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Stabilize `io_error_other` feature Per the FCP for rust-lang/rust#91946.
Add `FreezeLock` type and use it to store `Definitions` This adds a `FreezeLock` type which allows mutation using a lock until the value is frozen where it can be accessed lock-free. It's used to store `Definitions` in `Untracked` instead of a `RwLock`. Unlike the current scheme of leaking read guards this doesn't deadlock if definitions is written to after no mutation are expected.
… return value callee-invalid
Preserve ASAN-related symbols during LTO. Fixes rust-lang/rust#113404
…usage, r=est31
Lint on invalid usage of `UnsafeCell::raw_get` in reference casting
This PR proposes to take into account `UnsafeCell::raw_get` method call for non-Freeze types for the `invalid_reference_casting` lint.
The goal of this is to catch those kind of invalid reference casting:
```rust
fn as_mut<T>(x: &T) -> &mut T {
unsafe { &mut *std::cell::UnsafeCell::raw_get(x as *const _ as *const _) }
//~^ ERROR casting `&T` to `&mut T` is undefined behavior
}
```
r? `@est31`
Use a specialized varint + bitpacking scheme for DepGraph encoding The previous scheme here uses leb128 to encode the edge tables that represent the incr comp dependency graph. The problem with that scheme is that leb128 has overhead for larger values, and generally relies on the distribution of encoded values being heavily skewed towards smaller values. That is definitely not the case for a dep node index, since they are handed out sequentially and the whole range is covered, the distribution is actually biased in the opposite direction: Most dep nodes are large. This PR implements a different varint encoding scheme. Instead of applying varint encoding to individual dep node indices (which is extremely branchy) we now apply it per node. While being built, each node now stores its edges in a `SmallVec` with a bit of extra logic to track the max value of each edge. Then we varint encode the whole batch. This is a gamble: We save on space by only claiming 2 bits per node instead of ~3 bits per edge which is a nice savings but needs to balance out with the space overhead that a single large index in a node with a lot of edges will encode unnecessary bytes in each of that node's edge indices. Then, to keep the runtime overhead of this encoding scheme down we deserialize our indices by loading 4 bytes for each then masking off the bytes that are't ours. This is much less code and branches than leb128, but relies on having some readable bytes past the end of each edge list. We explicitly add such padding to the in-memory data during decoding. And we also do this decoding lazily, turning a dense on-disk encoding into a peak memory reduction. Then we apply a bit-packing scheme; since in rust-lang/rust#115391 we now have unused bits on `DepKind`, we use those unused bits (currently there are 7!) to store the 2 bits that we need for the byte width of the edges in each node, then use the remaining bits to store the length of the edge list, if it fits. r? `@nnethercote`
Stabilize `PATH` option for `--print KIND=PATH` This PR propose stabilizing the `PATH` option for `--print KIND=PATH`. This option was previously added in rust-lang/rust#113780 (as insta-stable before being un-stablized in rust-lang/rust#114139). Description of the `PATH` option: > A filepath may optionally be specified for each requested information kind, in the format `--print KIND=PATH`, just like for `--emit`. When a path is specified, information will be written there instead of to stdout. ------ Description of the original PR [\[link\]](rust-lang/rust#113780 (comment)): > **Support --print KIND=PATH command line syntax** > > As is already done for `--emit KIND=PATH` and `-L KIND=PATH`. > > In the discussion of rust-lang/rust#110785, it was pointed out that `--print KIND=PATH` is nicer than trying to apply the single global `-o path` to `--print`'s output, because in general there can be multiple print requests within a single rustc invocation, and anyway `-o` would already be used for a different meaning in the case of `link-args` and `native-static-libs`. > > I am interested in using `--print cfg=PATH` in Buck2. Currently Buck2 works around the lack of support for `--print KIND=PATH` by [indirecting through a Python wrapper script](https://github.com/facebook/buck2/blob/d43cf3a51a31f00be2c2248e78271b0fef0452b4/prelude/rust/tools/get_rustc_cfg.py) to redirect rustc's stdout into the location dictated by the build system. > > From skimming Cargo's usages of `--print`, it definitely seems like it would benefit from `--print KIND=PATH` too. Currently it is working around the lack of this by inserting `--crate-name=___ --print=crate-name` so that it can look for a line containing `___` as a delimiter between the 2 other `--print` informations it actually cares about. This is commented as a "HACK" and "abuse". https://github.com/rust-lang/cargo/blob/31eda6f7c360d9911f853b3014e057db61238f3e/src/cargo/core/compiler/build_context/target_info.rs#L242 ----- cc `@dtolnay` r? `@jackh726`
…aumeGomez rustdoc: show inner enum and struct in type definition for concrete type This PR implements the [Display enum variants for generic enum in type def page](https://rust-lang.zulipchat.com/#narrow/stream/266220-rustdoc/topic/Display.20enum.20variants.20for.20generic.20enum.20in.20type.20def.20page) #rustdoc/zulip proposal. This proposal comes from looking at [`TyKind`](https://doc.rust-lang.org/nightly/nightly-rustc/rustc_middle/ty/sty/type.TyKind.html) typedef from the compiler. On that page, the documentation is able to show the layout for each variant, but not the variants themselves. This proposal suggests showing the fields and variants for those "concrete type". This would mean that instead of having many unresolved generics, like in `IrTyKind`: ```rust Array(I::Ty, I::Const), Slice(I::Ty), RawPtr(I::TypeAndMut), Ref(I::Region, I::Ty, I::Mutability), FnDef(I::DefId, I::GenericArgsRef), ``` those would be resolved with direct links to the proper types in the `TyKind` typedef page: ```rust Array(Ty<'tcx>, Const<'tcx>), Slice(Ty<'tcx>), RawPtr(TypeAndMut<'tcx>), Ref(Region<'tcx>, Ty<'tcx>, Mutability<'tcx>), FnDef(DefId<'tcx>, GenericArgsRef<'tcx>), ``` Saving both time and confusion. ----- <details> <summary>Old description</summary> I've chosen to add the enums and structs under the "Show Aliased Type" details, as well as showing the variants and fields under the usual "Variants" and "Fields" sections. ~~*under new the `Inner Variants` and `Inner Fields` sections (except for their names, they are identical to the one found in the enum, struct and union pages). Those sections are complementary and do not replace anything else.*~~ This PR proposes the following condition for showing the aliased type (basically, has the aliased type some generics that are all of them resolved): - the typedef does NOT have any generics (modulo lifetimes) - AND the aliased type has some generics </details> ### Examples ```rust pub enum IrTyKind<'a, I: Interner> { /// Doc comment for AdtKind AdtKind(&'a I::Adt), /// and another one for TyKind TyKind(I::Adt, I::Ty), // no comment StructKind { a: I::Adt, }, } pub type TyKind<'a> = IrTyKind<'a, TyCtxt>; ```  <details> <summary>Old</summary>    </details> ```rust pub struct One<T> { pub val: T, #[doc(hidden)] pub inner_tag: u64, __hidden: T, } /// `One` with `u64` as payload pub type OneU64 = One<u64>; ```  <details> <summary>Old</summary>    </details> r? `@GuillaumeGomez`
Don't require `Drop` for `[PhantomData<T>; N]` where `N` and `T` are generic, if `T` requires `Drop` fixes rust-lang/rust#115403 fixes rust-lang/rust#115410 This was accidentally regressed in rust-lang/rust#114134, because it was accidentally stabilized in #102204 (cc `@rust-lang/lang,` seems like an innocent stabilization, considering this PR is more of a bugfix than a feature). While we have a whole month to beta backport this change before the regression hits stable, I'd still prefer not to go through an FCP on this PR (which fixes a regression), if T-lang wants an FCP, I can can open an issue about the change itself.
Add char::MIN ACP: rust-lang/libs-team#252 Tracking issue: #114298 r? `@rust-lang/libs-api`
miri: catch function calls where the argument is caller-invalid / the return value callee-invalid When doing a type-changing copy, we must validate the data both at the old and new type. Fixes #3017
Add CL and CMD into to pdb debug info Partial fix for rust-lang/rust#96475 The Arg0 and CommandLineArgs of the MCTargetOptions cpp class are not set within https://github.com/rust-lang/rust/blob/bb548f964572f7fe652716f5897d9050a31c936e/compiler/rustc_llvm/llvm-wrapper/PassWrapper.cpp#L378 This causes LLVM to not neither output any compiler path (cl) nor the arguments that were used when invoking it (cmd) in the PDB file. This fix adds the missing information to the target machine so LLVM can use it.
add rustc_abi(assert_eq) to test some guaranteed or at least highly expected ABI compatibility guarantees This new repr(transparent) test is super useful, it would have found rust-lang/rust#115336 and found rust-lang/rust#115404, rust-lang/rust#115481, rust-lang/rust#115509.
