Fix the conflict problem between the diagnostics fixes of lint `unnecessary_qualification` and `unused_imports`
fixes#121331
For an `item` that triggers lint unnecessary_qualification, if the `use item` which imports this item is also trigger unused import, fixing the two lints at the same time may lead to the problem that the `item` cannot be found.
This PR will avoid reporting lint unnecessary_qualification when conflict occurs.
r? ``@petrochenkov``
coverage: Initial support for branch coverage instrumentation
(This is a review-ready version of the changes that were drafted in #118305.)
This PR adds support for branch coverage instrumentation, gated behind the unstable flag value `-Zcoverage-options=branch`. (Coverage instrumentation must also be enabled with `-Cinstrument-coverage`.)
During THIR-to-MIR lowering (MIR building), if branch coverage is enabled, we collect additional information about branch conditions and their corresponding then/else blocks. We inject special marker statements into those blocks, so that the `InstrumentCoverage` MIR pass can reliably identify them even after the initially-built MIR has been simplified and renumbered.
The rest of the changes are mostly just plumbing needed to gather up the information that was collected during MIR building, and include it in the coverage metadata that we embed in the final binary.
Note that `llvm-cov show` doesn't print branch coverage information in its source views by default; that needs to be explicitly enabled with `--show-branches=count` or similar.
---
The current implementation doesn't have any support for instrumenting `if let` or let-chains. I think it's still useful without that, and adding it would be non-trivial, so I'm happy to leave that for future work.
more eagerly instantiate binders
The old solver sometimes incorrectly used `sub`, change it to explicitly instantiate binders and use `eq` instead. While doing so I also moved the instantiation before the normalize calls. This caused some observable changes, will explain these inline. This PR therefore requires a crater run and an FCP.
r? types
Add a test that `f16` and `f128` are usable with the feature gate
enabled, as well as a test that user types with the same name as
primitives are not improperly gated.
Includes related tests and documentation pages.
Michael Goulet: Don't issue feature error in resolver for f16/f128
unless finalize
Co-authored-by: Michael Goulet <michael@errs.io>
Ungate the `UNKNOWN_OR_MALFORMED_DIAGNOSTIC_ATTRIBUTES` lint
This was missed during stablisation of the `#[diagnostic]` attribute namespace.
Fixes#122446
add test ensuring simd codegen checks don't run when a static assertion failed
stdarch relies on this to ensure that SIMD indices are in bounds.
I would love to know why this works, but I can't figure out where codegen decides to not codegen a function if a required-const does not evaluate. `@oli-obk` `@bjorn3` do you have any idea?
rustdoc-search: depth limit `T<U>` -> `U` unboxing
Profiler output:
https://notriddle.com/rustdoc-html-demo-9/search-unbox-limit/ (the only significant change is that one of the `rust` tests went from 378416ms to 16ms).
This is a performance enhancement aimed at a problem I found while using type-driven search on the Rust compiler. It is caused by [`Interner`], a trait with 41 associated types, many of which recurse back to `Self` again.
This caused search.js to struggle. It eventually terminates, after about 10 minutes of turning my PC into a space header, but it's doing `41!` unifications and that's too slow.
[`Interner`]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_middle/ty/trait.Interner.html
const-eval: organize and extend tests for required-consts
This includes some tests that are known-broken and hence disabled (due to https://github.com/rust-lang/rust/issues/107503).
r? `````@oli-obk`````
Add methods to create StableMIR constant
I've been experimenting with transforming the StableMIR to instrument the code with potential UB checks.
The modified body will only be used by our analysis tool, however, constants in StableMIR must be backed by rustc constants. Thus, I'm adding a few functions to build constants, such as building string and other primitives.
One question I have is whether we should create a global allocation instead for strings.
r? ``````@oli-obk``````
rustdoc-search: search types by higher-order functions
This feature extends rustdoc with syntax and search index information for searching function pointers and closures (Higher-Order Functions, or HOF). Part of https://github.com/rust-lang/rust/issues/60485
This PR adds two syntaxes: a high-level one for finding any kind of HOF, and a direct implementation of the parenthesized path syntax that Rust itself uses.
## Preview pages
| Query | Results |
|-------|---------|
| [`option<T>, (fnonce (T) -> bool) -> option<T>`][optionfilter] | `Option::filter` |
| [`option<T>, (T -> bool) -> option<T>`][optionfilter2] | `Option::filter` |
Updated chapter of the book: https://notriddle.com/rustdoc-html-demo-9/search-hof/rustdoc/read-documentation/search.html
[optionfilter]: https://notriddle.com/rustdoc-html-demo-9/search-hof/std/vec/struct.Vec.html?search=option<T>%2C+(fnonce+(T)+->+bool)+->+option<T>&filter-crate=std
[optionfilter2]: https://notriddle.com/rustdoc-html-demo-9/search-hof/std/vec/struct.Vec.html?search=option<T>%2C+(T+->+bool)+->+option<T>&filter-crate=std
## Motivation
When type-based search was first landed, it was directly [described as incomplete][a comment].
[a comment]: https://github.com/rust-lang/rust/pull/23289#issuecomment-79437386
Filling out the missing functionality is going to mean adding support for more of Rust's [type expression] syntax, such as references, raw pointers, function pointers, and closures. This PR adds function pointers and closures.
[type expression]: https://doc.rust-lang.org/reference/types.html#type-expressions
There's been demand for something "like Hoogle, but for Rust" expressed a few times [1](https://www.reddit.com/r/rust/comments/y8sbid/is_there_a_website_like_haskells_hoogle_for_rust/) [2](https://users.rust-lang.org/t/rust-equivalent-of-haskells-hoogle/102280) [3](https://internals.rust-lang.org/t/std-library-inclusion-policy/6852/2) [4](https://discord.com/channels/442252698964721669/448238009733742612/1109502307495858216). Some of them just don't realize what functionality already exists ([`Duration -> u64`](https://doc.rust-lang.org/nightly/std/?search=duration%20-%3E%20u64) already works), but a lot of them specifically want to search for higher-order functions like option combinators.
## Guide-level explanation (from the Rustdoc book)
To search for a function that accepts a function as a parameter, like `Iterator::all`, wrap the nested signature in parenthesis, as in [`Iterator<T>, (T -> bool) -> bool`][iterator-all]. You can also search for a specific closure trait, such as `Iterator<T>, (FnMut(T) -> bool) -> bool`, but you need to know which one you want.
[iterator-all]: https://notriddle.com/rustdoc-html-demo-9/search-hof/std/vec/struct.Vec.html?search=Iterator<T>%2C+(T+->+bool)+->+bool&filter-crate=std
## Reference-level description (also from the Rustdoc book)
### Primitives with Special Syntax
<table>
<thead>
<tr>
<th>Shorthand</th>
<th>Explicit names</th>
</tr>
</thead>
<tbody>
<tr><td colspan="2">Before this PR</td></tr>
<tr>
<td><code>[]</code></td>
<td><code>primitive:slice</code> and/or <code>primitive:array</code></td>
</tr>
<tr>
<td><code>[T]</code></td>
<td><code>primitive:slice<T></code> and/or <code>primitive:array<T></code></td>
</tr>
<tr>
<td><code>!</code></td>
<td><code>primitive:never</code></td>
</tr>
<tr>
<td><code>()</code></td>
<td><code>primitive:unit</code> and/or <code>primitive:tuple</code></td>
</tr>
<tr>
<td><code>(T)</code></td>
<td><code>T</code></td>
</tr>
<tr>
<td><code>(T,)</code></td>
<td><code>primitive:tuple<T></code></td>
</tr>
<tr><td colspan="2">After this PR</td></tr>
<tr>
<td><code>(T, U -> V, W)</code></td>
<td><code>fn(T, U) -> (V, W)</code>, Fn, FnMut, and FnOnce</td>
</tr>
</tbody>
</table>
The `->` operator has lower precedence than comma. If it's not wrapped in brackets, it delimits the return value for the function being searched for. To search for functions that take functions as parameters, use parenthesis.
