This commit updates the compiler's handling of the `#[target_feature]`
attribute when applied to functions on WebAssembly-based targets. The
compiler in general requires that any functions with `#[target_feature]`
are marked as `unsafe` as well, but this commit relaxes the restriction
for WebAssembly targets where the attribute can be applied to safe
functions as well.
The reason this is done is that the motivation for this feature of the
compiler is not applicable for WebAssembly targets. In general the
`#[target_feature]` attribute is used to enhance target CPU features
enabled beyond the basic level for the rest of the compilation. If done
improperly this means that your program could execute an instruction
that the CPU you happen to be running on does not understand. This is
considered undefined behavior where it is unknown what will happen (e.g.
it's not a deterministic `SIGILL`).
For WebAssembly, however, the target is different. It is not possible
for a running WebAssembly program to execute an instruction that the
engine does not understand. If this were the case then the program would
not have validated in the first place and would not run at all. Even if
this were allowed in some hypothetical future where engines have some
form of runtime feature detection (which they do not right now) any
implementation of such a feature would generate a trap if a module
attempts to execute an instruction the module does not understand. This
deterministic trap behavior would still not fall into the category of
undefined behavior because the trap is deterministic.
For these reasons the `#[target_feature]` attribute is now allowed on
safe functions, but only for WebAssembly targets. This notably enables
the wasm-SIMD intrinsics proposed for stabilization in #74372 to be
marked as safe generally instead of today where they're all `unsafe` due
to the historical implementation of `#[target_feature]` in the compiler.
const-eval: disallow unwinding across functions that `!fn_can_unwind()`
Following https://github.com/rust-lang/miri/pull/1776#discussion_r633074343, so r? `@RalfJung`
This PR turns `unwind` in `StackPopCleanup::Goto` into a new enum `StackPopUnwind`, with a `NotAllowed` variant to indicate that unwinding is not allowed. This variant is chosen based on `rustc_middle::ty::layout::fn_can_unwind()` in `eval_fn_call()` when pushing the frame. A check is added in `unwind_to_block()` to report UB if unwinding happens across a `StackPopUnwind::NotAllowed` frame.
Tested with Miri `HEAD` with [minor changes](https://github.com/rust-lang/miri/compare/HEAD..9cf3c7f0d86325a586fbcbf2acdc9232b861f1d8) and the rust-lang/miri#1776 branch with [these changes](d866c1c52f..626638fbfe).
Fix incorrect suggestions for E0605
Fixes#84598. Here is a simplified version of the problem presented in issue #84598:
```Rust
#![allow(unused_variables)]
#![allow(dead_code)]
trait T { fn t(&self) -> i32; }
unsafe fn foo(t: *mut dyn T) {
(t as &dyn T).t();
}
fn main() {}
```
The current output is:
```
error[E0605]: non-primitive cast: `*mut (dyn T + 'static)` as `&dyn T`
--> src/main.rs:7:5
|
7 | (t as &dyn T).t();
| ^^^^^^^^^^^^^ invalid cast
|
help: borrow the value for the cast to be valid
|
7 | (&t as &dyn T).t();
| ^
```
This is incorrect, though: The cast will _not_ be valid when writing `&t` instead of `t`:
```
error[E0277]: the trait bound `*mut (dyn T + 'static): T` is not satisfied
--> t4.rs:7:6
|
7 | (&t as &dyn T).t();
| ^^ the trait `T` is not implemented for `*mut (dyn T + 'static)`
|
= note: required for the cast to the object type `dyn T`
```
The correct suggestion is `&*t`, which I have implemented in this pull request. Of course, this suggestion will always require an unsafe block, but arguably, that's what the user really wants if they're trying to cast a pointer to a reference.
In any case, claiming that the cast will be valid after implementing the suggestion is overly optimistic, as the coercion logic doesn't seem to resolve all nested obligations, i.e. the cast may still be invalid after implementing the suggestion. I have therefore rephrased the suggestion slightly ("consider borrowing the value" instead of "borrow the value for the cast to be valid").
