Add support for `for await` loops
This adds support for `for await` loops. This includes parsing, desugaring in AST->HIR lowering, and adding some support functions to the library.
Given a loop like:
```rust
for await i in iter {
...
}
```
this is desugared to something like:
```rust
let mut iter = iter.into_async_iter();
while let Some(i) = loop {
match core::pin::Pin::new(&mut iter).poll_next(cx) {
Poll::Ready(i) => break i,
Poll::Pending => yield,
}
} {
...
}
```
This PR also adds a basic `IntoAsyncIterator` trait. This is partly for symmetry with the way `Iterator` and `IntoIterator` work. The other reason is that for async iterators it's helpful to have a place apart from the data structure being iterated over to store state. `IntoAsyncIterator` gives us a good place to do this.
I've gated this feature behind `async_for_loop` and opened #118898 as the feature tracking issue.
r? `@compiler-errors`
Refactor AST trait bound modifiers
Instead of having two types to represent trait bound modifiers in the parser / the AST (`parser::ty::BoundModifiers` & `ast::TraitBoundModifier`), only to map one to the other later, just use `parser::ty::BoundModifiers` (moved & renamed to `ast::TraitBoundModifiers`).
The struct type is more extensible and easier to deal with (see [here](https://github.com/rust-lang/rust/pull/119099/files#r1430749981) and [here](https://github.com/rust-lang/rust/pull/119099/files#r1430752116) for context) since it more closely models what it represents: A compound of two kinds of modifiers, constness and polarity. Modeling this as an enum (the now removed `ast::TraitBoundModifier`) meant one had to add a new variant per *combination* of modifier kind, which simply isn't scalable and which lead to a lot of explicit non-DRY matches.
NB: `hir::TraitBoundModifier` being an enum is fine since HIR doesn't need to worry representing invalid modifier kind combinations as those get rejected during AST validation thereby immensely cutting down the number of possibilities.
Collect lang items from AST, get rid of `GenericBound::LangItemTrait`
r? `@cjgillot`
cc #115178
Looking forward, the work to remove `QPath::LangItem` will also be significantly more difficult, but I plan on doing it as well. Specifically, we have to change:
1. A lot of `rustc_ast_lowering` for things like expr `..`
2. A lot of astconv, since we actually instantiate lang and non-lang paths quite differently.
3. A ton of diagnostics and clippy lints that are special-cased via `QPath::LangItem`
Meanwhile, it was pretty easy to remove `GenericBound::LangItemTrait`, so I just did that here.
Introduce support for `async gen` blocks
I'm delighted to demonstrate that `async gen` block are not very difficult to support. They're simply coroutines that yield `Poll<Option<T>>` and return `()`.
**This PR is WIP and in draft mode for now** -- I'm mostly putting it up to show folks that it's possible. This PR needs a lang-team experiment associated with it or possible an RFC, since I don't think it falls under the jurisdiction of the `gen` RFC that was recently authored by oli (https://github.com/rust-lang/rfcs/pull/3513, https://github.com/rust-lang/rust/issues/117078).
### Technical note on the pre-generator-transform yield type:
The reason that the underlying coroutines yield `Poll<Option<T>>` and not `Poll<T>` (which would make more sense, IMO, for the pre-transformed coroutine), is because the `TransformVisitor` that is used to turn coroutines into built-in state machine functions would have to destructure and reconstruct the latter into the former, which requires at least inserting a new basic block (for a `switchInt` terminator, to match on the `Poll` discriminant).
This does mean that the desugaring (at the `rustc_ast_lowering` level) of `async gen` blocks is a bit more involved. However, since we already need to intercept both `.await` and `yield` operators, I don't consider it much of a technical burden.
r? `@ghost`
never_patterns: Parse match arms with no body
Never patterns are meant to signal unreachable cases, and thus don't take bodies:
```rust
let ptr: *const Option<!> = ...;
match *ptr {
None => { foo(); }
Some(!),
}
```
This PR makes rustc accept the above, and enforces that an arm has a body xor is a never pattern. This affects parsing of match arms even with the feature off, so this is delicate. (Plus this is my first non-trivial change to the parser).
~~The last commit is optional; it introduces a bit of churn to allow the new suggestions to be machine-applicable. There may be a better solution? I'm not sure.~~ EDIT: I removed that commit
r? `@compiler-errors`
Remove `#[rustc_host]`, use internal desugaring
Also removed a way for users to explicitly specify the host param since that isn't particularly useful. This should eliminate any pain with encoding attributes across crates and etc.
r? `@compiler-errors`
`DefPathData::(ClosureExpr,ImplTrait)` are renamed to match `DefKind::(Closure,OpaqueTy)`.