### Search query grammar
```ebnf
ident = *(ALPHA / DIGIT / "_")
path = ident *(DOUBLE-COLON ident) [BANG]
slice-like = OPEN-SQUARE-BRACKET [ nonempty-arg-list ] CLOSE-SQUARE-BRACKET
tuple-like = OPEN-PAREN [ nonempty-arg-list ] CLOSE-PAREN
arg = [type-filter *WS COLON *WS] (path [generics] / slice-like / tuple-like)
type-sep = COMMA/WS *(COMMA/WS)
nonempty-arg-list = *(type-sep) arg *(type-sep arg) *(type-sep) [ return-args ]
generic-arg-list = *(type-sep) arg [ EQUAL arg ] *(type-sep arg [ EQUAL arg ]) *(type-sep)
normal-generics = OPEN-ANGLE-BRACKET [ generic-arg-list ] *(type-sep)
CLOSE-ANGLE-BRACKET
fn-like-generics = OPEN-PAREN [ nonempty-arg-list ] CLOSE-PAREN [ RETURN-ARROW arg ]
generics = normal-generics / fn-like-generics
return-args = RETURN-ARROW *(type-sep) nonempty-arg-list
exact-search = [type-filter *WS COLON] [ RETURN-ARROW ] *WS QUOTE ident QUOTE [ generics ]
type-search = [ nonempty-arg-list ]
query = *WS (exact-search / type-search) *WS
; unchanged parts of the grammar, like the full list of type filters, are omitted
```
## Future direction
### The remaining type expression grammar
As described in https://github.com/rust-lang/rust/pull/118194, this is another step in the type expression grammar: BareFunction, and the function-like mode of TypePath, are now supported.
* RawPointerType and ReferenceType actually are a priority.
* ImplTraitType and TraitObjectType (and ImplTraitTypeOneBound and TraitObjectTypeOneBound) aren't as much of a priority, since they desugar pretty easily.
### Search subtyping and traits
This is the other major factor that makes it less useful than it should be.
* `iterator<result<t>> -> result<t>` doesn't find `Result::from_iter`. You have to search [`intoiterator<result<t>> -> result<t>`](https://notriddle.com/rustdoc-html-demo-9/search-hof/std/vec/struct.Vec.html?search=intoiterator%3Cresult%3Ct%3E%3E%20-%3E%20result%3Ct%3E&filter-crate=std). Nobody's going to search for IntoIterator unless they basically already know about it and don't need the search engine anyway.
* Iterator combinators are usually structs that happen to implement Iterator, like `std::iter::Map`.
To solve these cases, it needs to look at trait implementations, knowing that Iterator is a "subtype of" IntoIterator, and Map is a "subtype of" Iterator, so `iterator -> result` is a subtype of `intoiterator -> result` and `iterator<t>, (t -> u) -> iterator<u>` is a subtype of [`iterator<t>, (t -> u) -> map<t -> u>`](https://notriddle.com/rustdoc-html-demo-9/search-hof/std/vec/struct.Vec.html?search=iterator%3Ct%3E%2C%20(t%20-%3E%20u)%20-%3E%20map%3Ct%20-%3E%20u%3E&filter-crate=std).
Downgrade const eval dangling ptr in final to future incompat lint
Short term band-aid for issue #121610, downgrading the prior hard error to a future-incompat lint (tracked in issue #122153).
Note we should not mark #121610 as resolved until after this (or something analogous) is beta backported.
When encountering a lifetime error on a type that *holds* a type that
doesn't implement `Clone`, explore the item's body for potential calls
to `.clone()` that are only cloning the reference `&T` instead of `T`
because `T: !Clone`. If we find this, suggest `T: Clone`.
```
error[E0502]: cannot borrow `*list` as mutable because it is also borrowed as immutable
--> $DIR/clone-on-ref.rs:7:5
|
LL | for v in list.iter() {
| ---- immutable borrow occurs here
LL | cloned_items.push(v.clone())
| ------- this call doesn't do anything, the result is still `&T` because `T` doesn't implement `Clone`
LL | }
LL | list.push(T::default());
| ^^^^^^^^^^^^^^^^^^^^^^^ mutable borrow occurs here
LL |
LL | drop(cloned_items);
| ------------ immutable borrow later used here
|
help: consider further restricting this bound
|
LL | fn foo<T: Default + Clone>(list: &mut Vec<T>) {
| +++++++
```
```
error[E0505]: cannot move out of `x` because it is borrowed
--> $DIR/clone-on-ref.rs:23:10
|
LL | fn qux(x: A) {
| - binding `x` declared here
LL | let a = &x;
| -- borrow of `x` occurs here
LL | let b = a.clone();
| ------- this call doesn't do anything, the result is still `&A` because `A` doesn't implement `Clone`
LL | drop(x);
| ^ move out of `x` occurs here
LL |
LL | println!("{b:?}");
| ----- borrow later used here
|
help: consider annotating `A` with `#[derive(Clone)]`
|
LL + #[derive(Clone)]
LL | struct A;
|
```
Safe Transmute: Require that source referent is smaller than destination
`BikeshedIntrinsicFrom` currently models transmute-via-union; i.e., it attempts to provide a `where` bound for this function:
```rust
pub unsafe fn transmute_via_union<Src, Dst>(src: Src) -> Dst {
use core::mem::*;
#[repr(C)]
union Transmute<T, U> {
src: ManuallyDrop<T>,
dst: ManuallyDrop<U>,
}
let transmute = Transmute { src: ManuallyDrop::new(src) };
// SAFETY: The caller must guarantee that the transmutation is safe.
let dst = transmute.dst;
ManuallyDrop::into_inner(dst)
}
```
A quirk of this model is that it admits padding extensions in value-to-value transmutation: The destination type can be bigger than the source type, so long as the excess consists of uninitialized bytes. However, this isn't permissible for reference-to-reference transmutations (introduced in #110662) — extra referent bytes cannot come from thin air.
This PR patches our analysis for reference-to-reference transmutations to require that the destination referent is no larger than the source referent.
r? `@compiler-errors`
pattern analysis: remove `MaybeInfiniteInt::JustAfterMax`
It was inherited from before half-open ranges, but it doesn't pull its weight anymore. We lose a tiny bit of diagnostic precision as can be seen in the test. I'm generally in favor of half-open ranges over explicit `x..=MAX` ranges anyway.
The source referent absolutely must be smaller than the destination
referent of a ref-to-ref transmute; the excess bytes referenced
cannot arise from thin air, even if those bytes are uninitialized.
Represent `Result<usize, Box<T>>` as ScalarPair(i64, ptr)
This allows types like `Result<usize, std::io::Error>` (and integers of differing sign, e.g. `Result<u64, i64>`) to be passed in a pair of registers instead of through memory, like `Result<u64, u64>` or `Result<Box<T>, Box<U>>` are today.
Fixes#97540.
r? `@ghost`
I attempted to do this in a manner that preserved the line numbers to reduce the
review effort on the resulting diff, but we still have to deal with the
ramifications of how a future-incompat lint behaves compared to a hard-error (in
terms of its impact on the diagnostic output).
delay expand macro bang when there has indeterminate path
Related #98291
I will attempt to clarify the root problem through several examples:
Firstly,
```rs
// rustc code.rs --edition=2018
macro_rules! wrap {
() => {
macro_rules! _a {
() => {
"Hello world"
};
}
};
}
wrap!();
use _a as a;
fn main() {
format_args!(_a!());
}
```
The above case will compile successfully because `_a` is defined after the `wrap` expaned, ensuring `_a` can be resolved without any issues.
And,
```rs
// rustc code.rs --edition=2018
macro_rules! wrap {
() => {
macro_rules! _a {
() => {
"Hello world"
};
}
};
}
wrap!();
use _a as a;
fn main() {
format_args!("{}", a!());
}
```
The above example will also compile successfully because the `parse_args` in `expand_format_args_impl` will return a value `MacroInput { fmtstr: Expr::Lit::Str, args: [Expr::MacroCall]}`. Since the graph for `args` will be build lately, `a` will eventually be resolved.
