Document subdirectories of UI tests with README files
Part of rust-lang/rust#133895 and the [2025 Google Summer of Code](https://blog.rust-lang.org/2025/05/08/gsoc-2025-selected-projects/) associated project.
When adding a new UI test, one is faced with hundreds of subdirectories in `tests/ui` reflecting various categories. Knowing where to put the new test is not trivial, as many of the categories have slightly misleading names. For example, `moves` does not only refer to the `move` keyword but to functions taking ownership in general, whereas `allocator` does not refer to allocation in general but rather to the very specific `allocator_api` and `global_allocator` features.
Many contributors will therefore place their test at the top level of ̀`tests/ui` where it will be mixed with hundreds of unrelated tests.
This PR is a tentative move towards more clearly defined tag/categories, with a SUMMARY.md file documenting the true purpose of each subdirectory, placed inside `tests/ui`.
r? ``@jieyouxu``
Skip no-op drop glue
Since rust-lang/rust#122662 this no longer gets used in vtables, so we're safe to fully
drop generating functions from vtables. Those are eventually cleaned up
by LLVM, but it's wasteful to produce them in the first place.
This doesn't appear to be a significant win (and shows some slight regressions) but
seems like the right thing to do. At minimum it reduces noise in the LLVM IR we generate,
which seems like a good thing.
Rollup of 10 pull requests
Successful merges:
- rust-lang/rust#142458 (Merge unboxed trait object error suggestion into regular dyn incompat error)
- rust-lang/rust#142593 (Add a warning to LateContext::get_def_path)
- rust-lang/rust#142594 (Add DesugaringKind::FormatLiteral)
- rust-lang/rust#142740 (Clean-up `FnCtxt::is_destruct_assignment_desugaring`)
- rust-lang/rust#142780 (Port `#[must_use]` to new attribute parsing infrastructure)
- rust-lang/rust#142798 (Don't fail to parse a struct if a semicolon is used to separate fields)
- rust-lang/rust#142856 (Add a few inline directives in rustc_serialize.)
- rust-lang/rust#142868 (remove few allow(dead_code))
- rust-lang/rust#142874 (cranelift: fix target feature name typo: "fxsr")
- rust-lang/rust#142877 (Document why tidy checks if `eslint` is installed via `npm`)
r? `@ghost`
`@rustbot` modify labels: rollup
Add DesugaringKind::FormatLiteral
Implements `DesugaringKind::FormatLiteral` to mark the FormatArgs desugaring of format literals. The main use for this is to stop yapping about about formatting parameters if we're not anywhere near a format literal. The other use case is to fix suggestions such as https://github.com/rust-lang/rust/issues/141350. It might also be useful for new or existing diagnostics that check whether they're in a format-like macro.
cc `@xizheyin` `@fmease`
Merge unboxed trait object error suggestion into regular dyn incompat error
Another hir-walker removed from the well-formed queries. This error was always a duplicate of another, but it was able to provide more information because it could invoke `is_dyn_compatible` without worrying about cycle errors. That's also the reason we can't put the error directly into hir_ty_lowering when lowering a `dyn Trait` within an associated item signature. So instead I packed it into the error handling of wf obligation checking.
completely deduplicate `Visitor` and `MutVisitor`
r? oli-obk
This closesrust-lang/rust#127615.
### Discussion
> * Give every `MutVisitor::visit_*` method a corresponding `flat_map_*` method.
Not every AST node exists in a location where they can be mapped to multiple instances of themselves. Not every AST node exists in a location where they can be removed from existence (e.g. `filter_map_expr`). I don't think this is doable.
> * Give every `MutVisitor::visit_*` method a corresponding `Visitor` method and vice versa
The only three remaining method-level asymmetries after this PR are `visit_stmt` and `visit_nested_use_tree` (only on `Visitor`) and `visit_span` (only on `MutVisitor`).
`visit_stmt` doesn't seem applicable to `MutVisitor` because `walk_flat_map_stmt_kind` will ask `flat_map_item` / `filter_map_expr` to potentially turn a single `Stmt` to multiple based on what a visitor wants. So only using `flat_map_stmt` seems appropriate.
`visit_nested_use_tree` is used for `rustc_resolve` to track stuff. Not useful for `MutVisitor` for now.
`visit_span` is currently not used for `MutVisitor` already, it was just kept in case we want to revive rust-lang/rust#127241. cc `@cjgillot` maybe we could remove for now and re-insert later if we find a use-case? It does involve some extra effort to maintain.