Additionally, I have fixed another incorrect suggestion not mentioned in #84598, which relates to casting immutable references to mutable ones:
```rust
fn main() {
let mut x = 0;
let m = &x as &mut i32;
}
```
currently leads to
```
error[E0605]: non-primitive cast: `&i32` as `&mut i32`
--> t5.rs:3:13
|
3 | let m = &x as &mut i32;
| ^^^^^^^^^^^^^^ invalid cast
|
help: borrow the value for the cast to be valid
|
3 | let m = &mut &x as &mut i32;
| ^^^^
```
which is obviously incorrect:
```
error[E0596]: cannot borrow data in a `&` reference as mutable
--> t5.rs:3:13
|
3 | let m = &mut &x as &mut i32;
| ^^^^^^^ cannot borrow as mutable
```
I've changed the suggestion to a note explaining the problem:
```
error[E0605]: non-primitive cast: `&i32` as `&mut i32`
--> t5.rs:3:13
|
3 | let m = &x as &mut i32;
| ^^^^^^^^^^^^^^ invalid cast
|
note: this reference is immutable
--> t5.rs:3:13
|
3 | let m = &x as &mut i32;
| ^^
note: trying to cast to a mutable reference type
--> t5.rs:3:19
|
3 | let m = &x as &mut i32;
| ^^^^^^^^
```
In this example, it would have been even nicer to suggest replacing `&x` with `&mut x`, but this would be much more complex because we would have to take apart the expression to be cast (currently, we only look at its type), and `&x` could be stored in a variable, where such a suggestion would not even be directly applicable:
```rust
fn main() {
let mut x = 0;
let r = &x;
let m = r as &mut i32;
}
```
My solution covers this case, too.
Sync rustc_codegen_cranelift
The main highlight this sync is the removal of several dependencies, making compilation of cg_clif itself faster. There have also been a couple of new features like `#[link_section]` now supporting different segments for Mach-O binaries (thanks `@eggyal!)` and the `imported_main` feature, which is currently unstable.
r? `@ghost`
`@rustbot` label +A-codegen +A-cranelift +T-compiler
Update cc
Recent commits have improved `cc`'s finding of MSVC tools on Windows. In particular it should help to address these issues: #83043 and #43468
readd capture disjoint fields gate
This readds a feature gate guard that was added in PR #83521. (Basically, there were unintended consequences to the code exposed by removing the feature gate guard.)
The root bug still remains to be resolved, as discussed in issue #85561. This is just a band-aid suitable for a beta backport.
Cc issue #85435
Note that the latter issue is unfixed until we backport this (or another fix) to 1.53 beta
stabilize member constraints
Stabilizes the use of "member constraints" in solving `impl Trait` bindings. This is a step towards stabilizing a "MVP" of "named impl Trait".
# Member constraint stabilization report
| Info | |
| --- | --- |
| Tracking issue | [rust-lang/rust#61997](https://github.com/rust-lang/rust/issues/61997) |
| Implementation history | [rust-lang/rust#61775] |
| rustc-dev-guide coverage | [link](https://rustc-dev-guide.rust-lang.org/borrow_check/region_inference/member_constraints.html) |
| Complications | [rust-lang/rust#61773] |
[rust-lang/rust#61775]: https://github.com/rust-lang/rust/pull/61775
[rust-lang/rust#61773]: https://github.com/rust-lang/rust/issues/61773
## Background
Member constraints are an extension to our region solver that was introduced to make async fn region solving tractable. There are used in situations like the following:
```rust
fn foo<'a, 'b>(...) -> impl Trait<'a, 'b> { .. }
```
The problem here is that every region R in the hidden type must be equal to *either* `'a` *or* `'b` (or `'static`). This cannot be expressed simply via 'outlives constriants' like `R: 'a`. Therefore, we introduce a 'member constraint' `R member of ['a, 'b]`.
These constraints were introduced in [rust-lang/rust#61775]. At the time, we kept them feature gated and used them only for `impl Trait` return types that are derived from `async fn`. The intention, however, was always to support them in other contexts once we had time to gain more experience with them.