However, in the case of:
```rs
// rustc code.rs --edition=2018
macro_rules! wrap {
() => {
macro_rules! _a {
() => {
"Hello world"
};
}
};
}
wrap!();
use _a as a;
fn main() {
format_args!(a!());
}
```
The result of `parse_args` is `MacroInput {fmtstr: Expr::Lit::Macro, args: [] }`, we attempt to expand `fmtstr` **eagerly** within `expr_to_spanned_string`. Although we have recorded `(root, _a)` into resolutions, `use _a as a` is an indeterminate import, which will not try to resolve under the conditions of `expander.monotonic = false`.
Therefore, I've altered the strategy for resolving indeterminate imports, ensuring it will also resolve during eager expansion. This could be a significant change to the resolution infra. However, I think it's acceptable if the goal of avoiding resolution under eager expansion is to save time.
r? `@petrochenkov`
Rollup of 10 pull requests
Successful merges:
- #121820 (pattern analysis: Store field indices in `DeconstructedPat` to avoid virtual wildcards)
- #121908 (match lowering: don't collect test alternatives ahead of time)
- #122203 (Add `intrinsic_name` to get plain intrinsic name)
- #122226 (coverage: Remove or migrate all unstable values of `-Cinstrument-coverage`)
- #122255 (Use `min_exhaustive_patterns` in core & std)
- #122360 ( Don't Create `ParamCandidate` When Obligation Contains Errors )
- #122383 (Enable PR tracking review assignment for rust-lang/rust)
- #122386 (Move `Once` implementations to `sys`)
- #122400 (Fix ICE in diagnostics for parenthesized type arguments)
- #122410 (rustdoc: do not preload fonts when browsing locally)
r? `@ghost`
`@rustbot` modify labels: rollup
Don't Create `ParamCandidate` When Obligation Contains Errors
Fixes#121941
I'm not sure if I understand this correctly but this bug was caused by an error type incorrectly matching against `ParamCandidate`. This was introduced by the changes made in #72621 (figured using cargo-bisect-rustc).
This PR fixes it by skipping `ParamCandidate` generation when an error type is involved. Also, this is similar to #73005 but addresses `ParamCandidate` instead of `ImplCandidate`.
coverage: Remove or migrate all unstable values of `-Cinstrument-coverage`
(This PR was substantially overhauled from its original version, which migrated all of the existing unstable values intact.)
This PR takes the three nightly-only values that are currently accepted by `-Cinstrument-coverage`, completely removes two of them (`except-unused-functions` and `except-unused-generics`), and migrates the third (`branch`) over to a newly-introduced unstable flag `-Zcoverage-options`.
I have a few motivations for wanting to do this:
- It's unclear whether anyone actually uses the `except-unused-*` values, so this serves as an opportunity to either remove them, or prompt existing users to object to their removal.
- After #117199, the stable values of `-Cinstrument-coverage` treat it as a boolean-valued flag, so having nightly-only extra values feels out-of-place.
- Nightly-only values also require extra ad-hoc code to make sure they aren't accidentally exposed to stable users.
- The new system allows multiple different settings to be toggled independently, which isn't possible in the current single-value system.
- The new system makes it easier to introduce new behaviour behind an unstable toggle, and then gather nightly-user feedback before possibly making it the default behaviour for all users.
- The new system also gives us a convenient place to put relatively-narrow options that won't ever be the default, but that nightly users might still want access to.
- It's likely that we will eventually want to give stable users more fine-grained control over coverage instrumentation. The new flag serves as a prototype of what that stable UI might eventually look like.
The `branch` option is a placeholder that currently does nothing. It will be used by #122322 to opt into branch coverage instrumentation.
---
I see `-Zcoverage-options` as something that will exist more-or-less indefinitely, though individual sub-options might come and go as appropriate. I think there will always be some demand for nightly-only toggles, so I don't see `-Zcoverage-options` itself ever being stable, though we might eventually stabilize something similar to it.
Add `intrinsic_name` to get plain intrinsic name
Add an `intrinsic_name` API to retrieve the plain intrinsic name. The plain name does not include type arguments (as `trimmed_name` does), which is more convenient to match with intrinsic symbols.
match lowering: don't collect test alternatives ahead of time
I'm very happy with this one. Before this, when sorting candidates into the possible test branches, we manually computed `usize` indices to determine in which branch each candidate goes. To make this work we had a first pass that collected the possible alternatives we'd have to deal with, and a second pass that actually sorts the candidates.
In this PR, I replace `usize` indices with a dedicated enum. This makes `sort_candidates` easier to follow, and we don't need the first pass anymore.
r? ``@matthewjasper``
This new nightly-only flag can be used to toggle fine-grained flags that
control the details of coverage instrumentation.
Currently the only supported flag value is `branch` (or `no-branch`), which is
a placeholder for upcoming support for branch coverage. Other flag values can
be added in the future, to prototype proposed new behaviour, or to enable
special non-default behaviour.
rustdoc: fix up old test
`tests/rustdoc/line-breaks.rs` had several issues:
1. It used `//`@count`` instead of `// `@count`` (notice the space!) which gets treated as a `ui_test` directive instead of a `htmldocck` one. `compiletest` didn't flag it as an error because it's allowlisted ([#121561](https://github.com/rust-lang/rust/pull/121561)) presumably precisely because of this test. And before the compiletest→ui_test migration, these directives must've been ignored, too, because …
2. … the checks themselves no longer work either: The count of `<br>`s is actually 0 in all 3 cases because – well – we no longer generate any `<br>`s inside `<pre>`s.
Since I don't know how to ``@count`` `\n`s instead of `<br>`s, I've turned them into ``@matches`.` Btw, I don't know if this test is still desirable or if we have other tests that cover this (I haven't checked).
r? rustdoc
Add tests for the generated assembly of mask related simd instructions.
The tests show that the code generation currently uses the least significant bits of <iX x N> vector masks when converting to <i1 xN>. This leads to an additional left shift operation in the assembly for x86, since mask operations on x86 operate based on the most significant bit.
The exception is simd_bitmask, which already uses the most-significant bit.
This additional instruction would be removed by the changes in #104693, which makes all mask operations consistently use the most significant bits.
By using the "C" calling convention the tests should be stable regarding changes in register allocation, but it is possible that future llvm updates will require updating some of the checks.
Ensure nested allocations in statics neither get deduplicated nor duplicated
This PR generates new `DefId`s for nested allocations in static items and feeds all the right queries to make the compiler believe these are regular `static` items. I chose this design, because all other designs are fragile and make the compiler horribly complex for such a niche use case.
At present this wrecks incremental compilation performance *in case nested allocations exist* (because any query creating a `DefId` will be recomputed and never loaded from the cache). This will be resolved later in https://github.com/rust-lang/rust/pull/115613 . All other statics are unaffected by this change and will not have performance regressions (heh, famous last words)
This PR contains various smaller refactorings that can be pulled out into separate PRs. It is best reviewed commit-by-commit. The last commit is where the actual magic happens.
r? `@RalfJung` on the const interner and engine changes
fixes https://github.com/rust-lang/rust/issues/79738
Rename `wasm32-wasi-preview1-threads` to `wasm32-wasip1-threads`
This commit renames the current `wasm32-wasi-preview1-threads` target to `wasm32-wasip1-threads`. The need for this rename is a bit unfortunate as the previous name was chosen in an attempt to be future-compatible with other WASI targets. Originally this target was proposed to be `wasm32-wasi-threads`, and that's what was originally implemented in wasi-sdk as well. After discussion though and with the plans for the upcoming component-model target (now named `wasm32-wasip2`) the "preview1" naming was chosen for the threads-based target. The WASI subgroup later decided that it was time to drop the "preview" terminology and recommends "pX" instead, hence previous PRs to add `wasm32-wasip2` and rename `wasm32-wasi` to `wasm32-wasip1`.
So, with all that history, the "proper name" for this target is different than its current name, so one way or another a rename is required. This PR proposes renaming this target cold-turkey, unlike `wasm32-wasi` which is having a long transition period to change its name. The threads-based target is predicted to see only a fraction of the traffic of `wasm32-wasi` due to the unstable nature of the WASI threads proposal itself.
