Clarify "owned data" in E0515.md
This clarifies the explanation of why this is not allowed and also what to do instead.
Fixes#62071
PS There was suggestion of adding a link to the book. I did not yet do that, but if desired that could be added.
Move `hir::Item::ident` into `hir::ItemKind`.
`hir::Item` has an `ident` field.
- It's always non-empty for these item kinds: `ExternCrate`, `Static`, `Const`, `Fn`, `Macro`, `Mod`, `TyAlias`, `Enum`, `Struct`, `Union`, Trait`, TraitAalis`.
- It's always empty for these item kinds: `ForeignMod`, `GlobalAsm`, `Impl`.
- For `Use`, it is non-empty for `UseKind::Single` and empty for `UseKind::{Glob,ListStem}`.
All of this is quite non-obvious; the only documentation is a single comment saying "The name might be a dummy name in case of anonymous items". Some sites that handle items check for an empty ident, some don't. This is a very C-like way of doing things, but this is Rust, we have sum types, we can do this properly and never forget to check for the exceptional case and never YOLO possibly empty identifiers (or possibly dummy spans) around and hope that things will work out.
This is step towards `kw::Empty` elimination (#137978).
r? `@fmease`
`hir::Item` has an `ident` field.
- It's always non-empty for these item kinds: `ExternCrate`, `Static`,
`Const`, `Fn`, `Macro`, `Mod`, `TyAlias`, `Enum`, `Struct`, `Union`,
Trait`, TraitAalis`.
- It's always empty for these item kinds: `ForeignMod`, `GlobalAsm`,
`Impl`.
- For `Use`, it is non-empty for `UseKind::Single` and empty for
`UseKind::{Glob,ListStem}`.
All of this is quite non-obvious; the only documentation is a single
comment saying "The name might be a dummy name in case of anonymous
items". Some sites that handle items check for an empty ident, some
don't. This is a very C-like way of doing things, but this is Rust, we
have sum types, we can do this properly and never forget to check for
the exceptional case and never YOLO possibly empty identifiers (or
possibly dummy spans) around and hope that things will work out.
The commit is large but it's mostly obvious plumbing work. Some notable
things.
- A similar transformation makes sense for `ast::Item`, but this is
already a big change. That can be done later.
- Lots of assertions are added to item lowering to ensure that
identifiers are empty/non-empty as expected. These will be removable
when `ast::Item` is done later.
- `ItemKind::Use` doesn't get an `Ident`, but `UseKind::Single` does.
- `lower_use_tree` is significantly simpler. No more confusing `&mut
Ident` to deal with.
- `ItemKind::ident` is a new method, it returns an `Option<Ident>`. It's
used with `unwrap` in a few places; sometimes it's hard to tell
exactly which item kinds might occur. None of these unwraps fail on
the test suite. It's conceivable that some might fail on alternative
input. We can deal with those if/when they happen.
- In `trait_path` the `find_map`/`if let` is replaced with a loop, and
things end up much clearer that way.
- `named_span` no longer checks for an empty name; instead the call site
now checks for a missing identifier if necessary.
- `maybe_inline_local` doesn't need the `glob` argument, it can be
computed in-function from the `renamed` argument.
- `arbitrary_source_item_ordering::check_mod` had a big `if` statement
that was just getting the ident from the item kinds that had one. It
could be mostly replaced by a single call to the new `ItemKind::ident`
method.
- `ItemKind` grows from 56 to 64 bytes, but `Item` stays the same size,
and that's what matters, because `ItemKind` only occurs within `Item`.
change config.toml to bootstrap.toml
Currently, both Bootstrap and Cargo uses same name as their configuration file, which can be confusing. This PR is based on a discussion to rename `config.toml` to `bootstrap.toml` for Bootstrap. Closes: https://github.com/rust-lang/rust/issues/126875.
I have split the PR into atomic commits to make it easier to review. Once the changes are finalized, I will squash them. I am particularly concerned about the changes made to modules that are not part of Bootstrap. How should we handle those changes? Should we ping the respective maintainers?
Improve upvar analysis for deref of child capture
Two fixes to the heuristic I implemented in #123660. As I noted in the code:
> Luckily, if this function is not correct, then the program is not unsound, since we still borrowck and validate the choices made from this function -- the only side-effect is that the user may receive unnecessary borrowck errors.