**In the time since their introduction, we have encountered no surprises or bugs due to these member constraints.** They are tested extensively as part of every async function that involves multiple unrelated lifetimes in its arguments.
## Tests
The behavior of member constraints is covered by the following tests:
* [`src/test/ui/async-await/multiple-lifetimes`](20e032e650/src/test/ui/async-await/multiple-lifetimes) -- tests using the async await, which are mostly already stabilized
* [`src/test/ui/impl-trait/multiple-lifetimes.rs`](20e032e650/src/test/ui/impl-trait/multiple-lifetimes.rs)
* [`src/test/ui/impl-trait/multiple-lifetimes/ordinary-bounds-unsuited.rs`](20e032e650/src/test/ui/impl-trait/multiple-lifetimes/ordinary-bounds-unsuited.rs)
* [`src/test/ui/async-await/multiple-lifetimes/ret-impl-trait-fg.rs`](20e032e650/src/test/ui/async-await/multiple-lifetimes/ret-impl-trait-fg.rs)
* [`src/test/ui/async-await/multiple-lifetimes/ret-impl-trait-one.rs`](20e032e650/src/test/ui/async-await/multiple-lifetimes/ret-impl-trait-one.rs)
These tests cover a number of scenarios:
* `-> implTrait<'a, 'b>` with unrelated lifetimes `'a` and `'b`, as described above
* `async fn` that returns an `impl Trait` like the previous case, which desugars to a kind of "nested" impl trait like `impl Future<Output = impl Trait<'a, 'b>>`
## Potential concerns
There is a potential interaction with `impl Trait` on local variables, described in [rust-lang/rust#61773]. The challenge is that if you have a program like:
```rust=
trait Foo<'_> { }
impl Foo<'_> for &u32 { }
fn bar() {
let x: impl Foo<'_> = &44; // let's call the region variable for `'_` `'1`
}
```
then we would wind up with `'0 member of ['1, 'static]`, where `'0` is the region variable in the hidden type (`&'0 u32`) and `'1` is the region variable in the bounds `Foo<'1>`. This is tricky because both `'0` and `'1` are being inferred -- so making them equal may have other repercussions.
That said, `impl Trait` in bindings are not stable, and the implementation is pretty far from stabilization. Moreover, the difficulty highlighted here is not due to the presence of member constraints -- it's inherent to the design of the language. In other words, stabilizing member constraints does not actually cause us to accept anything that would make this problem any harder.
So I don't see this as a blocker to stabilization of member constraints; it is potentially a blocker to stablization of `impl trait` in let bindings.
E0599 suggestions and elision of generic argument if no canditate is found
fixes#81576
changes: In error E0599 (method not found) generic argument are eluded if the method was not found anywhere. If the method was found in another inherent implementation suggest that it was found elsewhere.
Example
```rust
struct Wrapper<T>(T);
struct Wrapper2<T> {
x: T,
}
impl Wrapper2<i8> {
fn method(&self) {}
}
fn main() {
let wrapper = Wrapper(i32);
wrapper.method();
let wrapper2 = Wrapper2{x: i32};
wrapper2.method();
}
```
```
Error[E0599]: no method named `method` found for struct `Wrapper<_>` in the current scope
....
error[E0599]: no method named `method` found for struct `Wrapper2<i32>` in the current scope
...
= note: The method was found for Wrapper2<i8>.
```
I am not very happy with the ```no method named `test` found for struct `Vec<_, _>` in the current scope```. I think it might be better to show only one generic argument `Vec<_>` if there is a default one. But I haven't yet found a way to do that,
While stdlib implementations of the unchecked methods require unchecked
math, there is no reason to gate it behind this for external users. The
reasoning for a separate `step_trait_ext` feature is unclear, and as
such has been merged as well.
Post-monomorphization errors traces MVP
This PR works towards better diagnostics for the errors encountered in #85155 and similar.