Improvements to dataflow const-prop Partially cherry-picked from rust-lang/rust#110719 r? `@oli-obk` cc `@jachris`
Use `Freeze` for `SourceFile` This uses the `Freeze` type in `SourceFile` to let accessing `external_src` and `lines` be lock-free. Behavior of `add_external_src` is changed to set `ExternalSourceKind::AbsentErr` on a hash mismatch which matches the documentation. `ExternalSourceKind::Unneeded` was removed as it's unused. Based on rust-lang/rust#115401.
lto: load bitcode sections by name Upstream change llvm/llvm-project@6b539f5 changed `isSectionBitcode` works and it now only respects `.llvm.lto` sections instead of also `.llvmbc`, which it says was never intended to be used for LTO. We instead load sections by name, and sniff for raw bitcode by hand. This is an alternative approach to #115136, where we tried the same thing using the `object` crate, but it got too fraught to continue. r? `@nikic` `@rustbot` label: +llvm-main
Use the same DISubprogram for each instance of the same inlined function within a caller
# Issue Details:
The call to `panic` within a function like `Option::unwrap` is translated to LLVM as a `tail call` (as it will never return), when multiple calls to the same function like this are inlined LLVM will notice the common `tail call` block (i.e., loading the same panic string + location info and then calling `panic`) and merge them together.
When merging these instructions together, LLVM will also attempt to merge the debug locations as well, but this fails (i.e., debug info is dropped) as Rust emits a new `DISubprogram` at each inline site thus LLVM doesn't recognize that these are actually the same function and so thinks that there isn't a common debug location.
As an example of this, consider the following program:
```rust
#[no_mangle]
fn add_numbers(x: &Option<i32>, y: &Option<i32>) -> i32 {
let x1 = x.unwrap();
let y1 = y.unwrap();
x1 + y1
}
```
When building for x86_64 Windows using 1.72 it generates (note the lack of `.cv_loc` before the call to `panic`, thus it will be attributed to the same line at the `addq` instruction):
```llvm
.cv_loc 0 1 3 0 # src\lib.rs:3:0
addq $40, %rsp
retq
leaq .Lalloc_f570dea0a53168780ce9a91e67646421(%rip), %rcx
leaq .Lalloc_629ace53b7e5b76aaa810d549cc84ea3(%rip), %r8
movl $43, %edx
callq _ZN4core9panicking5panic17h12e60b9063f6dee8E
int3
```
# Fix Details:
Cache the `DISubprogram` emitted for each inlined function instance within a caller so that this can be reused if that instance is encountered again.
Ideally, we would also deduplicate child scopes and variables, however my attempt to do that with #114643 resulted in asserts when building for Linux (#115156) which would require some deep changes to Rust to fix (#115455).
Instead, when using an inlined function as a debug scope, we will also create a new child scope such that subsequent child scopes and variables do not collide (from LLVM's perspective).
After this change the above assembly now (with <https://reviews.llvm.org/D159226> as well) shows the `panic!` was inlined from `unwrap` in `option.rs` at line 935 into the current function in `lib.rs` at line 0 (line 0 is emitted since it is ambiguous which line to use as there were two inline sites that lead to this same code):
```llvm
.cv_loc 0 1 3 0 # src\lib.rs:3:0
addq $40, %rsp
retq
.cv_inline_site_id 6 within 0 inlined_at 1 0 0
.cv_loc 6 2 935 0 # library\core\src\option.rs:935:0
leaq .Lalloc_5f55955de67e57c79064b537689facea(%rip), %rcx
leaq .Lalloc_e741d4de8cb5801e1fd7a6c6795c1559(%rip), %r8
movl $43, %edx
callq _ZN4core9panicking5panic17hde1558f32d5b1c04E
int3
```
…iddle rustdoc: Change syntax for anonymous functions set in JS This function is not very useful in itself but it slightly reduces the JS size so it's always that I suppose... No changes in behaviour. r? `@notriddle`
Avoid a `source_span` query when encoding Spans into query results This avoids a `source_span` query when encoding `Span`s into query results. It's not sound to execute queries here as the query caches can be locked and the dep graph is no longer writable. r? `@cjgillot`
Span tweaks Some minor improvements to code clarity. r? `@cjgillot`
…nsistent across targets
…otriddle Migrate GUI colors test to original CSS color format Follow-up of rust-lang/rust#111459. r? `@notriddle`
Allow redirecting subprocess stdout to our stderr etc. (redux) This is the code from #88561, tidied up, including review suggestions, and with the for-testing-only CI commit removed. FCP for the API completed in #88561. I have made a new MR to facilitate review. The discussion there is very cluttered and the branch is full of changes (in many cases as a result of changes to other Rust stdlib APIs since then). Assuming this MR is approvedl we should close that one. ### Reviewer doing a de novo review Just code review these four commits.. FCP discussion starts here: rust-lang/rust#88561 (comment) Portability tests: you can see that this branch works on Windows too by looking at the CI results in #88561, which has the same code changes as this branch but with an additional "DO NOT MERGE" commit to make the Windows tests run. ### Reviewer doing an incremental review from some version of #88561 Review the new commits since your last review. I haven't force pushed the branch there. git diff the two branches (eg `git diff 176886197d6..0842b69c219`). You'll see that the only difference is in gitlab CI files. You can also see that *this* MR doesn't touch those files.
…k, r=compiler-errors Abort if check nightly options failed on stable Fixes #115680 Also, if there are multiple unstable options passing on stable compiler, printing multiple same `note` and `help` seems noisy.
It is only used by miri which can create a new one using the Session.
…otriddle Migrate GUI colors test to original CSS color format Follow-up of rust-lang/rust#111459. r? `@notriddle`
QNX: pass a truncated thread name to the OS The maximum length the thread name can have is `_NTO_THREAD_NAME_MAX` fixes #114966
Implements LLVM intrisics needed to run most SSE2 functions from `core::arch::x86{,_64}`.
Also adds miri tests for those functions (mostly copied from core_arch tests).
Implement some `llvm.x86.sse2.*` intrinsics and add tests Continuation of #2989 with SSE2 intrinsics. Thankfully, a significant amount of SSE2 functions use `simd_*` intrinsics, which are already implemented in Miri.
…iser tests: re-enable pretty-std-collections on macOS Fixes #78665. I made some small modifications to this test so that it would pass for me locally (though I was only able to test using lldb without built-in Rust support, but that seems to be the mode in which it would fail). I ran it a few hundred times with stage one and stage two to see if I could re-produce the spurious failures that were being reported in #78665 and couldn't. From the discussion in #78665, it seemed like this was related to Xcode versions and could be reproduced locally fairly easily. It's been a couple years since this was disabled so a lot has changed. If this starts failing spuriously again then we can disable it and I can look into that. r? `@wesleywiser` (discussed in wg-debugging's triage meeting)
update Miri r? `@ghost`
Only suggest turbofish in patterns if we may recover Fixes [after backport] #115780. CC #103534.
Make compiletest output truncation less disruptive When the test output becomes too large, compiletest stops recording all of it. However: - this can lead to invalid JSON, which then causes compiletest itself to throw further errors - the note that output was truncated is in the middle of the output, with >100kb of text on each side; that makes it almost impossible to actually see that note in the terminal So assuming that we do need to keep the output truncation, I propose that we only ever do a cut at the end, so that it is very clear by looking at the end of the log that truncation happened. I added a message at the beginning of the output as well. Also I added some logic to make it less likely that we'll cut things off in the middle of a JSON record. (I tested that successfully by reducing the output limit to something very low and running a few ui tests.) Furthermore I increased the max buffer size to 512KB; that's really not a lot of memory compared to how much RAM it takes to build rustc (it's ~25% more than the previous maximum HEAD+TAIL length). And finally, the information that things got truncated is now propagated to the higher levels, so that we can fail the test instead of comparing the truncated output with the reference. Fixes rust-lang/rust#115675 Fixes rust-lang/rust#96229 Fixes rust-lang/rust#94322 Fixes rust-lang/rust#92211
…-obk Add explicit_predicates_of to SMIR Adding `explicit_predicates_of` so we can use it from Mir formality. r? `@oli-obk`
Folding comments r? `@WaffleLapkin`
Extend rustc -Zls This makes it show a lot more things and thus a lot more useful.
make the eval() functions on our const types return the resulting value This is a part of rust-lang/rust#115748 that's hopefully perf-neutral, and that does not depend on rust-lang/rust#115764.
Do not clone the Body for ConstProp ~Based on rust-lang/rust#115748 for the `POST_MONO_CHECKS` flag.~
Update Clippy r? `@Manishearth`
Rework `no_coverage` to `coverage(off)` As discussed at the tail of rust-lang/rust#84605 this replaces the `no_coverage` attribute with a `coverage` attribute that takes sub-parameters (currently `off` and `on`) to control the coverage instrumentation. Allows future-proofing for things like `coverage(off, reason="Tested live", issue="#12345")` or similar.
some inspect improvements split from #114810 because I still want to experiment a bunch with that PR and these changes are self-contained. r? `@compiler-errors`
Visit ExprField for lint levels. Fixes rust-lang/rust#115823
some ConstValue refactoring In particular, use AllocId instead of Allocation in ConstValue::ByRef. This helps avoid redundant AllocIds when a `ByRef` constant gets put back into the interpreter. r? `@oli-obk` Fixes rust-lang/rust#105536
…r=RalfJung Change `unsafe_op_in_unsafe_fn` to be `warn`-by-default from edition 2024 This was previously FCPed: rust-lang/rust#71668 (comment) There were two blocking requirements: * Fix the `unused_unsafe` lint, done in rust-lang/rust#100081 * Have `cargo fix` able to fix the lint, done in rust-lang/rust#112017
treat host effect params as erased in codegen This fixes the changes brought to codegen tests when effect params are added to libcore, by not attempting to monomorphize functions that get the host param by being `const fn`. r? `@oli-obk`
consistently pass ty::Const through valtrees Some drive-by things extracted from rust-lang/rust#115748.