`DefPathData::ImplTraitAssocTy` is replaced with `DefPathData::TypeNS(kw::Empty)` because both correspond to `DefKind::AssocTy`.
It's possible that introducing `(DefKind,DefPathData)::AssocOpaqueTy` could be a better solution, but that would be a much more invasive change.
Const generic parameters introduced for effects are moved from `DefPathData::TypeNS` to `DefPathData::ValueNS`, because constants are values.
`DefPathData` is no longer passed to `create_def` functions to avoid redundancy.
Add `never_patterns` feature gate
This PR adds the feature gate and most basic parsing for the experimental `never_patterns` feature. See the tracking issue (https://github.com/rust-lang/rust/issues/118155) for details on the experiment.
`@scottmcm` has agreed to be my lang-team liaison for this experiment.
They're identical to the same-named types from `ast`. I find it silly
(and inefficient) to have all this boilerplate code to convert one type
to an identical type.
There is already a small amount of type sharing between the AST and HIR,
e.g. `Attribute`, `MacroDef`.
The commit adds a `pub use` to `rustc_hir` so that, for example,
`ast::BinOp` can also be referred to as `hir::BinOp`. This is so the
many existing `hir`-qualified mentions of these types don't need to
change.
The commit also moves a couple of operations from the (removed) HIR
types to the AST types, e.g. `is_by_value`.
By default, `newtype_index!` types get a default `Encodable`/`Decodable`
impl. You can opt out of this with `custom_encodable`. Opting out is the
opposite to how Rust normally works with autogenerated (derived) impls.
This commit inverts the behaviour, replacing `custom_encodable` with
`encodable` which opts into the default `Encodable`/`Decodable` impl.
Only 23 of the 59 `newtype_index!` occurrences need `encodable`.
Even better, there were eight crates with a dependency on
`rustc_serialize` just from unused default `Encodable`/`Decodable`
impls. This commit removes that dependency from those eight crates.
- Sort dependencies and features sections.
- Add `tidy` markers to the sorted sections so they stay sorted.
- Remove empty `[lib`] sections.
- Remove "See more keys..." comments.
Excluded files:
- rustc_codegen_{cranelift,gcc}, because they're external.
- rustc_lexer, because it has external use.
- stable_mir, because it has external use.
Implement `gen` blocks in the 2024 edition
Coroutines tracking issue https://github.com/rust-lang/rust/issues/43122
`gen` block tracking issue https://github.com/rust-lang/rust/issues/117078
This PR implements `gen` blocks that implement `Iterator`. Most of the logic with `async` blocks is shared, and thus I renamed various types that were referring to `async` specifically.
An example usage of `gen` blocks is
```rust
fn foo() -> impl Iterator<Item = i32> {
gen {
yield 42;
for i in 5..18 {
if i.is_even() { continue }
yield i * 2;
}
}
}
```
The limitations (to be resolved) of the implementation are listed in the tracking issue
Rename AsyncCoroutineKind to CoroutineSource
pulled out of https://github.com/rust-lang/rust/pull/116447
Also refactors the printing infra of `CoroutineSource` to be ready for easily extending it with a `Gen` variant for `gen` blocks
Partially outline code inside the panic! macro
This outlines code inside the panic! macro in some cases. This is split out from https://github.com/rust-lang/rust/pull/115562 to exclude changes to rustc.
Pretty-print argument-position impl trait to name it.
This removes a corner case.
RPIT and TAIT keep having no name, and it would be wrong to use the one in HIR (Ident::empty), so I make this case ICE.
There was an incomplete version of the check in parsing and a second
version in AST validation. This meant that some, but not all, invalid
uses were allowed inside macros/disabled cfgs. It also means that later
passes have a hard time knowing when the let expression is in a valid
location, sometimes causing ICEs.
- Add a field to ExprKind::Let in AST/HIR to mark whether it's in a
valid location.
- Suppress later errors and MIR construction for invalid let
expressions.
Map RPIT duplicated lifetimes back to fn captured lifetimes
Use the [`lifetime_mapping`](https://doc.rust-lang.org/nightly/nightly-rustc/rustc_hir/hir/struct.OpaqueTy.html#structfield.lifetime_mapping) to map an RPIT's captured lifetimes back to the early- or late-bound lifetimes from its parent function. We may be going thru several layers of mapping, since opaques can be nested, so we introduce `TyCtxt::map_rpit_lifetime_to_fn_lifetime` to loop through several opaques worth of mapping, and handle turning it into a `ty::Region` as well.