We can encounter post-monomorphization errors (PMEs) when collecting mono items. The current diagnostics are confusing for these cases when they happen in a dependency (but are acceptable when they happen in the local crate).
These kinds of errors will be more likely now that `stdarch` uses const generics for its intrinsics' immediate arguments, and validates these const arguments with a mechanism that triggers such PMEs.
(Not to mention that the errors happen during codegen, so only when building code that actually uses these code paths. Check builds don't trigger them, neither does unused code)
So in this PR, we detect these kinds of errors during the mono item graph walk: if any error happens while collecting a node or its neighbors, we print a diagnostic about the current collection step, so that the user has at least some context of which erroneous code and dependency triggered the error.
The diagnostics for issue #85155 now have this note showing the source of the erroneous const argument:
```
note: the above error was encountered while instantiating `fn std::arch::x86_64::_mm_blend_ps::<51_i32>`
--> issue-85155.rs:11:24
|
11 | let _blended = _mm_blend_ps(a, b, 0x33);
| ^^^^^^^^^^^^^^^^^^^^^^^^
error: aborting due to previous error
```
Note that #85155 is a reduced version of a case happening in the wild, to indirect users of the `rustfft` crate, as seen in https://github.com/ejmahler/RustFFT/issues/74. The crate had a few of these out-of-range immediates. Here's how the diagnostics in this PR would have looked on one of its examples before it was fixed:
<details>
```
error[E0080]: evaluation of constant value failed
--> ./stdarch/crates/core_arch/src/macros.rs:8:9
|
8 | assert!(IMM >= MIN && IMM <= MAX, "IMM value not in expected range");
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the evaluated program panicked at 'IMM value not in expected range', ./stdarch/crates/core_arch/src/macros.rs:8:9
|
= note: this error originates in the macro `$crate::panic::panic_2015` (in Nightly builds, run with -Z macro-backtrace for more info)
note: the above error was encountered while instantiating `fn _mm_blend_ps::<51_i32>`
--> /tmp/RustFFT/src/avx/avx_vector.rs:1314:23
|
1314 | let blended = _mm_blend_ps(rows[0], rows[2], 0x33);
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
note: the above error was encountered while instantiating `fn _mm_permute_pd::<5_i32>`
--> /tmp/RustFFT/src/avx/avx_vector.rs:1859:9
|
1859 | _mm_permute_pd(self, 0x05)
| ^^^^^^^^^^^^^^^^^^^^^^^^^^
note: the above error was encountered while instantiating `fn _mm_permute_pd::<15_i32>`
--> /tmp/RustFFT/src/avx/avx_vector.rs:1863:32
|
1863 | (_mm_movedup_pd(self), _mm_permute_pd(self, 0x0F))
| ^^^^^^^^^^^^^^^^^^^^^^^^^^
error: aborting due to previous error
For more information about this error, try `rustc --explain E0080`.
error: could not compile `rustfft`
To learn more, run the command again with --verbose.
```
</details>
I've developed and discussed this with them, so maybe r? `@oli-obk` -- but feel free to redirect to someone else of course.
(I'm not sure we can say that this PR definitely closes issue 85155, as it's still unclear exactly which diagnostics and information would be interesting to report in such cases -- and we've discussed printing backtraces before. I have prototypes of some complete and therefore noisy backtraces I showed Oli, but we decided to not include them in this PR for now)
Disallow shadowing const parameters
This pull request fixes#85348. Trying to shadow a `const` parameter as follows:
```rust
fn foo<const N: i32>() {
let N @ _ = 0;
}
```
currently causes an ICE. With my changes, I get:
```
error[E0530]: let bindings cannot shadow const parameters
--> test.rs:2:9
|
1 | fn foo<const N: i32>() {
| - the const parameter `N` is defined here
2 | let N @ _ = 0;
| ^ cannot be named the same as a const parameter
error: aborting due to previous error
```
This is the same error you get when trying to shadow a constant:
```rust
const N: i32 = 0;
let N @ _ = 0;
```
```
error[E0530]: let bindings cannot shadow constants
--> src/lib.rs:3:5
|
2 | const N: i32 = 0;
| ----------------- the constant `N` is defined here
3 | let N @ _ = 0;
| ^ cannot be named the same as a constant
error: aborting due to previous error
```
The reason for disallowing shadowing in both cases is described [here](https://github.com/rust-lang/rust/issues/33118#issuecomment-233962221) (the comment there only talks about constants, but the same reasoning applies to `const` parameters).