While I was here I updated the in-tree documentation in the target spec file itself as most of the documentation was copied from the original WASI target and wasn't as applicable to this target.
Also, as an aside, I can at least try to apologize for all the naming confusion here, but this is hopefully the last WASI-related rename.
The tests show that the code generation currently uses the least
significant bits of <iX x N> vector masks when converting to <i1 xN>.
This leads to an additional left shift operation in the assembly for
x86, since mask operations on x86 operate based on the most significant
bit. On aarch64 the left shift is followed by a comparison against zero,
which repeats the sign bit across the whole lane.
The exception, which does not introduce an unneeded shift, is
simd_bitmask, because the code generation already shifts before
truncating.
By using the "C" calling convention the tests should be stable regarding
changes in register allocation, but it is possible that future llvm
updates will require updating some of the checks.
This additional instruction would be removed by the fix in #104693,
which uses the most significant bit for all mask operations.
Rollup of 8 pull requests
Successful merges:
- #115141 (Update Windows platform support)
- #121865 (Add FileCheck annotations to MIR-opt unnamed-fields tests)
- #122000 (Fix 32-bit overflows in LLVM composite constants)
- #122194 (Enable creating backtraces via -Ztreat-err-as-bug when stashing errors)
- #122319 (Don't ICE when non-self part of trait goal is constrained in new solver)
- #122339 (Update books)
- #122342 (Update /NODEFAUTLIB comment for msvc)
- #122343 (Remove some unnecessary `allow(incomplete_features)` in the test suite)
r? `@ghost`
`@rustbot` modify labels: rollup
Add FileCheck annotations to MIR-opt unnamed-fields tests
Part of #116971
Adds filecheck annotations to unnamed-fields mir-opt tests in `tests/mir-opt/unnamed-fields`
This is implemented, in addition to the ML-style one,
because Rust does it. If we don't, we'll never hear the end of it.
This commit also refactors some duplicate parts of the parser
into a dedicated function.
Option::map, for example, looks like this:
option<t>, (t -> u) -> option<u>
This syntax searches all of the HOFs in Rust: traits Fn, FnOnce,
and FnMut, and bare fn primitives.
Lower transmutes from int to pointer type as gep on null
I thought of this while looking at https://github.com/rust-lang/rust/pull/121242. See that PR's description for why this lowering is preferable.
The UI test that's being changed here crashes without changing the transmutes into casts. Based on that, this PR should not be merged without a crater build-and-test run.
Test wasm32-wasip1 in CI, not wasm32-unknown-unknown
This commit changes CI to no longer test the `wasm32-unknown-unknown` target and instead test the `wasm32-wasip1` target. There was some discussion of this in a [Zulip thread], and the motivations for this PR are:
* Runtime failures on `wasm32-unknown-unknown` print nothing, meaning all you get is "something failed". In contrast `wasm32-wasip1` can print to stdout/stderr.
* The unknown-unknown target is missing lots of pieces of libstd, and while `wasm32-wasip1` is also missing some pieces (e.g. threads) it's missing fewer pieces. This means that many more tests can be run.
Overall my hope is to improve the debuggability of wasm failures on CI and ideally be a bit less of a maintenance burden.
This commit specifically removes the testing of `wasm32-unknown-unknown` and replaces it with testing of `wasm32-wasip1`. Along the way there were a number of other archiectural changes made as well, including:
* A new `target.*.runtool` option can now be specified in `config.toml` which is passed as `--runtool` to `compiletest`. This is used to reimplement execution of WebAssembly in a less-wasm-specific fashion.
* The default value for `runtool` is an ambiently located WebAssembly runtime found on the system, if any. I've implemented logic for Wasmtime.
* Existing testing support for `wasm32-unknown-unknown` and Emscripten has been removed. I'm not aware of Emscripten testing being run any time recently and otherwise `wasm32-wasip1` is in theory the focus now.
* I've added a new `//@ needs-threads` directive for `compiletest` and classified a bunch of wasm-ignored tests as needing threads. In theory these tests can run on `wasm32-wasi-preview1-threads`, for example.
* I've tried to audit all existing tests that are either `ignore-emscripten` or `ignore-wasm*`. Many now run on `wasm32-wasip1` due to being able to emit error messages, for example. Many are updated with comments as to why they can't run as well.
* The `compiletest` output matching for `wasm32-wasip1` automatically uses "match a subset" mode implemented in `compiletest`. This is because WebAssembly runtimes often add extra information on failure, such as the `unreachable` instruction in `panic!`, which isn't able to be matched against the golden output from native platforms.
* I've ported most existing `run-make` tests that use custom Node.js wrapper scripts to the new run-make-based-in-Rust infrastructure. To do this I added `wasmparser` as a dependency of `run-make-support` for the various wasm tests to use that parse wasm files. The one test that executed WebAssembly now uses `wasmtime`-the-CLI to execute the test instead. I have not ported over an exception-handling test as Wasmtime doesn't implement this yet.
* I've updated the `test` crate to print out timing information for WASI targets as it can do that (gets a previously ignored test now passing).
* The `test-various` image now builds a WASI sysroot for the WASI target and additionally downloads a fixed release of Wasmtime, currently the latest one at 18.0.2, and uses that for testing.
[Zulip thread]: https://rust-lang.zulipchat.com/#narrow/stream/131828-t-compiler/topic/Have.20wasm.20tests.20ever.20caused.20problems.20on.20CI.3F/near/424317944
Make `DefiningAnchor::Bind` only store the opaque types that may be constrained, instead of the current infcx root item.
This makes `Bind` almost always be empty, so we can start forwarding it to queries, allowing us to remove `Bubble` entirely (not done in this PR)
The only behaviour change is in diagnostics.
r? `@lcnr` `@compiler-errors`
Rollup of 15 pull requests
Successful merges:
- #116791 (Allow codegen backends to opt-out of parallel codegen)
- #116793 (Allow targets to override default codegen backend)
- #117458 (LLVM Bitcode Linker: A self contained linker for nvptx and other targets)
- #119385 (Fix type resolution of associated const equality bounds (take 2))
- #121438 (std support for wasm32 panic=unwind)
- #121893 (Add tests (and a bit of cleanup) for interior mut handling in promotion and const-checking)
- #122080 (Clarity improvements to `DropTree`)
- #122152 (Improve diagnostics for parenthesized type arguments)
- #122166 (Remove the unused `field_remapping` field from `TypeLowering`)
- #122249 (interpret: do not call machine read hooks during validation)
- #122299 (Store backtrace for `must_produce_diag`)
- #122318 (Revision-related tweaks for next-solver tests)
- #122320 (Use ptradd for vtable indexing)
- #122328 (unix_sigpipe: Replace `inherit` with `sig_dfl` in syntax tests)
- #122330 (bootstrap readme: fix, improve, update)
r? `@ghost`
`@rustbot` modify labels: rollup
* The WASI targets deal with the `main` symbol a bit differently than
native so some `codegen` and `assembly` tests have been ignored.
* All `ignore-emscripten` directives have been updated to
`ignore-wasm32` to be more clear that all wasm targets are ignored and
it's not just Emscripten.
* Most `ignore-wasm32-bare` directives are now gone.
* Some ignore directives for wasm were switched to `needs-unwind`
instead.
* Many `ignore-wasm32*` directives are removed as the tests work with
WASI as opposed to `wasm32-unknown-unknown`.
This commit rewrites a number of `run-make` tests centered around wasm
to instead use `rmake.rs` and additionally use the `wasm32-wasip1`
target instead of `wasm32-unknown-unknown`. Testing no longer requires
Node.js and additionally uses the `wasmparser` crate from crates.io to
parse outputs and power assertions.
This commit renames the current `wasm32-wasi-preview1-threads` target to
`wasm32-wasip1-threads`. The need for this rename is a bit unfortunate
as the previous name was chosen in an attempt to be future-compatible
with other WASI targets. Originally this target was proposed to be
`wasm32-wasi-threads`, and that's what was originally implemented in
wasi-sdk as well. After discussion though and with the plans for the
upcoming component-model target (now named `wasm32-wasip2`) the
"preview1" naming was chosen for the threads-based target. The WASI
subgroup later decided that it was time to drop the "preview"
terminology and recommends "pX" instead, hence previous PRs to add
`wasm32-wasip2` and rename `wasm32-wasi` to `wasm32-wasip1`.