This indeed fixes unnecessary borrowck errors.
r? oli-obk
---
The heuristic is only valid if we deref a `&T`, not a `&mut T` or `Box<T>`, so make sure to check the type. This fixes:
```rust
struct Foo { precise: i32 }
fn mut_ref_inside_mut(f: &mut Foo) {
let x: impl AsyncFn() = async move || {
let y = &f.precise;
};
}
```
Since the capture from `f` to `&f.precise` needs to be treated as a lending borrow from the parent coroutine-closure to the child coroutine.
---
The heuristic is also valid if *any* deref projection in the child capture's projections is a `&T`, but we were only looking at the last one. This ensures that this function is considered not to be lending:
```rust
struct Foo { precise: i32 }
fn ref_inside_mut(f: &mut &Foo) {
let x: impl Fn() -> _ = async move || {
let y = &f.precise;
};
}
```
(Specifically, checking that `impl Fn() -> _` is satisfied is exercising that the coroutine is not considered to be lending.)
Misc print request handling cleanups + a centralized test for print request stability gating
I was working on implementing `--print=supported-crate-types`, then I noticed some things that were mildly annoying me, so I pulled out these changes. In this PR:
- First commit adds a centralized test `tests/ui/print/stability.rs` that is responsible for exercising stability gating of the print requests.
- AFAICT we didn't have any test that systematically checks this.
- I coalesced `tests/ui/feature-gates/feature-gate-print-check-cfg.rs` (for `--print=check-cfg`) into this test too, since `--print=check-cfg` is only `-Z unstable-options`-gated like other unstable print requests, and is not additionally feature-gated. cc ``@Urgau`` in case you have any concerns.
- Second commit alphabetically sorts the `PrintKind` enum for consistency because the `PRINT_KINDS` list (using the enum) is *already* alphabetically sorted.
- Third commit pulls out two helpers:
1. A helper `check_print_request_stability` for checking stability of print requests and the diagnostics for using unstable print requests without `-Z unstable-options`, to avoid repeating the same logic over and over.
2. A helper `emit_unknown_print_request_help` for the unknown print request diagnostics to make print request collection control flow more obvious.
- Fourth commit renames `PrintKind::{TargetSpec,AllTargetSpecs}` to `PrintKind::{TargetSpecJson,AllTargetSpecsJson}` to better reflect their actual print names, `--print={target-spec-json,all-target-specs-json}`.
r? ``@nnethercote`` (or compiler/reroll)
To correspond to their actual print request names, `target-spec-json`
and `all-target-specs-json`, and for consistency with other print name
<-> print kind mappings.
Remove `#[cfg(not(test))]` gates in `core`
These gates are unnecessary now that unit tests for `core` are in a separate package, `coretests`, instead of in the same files as the source code. They previously prevented the two `core` versions from conflicting with each other.
Add RTN support to rustdoc
This adds support to rustdoc and rustdoc-json for rendering `(..)` RTN (return type notation) style generics.
---
Cleaning `rustc_middle::ty::Ty` is not correct still, though, and ends up rendering a function like:
```rust
pub fn foreign<T: Foreign<bar(..): Send>>()
where
<T as Foreign>::bar(..): 'static,
T::bar(..): Sync,
```
Into this:
```rust
pub fn foreign<T>()
where
T: Foreign,
impl Future<Output = ()>: Send + 'static + Sync,
```
This is because `clean_middle_ty` doesn't actually have sufficient context about whether the RPITIT is in its "defining scope" or not, so we don't know if the type was originally written like `-> impl Trait` or with RTN like `T::method(..)`.
Partially addresses #123996 (i.e., HIR side, not middle::ty one)
Rollup of 5 pull requests
Successful merges:
- #138283 (Enforce type of const param correctly in MIR typeck)
- #138439 (feat: check ARG_MAX on Unix platforms)
- #138502 (resolve: Avoid some unstable iteration)
- #138514 (Remove fake borrows of refs that are converted into non-refs in `MakeByMoveBody`)
- #138524 (Mark myself as unavailable for reviews temporarily)
r? `@ghost`
`@rustbot` modify labels: rollup
Remove fake borrows of refs that are converted into non-refs in `MakeByMoveBody`
Remove fake borrows of closure captures if that capture has been replaced with a by-move version of that capture.
For example, given an async closure that looks like:
```
let f: Foo;
let c = async move || {
match f { ... }
};
```
... in this pair of coroutine-closure + coroutine, we capture `Foo` in the parent and `&Foo` in the child. We will emit two fake borrows like:
```
_2 = &fake shallow (*(_1.0: &Foo));
_3 = &fake shallow (_1.0: &Foo);
```
However, since the by-move-body transform is responsible for replacing `_1.0: &Foo` with `_1.0: Foo` (since the `AsyncFnOnce` coroutine will own `Foo` by value), that makes the second fake borrow obsolete since we never have an upvar of type `&Foo`, and we should replace it with a `nop`.