Previously, we sorted the vec prior to hashing, making the hash
independent of the original (command-line argument) order. However, the
original vec was still always kept in the original order, so we were
relying on the rest of the compiler always working with it in an
'order-independent' way.
This assumption was not being upheld by the `native_libraries` query -
the order of the entires in its result depends on the order of entries
in `Options.libs`. This lead to an 'unstable fingerprint' ICE when the
`-l` arguments were re-ordered.
This PR removes the sorting logic entirely. Re-ordering command-line
arguments (without adding/removing/changing any arguments) seems like a
really niche use case, and correctly optimizing for it would require
additional work. By always hashing arguments in their original order, we
can entirely avoid a cause of 'unstable fingerprint' errors.
Emit a diagnostic when the monomorphized item collector
encounters errors during a step of the recursive item collection.
These post-monomorphization errors otherwise only show the
erroneous expression without a trace, making them very obscure
and hard to pinpoint whenever they happen in dependencies.
deal with `const_evaluatable_checked` in `ConstEquate`
Failing to evaluate two constants which do not contain inference variables should not result in ambiguity.
Use TargetTriple::from_path in rustdoc
This fixes the problem reported in https://github.com/Rust-for-Linux/linux/pull/272 where rustdoc requires the absolute path of a target spec json instead of accepting a relative path like rustc.
Bump bootstrap compiler to beta 1.53.0
This PR bumps the bootstrap compiler to version 1.53.0 beta, as part of our usual release process (this was supposed to be Wednesday's step, but creating the beta release took longer than expected).
The PR also includes the "Bootstrap: skip rustdoc fingerprint for building docs" commit, see the reasoning [on Zulip](https://zulip-archive.rust-lang.org/241545trelease/88450153betabootstrap.html).
r? `@Mark-Simulacrum`
Make building THIR a stealable query
This PR creates a stealable `thir_body` query so that we can build the THIR only once for THIR unsafeck and MIR build.
Blocked on #83842.
r? `@nikomatsakis`
Extend `rustc_on_implemented` to improve more `?` error messages
`_Self` could match the generic definition; this adds that functionality for matching the generic definition of type parameters too.
Your advice welcome on the wording of all these messages, and which things belong in the message/label/note.
r? `@estebank`
CTFE get_alloc_extra_mut: also provide ref to MemoryExtra
This would let me use mutable references in more places in Stacked Borrows, avoiding some `RefCell` overhead. :)
r? `@oli-obk`
Swap TargetOptions::linker_is_gnu default from false to true and update targets as appropriate.
#85274 gated the `--gc-sections` flag on targets that specified `linker_is_gnu` to stop us from passing it to incompatible linkers. But that had the unintended effect of the flag no longer being passed on targets for which it is valid and hence caused a regression in binary size. Given that most `ld`-style linkers are GNU compatible, this change flips our default for `linker_is_gnu` from false to true. That also means updating the targets that relied on the previous default:
* Apple
* Illumos
* L4Re (not sure about this one)
* MSVC
* NvtPtx
* Solaris
Fixes#85519
Rollup of 4 pull requests
Successful merges:
- #85506 (Reset "focusedByTab" field when doing another search)
- #85548 (Remove dead toggle JS code)
- #85550 (facepalm: operator precedence fail on my part.)
- #85555 (Check for more things in THIR unsafeck)
Failed merges:
r? `@ghost`
`@rustbot` modify labels: rollup
Adjust self-type check to require equality
When we encounter `SomeType::<X>::foo`, `self_ty` is `SomeType<X>` and the method is defined in an impl on `SomeType<A>`. Previously, we required simply that `self_ty <: impl_ty`, but this is too lax: we should require equality in order to use the method. This was found as part of unrelated work on never type stabilization, but also fixes one of the wf test cases.