So, with all that history, the "proper name" for this target is
different than its current name, so one way or another a rename is
required. This PR proposes renaming this target cold-turkey, unlike
`wasm32-wasi` which is having a long transition period to change its
name. The threads-based target is predicted to see only a fraction of
the traffic of `wasm32-wasi` due to the unstable nature of the WASI
threads proposal itself.
While I was here I updated the in-tree documentation in the target spec
file itself as most of the documentation was copied from the original
WASI target and wasn't as applicable to this target.
Also, as an aside, I can at least try to apologize for all the naming
confusion here, but this is hopefully the last WASI-related rename.
unix_sigpipe: Replace `inherit` with `sig_dfl` in syntax tests
The `sig_dfl` variant of the attribute is the most likely variant to be stabilized first, and thus to become the "most allowed" variant of the attribute. Because of this, it is the most appropriate variant to use in syntax tests, because even if the most allowed variant is used, the compiler shall still emit errors if it e.g. is used in the wrong places.
r? ``@davidtwco`` who already [approved ](https://github.com/rust-lang/rust/pull/120832#pullrequestreview-1875075341) this commit in https://github.com/rust-lang/rust/pull/120832.
It would be nice to land the last preparatory commit of that PR before we begin to [rename ](https://github.com/rust-lang/rust/pull/120832#issuecomment-1987023484) things which will of course create a lot of code conflicts.
Use ptradd for vtable indexing
Extension of #121665.
After this, the only remaining usages of GEP are [this](cd81f5b27e/compiler/rustc_codegen_llvm/src/intrinsic.rs (L909-L920)) kinda janky Emscription EH code, which I'll change in a future PR, and array indexing / pointer offsets, where there isn't yet a canonical `ptradd` form. (Out of curiosity I tried converting the latter to `ptradd(ptr, mul(size, index))`, but that causes codegen regressions right now.)
r? `@nikic`
Revision-related tweaks for next-solver tests
1. Add `ignore-compare-mode-next-solver` to any test that already has explicit `current next` revisions, since the test failures when testing with `--compare-mode=next-solver` will be false positives.
2. Explicitly add revisions to a handful of tests where we expect behavior to diverge.
r? lcnr
Add tests (and a bit of cleanup) for interior mut handling in promotion and const-checking
Basically these are the parts of https://github.com/rust-lang/rust/pull/121786 that can be salvaged.
r? ``@oli-obk``
Fix type resolution of associated const equality bounds (take 2)
Instead of trying to re-resolve the type of assoc const bindings inside the `type_of` query impl in an incomplete manner, transfer the already (correctly) resolved type from `add_predicates_for_ast_type_binding` to `type_of`/`anon_type_of` through query feeding.
---
Together with #118668 (merged) and #121258, this supersedes #118360.
Fixes#118040.
r? ``@ghost``
Run a single huge par_body_owners instead of many small ones after each other.
This improves parallel rustc parallelism by avoiding the bottleneck after each individual `par_body_owners` (because it needs to wait for queries to finish, so if there is one long running one, a lot of cores will be idle while waiting for the single query).
This improves parallel rustc parallelism by avoiding the bottleneck after each individual `par_body_owners` (because it needs to wait for queries to finish, so if there is one long running one, a lot of cores will be idle while waiting for the single query).
Allow multiple `impl Into<{D,Subd}iagMessage>` parameters in a function.
The internal diagnostic lint currently only allows one, because that was all that occurred in practice. But rust-lang/rust-clippy/pull/12453 wants to introduce functions with more than one, and this limitation is getting in the way.
r? `@Nilstrieb`
Expose the Freeze trait again (unstably) and forbid implementing it manually
non-emoji version of https://github.com/rust-lang/rust/pull/121501
cc #60715
This trait is useful for generic constants (associated consts of generic traits). See the test (`tests/ui/associated-consts/freeze.rs`) added in this PR for a usage example. The builtin `Freeze` trait is the only way to do it, users cannot work around this issue.
It's also a useful trait for building some very specific abstrations, as shown by the usage by the `zerocopy` crate: https://github.com/google/zerocopy/issues/941
cc ```@RalfJung```
T-lang signed off on reexposing this unstably: https://github.com/rust-lang/rust/pull/121501#issuecomment-1969827742
The internal diagnostic lint currently only allows one, because that was
all that occurred in practice. But rust-lang/rust-clippy/pull/12453
wants to introduce functions with more than one, and this limitation is
getting in the way.
The `sig_dfl` variant of the attribute is the most likely variant to be
stabilized first, and thus to become the "most allowed" variant of the
attribute. Because of this, it is the most appropriate variant to use in
syntax tests, because even if the most allowed variant is used, the
compiler shall still emit errors if it e.g. is used in the wrong places.
Stop using LLVM struct types for byval/sret
For `byval` and `sret`, the type has no semantic meaning, only the size matters\*†. Using `[N x i8]` is a more direct way to specify that we want `N` bytes, and avoids relying on LLVM's struct layout.
\*: The alignment would matter, if we didn't explicitly specify it. From what I can tell, we always specified the alignment for `sret`; for `byval`, we didn't until #112157.
†: For `byval`, the hidden copy may be impacted by padding in the LLVM struct type, i.e. padding bytes may not be copied. (I'm not sure if this is done today, but I think it would be legal.) But we manually pad our LLVM struct types specifically to avoid there ever being LLVM-visible padding, so that shouldn't be an issue.
Split out from #121577.
r? `@nikic`
diagnostics: Do not suggest using `#[unix_sigpipe]` without a value
Remove `Word` from the `unix_sigpipe` attribute template so that plain `#[unix_sigpipe]` is not included in suggestions of valid forms of the attribute. Also re-arrange diagnostics code slightly to avoid duplicate diagnostics.
Tracking issue is https://github.com/rust-lang/rust/issues/97889.
MIR printing: print the path of uneval'd const
Currently it just prints `const _` which makes it impossible to say which constant is being referred to.
Also refer to promoteds in a consistent way; previously MIR printing would do
```
promoted[0] in C1: &Option<Cell<i32>> = {
// ...
}
```
Now that should be
```
const C1::promoted[0]: &Option<Cell<i32>> = {
// ...
}
```
We don't seem to have a test for that so I tried it by hand, it seems to work:
```
const main::promoted[12]: &[&str; 3] = {
let mut _0: &[&str; 3];
let mut _1: [&str; 3];
let mut _2: &str;
let mut _3: &str;
let mut _4: &str;
let mut _5: &str;
bb0: {
_3 = const "b";
_2 = &(*_3);
_5 = const "c";
_4 = &(*_5);
_1 = [const "a", move _2, move _4];
_0 = &_1;
return;
}
}
```
Detect typos for compiletest test directives
Checks directives against a known list of compiletest directives collected during migration from legacy-style compiletest directives. A suggestion for the best matching known directive will be made if an invalid directive is found.
This PR does not attempt to implement checks for Makefile directives because they still have the problem of regular comments and directives sharing the same comment prefix `#`.
Closes#83551.
Remove `Word` from the `unix_sigpipe` attribute template so that plain
`#[unix_sigpipe]` is not included in suggestions of valid forms of the
attribute. Also re-arrange diagnostics code slightly to avoid duplicate
diagnostics.
Fixing shellcheck comments on lvi test script
Running `shellcheck` on `tests/run-make/x86_64-fortanix-unknown-sgx-lvi/script.sh` gives plenty of warnings. This PR fixes those issues. For completeness: #121683 fixes another warning as well
Update a test to support Symbol Mangling V0
Note that since this is a symbol from `std`, overriding the symbol mangling version via the `compile-flags` directive does not work.
Distinguish between library and lang UB in assert_unsafe_precondition
As described in https://github.com/rust-lang/rust/pull/121583#issuecomment-1963168186, `assert_unsafe_precondition` now explicitly distinguishes between language UB (conditions we explicitly optimize on) and library UB (things we document you shouldn't do, and maybe some library internals assume you don't do).