Improve invalid let expression handling - Move all of the checks for valid let expression positions to parsing. - Add a field to ExprKind::Let in AST/HIR to mark whether it's in a valid location. - Suppress some later errors and MIR construction for invalid let expressions. - Fix a (drop) scope issue that was also responsible for #104172. Fixes #104172 Fixes #104868
Fallback effects even if types also fallback `||` is short circuiting, so if we do ty/int var fallback, we *don't* do effect fallback 😸 r? `@fee1-dead` or `@oli-obk` Fixes #115791 Fixes #115842
Automatic sync from rustc
pitaj
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Jan 20, 2024
Stabilize `async fn` and return-position `impl Trait` in trait # Stabilization report This report proposes the stabilization of `#![feature(return_position_impl_trait_in_trait)]` ([RPITIT][RFC 3425]) and `#![feature(async_fn_in_trait)]` ([AFIT][RFC 3185]). These are both long awaited features that increase the expressiveness of the Rust language and trait system. Closes #91611 [RFC 3185]: https://rust-lang.github.io/rfcs/3185-static-async-fn-in-trait.html [RFC 3425]: https://rust-lang.github.io/rfcs/3425-return-position-impl-trait-in-traits.html ## Updates from thread The thread has covered two major concerns: * [Given that we don't have RTN, what should we stabilize?](rust-lang/rust#115822 (comment)) -- proposed resolution is [adding a lint](rust-lang/rust#115822 (comment)) and [careful messaging](rust-lang/rust#115822 (comment)) * [Interaction between outlives bounds and capture semantics](rust-lang/rust#115822 (comment)) -- This is fixable in a forwards-compatible way via #116040, and also eventually via ATPIT. ## Stabilization Summary This stabilization allows the following examples to work. ### Example of return-position `impl Trait` in trait definition ```rust trait Bar { fn bar(self) -> impl Send; } ``` This declares a trait method that returns *some* type that implements `Send`. It's similar to writing the following using an associated type, except that the associated type is anonymous. ```rust trait Bar { type _0: Send; fn bar(self) -> Self::_0; } ``` ### Example of return-position `impl Trait` in trait implementation ```rust impl Bar for () { fn bar(self) -> impl Send {} } ``` This defines a method implementation that returns an opaque type, just like [RPIT][RFC 1522] does, except that all in-scope lifetimes are captured in the opaque type (as is already true for `async fn` and as is expected to be true for RPIT in Rust Edition 2024), as described below. [RFC 1522]: https://rust-lang.github.io/rfcs/1522-conservative-impl-trait.html ### Example of `async fn` in trait ```rust trait Bar { async fn bar(self); } impl Bar for () { async fn bar(self) {} } ``` This declares a trait method that returns *some* [`Future`](https://doc.rust-lang.org/core/future/trait.Future.html) and a corresponding method implementation. This is equivalent to writing the following using RPITIT. ```rust use core::future::Future; trait Bar { fn bar(self) -> impl Future<Output = ()>; } impl Bar for () { fn bar(self) -> impl Future<Output = ()> { async {} } } ``` The desirability of this desugaring being available is part of why RPITIT and AFIT are being proposed for stabilization at the same time. ## Motivation Long ago, Rust added [RPIT][RFC 1522] and [`async`/`await`][RFC 2394]. These are major features that are widely used in the ecosystem. However, until now, these feature could not be used in *traits* and trait implementations. This left traits as a kind of second-class citizen of the language. This stabilization fixes that. [RFC 2394]: https://rust-lang.github.io/rfcs/2394-async_await.html ### `async fn` in trait Async/await allows users to write asynchronous code much easier than they could before. However, it doesn't play nice with other core language features that make Rust the great language it is, like traits. Support for `async fn` in traits has been long anticipated and was not added before due to limitations in the compiler that have now been lifted. `async fn` in traits will unblock a lot of work in the ecosystem and the standard library. It is not currently possible to write a trait that is implemented using `async fn`. The workarounds that exist are undesirable because they require allocation and dynamic dispatch, and any trait that uses them will become obsolete once native `async fn` in trait is stabilized. We also have ample evidence that there is demand for this feature from the [`async-trait` crate][async-trait], which emulates the feature using dynamic dispatch. The async-trait crate is currently the #5 async crate on crates.io ranked by recent downloads, receiving over 78M all-time downloads. According to a [recent analysis][async-trait-analysis], 4% of all crates use the `#[async_trait]` macro it provides, representing 7% of all function and method signatures in trait definitions on crates.io. We think this is a *lower bound* on demand for the feature, because users are unlikely to use `#[async_trait]` on public traits on crates.io for the reasons already given. [async-trait]: https://crates.io/crates/async-trait [async-trait-analysis]: https://rust-lang.zulipchat.com/#narrow/stream/315482-t-compiler.2Fetc.2Fopaque-types/topic/RPIT.20capture.20rules.20.28capturing.20everything.29/near/389496292 ### Return-position `impl Trait` in trait `async fn` always desugars to a function that returns `impl Future`. ```rust! async fn foo() -> i32 { 100 } // Equivalent to: fn foo() -> impl Future<Output = i32> { async { 100 } } ``` All `async fn`s today can be rewritten this way. This is useful because it allows adding behavior that runs at the time of the function call, before the first `.await` on the returned future. In the spirit of supporting the same set of features on `async fn` in traits that we do outside of traits, it makes sense to stabilize this as well. As described by the [RPITIT RFC][rpitit-rfc], this includes the ability to mix and match the equivalent forms in traits and their corresponding impls: ```rust! trait Foo { async fn foo(self) -> i32; } // Can be implemented as: impl Foo for MyType { fn foo(self) -> impl Future<Output = i32> { async { 100 } } } ``` Return-position `impl Trait` in trait is useful for cases beyond async, just as regular RPIT is. As a simple example, the RFC showed an alternative way of writing the `IntoIterator` trait with one fewer associated type. ```rust! trait NewIntoIterator { type Item; fn new_into_iter(self) -> impl Iterator<Item = Self::Item>; } impl<T> NewIntoIterator for Vec<T> { type Item = T; fn new_into_iter(self) -> impl Iterator<Item = T> { self.into_iter() } } ``` [rpitit-rfc]: https://rust-lang.github.io/rfcs/3425-return-position-impl-trait-in-traits.html ## Major design decisions This section describes the major design decisions that were reached after the RFC was accepted: - EDIT: Lint against async fn in trait definitions - Until the [send bound problem](https://smallcultfollowing.com/babysteps/blog/2023/02/01/async-trait-send-bounds-part-1-intro/) is resolved, the use of `async fn` in trait definitions could lead to a bad experience for people using work-stealing executors (by far the most popular choice). However, there are significant use cases for which the current support is all that is needed (single-threaded executors, such as those used in embedded use cases, as well as thread-per-core setups). We are prioritizing serving users well over protecting people from misuse, and therefore, we opt to stabilize the full range of functionality; however, to help steer people correctly, we are will issue a warning on the use of `async fn` in trait definitions that advises users about the limitations. (See [this summary comment](rust-lang/rust#115822 (comment)) for the details of the concern, and [this comment](rust-lang/rust#115822 (comment)) for more details about the reasoning that led to this conclusion.) - Capture rules: - The RFC's initial capture rules for lifetimes in impls/traits were found to be imprecisely precise and to introduce various inconsistencies. After much discussion, the decision was reached to make `-> impl Trait` in traits/impls capture *all* in-scope parameters, including both lifetimes and types. This is a departure from the behavior of RPITs in other contexts; an RFC is currently being authored to change the behavior of RPITs in other contexts in a future edition. - Major discussion links: - [Lang team design meeting from 2023-07-26](https://hackmd.io/sFaSIMJOQcuwCdnUvCxtuQ?view) - Refinement: - The [refinement RFC] initially proposed that impl signatures that are more specific than their trait are not allowed unless the `#[refine]` attribute was included, but left it as an open question how to implement this. The stabilized