As a side-note, we don't actually even care about fake borrows here at all since they're fully a MIR borrowck artifact, and we don't need to borrowck by-move MIR bodies. But it's best to preserve as much as we can between these two bodies :)
Fixes#138501
r? oli-obk
feat: check ARG_MAX on Unix platforms
On Unix the limits can be gargantuan anyway so we're pretty unlikely to hit them, but might still exceed it.
We consult ARG_MAX here to get an estimate.
Fixes#138421
r? `@jieyouxu`
Enforce type of const param correctly in MIR typeck
Properly intercepts and then annotates the type for a `ConstKind::Param` in the MIR.
This code should probably be cleaned up, it's kinda spaghetti, but no better structure really occurred to me when writing this case.
We could probably gate this behind the feature gate or add a fast path when the args have no free regions if perf is bad.
r? `@BoxyUwU`
Use `rustc_type_ir` directly less in the codebase
cc https://github.com/rust-lang/rust/issues/138449
This is a somewhat opinionated bundle of changes that will make working on https://github.com/rust-lang/rust/issues/138449 more easy, since it cuts out the bulk of the changes that would be necessitated by the lint. Namely:
1. Fold `rustc_middle::ty::fold` and `rustc_middle::ty::visit` into `rustc_middle::ty`. This is because we already reexport some parts of these modules into `rustc_middle::ty`, and there's really no benefit from namespacing away the rest of these modules's functionality given how important folding and visiting is to the type layer.
2. Rename `{Decodable,Encodable}_Generic` to `{Decodable,Encodable}_NoContext`[^why], change it to be "perfect derive" (`synstructure::AddBounds::Fields`), use it throughout `rustc_type_ir` instead of `TyEncodable`/`TyDecodable`.
3. Make `TyEncodable` and `TyDecodable` derives use `::rustc_middle::ty::codec::TyEncoder` (etc) for its generated paths, and move the `rustc_type_ir::codec` module back to `rustc_middle::ty::codec` 🎉.
4. Stop using `rustc_type_ir` in crates that aren't "fundamental" to the type system, namely middle/infer/trait-selection. This amounted mostly to changing imports from `use rustc_type_ir::...` to `use rustc_middle::ty::...`, but also this means that we can't glob import `TyKind::*` since the reexport into `rustc_middle::ty::TyKind` is a type alias. Instead, use the prefixed variants like `ty::Str` everywhere -- IMO this is a good change, since it makes it more regularized with most of the rest of the compiler.
[^why]: `_NoContext` is the name for derive macros with no additional generic bounds and which do "perfect derive" by generating bounds based on field types. See `HashStable_NoContext`.
I'm happy to cut out some of these changes into separate PRs to make landing it a bit easier, though I don't expect to have much trouble with bitrot.
r? lcnr
Do not suggest using `-Zmacro-backtrace` for builtin macros
For macros that are implemented on the compiler, or that are annotated with `rustc_diagnostic_item`, which have arbitrary implementations from the point of view of the user and might as well be intrinsics, we do *not* mention the `-Zmacro-backtrace` flag. This includes `derive`s and standard macros like `panic!` and `format!`.
This PR adds a field to every `Span`'s `ExpnData` stating whether it comes from a builtin macro. This is determined by the macro being annotated with either `#[rustc_builtin_macro]` or `#[rustc_diagnostic_item]`. An alternative to using these attributes that already exist for other uses would be to introduce another attribute like `#[rustc_no_backtrace]` to have finer control on which macros are affected (for example, an error within `vec![]` now doesn't mention the backtrace, but one could make the case that it should). Ideally, instead of carrying this information in the `ExpnData` we'd instead try to query the `DefId` of the macro (that is already stored) to see if it is annotated in some way, but we do not have access to the `TyCtxt` from `rustc_errors`.
r? `@petrochenkov`
Fix HIR printing of parameters
HIR pretty printing does the wrong thing for anonymous parameters, and there is no test coverage for it. This PR remedies both of those things.
r? ``@lcnr``
Refactor is_snake_case.
I wondered what the definition of this actually was, and found the original hard to read. I believe this change preserves the original behavior, but is hopefully clearer.
rustc_target: Add target features for LoongArch v1.1
This patch adds new target features for LoongArch v1.1:
* div32
* lam-bh
* lamcas
* ld-seq-sa
* scq
Matthias Krüger