`debug_assert_nounwind` was originally added to avoid the "only at runtime" aspect of `assert_unsafe_precondition`. Since then the difference between the macros has gotten muddied. This totally revamps the situation.
Now _all_ preconditions shall be checked with `assert_unsafe_precondition`. If you have a precondition that's only checkable at runtime, do a `const_eval_select` hack, as done in this PR.
r? RalfJung
Vec::try_with_capacity
Related to #91913
Implements try_with_capacity for `Vec`, `VecDeque`, and `String`. I can follow it up with more collections if desired.
`Vec::try_with_capacity()` is functionally equivalent to the current stable:
```rust
let mut v = Vec::new();
v.try_reserve_exact(n)?
```
However, `try_reserve` calls non-inlined `finish_grow`, which requires old and new `Layout`, and is designed to reallocate memory. There is benefit to using `try_with_capacity`, besides syntax convenience, because it generates much smaller code at the call site with a direct call to the allocator. There's codegen test included.
It's also a very desirable functionality for users of `no_global_oom_handling` (Rust-for-Linux), since it makes a very commonly used function available in that environment (`with_capacity` is used much more frequently than all `(try_)reserve(_exact)`).
Eagerly translate `HelpUseLatestEdition` in parser diagnostics
Fixes#122130.
This makes me suspicious of these other two usage of `add_to_diagnostic()`. Would they *also* crash? I haven't attempted to construct test cases for them.
```
compiler/rustc_parse/src/parser/expr.rs
3453: errors::HelpUseLatestEdition::new().add_to_diagnostic(e);
compiler/rustc_hir_typeck/src/expr.rs
2603: HelpUseLatestEdition::new().add_to_diagnostic(&mut err);
```
This also seems like a footgun?
Misc improvements to non local defs lint implementation
This PR is a collection of small improvements I found when I [needlessly tried](https://www.github.com/rust-lang/rust/pull/120393#issuecomment-1971787475) to fix a "perf-regression" in the lint implementation.
I recommend looking at each commit individually.
Lint singleton gaps after exclusive ranges
In the discussion to stabilize exclusive range patterns (https://github.com/rust-lang/rust/issues/37854), it has often come up that they're likely to cause off-by-one mistakes. We already have the `overlapping_range_endpoints` lint, so I [proposed](https://github.com/rust-lang/rust/issues/37854#issuecomment-1845580712) a lint to catch the complementary mistake.
This PR adds a new `non_contiguous_range_endpoints` lint that catches likely off-by-one errors with exclusive range patterns. Here's the idea (see the test file for more examples):
```rust
match x {
0..10 => ..., // WARN: this range doesn't match `10_u8` because `..` is an exclusive range
11..20 => ..., // this could appear to continue range `0_u8..10_u8`, but `10_u8` isn't matched by either of them
_ => ...,
}
// help: use an inclusive range instead: `0_u8..=10_u8`
```
More precisely: for any exclusive range `lo..hi`, if `hi+1` is matched by another range but `hi` isn't, we suggest writing an inclusive range `lo..=hi` instead. We also catch `lo..T::MAX`.
Don't ICE if we collect no RPITITs unless there are no unification errors
Move an assertion in `collect_return_position_impl_trait_in_trait_tys` to after the `ObligationCtxt::eq` calls, so that we only assert and ICE if we have unification errors.
Fixes#121468
Merge `collect_mod_item_types` query into `check_well_formed`
follow-up to https://github.com/rust-lang/rust/pull/121154
this removes more potential parallel-compiler bottlenecks and moves diagnostics for the same items next to each other, instead of grouping diagnostics by analysis kind
Use `ControlFlow` in visitors.
Follow up to #121256
This does have a few small behaviour changes in some diagnostic output where the visitor will now find the first match rather than the last match. The change in `find_anon_types.rs` has the only affected test. I don't see this being an issue as the last occurrence isn't any better of a choice than the first.
Refactor pre-getopts command line argument handling
Rebased version of #111658. I've also fixed the Windows CI failure (although I don't have access to Windows to test it myself).
add known-bug tests for derive failure to detect packed repr
We only taint if it was a normal item. Modules and imports are untouched. Tainting them needs to be done differently, and it's unclear if that would be useful or desirable. If we just taint them into `Res::Err`, we end up losing some duplicate name messages *in the presence of other resolution errors*.
r? `@petrochenkov`
Make TAITs and ATPITs capture late-bound lifetimes in scope
This generalizes the behavior that RPITs have, where they duplicate their in-scope lifetimes so that they will always *reify* late-bound lifetimes that they capture. This allows TAITs and ATPITs to properly error when they capture in-scope late-bound lifetimes.
r? `@oli-obk` cc `@aliemjay`
Fixes#122093 and therefore https://github.com/rust-lang/rust/pull/120700#issuecomment-1981213868
Add asm goto support to `asm!`
Tracking issue: #119364
This PR implements asm-goto support, using the syntax described in "future possibilities" section of [RFC2873](https://rust-lang.github.io/rfcs/2873-inline-asm.html#asm-goto).
Currently I have only implemented the `label` part, not the `fallthrough` part (i.e. fallthrough is implicit). This doesn't reduce the expressive though, since you can use label-break to get arbitrary control flow or simply set a value and rely on jump threading optimisation to get the desired control flow. I can add that later if deemed necessary.
r? ``@Amanieu``
cc ``@ojeda``
Add arm64ec-pc-windows-msvc target
Introduces the `arm64ec-pc-windows-msvc` target for building Arm64EC ("Emulation Compatible") binaries for Windows.
For more information about Arm64EC see <https://learn.microsoft.com/en-us/windows/arm/arm64ec>.
## 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.)
I will be the maintainer for this target.
> 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.
Target uses the `arm64ec` architecture to match LLVM and MSVC, and the `-pc-windows-msvc` suffix to indicate that it targets Windows via the MSVC environment.
> 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.
Target name exactly specifies the type of code that will be produced.
> If possible, use only letters, numbers, dashes and underscores for the name. Periods (.) are known to cause issues in Cargo.
Done.
> 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 must not introduce license incompatibilities.
Uses the same dependencies, requirements and licensing as the other `*-pc-windows-msvc` targets.
> Anything added to the Rust repository must be under the standard Rust license (MIT OR Apache-2.0).
Understood.
> 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.
> 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.
> "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.
Uses the same dependencies, requirements and licensing as the other `*-pc-windows-msvc` targets.
> 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, I am not a member of the Rust team.
> 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.
Both `core` and `alloc` are supported.
Support for `std` depends on making changes to the standard library, `stdarch` and `backtrace` which cannot be done yet as they require fixes coming in LLVM 18.
> 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.
Documentation is provided in src/doc/rustc/src/platform-support/arm64ec-pc-windows-msvc.md
> 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.
> 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.
Understood.
AST validation: Improve handling of inherent impls nested within functions and anon consts
Minimal fix for issue #121607 extracted from PR #120698 for ease of backporting and since I'd like to improve PR #120698 in such a way that it makes AST validator truly robust against such sort of regressions (AST validator is generally *beyond* footgun-y atm). The current version of PR #120698 sort of does that already but there's still room for improvement.
Fixes#89342.
Fixes [after beta-backport] #121607.
Partially addresses #119924 (#120698 aims to fully fix it).
---
### Explainer
The last commit of PR #119505 regressed issue #121607.
Previously we would reject visibilities on associated items with `visibility_not_permitted` if we were in a trait (by checking the parameter `ctxt` of `visit_assoc_item` which was 100% accurate) or if we were in a trait impl (by checking a flag called `in_trait_impl` tracked in `AstValidator` which was/is only accurate if the visitor methods correctly updated it which isn't actually the case giving rise to the old open issue #89342).