proposal is that it is not a hard error to omit `#[refine]`, but there is a lint which fires if the impl's return type is more precise than the trait. This greatly simplified the desugaring and implementation while still achieving the original goal of ensuring that users do not accidentally commit to a more specific return type than they intended. - Major discussion links: - [Zulip thread](https://rust-lang.zulipchat.com/#narrow/stream/213817-t-lang/topic/.60.23.5Brefine.5D.60.20as.20a.20lint) [refinement RFC]: https://rust-lang.github.io/rfcs/3245-refined-impls.html ## What is stabilized ### Async functions in traits and trait implementations * `async fn` are now supported in traits and trait implementations. * Associated functions in traits that are `async` may have default bodies. ### Return-position impl trait in traits and trait implementations * Return-position `impl Trait`s are now supported in traits and trait implementations. * Return-position `impl Trait` in implementations are treated like regular return-position `impl Trait`s, and therefore behave according to the same inference rules for hidden type inference and well-formedness. * Associated functions in traits that name return-position `impl Trait`s may have default bodies. * Implementations may provide either concrete types or `impl Trait` for each corresponding `impl Trait` in the trait method signature. For a detailed exploration of the technical implementation of return-position `impl Trait` in traits, see [the dev guide](https://rustc-dev-guide.rust-lang.org/return-position-impl-trait-in-trait.html). ### Mixing `async fn` in trait and return-position `impl Trait` in trait A trait function declaration that is `async fn ..() -> T` may be satisfied by an implementation function that returns `impl Future<Output = T>`, or vice versa. ```rust trait Async { async fn hello(); } impl Async for () { fn hello() -> impl Future<Output = ()> { async {} } } trait RPIT { fn hello() -> impl Future<Output = String>; } impl RPIT for () { async fn hello() -> String { "hello".to_string() } } ``` ### Return-position `impl Trait` in traits and trait implementations capture all in-scope lifetimes Described above in "major design decisions". ### Return-position `impl Trait` in traits are "always revealing" When a trait uses `-> impl Trait` in return position, it logically desugars to an associated type that represents the return (the actual implementation in the compiler is different, as described below). The value of this associated type is determined by the actual return type written in the impl; if the impl also uses `-> impl Trait` as the return type, then the value of the associated type is an opaque type scoped to the impl method (similar to what you would get when calling an inherent function returning `-> impl Trait`). As with any associated type, the value of this special associated type can be revealed by the compiler if the compiler can figure out what impl is being used. For example, given this trait: ```rust trait AsDebug { fn as_debug(&self) -> impl Debug; } ``` A function working with the trait generically is only able to see that the return value is `Debug`: ```rust fn foo<T: AsDebug>(t: &T) { let u = t.as_debug(); println!("{}", u); // ERROR: `u` is not known to implement `Display` } ``` But if a function calls `as_debug` on a known type (say, `u32`), it may be able to resolve the return type more specifically, if that implementation specifies a concrete type as well: ```rust impl AsDebug for u32 { fn as_debug(&self) -> u32 { *self } } fn foo(t: &u32) { let u: u32 = t.as_debug(); // OK! println!("{}", t.as_debug()); // ALSO OK (since `u32: Display`). } ``` The return type used in the impl therefore represents a **semver binding** promise from the impl author that the return type of `<u32 as AsDebug>::as_debug` will not change. This could come as a surprise to users, who might expect that they are free to change the return type to any other type that implements `Debug`. To address this, we include a [`refining_impl_trait` lint](rust-lang/rust#115582) that warns if the impl uses a specific type -- the `impl AsDebug for u32` above, for example, would toggle the lint. The lint message explains what is going on and encourages users to `allow` the lint to indicate that they meant to refine the return type: ```rust impl AsDebug for u32 { #[allow(refining_impl_trait)] fn as_debug(&self) -> u32 { *self } } ``` [RFC rust-lang#3245](rust-lang/rfcs#3245) proposed a new attribute, `#[refine]`, that could also be used to "opt-in" to refinements like this (and which would then silence the lint). That RFC is not currently implemented -- the `#[refine]` attribute is also expected to reveal other details from the signature and has not yet been fully implemented. ### Return-position `impl Trait` and `async fn` in traits are opted-out of object safety checks when the parent function has `Self: Sized` ```rust trait IsObjectSafe { fn rpit() -> impl Sized where Self: Sized; async fn afit() where Self: Sized; } ``` Traits that mention return-position `impl Trait` or `async fn` in trait when the associated function includes a `Self: Sized` bound will remain object safe. That is because the associated function that defines them will be opted-out of the vtable of the trait, and the associated types will be unnameable from any trait object. This can alternatively be seen as a consequence of rust-lang/rust#112319 (comment) and the desugaring of return-position `impl Trait` in traits to associated types which inherit the where-clauses of the associated function that defines them. ## What isn't stabilized (aka, potential future work) ### Dynamic dispatch As stabilized, traits containing RPITIT and AFIT are **not dyn compatible**. This means that you cannot create `dyn Trait` objects from them and can only use static dispatch. The reason for this limitation is that dynamic dispatch support for RPITIT and AFIT is more complex than static dispatch, as described on the [async fundamentals page](https://rust-lang.github.io/async-fundamentals-initiative/evaluation/challenges/dyn_traits.html). The primary challenge to using `dyn Trait` in today's Rust is that **`dyn Trait` today must list the values of all associated types**. This means you would have to write `dyn for<'s> Trait<Foo<'s> = XXX>` where `XXX` is the future type defined by the impl, such as `F_A`. This is not only verbose (or impossible), it also uniquely ties the `dyn Trait` to a particular impl, defeating the whole point of `dyn Trait`. The precise design for handling dynamic dispatch is not yet determined. Top candidates include: - [callee site selection][], in which we permit unsized return values so that the return type for an `-> impl Foo` method be can be `dyn Foo`, but then users must specify the type of wide pointer at the call-site in some fashion. - [`dyn*`][], where we create a built-in encapsulation of a "wide pointer" and map the associated type corresponding to an RPITIT to the corresponding `dyn*` type (`dyn*` itself is not exposed to users as a type in this proposal, though that could be a future extension). [callee site selection]: https://smallcultfollowing.com/babysteps/blog/2022/09/21/dyn-async-traits-part-9-callee-site-selection/ [`dyn*`]: https://smallcultfollowing.com/babysteps/blog/2022/03/29/dyn-can-we-make-dyn-sized/ ### Where-clause bounds on return-position `impl Trait` in traits or async futures (RTN/ART) One limitation of async fn in traits and RPITIT as stabilized is that there is no way for users to write code that adds additional bounds beyond those listed in the `-> impl Trait`. The most common example is wanting to write a generic function that requires that the future returned from an `async fn` be `Send`: ```rust trait Greet { async fn greet(&self); } fn greet_in_parallel<G: Greet>(g: &G) { runtime::spawn(async move { g.greet().await; //~ ERROR: future returned by `greet` may not be `Send` }) } ``` Currently, since the associated types added for the return type are anonymous, there is no where-clause that could be added to make this code compile. There have been various proposals for how to address this problem (e.g., [return type notation][rtn] or having an annotation to give a name to the associated type), but we leave the selection of one of those mechanisms to future work. [rtn]: https://smallcultfollowing.com/babysteps/blog/2023/02/13/return-type-notation-send-bounds-part-2/ In the meantime, there are workarounds that one can use to address this problem, listed below. #### Require all futures to be `Send` For many users, the trait may only ever be used with `Send` futures, in which case one can write an explicit `impl Future + Send`: ```rust trait Greet { fn greet(&self) -> impl Future<Output = ()> + Send; } ``` The