We can then use this instead of the identity substs for RPITs in `check_opaque_meets_bounds` to address #114285.
We can then also use `map_rpit_lifetime_to_fn_lifetime` to properly install bidirectional-outlives predicates for both RPITs and RPITITs. This addresses #114601.
I based this on #114574, but I don't actually know how much of that PR we still need, so some code may be redundant now... 🤷
---
Fixes#114597Fixes#114579Fixes#114285
Also fixes#114601, since it turns out we had other bugs with RPITITs and their duplicated lifetime params 😅.
Supersedes #114574
r? `@oli-obk`
Store the laziness of type aliases in their `DefKind`
Previously, we would treat paths referring to type aliases as *lazy* type aliases if the current crate had lazy type aliases enabled independently of whether the crate which the alias was defined in had the feature enabled or not.
With this PR, the laziness of a type alias depends on the crate it is defined in. This generally makes more sense to me especially if / once lazy type aliases become the default in a new edition and we need to think about *edition interoperability*:
Consider the hypothetical case where the dependency crate has an older edition (and thus eager type aliases), it exports a type alias with bounds & a where-clause (which are void but technically valid), the dependent crate has the latest edition (and thus lazy type aliases) and it uses that type alias. Arguably, the bounds should *not* be checked since at any time, the dependency crate should be allowed to change the bounds at will with a *non*-major version bump & without negatively affecting downstream crates.
As for the reverse case (dependency: lazy type aliases, dependent: eager type aliases), I guess it rules out anything from slight confusion to mild annoyance from upstream crate authors that would be caused by the compiler ignoring the bounds of their type aliases in downstream crates with older editions.
---
This fixes#114468 since before, my assumption that the type alias associated with a given weak projection was lazy (and therefore had its variances computed) did not necessarily hold in cross-crate scenarios (which [I kinda had a hunch about](https://github.com/rust-lang/rust/pull/114253#discussion_r1278608099)) as outlined above. Now it does hold.
`@rustbot` label F-lazy_type_alias
r? `@oli-obk`
Improve spans for indexing expressions
fixes#114388
Indexing is similar to method calls in having an arbitrary left-hand-side and then something on the right, which is the main part of the expression. Method calls already have a span for that right part, but indexing does not. This means that long method chains that use indexing have really bad spans, especially when the indexing panics and that span in coverted into a panic location.
This does the same thing as method calls for the AST and HIR, storing an extra span which is then put into the `fn_span` field in THIR.
r? compiler-errors
Indexing is similar to method calls in having an arbitrary
left-hand-side and then something on the right, which is the main part
of the expression. Method calls already have a span for that right part,
but indexing does not. This means that long method chains that use
indexing have really bad spans, especially when the indexing panics and
that span in coverted into a panic location.
This does the same thing as method calls for the AST and HIR, storing an
extra span which is then put into the `fn_span` field in THIR.
It lints against features that are inteded to be internal to the
compiler and standard library. Implements MCP #596.
We allow `internal_features` in the standard library and compiler as those
use many features and this _is_ the standard library from the "internal to the compiler and
standard library" after all.
Marking some features as internal wasn't exactly the most scientific approach, I just marked some
mostly obvious features. While there is a categorization in the macro,
it's not very well upheld (should probably be fixed in another PR).
We always pass `-Ainternal_features` in the testsuite
About 400 UI tests and several other tests use internal features.
Instead of throwing the attribute on each one, just always allow them.
There's nothing wrong with testing internal features^^
`hir`: Add `Become` expression kind (explicit tail calls experiment)
This adds `hir::ExprKind::Become` alongside ast lowering. During hir-thir lowering we currently lower `become` as `return`, so that we can partially test `become` without ICEing.
cc `@scottmcm`
r? `@Nilstrieb`
Remove `box_free` lang item
This PR removes the `box_free` lang item, replacing it with `Box`'s `Drop` impl. Box dropping is still slightly magic because the contained value is still dropped by the compiler.
Only depend on CFG_VERSION in rustc_interface
This avoids having to rebuild the whole compiler on each commit when `omit-git-hash = false`.
cc https://github.com/rust-lang/rust/issues/76720 - this won't fix it, and I'm not suggesting we turn this on by default, but it will make it less painful for people who do have `omit-git-hash` on as a workaround.
Add cross-language LLVM CFI support to the Rust compiler
This PR adds cross-language LLVM Control Flow Integrity (CFI) support to the Rust compiler by adding the `-Zsanitizer-cfi-normalize-integers` option to be used with Clang `-fsanitize-cfi-icall-normalize-integers` for normalizing integer types (see https://reviews.llvm.org/D139395).