In PR #119505, I moved even more state into the `AstValidator` by generalizing the flag `in_trait_impl` to `trait_or_trait_impl` to be able to report more precise diagnostics (modeling *Trait | TraitImpl*). However since we/I didn't update `trait_or_trait_impl` in all places to reflect reality (similar to us not updating `in_trait_impl` before), this lead to https://github.com/rust-lang/rust/issues/121607#issuecomment-1963084636 getting wrongfully rejected. Since PR #119505 we reject visibilities if the “globally tracked” (wrt. to `AstValidator`) `outer_trait_or_trait_impl` is `Some`.
Crucially, when visiting an inherent impl, I never reset `outer_trait_or_trait_impl` back to `None` leading us to believe that `bar` in the stack [`trait Foo` > `fn foo` > `impl Bar` > `pub fn bar`] (from the MCVE) was an inherent associated item (we saw `trait Foo` but not `impl Bar` before it).
The old open issue #89342 is caused by the aforementioned issue of us never updating `in_trait_impl` prior to my PR #119505 / `outer_trait_or_trait` after my PR. Stack: [`impl Default for Foo` > `{` > `impl Foo` > `pub const X`] (we only saw `impl Default for Foo` but not the `impl Foo` before it).
---
This PR is only meant to be a *hot fix*. I plan on completely *rewriting* `AstValidator` from the ground up to not rely on “globally tracked” state like this or at least make it close to impossible to forget updating it when descending into nested items (etc.). Other visitors do a way better job at that (e.g. AST lowering). I actually plan on experimenting with moving more and more logic from `AstValidator` into the AST lowering pass/stage/visitor to follow the [Parse, don't validate](https://lexi-lambda.github.io/blog/2019/11/05/parse-don-t-validate/) “pattern”.
---
r? `@compiler-errors`
Remove `feed_local_def_id`
best reviewed commit by commit
Basically I returned `TyCtxtFeed` from `create_def` and then preserved that in the local caches
based on https://github.com/rust-lang/rust/pull/121084
r? ````@petrochenkov````
Stabilize the `#[diagnostic]` namespace and `#[diagnostic::on_unimplemented]` attribute
This PR stabilizes the `#[diagnostic]` attribute namespace and a minimal option of the `#[diagnostic::on_unimplemented]` attribute.
The `#[diagnostic]` attribute namespace is meant to provide a home for attributes that allow users to influence error messages emitted by the compiler. The compiler is not guaranteed to use any of this hints, however it should accept any (non-)existing attribute in this namespace and potentially emit lint-warnings for unused attributes and options. This is meant to allow discarding certain attributes/options in the future to allow fundamental changes to the compiler without the need to keep then non-meaningful options working.
The `#[diagnostic::on_unimplemented]` attribute is allowed to appear on a trait definition. This allows crate authors to hint the compiler to emit a specific error message if a certain trait is not implemented. For the `#[diagnostic::on_unimplemented]` attribute the following options are implemented:
* `message` which provides the text for the top level error message
* `label` which provides the text for the label shown inline in the broken code in the error message
* `note` which provides additional notes.
The `note` option can appear several times, which results in several note messages being emitted. If any of the other options appears several times the first occurrence of the relevant option specifies the actually used value. Any other occurrence generates an lint warning. For any other non-existing option a lint-warning is generated.
All three options accept a text as argument. This text is allowed to contain format parameters referring to generic argument or `Self` by name via the `{Self}` or `{NameOfGenericArgument}` syntax. For any non-existing argument a lint warning is generated.
This allows to have a trait definition like:
```rust
#[diagnostic::on_unimplemented(
message = "My Message for `ImportantTrait<{A}>` is not implemented for `{Self}`",
label = "My Label",
note = "Note 1",
note = "Note 2"
)]
trait ImportantTrait<A> {}
```
which then generates for the following code
```rust
fn use_my_trait(_: impl ImportantTrait<i32>) {}
fn main() {
use_my_trait(String::new());
}
```
this error message:
```
error[E0277]: My Message for `ImportantTrait<i32>` is not implemented for `String`
--> src/main.rs:14:18
|
14 | use_my_trait(String::new());
| ------------ ^^^^^^^^^^^^^ My Label
| |
| required by a bound introduced by this call
|
= help: the trait `ImportantTrait<i32>` is not implemented for `String`
= note: Note 1
= note: Note 2
```
[Playground with the unstable feature](https://play.rust-lang.org/?version=nightly&mode=debug&edition=2021&gist=05133acce8e1d163d481e97631f17536)
Fixes#111996
Don't require specifying unrelated assoc types when trait alias is in `dyn` type
Object types must specify the associated types for all of the principal trait ref's supertraits. However, we weren't doing elaboration properly, so we incorrectly errored with erroneous suggestions to specify associated types that were unrelated to that principal trait ref. To fix this, use proper supertrait elaboration when expanding trait aliases in `conv_object_ty_poly_trait_ref`.
**NOTE**: Please use the ignore-whitespace option when reviewing. This only touches a handful of lines.
r? oli-obk or please feel free to reassign.
Fixes#122118
Make not finding core a fatal error
Similar to https://github.com/rust-lang/rust/pull/120472, this prevents terminal spam. In particular, it makes the good diagnostic visible when you try to use a target that's not installed.
silence mismatched types errors for implied projections
Currently, if a trait bound is not satisfied, then we suppress any errors for the trait's supertraits not being satisfied, but still report errors for super projections not being satisfied.
For example:
```rust
trait Super {
type Assoc;
}
trait Sub: Super<Assoc = ()> {}
```
Before this PR, if `T: Sub` is not satisfied, then errors for `T: Super` are suppressed, but errors for `<T as Super>::Assoc == ()` are still shown. This PR makes it so that errors about super projections not being satisfied are also suppressed.
The errors are only suppressed if the span of the trait obligation matches the span of the super predicate obligation to avoid silencing error that are not related. This PR removes some differences between the spans of supertraits and super projections to make the suppression work correctly.
This PR fixes the majority of the diagnostics fallout when making `Thin` a supertrait of `Sized` (in a future PR).
cc https://github.com/rust-lang/rust/pull/120354#issuecomment-1930585382
cc `@lcnr`
Rollup of 9 pull requests
Successful merges:
- #121958 (Fix redundant import errors for preload extern crate)
- #121976 (Add an option to have an external download/bootstrap cache)
- #122022 (loongarch: add frecipe and relax target feature)
- #122026 (Do not try to format removed files)
- #122027 (Uplift some feeding out of `associated_type_for_impl_trait_in_impl` and into queries)
- #122063 (Make the lowering of `thir::ExprKind::If` easier to follow)
- #122074 (Add missing PartialOrd trait implementation doc for array)
- #122082 (remove outdated fixme comment)
- #122091 (Note why we're using a new thread in `test_get_os_named_thread`)
r? `@ghost`
`@rustbot` modify labels: rollup
Introduces the `arm64ec-pc-windows-msvc` target for building Arm64EC ("Emulation Compatible") binaries for Windows.
For more information about Arm64EC see <https://learn.microsoft.com/en-us/windows/arm/arm64ec>.
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.)
I will be the maintainer for this target.
> 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.
Target uses the `arm64ec` architecture to match LLVM and MSVC, and the `-pc-windows-msvc` suffix to indicate that it targets Windows via the MSVC environment.
> 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.
Target name exactly specifies the type of code that will be produced.
> If possible, use only letters, numbers, dashes and underscores for the name. Periods (.) are known to cause issues in Cargo.
Done.
> 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 must not introduce license incompatibilities.
Uses the same dependencies, requirements and licensing as the other `*-pc-windows-msvc` targets.
> Anything added to the Rust repository must be under the standard Rust license (MIT OR Apache-2.0).
Understood.
> 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.
> 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.
> "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.
Uses the same dependencies, requirements and licensing as the other `*-pc-windows-msvc` targets.
> 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, I am not a member of the Rust team.
> 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.
Both `core` and `alloc` are supported.
Support for `std` dependends on making changes to the standard library, `stdarch` and `backtrace` which cannot be done yet as the bootstrapping compiler raises a warning ("unexpected `cfg` condition value") for `target_arch = "arm64ec"`.
> 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.
Documentation is provided in src/doc/rustc/src/platform-support/arm64ec-pc-windows-msvc.md
> 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.
> 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.
Understood.
It seems that LLVM 17 doesn't fully optimize out unwrap_unchecked.