nice thing about this is that it is still compatible with using `async fn` in the trait impl. In the async working group case studies, we found that this could work for the [builder provider API](https://rust-lang.github.io/async-fundamentals-initiative/evaluation/case-studies/builder-provider-api.html). This is also the default approach used by the `#[async_trait]` crate which, as we have noted, has seen widespread adoption. #### Avoid generics This problem only applies when the `Self` type is generic. If the `Self` type is known, then the precise return type from an `async fn` is revealed, and the `Send` bound can be inferred thanks to auto-trait leakage. Even in cases where generics may appear to be required, it is sometimes possible to rewrite the code to avoid them. The [socket handler refactor](https://rust-lang.github.io/async-fundamentals-initiative/evaluation/case-studies/socket-handler.html) case study provides one such example. ### Unify capture behavior for `-> impl Trait` in inherent methods and traits As stabilized, the capture behavior for `-> impl Trait` in a trait (whether as part of an async fn or a RPITIT) captures all types and lifetimes, whereas the existing behavior for inherent methods only captures types and lifetimes that are explicitly referenced. Capturing all lifetimes in traits was necessary to avoid various surprising inconsistencies; the expressed intent of the lang team is to extend that behavior so that we also capture all lifetimes in inherent methods, which would create more consistency and also address a common source of user confusion, but that will have to happen over the 2024 edition. The RFC is in progress. Should we opt not to accept that RFC, we can bring the capture behavior for `-> impl Trait` into alignment in other ways as part of the 2024 edition. ### `impl_trait_projections` Orthgonal to `async_fn_in_trait` and `return_position_impl_trait_in_trait`, since it can be triggered on stable code. This will be stabilized separately in [#115659](rust-lang/rust#115659). <details> If we try to write this code without `impl_trait_projections`, we will get an error: ```rust #![feature(async_fn_in_trait)] trait Foo { type Error; async fn foo(&mut self) -> Result<(), Self::Error>; } impl<T: Foo> Foo for &mut T { type Error = T::Error; async fn foo(&mut self) -> Result<(), Self::Error> { T::foo(self).await } } ``` The error relates to the use of `Self` in a trait impl when the self type has a lifetime. It can be worked around by rewriting the impl not to use `Self`: ```rust #![feature(async_fn_in_trait)] trait Foo { type Error; async fn foo(&mut self) -> Result<(), Self::Error>; } impl<T: Foo> Foo for &mut T { type Error = T::Error; async fn foo(&mut self) -> Result<(), <&mut T as Foo>::Error> { T::foo(self).await } } ``` </details> ## Tests Tests are generally organized between return-position `impl Trait` and `async fn` in trait, when the distinction matters. * RPITIT: https://github.com/rust-lang/rust/tree/master/tests/ui/impl-trait/in-trait * AFIT: https://github.com/rust-lang/rust/tree/master/tests/ui/async-await/in-trait ## Remaining bugs and open issues * #112047: Indirection introduced by `async fn` and return-position `impl Trait` in traits may hide cycles in opaque types, causing overflow errors that can only be discovered by monomorphization. * #111105 - `async fn` in trait is susceptible to issues with checking auto traits on futures' generators, like regular `async`. This is a manifestation of #110338. * This was deemed not blocking because fixing it is forwards-compatible, and regular `async` is subject to the same issues. * #104689: `async fn` and return-position `impl Trait` in trait requires the late-bound lifetimes in a trait and impl function signature to be equal. * This can be relaxed in the future with a smarter lexical region resolution algorithm. * #102527: Nesting return-position `impl Trait` in trait deeply may result in slow compile times. * This has only been reported once, and can be fixed in the future. * #108362: Inference between return types and generics of a function may have difficulties when there's an `.await`. * This isn't related to AFIT (rust-lang/rust#108362 (comment)) -- using traits does mean that there's possibly easier ways to hit it. * #112626: Because `async fn` and return-position `impl Trait` in traits lower to associated types, users may encounter strange behaviors when implementing circularly dependent traits. * This is not specific to RPITIT, and is a limitation of associated types: rust-lang/rust#112626 (comment) * **(Nightly)** #108309: `async fn` and return-position `impl Trait` in trait do not support specialization. This was deemed not blocking, since it can be fixed in the future (e.g. #108321) and specialization is a nightly feature. #### (Nightly) Return type notation bugs RTN is not being stabilized here, but there are some interesting outstanding bugs. None of them are blockers for AFIT/RPITIT, but I'm noting them for completeness. <details> * #109924 is a bug that occurs when a higher-ranked trait bound has both inference variables and associated types. This is pre-existing -- RTN just gives you a more convenient way of producing them. This should be fixed by the new trait solver. * #109924 is a manifestation of a more general issue with `async` and auto-trait bounds: #110338. RTN does not cause this issue, just allows us to put `Send` bounds on the anonymous futures that we have in traits. * #112569 is a bug similar to associated type bounds, where nested bounds are not implied correctly. </details> ## Alternatives ### Do nothing We could choose not to stabilize these features. Users that can use the `#[async_trait]` macro would continue to do so. Library maintainers would continue to avoid async functions in traits, potentially blocking the stable release of many useful crates. ### Stabilize `impl Trait` in associated type instead AFIT and RPITIT solve the problem of returning unnameable types from trait methods. It is also possible to solve this by using another unstable feature, `impl Trait` in an associated type. Users would need to define an associated type in both the trait and trait impl: ```rust! trait Foo { type Fut<'a>: Future<Output = i32> where Self: 'a; fn foo(&self) -> Self::Fut<'_>; } impl Foo for MyType { type Fut<'a> where Self: 'a = impl Future<Output = i32>; fn foo(&self) -> Self::Fut<'_> { async { 42 } } } ``` This also has the advantage of allowing generic code to bound the associated type. However, it is substantially less ergonomic than either `async fn` or `-> impl Future`, and users still expect to be able to use those features in traits. **Even if this feature were stable, we would still want to stabilize AFIT and RPITIT.** That said, we can have both. `impl Trait` in associated types is desireable because it can be used in existing traits with explicit associated types, among other reasons. We *should* stabilize this feature once it is ready, but that's outside the scope of this proposal. ### Use the old capture semantics for RPITIT We could choose to make the capture rules for RPITIT consistent with the existing rules for RPIT. However, there was strong consensus in a recent [lang team meeting](https://hackmd.io/sFaSIMJOQcuwCdnUvCxtuQ?view) that we should *change* these rules, and furthermore that new features should adopt the new rules. This is consistent with the tenet in RFC 3085 of favoring ["Uniform behavior across editions"](https://rust-lang.github.io/rfcs/3085-edition-2021.html#uniform-behavior-across-editions) when possible. It greatly reduces the complexity of the feature by not requiring us to answer, or implement, the design questions that arise out of the interaction between the current capture rules and traits. This reduction in complexity – and eventual technical debt – is exactly in line with the motivation listed in the aforementioned RFC. ### Make refinement a hard error Refinement (`refining_impl_trait`) is only a concern for library authors, and therefore doesn't really warrant making into a deny-by-default warning or an error. Additionally, refinement is currently checked via a lint that compares bounds in the `impl Trait`s in the trait and impl syntactically. This is good enough for a warning that can be opted-out, but not if this were a hard error, which would ideally be implemented using fully semantic, implicational logic. This was implemented (#111931), but also is an unnecessary burden on the type system for little pay-off. ## History - Dec 7, 2021: [RFC rust-lang#3185: Static async fn in traits](https://rust-lang.github.io/rfcs/3185-static-async-fn-in-trait.html) merged - Sep 9, 2022: [Initial implementation](rust-lang/rust#101224) of AFIT and RPITIT landed - Jun 13, 2023: [RFC rust-lang#3425: Return position `impl Trait` in traits](https://rust-lang.github.io/rfcs/3425-return-position-impl-trait-in-traits.html) merged <!--These will render pretty when pasted into github--> Non-exhaustive list of PRs that are particularly relevant to the implementation: - #101224 - #103491 - #104592 - #108141 - #108319 - #108672 - #112988 - #113182 (later made redundant by #114489) - #113215 - #114489 - #115467 - #115582 Doc co-authored by `@nikomatsakis,` `@tmandry,` `@traviscross.` Thanks also to `@spastorino,` `@cjgillot` (for changes to opaque captures!), `@oli-obk` for many reviews, and many other contributors and issue-filers. Apologies if I left your name off 😺