It provides forward-edge control flow protection for C or C++ and Rust -compiled code "mixed binaries" (i.e., for when C or C++ and Rust -compiled code share the same virtual address space). For more information about LLVM CFI and cross-language LLVM CFI support for the Rust compiler, see design document in the tracking issue #89653.
Cross-language LLVM CFI can be enabled with -Zsanitizer=cfi and -Zsanitizer-cfi-normalize-integers, and requires proper (i.e., non-rustc) LTO (i.e., -Clinker-plugin-lto).
Thank you again, ``@bjorn3,`` ``@nikic,`` ``@samitolvanen,`` and the Rust community for all the help!
This commit adds cross-language LLVM Control Flow Integrity (CFI)
support to the Rust compiler by adding the
`-Zsanitizer-cfi-normalize-integers` option to be used with Clang
`-fsanitize-cfi-icall-normalize-integers` for normalizing integer types
(see https://reviews.llvm.org/D139395).
It provides forward-edge control flow protection for C or C++ and Rust
-compiled code "mixed binaries" (i.e., for when C or C++ and Rust
-compiled code share the same virtual address space). For more
information about LLVM CFI and cross-language LLVM CFI support for the
Rust compiler, see design document in the tracking issue #89653.
Cross-language LLVM CFI can be enabled with -Zsanitizer=cfi and
-Zsanitizer-cfi-normalize-integers, and requires proper (i.e.,
non-rustc) LTO (i.e., -Clinker-plugin-lto).
Add `ConstParamTy` trait
This is a bit sketch, but idk.
r? `@BoxyUwU`
Yet to be done:
- [x] ~~Figure out if it's okay to implement `StructuralEq` for primitives / possibly remove their special casing~~ (it should be okay, but maybe not in this PR...)
- [ ] Maybe refactor the code a little bit
- [x] Use a macro to make impls a bit nicer
Future work:
- [ ] Actually™ use the trait when checking if a `const` generic type is allowed
- [ ] _Really_ refactor the surrounding code
- [ ] Refactor `marker.rs` into multiple modules for each "theme" of markers
I was curious about how many `Encodable`/`Decodable` derives we have.
Some grepping revealed that it's over 500 of each, but the number of
`Encodable` ones was higher, which was weird. Most of the
`Encodable`-only ones were in `hir.rs`. This commit removes them all,
plus some other unnecessary derives in that file and others that I found
via trial and error.
Add suggestion to use closure argument instead of a capture on borrowck error
Fixes#109271
r? `@compiler-errors`
This should probably be refined a bit, but opening a PR so that I don't forget anything.
Alloc `hir::Lit` in an arena to remove the destructor from `Expr`
This allows allocating `Expr`s into a dropless arena, which is useful for using length prefixed thing slices in HIR, since these can only be allocated in the dropless arena and not in a typed arena.
This allows allocating `Expr`s into a dropless arena, which is useful
for using length prefixed thing slices in HIR, since these can only be
allocated in the dropless arena and not in a typed arena. This is
something I'm working on.
Initial support for return type notation (RTN)
See: https://smallcultfollowing.com/babysteps/blog/2023/02/13/return-type-notation-send-bounds-part-2/
1. Only supports `T: Trait<method(): Send>` style bounds, not `<T as Trait>::method(): Send`. Checking validity and injecting an implicit binder for all of the late-bound method generics is harder to do for the latter.
* I'd add this in a follow-up.
3. ~Doesn't support RTN in general type position, i.e. no `let x: <T as Trait>::method() = ...`~
* I don't think we actually want this.
5. Doesn't add syntax for "eliding" the function args -- i.e. for now, we write `method(): Send` instead of `method(..): Send`.
* May be a hazard if we try to add it in the future. I'll probably add it in a follow-up later, with a structured suggestion to change `method()` to `method(..)` once we add it.
7. ~I'm not in love with the feature gate name 😺~
* I renamed it to `return_type_notation` ✔️
Follow-up PRs will probably add support for `where T::method(): Send` bounds. I'm not sure if we ever want to support return-type-notation in arbitrary type positions. I may also make the bounds require `..` in the args list later.
r? `@ghost`
Insert alignment checks for pointer dereferences when debug assertions are enabled
Closes https://github.com/rust-lang/rust/issues/54915
- [x] Jake tells me this sounds like a place to use `MirPatch`, but I can't figure out how to insert a new basic block with a new terminator in the middle of an existing basic block, using `MirPatch`. (if nobody else backs up this point I'm checking this as "not actually a good idea" because the code looks pretty clean to me after rearranging it a bit)
- [x] Using `CastKind::PointerExposeAddress` is definitely wrong, we don't want to expose. Calling a function to get the pointer address seems quite excessive. ~I'll see if I can add a new `CastKind`.~ `CastKind::Transmute` to the rescue!