PassWrapper: update for LLVM change D102093
In https://reviews.llvm.org/D102093 lots of things stopped taking the
DebugLogging boolean parameter. Mercifully we appear to always set
DebugPassManager to false, so I don't think we're losing anything by not
passing this parameter.
Always produce sub-obligations when using cached projection result
See https://github.com/rust-lang/rust/issues/85360
When we skip adding the sub-obligations to the `obligation` list, we can affect whether or not the final result is `EvaluatedToOk` or `EvaluatedToOkModuloObligations`. This creates problems for incremental compilation, since the projection cache is untracked shared state.
To solve this issue, we unconditionally process the sub-obligations. Surprisingly, this is a slight performance *win* in many cases.
Fix missing lifetimes diagnostics after #83759
In #83759 while rebasing I didn't realize there was a new function for suggesting to add lifetime arguments. It relied on some invariants, namely that if a generic type/trait has angle brackets then it must have some generic argument, which is now no longer true. This PR updates that function to handle the new invariants.
This also adds a new regression test but I'm not sure if that's the correct place for it.
Fixes#85347
Update list of allowed aarch64 features
I recently added these features to std_detect for aarch64 linux, pending [review](https://github.com/rust-lang/stdarch/pull/1146).
I have commented any features not supported by LLVM 9, the current minimum version for Rust. Some (PAuth at least) were renamed between 9 & 12 and I've left them disabled. TME, however, is not in LLVM 9 but I've left it enabled.
See https://github.com/rust-lang/stdarch/issues/993
CTFE Machine: do not expose Allocation
`Memory` is careful now to not expose direct access to `Allocation`, but this one slipped through.
r? ``@oli-obk``
impl FromStr for proc_macro::Literal
Note that unlike `impl FromStr for proc_macro::TokenStream`, this impl does not permit whitespace or comments. The input string must consist of nothing but your literal.
- `"1".parse::<Literal>()` ⟶ ok
- `"1.0".parse::<Literal>()` ⟶ ok
- `"'a'".parse::<Literal>()` ⟶ ok
- `"\"\n\"".parse::<Literal>()` ⟶ ok
- `"0 1".parse::<Literal>()` ⟶ LexError
- `" 0".parse::<Literal>()` ⟶ LexError
- `"0 ".parse::<Literal>()` ⟶ LexError
- `"/* comment */0".parse::<Literal>()` ⟶ LexError
- `"0/* comment */".parse::<Literal>()` ⟶ LexError
- `"0// comment".parse::<Literal>()` ⟶ LexError
---
## Use case
```rust
let hex_int: Literal = format!("0x{:x}", int).parse().unwrap();
```
The only way this is expressible in the current API is significantly worse.
```rust
let hex_int = match format!("0x{:x}", int)
.parse::<TokenStream>()
.unwrap()
.into_iter()
.next()
.unwrap()
{
TokenTree::Literal(literal) => literal,
_ => unreachable!(),
};
```
CTFE core engine allocation & memory API improvemenets
This is a first step towards https://github.com/rust-lang/miri/issues/841.
- make `Allocation` API offset-based (no more making up `Pointer`s just to access an `Allocation`)
- make `Memory` API higher-level (combine checking for access and getting access into one operation)
The Miri-side PR is at https://github.com/rust-lang/miri/pull/1804.
r? `@oli-obk`
Set dso_local for more items
Related to https://github.com/rust-lang/rust/pull/83592. (cc `@nagisa)`
Noticed that on x86_64 with `relocation-model: static` `R_X86_64_GOTPCREL` relocations were still generated in some cases. (related: https://github.com/Rust-for-Linux/linux/issues/135; Rust-for-Linux needs these fixes to successfully build)
First time doing anything with LLVM so not sure whether this is correct but the following are some of the things I've tried to convince myself.