pitaj
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Change prefetch to avoid deadlock Was abled to reproduce the deadlock in #118205 and created a coredump when it happen. When looking at the backtraces I noticed that the prefetch of exported_symbols (Thread 17 frame 4) started after the "actual" exported_symbols (Thread 2 frame 18) but it also is working on some of the collect_crate_mono_items (Thread 17 frame12 ) that Thread 2 is blocked on resulting in a deadlock. This PR results in less parallell work that can be done at the same time but from what I can find we do not call the query exported_symbols from multiple places in the same join call any more. ``` Thread 17 (Thread 0x7f87b6299700 (LWP 11370)): #0 syscall () at ../sysdeps/unix/sysv/linux/x86_64/syscall.S:38 #1 0x00007f87be5166a9 in <parking_lot::condvar::Condvar>::wait_until_internal () from /home/andjo403/.rustup/toolchains/stage1/lib/librustc_driver-70ddb84e8f7ce707.so #2 0x00007f87be12d854 in <rustc_query_system::query::job::QueryLatch>::wait_on () from /home/andjo403/.rustup/toolchains/stage1/lib/librustc_driver-70ddb84e8f7ce707.so #3 0x00007f87bd27d16f in rustc_query_system::query::plumbing::try_execute_query::<rustc_query_impl::DynamicConfig<rustc_query_system::query::caches::VecCache<rustc_span::def_id::CrateNum, rustc_middle::query::erase::Erased<[u8; 16]>>, false, false, false>, rustc_query_impl::plumbing::QueryCtxt, false> () from /home/andjo403/.rustup/toolchains/stage1/lib/librustc_driver-70ddb84e8f7ce707.so #4 0x00007f87bd0b5b6a in rustc_query_impl::query_impl::exported_symbols::get_query_non_incr::__rust_end_short_backtrace () from /home/andjo403/.rustup/toolchains/stage1/lib/librustc_driver-70ddb84e8f7ce707.so #5 0x00007f87bdaebb0a in rustc_metadata::rmeta::encoder::encode_metadata::{closure#1}::{closure#1} () from /home/andjo403/.rustup/toolchains/stage1/lib/librustc_driver-70ddb84e8f7ce707.so #6 0x00007f87bdae1509 in rayon_core::join::join_context::call_b::<core::option::Option<rustc_data_structures::marker::FromDyn<&[(rustc_middle::middle::exported_symbols::ExportedSymbol, rustc_middle::middle::exported_symbols::SymbolExportInfo)]>>, rayon_core::join::join::call<core::option::Option<rustc_data_structures::marker::FromDyn<&[(rustc_middle::middle::exported_symbols::ExportedSymbol, rustc_middle::middle::exported_symbols::SymbolExportInfo)]>>, rustc_data_structures::sync::parallel::enabled::join<rustc_metadata::rmeta::encoder::encode_metadata::{closure#1}::{closure#0}, rustc_metadata::rmeta::encoder::encode_metadata::{closure#1}::{closure#1}, (), &[(rustc_middle::middle::exported_symbols::ExportedSymbol, rustc_middle::middle::exported_symbols::SymbolExportInfo)]>::{closure#0}::{closure#1}>::{closure#0}>::{closure#0} () from /home/andjo403/.rustup/toolchains/stage1/lib/librustc_driver-70ddb84e8f7ce707.so #7 0x00007f87bdae32ff in <rayon_core::job::StackJob<rayon_core::latch::SpinLatch, rayon_core::join::join_context::call_b<core::option::Option<rustc_data_structures::marker::FromDyn<&[(rustc_middle::middle::exported_symbols::ExportedSymbol, rustc_middle::middle::exported_symbols::SymbolExportInfo)]>>, rayon_core::join::join::call<core::option::Option<rustc_data_structures::marker::FromDyn<&[(rustc_middle::middle::exported_symbols::ExportedSymbol, rustc_middle::middle::exported_symbols::SymbolExportInfo)]>>, rustc_data_structures::sync::parallel::enabled::join<rustc_metadata::rmeta::encoder::encode_metadata::{closure#1}::{closure#0}, rustc_metadata::rmeta::encoder::encode_metadata::{closure#1}::{closure#1}, (), &[(rustc_middle::middle::exported_symbols::ExportedSymbol, rustc_middle::middle::exported_symbols::SymbolExportInfo)]>::{closure#0}::{closure#1}>::{closure#0}>::{closure#0}, core::option::Option<rustc_data_structures::marker::FromDyn<&[(rustc_middle::middle::exported_symbols::ExportedSymbol, rustc_middle::middle::exported_symbols::SymbolExportInfo)]>>> as rayon_core::job::Job>::execute () from /home/andjo403/.rustup/toolchains/stage1/lib/librustc_driver-70ddb84e8f7ce707.so #8 0x00007f87b8338823 in <rayon_core::registry::WorkerThread>::wait_until_cold () from /home/andjo403/.rustup/toolchains/stage1/lib/librustc_driver-70ddb84e8f7ce707.so #9 0x00007f87bc2edbaf in rayon_core::join::join_context::<rayon::iter::plumbing::bridge_producer_consumer::helper<rayon::vec::DrainProducer<rustc_middle::mir::mono::MonoItem>, rayon::iter::for_each::ForEachConsumer<rustc_data_structures::sync::parallel::enabled::par_for_each_in<rustc_middle::mir::mono::MonoItem, alloc::vec::Vec<rustc_middle::mir::mono::MonoItem>, rustc_monomorphize::collector::collect_crate_mono_items::{closure#1}::{closure#0}>::{closure#0}::{closure#0}>>::{closure#0}, rayon::iter::plumbing::bridge_producer_consumer::helper<rayon::vec::DrainProducer<rustc_middle::mir::mono::MonoItem>, rayon::iter::for_each::ForEachConsumer<rustc_data_structures::sync::parallel::enabled::par_for_each_in<rustc_middle::mir::mono::MonoItem, alloc::vec::Vec<rustc_middle::mir::mono::MonoItem>, rustc_monomorphize::collector::collect_crate_mono_items::{closure#1}::{closure#0}>::{closure#0}::{closure#0}>>::{closure#1}, (), ()>::{closure#0} () from /home/andjo403/.rustup/toolchains/stage1/lib/librustc_driver-70ddb84e8f7ce707.so #10 0x00007f87bc2ed313 in rayon_core::registry::in_worker::<rayon_core::join::join_context<rayon::iter::plumbing::bridge_producer_consumer::helper<rayon::vec::DrainProducer<rustc_middle::mir::mono::MonoItem>, rayon::iter::for_each::ForEachConsumer<rustc_data_structures::sync::parallel::enabled::par_for_each_in<rustc_middle::mir::mono::MonoItem, alloc::vec::Vec<rustc_middle::mir::mono::MonoItem>, rustc_monomorphize::collector::collect_crate_mono_items::{closure#1}::{closure#0}>::{closure#0}::{closure#0}>>::{closure#0}, rayon::iter::plumbing::bridge_producer_consumer::helper<rayon::vec::DrainProducer<rustc_middle::mir::mono::MonoItem>, rayon::iter::for_each::ForEachConsumer<rustc_data_structures::sync::parallel::enabled::par_for_each_in<rustc_middle::mir::mono::MonoItem, alloc::vec::Vec<rustc_middle::mir::mono::MonoItem>, rustc_monomorphize::collector::collect_crate_mono_items::{closure#1}::{closure#0}>::{closure#0}::{closure#0}>>::{closure#1}, (), ()>::{closure#0}, ((), ())> () from /home/andjo403/.rustup/toolchains/stage1/lib/librustc_driver-70ddb84e8f7ce707.so #11 0x00007f87bc2db2a4 in rayon::iter::plumbing::bridge_producer_consumer::helper::<rayon::vec::DrainProducer<rustc_middle::mir::mono::MonoItem>, rayon::iter::for_each::ForEachConsumer<rustc_data_structures::sync::parallel::enabled::par_for_each_in<rustc_middle::mir::mono::MonoItem, alloc::vec::Vec<rustc_middle::mir::mono::MonoItem>, rustc_monomorphize::collector::collect_crate_mono_items::{closure#1}::{closure#0}>::{closure#0}::{closure#0}>> () from /home/andjo403/.rustup/toolchains/stage1/lib/librustc_driver-70ddb84e8f7ce707.so #12 0x00007f87bc2eead2 in <rayon_core::job::StackJob<rayon_core::latch::SpinLatch, rayon_core::join::join_context::call_b<(), rayon::iter::plumbing::bridge_producer_consumer::helper<rayon::vec::DrainProducer<rustc_middle::mir::mono::MonoItem>, rayon::iter::for_each::ForEachConsumer<rustc_data_structures::sync::parallel::enabled::par_for_each_in<rustc_middle::mir::mono::MonoItem, alloc::vec::Vec<rustc_middle::mir::mono::MonoItem>, rustc_monomorphize::collector::collect_crate_mono_items::{closure#1}::{closure#0}>::{closure#0}::{closure#0}>>::{closure#1}>::{closure#0}, ()> as rayon_core::job::Job>::execute () from /home/andjo403/.rustup/toolchains/stage1/lib/librustc_driver-70ddb84e8f7ce707.so #13 0x00007f87b8338823 in <rayon_core::registry::WorkerThread>::wait_until_cold () from /home/andjo403/.rustup/toolchains/stage1/lib/librustc_driver-70ddb84e8f7ce707.so rust-lang#14 0x00007f87be52d1f9 in <rayon_core::registry::ThreadBuilder>::run () from /home/andjo403/.rustup/toolchains/stage1/lib/librustc_driver-70ddb84e8f7ce707.so rust-lang#15 0x00007f87b8461c57 in <scoped_tls::ScopedKey<rustc_span::SessionGlobals>>::set::<rustc_interface::util::run_in_thread_pool_with_globals<rustc_interface::interface::run_compiler<core::result::Result<(), rustc_span::ErrorGuaranteed>, rustc_driver_impl::run_compiler::{closure#0}>::{closure#0}, core::result::Result<(), rustc_span::ErrorGuaranteed>>::{closure#3}::{closure#0}::{closure#0}::{closure#0}, ()> () from /home/andjo403/.rustup/toolchains/stage1/lib/librustc_driver-70ddb84e8f7ce707.so rust-lang#16 0x00007f87b846e465 in rustc_span::set_session_globals_then::<(), rustc_interface::util::run_in_thread_pool_with_globals<rustc_interface::interface::run_compiler<core::result::Result<(), rustc_span::ErrorGuaranteed>, rustc_driver_impl::run_compiler::{closure#0}>::{closure#0}, core::result::Result<(), rustc_span::ErrorGuaranteed>>::{closure#3}::{closure#0}::{closure#0}::{closure#0}> () from /home/andjo403/.rustup/toolchains/stage1/lib/librustc_driver-70ddb84e8f7ce707.so rust-lang#17 0x00007f87b844f282 in <<crossbeam_utils::thread::ScopedThreadBuilder>::spawn<<rayon_core::ThreadPoolBuilder>::build_scoped<rustc_interface::util::run_in_thread_pool_with_globals<rustc_interface::interface::run_compiler<core::result::Result<(), rustc_span::ErrorGuaranteed>, rustc_driver_impl::run_compiler::{closure#0}>::{closure#0}, core::result::Result<(), rustc_span::ErrorGuaranteed>>::{closure#3}::{closure#0}::{closure#0}, rustc_interface::util::run_in_thread_pool_with_globals<rustc_interface::interface::run_compiler<core::result::Result<(), rustc_span::ErrorGuaranteed>, rustc_driver_impl::run_compiler::{closure#0}>::{closure#0}, core::result::Result<(), rustc_span::ErrorGuaranteed>>::{closure#3}::{closure#0}::{closure#1}, core::result::Result<(), rustc_span::ErrorGuaranteed>>::{closure#0}::{closure#0}::{closure#0}, ()>::{closure#0} as core::ops::function::FnOnce<()>>::call_once::{shim:vtable#0} () from /home/andjo403/.rustup/toolchains/stage1/lib/librustc_driver-70ddb84e8f7ce707.so rust-lang#18 0x00007f87b846af58 in <<std::thread::Builder>::spawn_unchecked_<alloc::boxed::Box<dyn core::ops::function::FnOnce<(), Output = ()> + core::marker::Send>, ()>::{closure#1} as core::ops::function::FnOnce<()>>::call_once::{shim:vtable#0} () from /home/andjo403/.rustup/toolchains/stage1/lib/librustc_driver-70ddb84e8f7ce707.so rust-lang#19 0x00007f87b7898e85 in std::sys::unix::thread::Thread::new::thread_start () from /home/andjo403/.rustup/toolchains/stage1/lib/libstd-d570b0650d35d951.so rust-lang#20 0x00007f87b7615609 in start_thread (arg=<optimized out>) at pthread_create.c:477 rust-lang#21 0x00007f87b7755133 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95 Thread 2 (Thread 0x7f87b729b700 (LWP 11368)): #0 syscall () at ../sysdeps/unix/sysv/linux/x86_64/syscall.S:38 #1 0x00007f87b7887b51 in std::sys::unix::locks::futex_condvar::Condvar::wait () from /home/andjo403/.rustup/toolchains/stage1/lib/libstd-d570b0650d35d951.so #2 0x00007f87b8339478 in <rayon_core::sleep::Sleep>::sleep () from /home/andjo403/.rustup/toolchains/stage1/lib/librustc_driver-70ddb84e8f7ce707.so #3 0x00007f87b83387c3 in <rayon_core::registry::WorkerThread>::wait_until_cold () from /home/andjo403/.rustup/toolchains/stage1/lib/librustc_driver-70ddb84e8f7ce707.so #4 0x00007f87bc2edbaf in rayon_core::join::join_context::<rayon::iter::plumbing::bridge_producer_consumer::helper<rayon::vec::DrainProducer<rustc_middle::mir::mono::MonoItem>, rayon::iter::for_each::ForEachConsumer<rustc_data_structures::sync::parallel::enabled::par_for_each_in<rustc_middle::mir::mono::MonoItem, alloc::vec::Vec<rustc_middle::mir::mono::MonoItem>, rustc_monomorphize::collector::collect_crate_mono_items::{closure#1}::{closure#0}>::{closure#0}::{closure#0}>>::{closure#0}, rayon::iter::plumbing::bridge_producer_consumer::helper<rayon::vec::DrainProducer<rustc_middle::mir::mono::MonoItem>, rayon::iter::for_each::ForEachConsumer<rustc_data_structures::sync::parallel::enabled::par_for_each_in<rustc_middle::mir::mono::MonoItem, alloc::vec::Vec<rustc_middle::mir::mono::MonoItem>, rustc_monomorphize::collector::collect_crate_mono_items::{closure#1}::{closure#0}>::{closure#0}::{closure#0}>>::{closure#1}, (), ()>::{closure#0} () from /home/andjo403/.rustup/toolchains/stage1/lib/librustc_driver-70ddb84e8f7ce707.so #5 0x00007f87bc2ed313 in rayon_core::registry::in_worker::<rayon_core::join::join_context<rayon::iter::plumbing::bridge_producer_consumer::helper<rayon::vec::DrainProducer<rustc_middle::mir::mono::MonoItem>, rayon::iter::for_each::ForEachConsumer<rustc_data_structures::sync::parallel::enabled::par_for_each_in<rustc_middle::mir::mono::MonoItem, alloc::vec::Vec<rustc_middle::mir::mono::MonoItem>, rustc_monomorphize::collector::collect_crate_mono_items::{closure#1}::{closure#0}>::{closure#0}::{closure#0}>>::{closure#0}, rayon::iter::plumbing::bridge_producer_consumer::helper<rayon::vec::DrainProducer<rustc_middle::mir::mono::MonoItem>, rayon::iter::for_each::ForEachConsumer<rustc_data_structures::sync::parallel::enabled::par_for_each_in<rustc_middle::mir::mono::MonoItem, alloc::vec::Vec<rustc_middle::mir::mono::MonoItem>, rustc_monomorphize::collector::collect_crate_mono_items::{closure#1}::{closure#0}>::{closure#0}::{closure#0}>>::{closure#1}, (), ()>::{closure#0}, ((), ())> () from /home/andjo403/.rustup/toolchains/stage1/lib/librustc_driver-70ddb84e8f7ce707.so #6 0x00007f87bc2db50c in <rayon::vec::IntoIter<rustc_middle::mir::mono::MonoItem> as rayon::iter::ParallelIterator>::for_each::<rustc_data_structures::sync::parallel::enabled::par_for_each_in<rustc_middle::mir::mono::MonoItem, alloc::vec::Vec<rustc_middle::mir::mono::MonoItem>, rustc_monomorphize::collector::collect_crate_mono_items::{closure#1}::{closure#0}>::{closure#0}::{closure#0}> () from /home/andjo403/.rustup/toolchains/stage1/lib/librustc_driver-70ddb84e8f7ce707.so #7 0x00007f87bc2e8cd7 in <rustc_session::session::Session>::time::<(), rustc_monomorphize::collector::collect_crate_mono_items::{closure#1}> () from /home/andjo403/.rustup/toolchains/stage1/lib/librustc_driver-70ddb84e8f7ce707.so #8 0x00007f87bc2b8f2c in rustc_monomorphize::collector::collect_crate_mono_items () from /home/andjo403/.rustup/toolchains/stage1/lib/librustc_driver-70ddb84e8f7ce707.so #9 0x00007f87bc2c30d9 in rustc_monomorphize::partitioning::collect_and_partition_mono_items () from /home/andjo403/.rustup/toolchains/stage1/lib/librustc_driver-70ddb84e8f7ce707.so #10 0x00007f87bcf2cde6 in rustc_query_impl::plumbing::__rust_begin_short_backtrace::<rustc_query_impl::query_impl::collect_and_partition_mono_items::dynamic_query::{closure#2}::{closure#0}, rustc_middle::query::erase::Erased<[u8; 24]>> () from /home/andjo403/.rustup/toolchains/stage1/lib/librustc_driver-70ddb84e8f7ce707.so #11 0x00007f87bd156a3c in <rustc_query_impl::query_impl::collect_and_partition_mono_items::dynamic_query::{closure#2} as core::ops::function::FnOnce<(rustc_middle::ty::context::TyCtxt, ())>>::call_once () from /home/andjo403/.rustup/toolchains/stage1/lib/librustc_driver-70ddb84e8f7ce707.so #12 0x00007f87bd1c6a7d in rustc_query_system::query::plumbing::try_execute_query::<rustc_query_impl::DynamicConfig<rustc_query_system::query::caches::SingleCache<rustc_middle::query::erase::Erased<[u8; 24]>>, false, false, false>, rustc_query_impl::plumbing::QueryCtxt, false> () from /home/andjo403/.rustup/toolchains/stage1/lib/librustc_driver-70ddb84e8f7ce707.so #13 0x00007f87bd15df40 in rustc_query_impl::query_impl::collect_and_partition_mono_items::get_query_non_incr::__rust_end_short_backtrace () from /home/andjo403/.rustup/toolchains/stage1/lib/librustc_driver-70ddb84e8f7ce707.so rust-lang#14 0x00007f87bd7a0ad9 in rustc_codegen_ssa::back::symbol_export::exported_symbols_provider_local () from /home/andjo403/.rustup/toolchains/stage1/lib/librustc_driver-70ddb84e8f7ce707.so rust-lang#15 0x00007f87bcf29acb in rustc_query_impl::plumbing::__rust_begin_short_backtrace::<rustc_query_impl::query_impl::exported_symbols::dynamic_query::{closure#2}::{closure#0}, rustc_middle::query::erase::Erased<[u8; 16]>> () from /home/andjo403/.rustup/toolchains/stage1/lib/librustc_driver-70ddb84e8f7ce707.so rust-lang#16 0x00007f87bcfdb350 in <rustc_query_impl::query_impl::exported_symbols::dynamic_query::{closure#2} as core::ops::function::FnOnce<(rustc_middle::ty::context::TyCtxt, rustc_span::def_id::CrateNum)>>::call_once () from /home/andjo403/.rustup/toolchains/stage1/lib/librustc_driver-70ddb84e8f7ce707.so rust-lang#17 0x00007f87bd27d64f in rustc_query_system::query::plumbing::try_execute_query::<rustc_query_impl::DynamicConfig<rustc_query_system::query::caches::VecCache<rustc_span::def_id::CrateNum, rustc_middle::query::erase::Erased<[u8; 16]>>, false, false, false>, rustc_query_impl::plumbing::QueryCtxt, false> () from /home/andjo403/.rustup/toolchains/stage1/lib/librustc_driver-70ddb84e8f7ce707.so rust-lang#18 0x00007f87bd0b5b6a in rustc_query_impl::query_impl::exported_symbols::get_query_non_incr::__rust_end_short_backtrace () from /home/andjo403/.rustup/toolchains/stage1/lib/librustc_driver-70ddb84e8f7ce707.so