- [x] Implement a more helpful panic message like slice bounds checking.
r? `@oli-obk`
move Option::as_slice to intrinsic
````@scottmcm```` suggested on #109095 I use a direct approach of unpacking the operation in MIR lowering, so here's the implementation.
cc ````@nikic```` as this should hopefully unblock #107224 (though perhaps other changes to the prior implementation, which I left for bootstrapping, are needed).
Remove box expressions from HIR
After #108516, `#[rustc_box]` is used at HIR->THIR lowering and this is no longer emitted, so it can be removed.
This is based on top of #108471 to help with conflicts, so 43490488ccacd1a822e9c621f5ed6fca99959a0b is the only relevant commit (sorry for all the duplicated pings!)
````@rustbot```` label +S-blocked
Make fns from other crates with RPITIT work for -Zlower-impl-trait-in-trait-to-assoc-ty
Only the last two commits are meaningful.
r? `@compiler-errors`
Remove `identity_future` indirection
This was previously needed because the indirection used to hide some unexplained lifetime errors, which it turned out were related to the `min_choice` algorithm.
Removing the indirection also solves a couple of cycle errors, large moves and makes async blocks support the `#[track_caller]`annotation.
Fixes https://github.com/rust-lang/rust/issues/104826.
This was previously needed because the indirection used to hide some unexplained lifetime errors, which it turned out were related to the `min_choice` algorithm.
Removing the indirection also solves a couple of cycle errors, large moves and makes async blocks support the `#[track_caller]` annotation.
The crate hash is needed:
- if debug assertions are enabled, or
- if incr. comp. is enabled, or
- if metadata is being generated, or
- if `-C instrumentation-coverage` is enabled.
This commit avoids computing the crate hash when these conditions are
all false, such as when doing a release build of a binary crate.
It uses `Option` to store the hashes when needed, rather than
computing them on demand, because some of them are needed in multiple
places and computing them on demand would make compilation slower.
The commit also removes `Owner::hash_without_bodies`. There is no
benefit to pre-computing that one, it can just be done in the normal
fashion.
Remove `from` lang item
It was probably a leftover from the old `?` desugaring but anyways, it's unused now except for clippy, which can just use a diagnostics item.
Add rpitit queries
This is part of the changes we are making to lower RPITITs as an associated type. The rest of the stuff will follow under a `-Z` flag.
I still need to add comments to the code, explain stuff and also I'd need to avoid encoding in metadata when rpitit queries return `&[]`
r? `@compiler-errors`
Remove old FIXMEs referring to #19596
Having an inner function that accepts a mutable reference seems to be the only way this can be expressed. Taking a mutable reference would call the same function with a new type &mut F which then causes the infinite recursion error in #19596.
Move format_args!() into AST (and expand it during AST lowering)
Implements https://github.com/rust-lang/compiler-team/issues/541
This moves FormatArgs from rustc_builtin_macros to rustc_ast_lowering. For now, the end result is the same. But this allows for future changes to do smarter things with format_args!(). It also allows Clippy to directly access the ast::FormatArgs, making things a lot easier.
This change turns the format args types into lang items. The builtin macro used to refer to them by their path. After this change, the path is no longer relevant, making it easier to make changes in `core`.
This updates clippy to use the new language items, but this doesn't yet make clippy use the ast::FormatArgs structure that's now available. That should be done after this is merged.
make `CastError::NeedsDeref` create a `MachineApplicable` suggestion
Fixes#106903
Simple impl for the linked issue. I also made some other small changes:
- `CastError::ErrorGuaranteed` now owns an actual `ErrorGuaranteed`. This better enforces the static guarantees of `ErrorGuaranteed`.
- `CastError::NeedDeref` code simplified a bit, we now just suggest the `*`, instead of the whole expression as well.
- Eliminates all the `get_context` calls that async lowering created.
- Replace all `Local` `ResumeTy` types with `&mut Context<'_>`.
The `Local`s that have their types replaced are:
- The `resume` argument itself.
- The argument to `get_context`.
- The yielded value of a `yield`.
The `ResumeTy` hides a `&mut Context<'_>` behind an unsafe raw pointer, and the
`get_context` function is being used to convert that back to a `&mut Context<'_>`.
Ideally the async lowering would not use the `ResumeTy`/`get_context` indirection,
but rather directly use `&mut Context<'_>`, however that would currently
lead to higher-kinded lifetime errors.