* Remaining FIXMEs
`visit_lifetime` has an extra param for `Visitor` that's not in `MutVisitor`. This is again something only used by `rustc_resolve`. I think we can keep that symmetry for now.
Enable textrel-on-minimal-lib for Windows
`bin_name` needs to be used when building a runnable executable.
Addresses item in rust-lang/rust#128602
---
try-job: x86_64-mingw-*
try-job: x86_64-msvc-*
try-job: i686-msvc-*
Enable fmt-write-bloat for Windows
Seems to be working fine for MSVC once it has the correct binary name.
Addresses item in rust-lang/rust#128602
---
try-job: x86_64-mingw-*
try-job: x86_64-msvc-*
try-job: i686-msvc-*
All HIR attributes are outer
Fixes https://github.com/rust-lang/rust/issues/142649. Closes https://github.com/rust-lang/rust/pull/142759.
All HIR attributes, including parsed and not yet parsed, will now be rendered as outer attributes by `rustc_hir_pretty`. The original style of the corresponding AST attribute(s) is not relevant for pretty printing, only for diagnostics.
r? ````@jdonszelmann````
forward the bootstrap `runner` to `run-make`
The runner was already forwarded to `compiletest`, this just passes it on to `run-make` and uses it in the `run` functions.
The configuration can look like this
```toml
# in bootstrap.toml
[target.s390x-unknown-linux-gnu]
runner = "qemu-s390x -L /usr/s390x-linux-gnu"
```
Any C compilation automatically sets the correct target. Calls to rustc must use `.target(target())`. Then, a command like below will work by cross-compiling to the given target, and using the given runner for that target to execute the binary:
```
./x test tests/run-make/c-link-to-rust-va-list-fn --target s390x-unknown-linux-gnu
```
The runner can also be used for e.g. running with `valgrind`.
This PR also enables its use in the test case that I care about, hopefully that actually does work on the platforms that CI uses. We should probably run some try jobs to be sure?
r? `@jieyouxu`
try-job: test-various
try-job: armhf-gnu
Since 122662 this no longer gets used in vtables, so we're safe to fully
drop generating these empty functions. Those are eventually cleaned up
by LLVM, but it's wasteful to produce them in the first place.
This also adds a missing test for fn-ptr casts, which do still need to
generate no-op drop glue. It's possible a future optimization could
point all of those at the same drop glue (e.g., for *mut ()) rather than
for each separate type, but that would require extra work for CFI and
isn't particularly easy to do anyway.
Only traverse reachable blocks in JumpThreading.
Fixes https://github.com/rust-lang/rust/issues/131451
We only compute loop headers for reachable blocks. We shouldn't try to perform an opt on unreachable blocks anyway.
Improve diagnostics for `concat_bytes!` with C string literals
Use the same error as other invalid types for `concat_bytes!`, rather
than using `ConcatCStrLit` from `concat!`. Also add more information
with a note about why this doesn't work, and a suggestion to use a
null-terminated byte string instead.
add doc(alias("AsciiChar")) to core::ascii::Char
Added it to the reexported, which is intended rustdoc behavior, but is apparently untested, so I also added a test for it.
Add diagnostic items for Clippy
Clippy still uses some paths to access items from the standard library. Adding the missing diagnostic items allows removing the last remaining paths.
Closesrust-lang/rust-clippy#5393
error on calls to ABIs that cannot be called
We recently added `extern "custom"`, which cannot be called using a rust call expression. But there are more ABIs that can't be called in that way, because the call does not semantically make sense.
More details are in https://github.com/rust-lang/rust/issues/140566#issuecomment-2846205457
r? `@workingjubilee`
try-job: x86_64-gnu-llvm-19-3
rustdoc_json: improve handling of generic args
This PR fixes some inconsistencies and inefficiencies in how generic args are handled by rustdoc-json-types.
r? `@aDotInTheVoid`
They show up in three places: once as `Option<Box<GenericArgs>>`, once
as `Box<GenericArgs>`, and once as `GenericArgs`. The first option is
best. It is more compact because generic args are often missing. This
commit changes the latter two to the former.