rust-lang#19 0x00007f87bda927ce in rustc_middle::query::plumbing::query_get_at::<rustc_query_system::query::caches::VecCache<rustc_span::def_id::CrateNum, rustc_middle::query::erase::Erased<[u8; 16]>>> () from /home/andjo403/.rustup/toolchains/stage1/lib/librustc_driver-70ddb84e8f7ce707.so rust-lang#20 0x00007f87bda9c93f in <rustc_metadata::rmeta::encoder::EncodeContext>::encode_crate_root () from /home/andjo403/.rustup/toolchains/stage1/lib/librustc_driver-70ddb84e8f7ce707.so rust-lang#21 0x00007f87bdaa6ef7 in rustc_metadata::rmeta::encoder::encode_metadata_impl () from /home/andjo403/.rustup/toolchains/stage1/lib/librustc_driver-70ddb84e8f7ce707.so rust-lang#22 0x00007f87bdae0b77 in rayon_core::join::join_context::<rayon_core::join::join::call<core::option::Option<rustc_data_structures::marker::FromDyn<()>>, rustc_data_structures::sync::parallel::enabled::join<rustc_metadata::rmeta::encoder::encode_metadata::{closure#0}, rustc_metadata::rmeta::encoder::encode_metadata::{closure#1}, (), ()>::{closure#0}::{closure#0}>::{closure#0}, rayon_core::join::join::call<core::option::Option<rustc_data_structures::marker::FromDyn<()>>, rustc_data_structures::sync::parallel::enabled::join<rustc_metadata::rmeta::encoder::encode_metadata::{closure#0}, rustc_metadata::rmeta::encoder::encode_metadata::{closure#1}, (), ()>::{closure#0}::{closure#1}>::{closure#0}, core::option::Option<rustc_data_structures::marker::FromDyn<()>>, core::option::Option<rustc_data_structures::marker::FromDyn<()>>>::{closure#0} () from /home/andjo403/.rustup/toolchains/stage1/lib/librustc_driver-70ddb84e8f7ce707.so rust-lang#23 0x00007f87bdaded2f in rayon_core::registry::in_worker::<rayon_core::join::join_context<rayon_core::join::join::call<core::option::Option<rustc_data_structures::marker::FromDyn<()>>, rustc_data_structures::sync::parallel::enabled::join<rustc_metadata::rmeta::encoder::encode_metadata::{closure#0}, rustc_metadata::rmeta::encoder::encode_metadata::{closure#1}, (), ()>::{closure#0}::{closure#0}>::{closure#0}, rayon_core::join::join::call<core::option::Option<rustc_data_structures::marker::FromDyn<()>>, rustc_data_structures::sync::parallel::enabled::join<rustc_metadata::rmeta::encoder::encode_metadata::{closure#0}, rustc_metadata::rmeta::encoder::encode_metadata::{closure#1}, (), ()>::{closure#0}::{closure#1}>::{closure#0}, core::option::Option<rustc_data_structures::marker::FromDyn<()>>, core::option::Option<rustc_data_structures::marker::FromDyn<()>>>::{closure#0}, (core::option::Option<rustc_data_structures::marker::FromDyn<()>>, core::option::Option<rustc_data_structures::marker::FromDyn<()>>)> () from /home/andjo403/.rustup/toolchains/stage1/lib/librustc_driver-70ddb84e8f7ce707.so rust-lang#24 0x00007f87bdaa5a03 in rustc_metadata::rmeta::encoder::encode_metadata () from /home/andjo403/.rustup/toolchains/stage1/lib/librustc_driver-70ddb84e8f7ce707.so rust-lang#25 0x00007f87bdaed628 in rustc_metadata::fs::encode_and_write_metadata () from /home/andjo403/.rustup/toolchains/stage1/lib/librustc_driver-70ddb84e8f7ce707.so rust-lang#26 0x00007f87b86608be in rustc_interface::passes::start_codegen () from /home/andjo403/.rustup/toolchains/stage1/lib/librustc_driver-70ddb84e8f7ce707.so rust-lang#27 0x00007f87b8664946 in <rustc_middle::ty::context::GlobalCtxt>::enter::<<rustc_interface::queries::Queries>::codegen_and_build_linker::{closure#0}, core::result::Result<rustc_interface::queries::Linker, rustc_span::ErrorGuaranteed>> () from /home/andjo403/.rustup/toolchains/stage1/lib/librustc_driver-70ddb84e8f7ce707.so rust-lang#28 0x00007f87b864db00 in <rustc_interface::queries::Queries>::codegen_and_build_linker () from /home/andjo403/.rustup/toolchains/stage1/lib/librustc_driver-70ddb84e8f7ce707.so rust-lang#29 0x00007f87b849400f in <rustc_interface::interface::Compiler>::enter::<rustc_driver_impl::run_compiler::{closure#0}::{closure#0}, core::result::Result<core::option::Option<rustc_interface::queries::Linker>, rustc_span::ErrorGuaranteed>> () from /home/andjo403/.rustup/toolchains/stage1/lib/librustc_driver-70ddb84e8f7ce707.so rust-lang#30 0x00007f87b846e067 in rustc_span::set_source_map::<core::result::Result<(), rustc_span::ErrorGuaranteed>, rustc_interface::interface::run_compiler<core::result::Result<(), rustc_span::ErrorGuaranteed>, rustc_driver_impl::run_compiler::{closure#0}>::{closure#0}::{closure#0}> () from /home/andjo403/.rustup/toolchains/stage1/lib/librustc_driver-70ddb84e8f7ce707.so rust-lang#31 0x00007f87b844dc13 in <rayon_core::thread_pool::ThreadPool>::install::<rustc_interface::interface::run_compiler<core::result::Result<(), rustc_span::ErrorGuaranteed>, rustc_driver_impl::run_compiler::{closure#0}>::{closure#0}, core::result::Result<(), rustc_span::ErrorGuaranteed>>::{closure#0} () from /home/andjo403/.rustup/toolchains/stage1/lib/librustc_driver-70ddb84e8f7ce707.so rust-lang#32 0x00007f87b84509a1 in <rayon_core::job::StackJob<rayon_core::latch::LatchRef<rayon_core::latch::LockLatch>, <rayon_core::registry::Registry>::in_worker_cold<<rayon_core::thread_pool::ThreadPool>::install<rustc_interface::interface::run_compiler<core::result::Result<(), rustc_span::ErrorGuaranteed>, rustc_driver_impl::run_compiler::{closure#0}>::{closure#0}, core::result::Result<(), rustc_span::ErrorGuaranteed>>::{closure#0}, core::result::Result<(), rustc_span::ErrorGuaranteed>>::{closure#0}::{closure#0}, core::result::Result<(), rustc_span::ErrorGuaranteed>> as rayon_core::job::Job>::execute () from /home/andjo403/.rustup/toolchains/stage1/lib/librustc_driver-70ddb84e8f7ce707.so rust-lang#33 0x00007f87b8338823 in <rayon_core::registry::WorkerThread>::wait_until_cold () from /home/andjo403/.rustup/toolchains/stage1/lib/librustc_driver-70ddb84e8f7ce707.so rust-lang#34 0x00007f87be52d1f9 in <rayon_core::registry::ThreadBuilder>::run () from /home/andjo403/.rustup/toolchains/stage1/lib/librustc_driver-70ddb84e8f7ce707.so rust-lang#35 0x00007f87b8461c57 in <scoped_tls::ScopedKey<rustc_span::SessionGlobals>>::set::<rustc_interface::util::run_in_thread_pool_with_globals<rustc_interface::interface::run_compiler<core::result::Result<(), rustc_span::ErrorGuaranteed>, rustc_driver_impl::run_compiler::{closure#0}>::{closure#0}, core::result::Result<(), rustc_span::ErrorGuaranteed>>::{closure#3}::{closure#0}::{closure#0}::{closure#0}, ()> () from /home/andjo403/.rustup/toolchains/stage1/lib/librustc_driver-70ddb84e8f7ce707.so rust-lang#36 0x00007f87b846e465 in rustc_span::set_session_globals_then::<(), rustc_interface::util::run_in_thread_pool_with_globals<rustc_interface::interface::run_compiler<core::result::Result<(), rustc_span::ErrorGuaranteed>, rustc_driver_impl::run_compiler::{closure#0}>::{closure#0}, core::result::Result<(), rustc_span::ErrorGuaranteed>>::{closure#3}::{closure#0}::{closure#0}::{closure#0}> () from /home/andjo403/.rustup/toolchains/stage1/lib/librustc_driver-70ddb84e8f7ce707.so rust-lang#37 0x00007f87b844f282 in <<crossbeam_utils::thread::ScopedThreadBuilder>::spawn<<rayon_core::ThreadPoolBuilder>::build_scoped<rustc_interface::util::run_in_thread_pool_with_globals<rustc_interface::interface::run_compiler<core::result::Result<(), rustc_span::ErrorGuaranteed>, rustc_driver_impl::run_compiler::{closure#0}>::{closure#0}, core::result::Result<(), rustc_span::ErrorGuaranteed>>::{closure#3}::{closure#0}::{closure#0}, rustc_interface::util::run_in_thread_pool_with_globals<rustc_interface::interface::run_compiler<core::result::Result<(), rustc_span::ErrorGuaranteed>, rustc_driver_impl::run_compiler::{closure#0}>::{closure#0}, core::result::Result<(), rustc_span::ErrorGuaranteed>>::{closure#3}::{closure#0}::{closure#1}, core::result::Result<(), rustc_span::ErrorGuaranteed>>::{closure#0}::{closure#0}::{closure#0}, ()>::{closure#0} as core::ops::function::FnOnce<()>>::call_once::{shim:vtable#0} () from /home/andjo403/.rustup/toolchains/stage1/lib/librustc_driver-70ddb84e8f7ce707.so rust-lang#38 0x00007f87b846af58 in <<std::thread::Builder>::spawn_unchecked_<alloc::boxed::Box<dyn core::ops::function::FnOnce<(), Output = ()> + core::marker::Send>, ()>::{closure#1} as core::ops::function::FnOnce<()>>::call_once::{shim:vtable#0} () from /home/andjo403/.rustup/toolchains/stage1/lib/librustc_driver-70ddb84e8f7ce707.so rust-lang#39 0x00007f87b7898e85 in std::sys::unix::thread::Thread::new::thread_start () from /home/andjo403/.rustup/toolchains/stage1/lib/libstd-d570b0650d35d951.so rust-lang#40 0x00007f87b7615609 in start_thread (arg=<optimized out>) at pthread_create.c:477 rust-lang#41 0x00007f87b7755133 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95 ``` fixes #118205 fixes #117759 from the latest logs it is the same query map as in #118205 fixes #118529 fixes #117784 cc #118206 r? `@SparrowLii`
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