See <https://github.com/rust-lang/rust/issues/105501>.
The async lowering step and the type / lifetime inference / checking are
still using the `ResumeTy` indirection for the time being, and that indirection
is removed here. After this transform, the generator body only knows about `&mut Context<'_>`.
Convert all the crates that have had their diagnostic migration
completed (except save_analysis because that will be deleted soon and
apfloat because of the licensing problem).
HIR debug output is currently very verbose, especially when used with
the alternate (`#`) flag. This commit reduces the amount of noisy
newlines by forcing a few small key types to stay on one line, which
makes the output easier to read and scroll by.
```
$ rustc +after hello_world.rs -Zunpretty=hir-tree | wc -l
582
$ rustc +before hello_world.rs -Zunpretty=hir-tree | wc -l
932
```
Improve syntax of `newtype_index`
This makes it more like proper Rust and also makes the implementation a lot simpler.
Mostly just turns weird flags in the body into proper attributes.
It should probably also be converted to an attribute macro instead of function-like, but that can be done in a future PR.
Remove the `..` from the body, only a few invocations used it and it's
inconsistent with rust syntax.
Use `;` instead of `,` between consts. As the Rust syntax gods inteded.
Replace usage of `ResumeTy` in async lowering with `Context`
Replaces using `ResumeTy` / `get_context` in favor of using `&'static mut Context<'_>`.
Usage of the `'static` lifetime here is technically "cheating", and replaces the raw pointer in `ResumeTy` and the `get_context` fn that pulls the correct lifetimes out of thin air.
fixes https://github.com/rust-lang/rust/issues/104828 and https://github.com/rust-lang/rust/pull/104321#issuecomment-1336363077
r? `@oli-obk`
Add StableOrd trait as proposed in MCP 533.
The `StableOrd` trait can be used to mark types as having a stable sort order across compilation sessions. Collections that sort their items in a stable way can safely implement HashStable by hashing items in sort order.
See https://github.com/rust-lang/compiler-team/issues/533 for more information.
Replaces using `ResumeTy` / `get_context` in favor of using `&'static mut Context<'_>`.
Usage of the `'static` lifetime here is technically "cheating", and replaces
the raw pointer in `ResumeTy` and the `get_context` fn that pulls the
correct lifetimes out of thin air.
Remove useless borrows and derefs
They are nothing more than noise.
<sub>These are not all of them, but my clippy started crashing (stack overflow), so rip :(</sub>
The StableOrd trait can be used to mark types as having a stable
sort order across compilation sessions. Collections that sort their
items in a stable way can safely implement HashStable by
hashing items in sort order.
Prefer doc comments over `//`-comments in compiler
Doc comments are generally nicer: they show up in the documentation, they are shown in IDEs when you hover other mentions of items, etc. Thus it makes sense to use them instead of `//`-comments.
Rollup of 8 pull requests
Successful merges:
- #95836 (Use `rust_out{exe_suffix}` for doctests)
- #104882 (notify lcnr on changes to `ObligationCtxt`)
- #104892 (Explain how to get the discriminant out of a `#[repr(T)] enum` with payload)
- #104917 (Allow non-org members to label `requires-debug-assertions`)
- #104931 (Pretty-print generators with their `generator_kind`)
- #104934 (Remove redundant `all` in cfg)
- #104944 (Support unit tests for jsondoclint)
- #104946 (rustdoc: improve popover focus handling JS)
Failed merges:
r? `@ghost`
`@rustbot` modify labels: rollup
Pretty-print generators with their `generator_kind`
After removing `GenFuture`, I special-cased async generators to pretty-print as `impl Future<Output = X>` mainly to avoid too much diagnostics changes originally.
This now reverses that change so that async fn/blocks are pretty-printed as `[$async-type@$source-position]` in various diagnostics, and updates the tests that this touches.
Separate lifetime ident from lifetime resolution in HIR
Drive-by: change how suggested generic args are computed.
Fixes https://github.com/rust-lang/rust/issues/103815
I recommend reviewing commit-by-commit.
After removing `GenFuture`, I special-cased async generators to pretty-print as `impl Future<Output = X>` mainly to avoid too much diagnostics changes originally.
This now reverses that change so that async fn/blocks are pretty-printed as `[$movability `async` $something@$source-position]` in various diagnostics, and updates the tests that this touches.
Avoid `GenFuture` shim when compiling async constructs
Previously, async constructs would be lowered to "normal" generators, with an additional `from_generator` / `GenFuture` shim in between to convert from `Generator` to `Future`.