We can just loosen the check lines to account for this, since we don't
really care about the exact instructions, we just want to make sure that
inttoptr/ptrtoint aren't used for Box.
compiletest: Add a `//@ needs-threads` directive
This commit is extracted from #122036 and adds a new directive to the `compiletest` test runner, `//@ needs-threads`. This is intended to capture the need that a target must implement threading to execute a specific test, typically one that uses `std::thread`. This is primarily done for WebAssembly targets which currently do not have threads by default. This enables transitioning a lot of `//@ ignore-wasm*`-style ignores into a more self-documenting `//@ needs-threads` directive. Additionally the `wasm32-wasi-preview1-threads` target, for example, does actually have threads, but isn't tested in CI at this time. This change enables running these tests for that target, but not other wasm targets.
Uplift some feeding out of `associated_type_for_impl_trait_in_impl` and into queries
This PR moves the `type_of` and `generics_of` query feeding out of `associated_type_for_impl_trait_in_impl`, since eagerly feeding results in query cycles due to a subtle interaction with `resolve_bound_vars`.
Fixes#122019
r? spastorino
loongarch: add frecipe and relax target feature
This PR adds `frecipe` and `relax` target features to LoongArch:
* frecipe - Support frecipe.{s/d} and frsqrte.{s/d} instructions..
* relax - Enable Linker relaxation.
Fix linting paths with qself in `unused_qualifications`
Fixes#121999
`resolve_qpath` ends up being called again with `qself` set to `None` to check trait items from fully qualified paths. To avoid this the lint is moved to a place that accounts for this already
96561a8fd1/compiler/rustc_resolve/src/late.rs (L4074-L4088)
r? `````@petrochenkov`````
Rework `untranslatable_diagnostic` lint
Currently it only checks calls to functions marked with `#[rustc_lint_diagnostics]`. This PR changes it to check calls to any function with an `impl Into<{D,Subd}iagnosticMessage>` parameter. This greatly improves its coverage and doesn't rely on people remembering to add `#[rustc_lint_diagnostics]`. It also lets us add `#[rustc_lint_diagnostics]` to a number of functions that don't have an `impl Into<{D,Subd}iagnosticMessage>`, such as `Diag::span`.
r? ``@davidtwco``
avoid overlapping privacy suggestion for single nested imports
Fixes#114884
This PR aims to avoid confusion inside braces for import suggestions.
r? ``@petrochenkov``
Change the documented implicit value of `-C instrument-coverage` to `=yes`
The option-value parser for `-Cinstrument-coverage=` currently accepts the following stable values:
- `all` (implicit value of plain `-Cinstrument-coverage`)
- `yes`, `y`, `on`, `true` (undocumented aliases for `all`)
- `off` (default; same as not specifying `-Cinstrument-coverage`)
- `no`, `n`, `false`, `0` (undocumented aliases for `off`)
I'd like to rearrange and re-document the stable values as follows:
- `no` (default; same as not specifying `-Cinstrument-coverage`)
- `n`, `off`, `false` (documented aliases for `no`)
- `0` (undocumented alias for `no`)
- `yes` (implicit value of plain `-Cinstrument-coverage`)
- `y`, `on`, `true` (documented aliases for `yes`)
- `all` (documented as *currently* an alias for `yes` that may change; discouraged but not deprecated)
The main changes being:
- Documented default value changes from `off` to `no`
- Documented implicit value changes from `all` to `yes`
- Other boolean aliases (`n`, `off`, `false`, `y`, `on`, `true`) are explicitly documented
- `all` remains currently an alias for `yes`, but is explicitly documented as being able to change in the future
- `0` remains an undocumented but stable alias for `no`
- The actual behaviour of coverage instrumentation does not change
# Why?
The choice of `all` as the implicit value only really makes sense in the context of the unstable `except-unused-functions` and `except-unused-generics` values. That arrangement was fine for an unstable flag, but it's confusing for a stable flag whose only other stable value is `off`, and will only become more confusing if we eventually want to stabilize other fine-grained coverage option values.
(Currently I'm not aware of any plans to stabilize other coverage option values, but that's why I think now is a fine time to make this change, well before anyone actually has to care about it.)
For example, if we ever add support for opt-in instrumentation of things that are *not* instrumented by `-Cinstrument-coverage` by default, it will be very strange for the `all` value to not actually instrument all things that we know how to instrument.
# Compatibility impact
Because this is not a functional change, there is no immediate compatibility impact. However, changing the documented semantics of `all` opens up the possibility of future changes that could be considered retroactively breaking.
I don't think this is going to be a big deal in practice, for a few reasons:
- The exact behaviour of coverage instrumentation is allowed to change, so changing the behaviour of `all` is not a *stability-breaking* change, as long as it still exists and does something reasonable.
- `-Cinstrument-coverage` is mainly used by tools or scripts that can be easily updated if necessary. It's unusual for users to pass the flag directly, because processing the profiler output is complicated enough that tools/scripts tend to be necessary anyway.
- Most people who are using coverage are probably relying on `-Cinstrument-coverage` rather than explicitly passing `-Cinstrument-coverage=all`, so the number of users actually affected by this change is likely to be low, and plausibly zero.
bootstrap/libtest: print test name eagerly on failure even with `verbose-tests=false` / `--quiet`
Previously, libtest would wait until all tests finished running to print the progress, which made it
annoying to run many tests at once (since you don't know which have failed). Change it to print the
names as soon as they fail.
This makes it much easier to know which test failed without having to wait for compiletest to completely finish running. Before:
```
Testing stage0 compiletest suite=ui mode=ui (x86_64-unknown-linux-gnu)
running 15274 tests
iiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiii 88/15274
iiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiii 176/15274
iiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiii 264/15274
iiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiii 352/15274
iiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiii 440/15274
iiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiii 528/15274
iiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiFFiiiiiii
...
```
After:
```
Testing stage0 compiletest suite=ui mode=ui (x86_64-unknown-linux-gnu)
running 15274 tests
iiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiii 88/15274
iiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiii 176/15274
iiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiii 264/15274
iiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiii 352/15274
iiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiii 440/15274
iiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiii 528/15274
iiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiii
[ui] tests/ui/associated-type-bounds/implied-in-supertrait.rs ... F
[ui] tests/ui/associated-type-bounds/return-type-notation/basic.rs#next_with ... F
iiiiiiiiiiiii
...
```
This serves a similar use case to the existing RUSTC_TEST_FAIL_FAST, but is on by default and as a result much more discoverable. We should consider unifying RUSTC_TEST_FAIL_FAST with the `--no-fail-fast` flag in the future for consistency and discoverability.
This commit is extracted from #122036 and adds a new directive to the
`compiletest` test runner, `//@ needs-threads`. This is intended to
capture the need that a target must implement threading to execute a
specific test, typically one that uses `std::thread`. This is primarily
done for WebAssembly targets which currently do not have threads by
default. This enables transitioning a lot of `//@ ignore-wasm*`-style
ignores into a more self-documenting `//@ needs-threads` directive.
Additionally the `wasm32-wasi-preview1-threads` target, for example,
does actually have threads, but isn't tested in CI at this time. This
change enables running these tests for that target, but not other wasm
targets.
stricter hidden type wf-check [based on #115008]
Original work by `@aliemjay` in #115008. A huge thanks to them for originally figuring out this approach ❤️
Fixes https://github.com/rust-lang/rust/issues/114728
Fixes https://github.com/rust-lang/rust/issues/114572
Instead of adding the `WellFormed` obligations when relating opaque types, we now always emit such an obligation when defining the hidden type.
This causes nested opaque types which aren't wf to error, see the comment below for the described impact. I believe this change to be desirable as it significantly reduces complexity by removing special-cases.
It also caused an issue with RPITIT: in defaulted trait methods, we add a `Projection(synthetic_assoc, rpit_of_trait_method)` clause to the `param_env`. This clause is not added to the `ParamEnv` of the nested coroutines. This caused a normalization failure in `fn check_coroutine_obligations` with the new solver. I fixed that by using the env of the typeck root instead.
r? `@oli-obk`