Example output, before and after, for the `AssocItemConstraint` change:
```
{"name":"Offset","args":{"angle_bracketed":{"args":[],"constraints":[]}},"binding":{...}}
{"name":"Offset","args":null,"binding":{...}}
```
Example output, before and after, for the `Type::QualifiedPath` change:
```
{"qualified_path":{"name":"Offset","args":{"angle_bracketed":{"args":[],"constraints":[]}}, ...}}
{"qualified_path":{"name":"Offset","args":null, ...}}
```
This reduces JSON output size, but not by much (e.g. 0.5%), because
`AssocItemConstraint` and `Type::QualifiedPath` are uncommon.
A path without generic args, like `Reader`, currently has JSON produced
like this:
```
{"path":"Reader","id":286,"args":{"angle_bracketed":{"args":[],"constraints":[]}}}
```
Even though `types::Path::args` is `Option` and allows for "no args",
instead it gets represented as "empty args". (More like `Reader<>` than
`Reader`.)
This is due to a problem in `clean::Path::from_clean`. It only produces
`None` if the path is an empty string. This commit changes it to also
produce `None` if there are no generic args. The example above becomes:
```
{"path":"Reader","id":286,"args":null}
```
I looked at a few examples and saw this reduce the size of the JSON
output by 3-9%.
The commit also adds an assertion that non-final segments don't have any
generics; something the old code was implicitly relying on.
Note: the original sin here is that `clean::PathSegment::args` is not an
`Option`, unlike `{ast,hir}::PathSegment::args`. I want to fix that, but
it can be done separately.
Reason about borrowed classes in CopyProp.
Fixes https://github.com/rust-lang/rust/issues/141122
The current implementation of `CopyProp` avoids unifying two borrowed locals, as this would change the result of address comparison.
However, the implementation was inconsistent with the general algorithm, which identifies equivalence classes of locals and then replaces all locals by a single representative of their equivalence class.
This PR fixes it by forbidding the unification of two *classes* if any of those contain a borrowed local.
Marks ADT live if it appears in pattern
Marks ADT live if it appears in pattern, it implies the construction of the ADT.
1. Then we can detect unused private ADTs impl `Default`, without special logics for `Default` and other std traits.
2. We can also remove `rustc_trivial_field_reads` on `Default`, and the logic in `should_ignore_item` (introduced by rust-lang/rust#126302).
Fixesrust-lang/rust#120770
Extracted from rust-lang/rust#128637.
r? `@petrochenkov`
Insert parentheses around binary operation with attribute
Fixes the bug found by `@fmease` in https://github.com/rust-lang/rust/pull/134661#pullrequestreview-2538983253.
Previously, `-Zunpretty=expanded` would expand this program as follows:
```rust
#![feature(stmt_expr_attributes)]
#![allow(unused_attributes)]
macro_rules! group {
($e:expr) => {
$e
};
}
macro_rules! extra {
($e:expr) => {
#[allow()] $e
};
}
fn main() {
let _ = #[allow()] 1 + 1;
let _ = group!(#[allow()] 1) + 1;
let _ = 1 + group!(#[allow()] 1);
let _ = extra!({ 0 }) + 1;
let _ = extra!({ 0 } + 1);
}
```
```console
let _ = #[allow()] 1 + 1;
let _ = #[allow()] 1 + 1;
let _ = 1 + #[allow()] 1;
let _ = #[allow()] { 0 } + 1;
let _ = #[allow()] { 0 } + 1;
```
The first 4 statements are the correct expansion, but the last one is not. The attribute is supposed to apply to the entire binary operation, not only to the left operand.
After this PR, the 5th statement will expand to:
```console
let _ = #[allow()] ({ 0 } + 1);
```
In the future, as some subset of `stmt_expr_attributes` approaches stabilization, it is possible that we will need to do parenthesization for a number of additional cases depending on the outcome of https://github.com/rust-lang/rust/issues/127436. But for now, at least this PR makes the pretty-printer align with the current behavior of the parser.
r? fmease
correct template for `#[align]` attribute
Tracking issue: https://github.com/rust-lang/rust/issues/82232
related: https://github.com/rust-lang/rust/pull/142507
I didn't fully understand what `template!` did, clearly. An empty `#[align]` attribute was still rejected later, but without this change it does get suggested in certain cases.
I've also updated some outdated references to `#[repr(align)]` on functions.
r? ``@jdonszelmann``
Alternative candidates for a trait implementation are not printed when
the trait has a diagnostic name, to avoid printing alternatives for
common stdlib traits such as `Copy` or `Debug`. However, this affects
all traits for which a diagnostic item is added.
Here, the list of alternatives candidates for `Step` does not seem
useful, and `Step` is unstable, so this will not be missed.