The compiler will now special-case these generators internally so that async constructs will *directly* implement `Future` without the need to go through the `from_generator` / `GenFuture` shim.
The primary motivation for this change was hiding this implementation detail in stack traces and debuginfo, but it can in theory also help the optimizer as there is less abstractions to see through.
---
Given this demo code:
```rust
pub async fn a(arg: u32) -> Backtrace {
let bt = b().await;
let _arg = arg;
bt
}
pub async fn b() -> Backtrace {
Backtrace::force_capture()
}
```
I would get the following with the latest stable compiler (on Windows):
```
4: async_codegen:🅱️:async_fn$0
at .\src\lib.rs:10
5: core::future::from_generator::impl$1::poll<enum2$<async_codegen:🅱️:async_fn_env$0> >
at /rustc/897e37553bba8b42751c67658967889d11ecd120\library\core\src\future\mod.rs:91
6: async_codegen:🅰️:async_fn$0
at .\src\lib.rs:4
7: core::future::from_generator::impl$1::poll<enum2$<async_codegen:🅰️:async_fn_env$0> >
at /rustc/897e37553bba8b42751c67658967889d11ecd120\library\core\src\future\mod.rs:91
```
whereas now I get a much cleaner stack trace:
```
3: async_codegen:🅱️:async_fn$0
at .\src\lib.rs:10
4: async_codegen:🅰️:async_fn$0
at .\src\lib.rs:4
```
Previously, async constructs would be lowered to "normal" generators,
with an additional `from_generator` / `GenFuture` shim in between to
convert from `Generator` to `Future`.
The compiler will now special-case these generators internally so that
async constructs will *directly* implement `Future` without the need
to go through the `from_generator` / `GenFuture` shim.
The primary motivation for this change was hiding this implementation
detail in stack traces and debuginfo, but it can in theory also help
the optimizer as there is less abstractions to see through.
Improve spans for RPITIT object-safety errors
No reason why we can't point at the `impl Trait` that causes the object-safety violation.
Also [drive-by: Add is_async fn to hir::IsAsync](c4165f3a96), which touches clippy too.
Rollup of 8 pull requests
Successful merges:
- #102977 (remove HRTB from `[T]::is_sorted_by{,_key}`)
- #103378 (Fix mod_inv termination for the last iteration)
- #103456 (`unchecked_{shl|shr}` should use `u32` as the RHS)
- #103701 (Simplify some pointer method implementations)
- #104047 (Diagnostics `icu4x` based list formatting.)
- #104338 (Enforce that `dyn*` coercions are actually pointer-sized)
- #104498 (Edit docs for `rustc_errors::Handler::stash_diagnostic`)
- #104556 (rustdoc: use `code-header` class to format enum variants)
Failed merges:
r? `@ghost`
`@rustbot` modify labels: rollup
Clippy has an internal lint that checks for the usage of hardcoded def
paths and suggests to replace them with a lang or diagnostic item, if
possible. This was implemented with a hack, by getting all the variants
of the `LangItem` enum and then index into it with the position of the
`LangItem` in the `items` list. This is no longer possible, because the
`items` list can't be accessed anymore.
Rewrite implementation of `#[alloc_error_handler]`
The new implementation doesn't use weak lang items and instead changes `#[alloc_error_handler]` to an attribute macro just like `#[global_allocator]`.
The attribute will generate the `__rg_oom` function which is called by the compiler-generated `__rust_alloc_error_handler`. If no `__rg_oom` function is defined in any crate then the compiler shim will call `__rdl_oom` in the alloc crate which will simply panic.
This also fixes link errors with `-C link-dead-code` with `default_alloc_error_handler`: `__rg_oom` was previously defined in the alloc crate and would attempt to reference the `oom` lang item, even if it didn't exist. This worked as long as `__rg_oom` was excluded from linking since it was not called.
This is a prerequisite for the stabilization of `default_alloc_error_handler` (#102318).
The new implementation doesn't use weak lang items and instead changes
`#[alloc_error_handler]` to an attribute macro just like
`#[global_allocator]`.
The attribute will generate the `__rg_oom` function which is called by
the compiler-generated `__rust_alloc_error_handler`. If no `__rg_oom`
function is defined in any crate then the compiler shim will call
`__rdl_oom` in the alloc crate which will simply panic.
This also fixes link errors with `-C link-dead-code` with
`default_alloc_error_handler`: `__rg_oom` was previously defined in the
alloc crate and would attempt to reference the `oom` lang item, even if
it didn't exist. This worked as long as `__rg_oom` was excluded from
linking since it was not called.
