use braces with a "block"
style. Why?
- Consistency is good.
- The contents of the invocation is a block of code, so it's odd to use
parens. They are more normally used for function-like macros.
- Most importantly, the next commit will enable rustfmt for
`tests/mir-opt/`. rustfmt is more aggressive about formatting macros
that use parens than macros that use braces. Without this commit's
changes, rustfmt would break a couple of `mir!` macro invocations that
use braces within `tests/mir-opt` by inserting an extraneous comma.
E.g.:
```
mir!(type RET = (i32, bool);, { // extraneous comma after ';'
RET.0 = 1;
RET.1 = true;
Return()
})
```
Switching those `mir!` invocations to use braces avoids that problem,
resulting in this, which is nicer to read as well as being valid
syntax:
```
mir! {
type RET = (i32, bool);
{
RET.0 = 1;
RET.1 = true;
Return()
}
}
```
Do not suggest unresolvable builder methods
Fixes#125303
The issue was that when a builder method cannot be resolved we are suggesting alternatives that themselves cannot be resolved. This PR adds a check that filters them from the list of suggestions.
It has a clumsy type, with repeated `&'a [LintId]`, and sometimes
requires an empty string that isn't used in the `Err`+`None` case.
This commit splits it into two variants.
Avoid checking the edition as much as possible
Inside https://github.com/rust-lang/rust/pull/123865, we are adding support for the new semantics for expr2024, but we have noted a performance issue.
While talking with `@eholk,` we realized there is a redundant check for each token regarding an edition. This commit moves the edition check to the end, avoiding some extra checks that can slow down compilation time.
However, we should keep this issue under observation because we may want to improve the edition check if we are unable to significantly improve compiler performance.
r? ghost
Add some more specific checks to the MIR validator
None of the `PointerCoercion`s had any checks, so while there's probably more that could be done here, hopefully these are better than the previous nothing.
r? mir
Make repr(packed) vectors work with SIMD intrinsics
In #117116 I fixed `#[repr(packed, simd)]` by doing the expected thing and removing padding from the layout. This should be the last step in providing a solution to rust-lang/portable-simd#319
Inside #123865, we are adding support for the new semantics
for expr2024, but we have noted a performance issue.
We realized there is a redundant check for each
token regarding an edition. This commit moves the edition
check to the end, avoiding some extra checks that
can slow down compilation time.
Link: https://github.com/rust-lang/rust/pull/123865
Co-Developed-by: @eholk
Signed-off-by: Vincenzo Palazzo <vincenzopalazzodev@gmail.com>
Reject `CVarArgs` in `parse_ty_for_where_clause`
Fixes#125847. This regressed in #77035 where the `parse_ty` inside `parse_ty_where_predicate` was replaced with the at the time new `parse_ty_for_where_clause` which incorrectly stated it would permit CVarArgs (maybe a copy/paste error).
r? parser
Uplift `{Closure,Coroutine,CoroutineClosure}Args` and friends to `rustc_type_ir`
Part of converting the new solver's `structural_traits.rs` to be interner-agnostic.
I decided against aliasing `ClosureArgs<TyCtxt<'tcx>>` to `ClosureArgs<'tcx>` because it seemed so rare. I could do so if desired, though.
r? lcnr
Check index `value <= 0xFFFF_FF00`
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fixes#121126
check `idx <= FieldIdx::MAX_AS_U32` before calling `FieldIdx::from_u32` to avoid panic.
Stabilize `custom_code_classes_in_docs` feature
Fixes#79483.
This feature has been around for quite some time now, I think it's fine to stabilize it now.
## Summary
## 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.
EDIT(camelid): This description is out-of-date. Using `custom,class:language-c` will generate the output `<pre class="language-class:language-c">` as would be expected; it treats `class:language-c` as just the name of a language (similar to the langstring `c` or `js` or what have you) since it does not use the designed class syntax.
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)).
r? `@notriddle`
Also resolve the type of constants, even if we already turned it into an error constant
error constants can still have arbitrary types, and in this case it was turned into an error constant because there was an infer var in the *type* not the *const*.
fixes#125760
Stop using `translate_args` in the new solver
It was unnecessary and also sketchy, since it was doing an out-of-search-graph fulfillment loop. Added a test for the only really minor subtlety of translating args, though not sure if it was being tested before, though I wouldn't be surprised if it wasn't.
r? lcnr
coverage: Optionally instrument the RHS of lazy logical operators
(This is an updated version of #124644 and #124402. Fixes #124120.)
When `||` or `&&` is used outside of a branching context (such as the condition of an `if`), the rightmost value does not directly influence any branching decision, so branch coverage instrumentation does not treat it as its own true-or-false branch.
That is a correct and useful interpretation of “branch coverage”, but might be undesirable in some contexts, as described at #124120. This PR therefore adds a new coverage level `-Zcoverage-options=condition` that behaves like branch coverage, but also adds additional branch instrumentation to the right-hand-side of lazy boolean operators.
---
As discussed at https://github.com/rust-lang/rust/issues/124120#issuecomment-2092394586, this is mainly intended as an intermediate step towards fully-featured MC/DC instrumentation. It's likely that we'll eventually want to remove this coverage level (rather than stabilize it), either because it has been incorporated into MC/DC instrumentation, or because it's getting in the way of future MC/DC work. The main appeal of landing it now is so that work on tracking conditions can proceed concurrently with other MC/DC-related work.
````@rustbot```` label +A-code-coverage
Apply `x clippy --fix` and `x fmt` on Rustc
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Just run `x clippy --fix` and `x fmt`, and remove some changes like `impl Default`.