## C equivalent
Example from clang which also sets `dso_local` in these cases:
`clang-12 -fno-PIC -S -emit-llvm test.c`
```C
extern int A;
int* a() {
return &A;
}
int B;
int* b() {
return &B;
}
```
```
; ModuleID = 'test.c'
source_filename = "test.c"
target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
target triple = "x86_64-unknown-linux-gnu"
`@A` = external dso_local global i32, align 4
`@B` = dso_local global i32 0, align 4
; Function Attrs: noinline nounwind optnone uwtable
define dso_local i32* `@a()` #0 {
ret i32* `@A`
}
; Function Attrs: noinline nounwind optnone uwtable
define dso_local i32* `@b()` #0 {
ret i32* `@B`
}
attributes #0 = { noinline nounwind optnone uwtable "disable-tail-calls"="false" "frame-pointer"="all" "less-precise-fpmad"="false" "min-legal-vector-width"="0" "no-infs-fp-math"="false" "no-jump-tables"="false" "no-nans-fp-math"="false" "no-signed-zeros-fp-math"="false" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" "unsafe-fp-math"="false" "use-soft-float"="false" }
!llvm.module.flags = !{!0}
!llvm.ident = !{!1}
!0 = !{i32 1, !"wchar_size", i32 4}
!1 = !{!"clang version 12.0.0 (https://github.com/llvm/llvm-project/ b978a93635b584db380274d7c8963c73989944a1)"}
```
`clang-12 -fno-PIC -c test.c`
`objdump test.o -r`:
```
test.o: file format elf64-x86-64
RELOCATION RECORDS FOR [.text]:
OFFSET TYPE VALUE
0000000000000006 R_X86_64_64 A
0000000000000016 R_X86_64_64 B
RELOCATION RECORDS FOR [.eh_frame]:
OFFSET TYPE VALUE
0000000000000020 R_X86_64_PC32 .text
0000000000000040 R_X86_64_PC32 .text+0x0000000000000010
```
## Comparison to pre-LLVM 12 output
`rustc --emit=obj,llvm-ir --target=x86_64-unknown-none-linuxkernel --crate-type rlib test.rs`
```Rust
#![feature(no_core, lang_items)]
#![no_core]
#[lang="sized"]
trait Sized {}
#[lang="sync"]
trait Sync {}
#[lang = "drop_in_place"]
pub unsafe fn drop_in_place<T: ?Sized>(_: *mut T) {}
impl Sync for i32 {}
pub static STATIC: i32 = 32;
extern {
pub static EXT_STATIC: i32;
}
pub fn a() -> &'static i32 {
&STATIC
}
pub fn b() -> &'static i32 {
unsafe {&EXT_STATIC}
}
```
`objdump test.o -r`
nightly-2021-02-20 (rustc target is `x86_64-linux-kernel`):
```
RELOCATION RECORDS FOR [.text._ZN4test1a17h1024ba65f3424175E]:
OFFSET TYPE VALUE
0000000000000007 R_X86_64_32S _ZN4test6STATIC17h3adc41a83746c9ffE
RELOCATION RECORDS FOR [.text._ZN4test1b17h86a6a80c1190ac8dE]:
OFFSET TYPE VALUE
0000000000000007 R_X86_64_32S EXT_STATIC
```
nightly-2021-05-10:
```
RELOCATION RECORDS FOR [.text._ZN4test1a17he846f03bf37b2d20E]:
OFFSET TYPE VALUE
0000000000000007 R_X86_64_GOTPCREL _ZN4test6STATIC17h5a059515bf3d4968E-0x0000000000000004
RELOCATION RECORDS FOR [.text._ZN4test1b17h7e0f7f80fbd91125E]:
OFFSET TYPE VALUE
0000000000000007 R_X86_64_GOTPCREL EXT_STATIC-0x0000000000000004
```
This PR:
```
RELOCATION RECORDS FOR [.text._ZN4test1a17he846f03bf37b2d20E]:
OFFSET TYPE VALUE
0000000000000007 R_X86_64_32S _ZN4test6STATIC17h5a059515bf3d4968E
RELOCATION RECORDS FOR [.text._ZN4test1b17h7e0f7f80fbd91125E]:
OFFSET TYPE VALUE
0000000000000007 R_X86_64_32S EXT_STATIC
```
Only pass --[no-]gc-sections if linker is GNU ld.