This is a prerequisite for the stabilization of
`default_alloc_error_handler` (#102318).
spastorino noticed some silly expressions like `item_id.def_id.def_id`.
This commit renames several `def_id: OwnerId` fields as `owner_id`, so
those expressions become `item_id.owner_id.def_id`.
`item_id.owner_id.local_def_id` would be even clearer, but the use of
`def_id` for values of type `LocalDefId` is *very* widespread, so I left
that alone.
rename `ImplItemKind::TyAlias` to `ImplItemKind::Type`
The naming of this variant seems inconsistent given that this is not really a "type alias", and the associated type variant for `TraitItemKind` is just called `Type`.
`Res::SelfTy` currently has two `Option`s. When the second one is `Some`
the first one is never consulted. So we can split it into two variants,
`Res::SelfTyParam` and `Res::SelfTyAlias`, reducing the size of `Res`
from 24 bytes to 12. This then shrinks `hir::Path` and
`hir::PathSegment`, which are the HIR types that take up the most space.
Stabilize const `BTree{Map,Set}::new`
The FCP was completed in #71835.
Since `len` and `is_empty` are not const stable yet, this also creates a new feature for them since they previously used the same `const_btree_new` feature.
fix a ui test
use `into`
fix clippy ui test
fix a run-make-fulldeps test
implement `IntoQueryParam<DefId>` for `OwnerId`
use `OwnerId` for more queries
change the type of `ParentOwnerIterator::Item` to `(OwnerId, OwnerNode)`
Since `len` and `is_empty` are not const stable yet, this also
creates a new feature for them since they previously used the same
`const_btree_new` feature.
On later stages, the feature is already stable.
Result of running:
rg -l "feature.let_else" compiler/ src/librustdoc/ library/ | xargs sed -s -i "s#\\[feature.let_else#\\[cfg_attr\\(bootstrap, feature\\(let_else\\)#"
Avoid `Iterator::last`
Adapters like `Filter` and `Map` use the default implementation of `Iterator::last` which is not short-circuiting (and so does `core::str::Split`). The predicate function will be run for every single item of the underlying iterator. I hope that removing those calls to `last` results in slight performance improvements.
The `visit_path_segment` method of both the AST and HIR visitors has a
`path_span` argument that isn't necessary. This commit removes it.
There are two very small and inconsequential functional changes.
- One call to `NodeCollector::insert` now is passed a path segment
identifier span instead of a full path span. This span is only used in
a panic message printed in the case of an internal compiler bug.
- Likewise, one call to `LifetimeCollectVisitor::record_elided_anchor`
now uses a path segment identifier span instead of a full path span.
This span is used to make some `'_` lifetimes.
Tweak future opaque ty pretty printing
1. The `Return` type of a generator doesn't need to be a lang item just for diagnostic printing of types
2. We shouldn't suppress the `Output = Ty` of a opaque future if the type is a int or float var.
Rollup of 7 pull requests
Successful merges:
- #98933 (Opaque types' generic params do not imply anything about their hidden type's lifetimes)
- #101041 (translations(rustc_session): migrates rustc_session to use SessionDiagnostic - Pt. 2)
- #101424 (Adjust and slightly generalize operator error suggestion)
- #101496 (Allow lower_lifetime_binder receive a closure)
- #101501 (Allow lint passes to be bound by `TyCtxt`)
- #101515 (Recover from typo where == is used in place of =)
- #101545 (Remove unnecessary `PartialOrd` and `Ord`)
Failed merges:
r? `@ghost`
`@rustbot` modify labels: rollup
This shrinks `hir::Ty` from 72 to 48 bytes.
`visit_lifetime` is added to the HIR stats collector because these types
are now stored in memory on their own, instead of being within other
types.
`BindingAnnotation` refactor
* `ast::BindingMode` is deleted and replaced with `hir::BindingAnnotation` (which is moved to `ast`)
* `BindingAnnotation` is changed from an enum to a tuple struct e.g. `BindingAnnotation(ByRef::No, Mutability::Mut)`
* Associated constants added for convenience `BindingAnnotation::{NONE, REF, MUT, REF_MUT}`
One goal is to make it more clear that `BindingAnnotation` merely represents syntax `ref mut` and not the actual binding mode. This was especially confusing since we had `ast::BindingMode`->`hir::BindingAnnotation`->`thir::BindingMode`.
I wish there were more symmetry between `ByRef` and `Mutability` (variant) naming (maybe `Mutable::Yes`?), and I also don't love how long the name `BindingAnnotation` is, but this seems like the best compromise. Ideas welcome.