Fixes a regression from #84468 where linking now fails with solaris linkers. LinkerFlavor::Gcc does not always mean GNU ld specifically. And in the case of at least the solaris ld in illumos, that flag is unrecognized and will cause the linking step to fail.
Even though removing the `is_like_solaris` branch from `gc_sections` in #84468 made sense as `-z ignore/record` are more analogous to the `--[no-]-as-needed` flags, it inadvertently caused solaris linkers to be passed the `--gc-sections` flag. So let's just change it to be more explicit about when we pass those flags.
Implement the new desugaring from `try_trait_v2`
~~Currently blocked on https://github.com/rust-lang/rust/issues/84782, which has a PR in https://github.com/rust-lang/rust/pull/84811~~ Rebased atop that fix.
`try_trait_v2` tracking issue: https://github.com/rust-lang/rust/issues/84277
Unfortunately this is already touching a ton of things, so if you have suggestions for good ways to split it up, I'd be happy to hear them. (The combination between the use in the library, the compiler changes, the corresponding diagnostic differences, even MIR tests mean that I don't really have a great plan for it other than trying to have decently-readable commits.
r? `@ghost`
~~(This probably shouldn't go in during the last week before the fork anyway.)~~ Fork happened.
- make Allocation API offset-based (no more Pointer)
- make Memory API higher-level (combine checking for access and getting access into one operation)
Rollup of 7 pull requests
Successful merges:
- #84587 (rustdoc: Make "rust code block is empty" and "could not parse code block" warnings a lint (`INVALID_RUST_CODEBLOCKS`))
- #85280 (Toggle-wrap items differently than top-doc.)
- #85338 (Implement more Iterator methods on core::iter::Repeat)
- #85339 (Report an error if a lang item has the wrong number of generic arguments)
- #85369 (Suggest borrowing if a trait implementation is found for &/&mut <type>)
- #85393 (Suppress spurious errors inside `async fn`)
- #85415 (Clean up remnants of BorrowOfPackedField)
Failed merges:
r? `@ghost`
`@rustbot` modify labels: rollup
Suggest borrowing if a trait implementation is found for &/&mut <type>
This pull request fixes#84973 by suggesting to borrow if a trait is not implemented for some type `T`, but it is for `&T` or `&mut T`. For instance:
```rust
trait Ti {}
impl<T> Ti for &T {}
fn foo<T: Ti>(_: T) {}
trait Tm {}
impl<T> Tm for &mut T {}
fn bar<T: Tm>(_: T) {}
fn main() {
let a: i32 = 5;
foo(a);
let b: Box<i32> = Box::new(42);
bar(b);
}
```
gives, on current nightly:
```
error[E0277]: the trait bound `i32: Ti` is not satisfied
--> t2.rs:11:9
|
3 | fn foo<T: Ti>(_: T) {}
| -- required by this bound in `foo`
...
11 | foo(a);
| ^ the trait `Ti` is not implemented for `i32`
error[E0277]: the trait bound `Box<i32>: Tm` is not satisfied
--> t2.rs:14:9
|
7 | fn bar<T: Tm>(_: T) {}
| -- required by this bound in `bar`
...
14 | bar(b);
| ^ the trait `Tm` is not implemented for `Box<i32>`
error: aborting due to 2 previous errors
```
whereas with my changes, I get:
```
error[E0277]: the trait bound `i32: Ti` is not satisfied
--> t2.rs:11:9
|
3 | fn foo<T: Ti>(_: T) {}
| -- required by this bound in `foo`
...
11 | foo(a);
| ^
| |
| expected an implementor of trait `Ti`
| help: consider borrowing here: `&a`
error[E0277]: the trait bound `Box<i32>: Tm` is not satisfied
--> t2.rs:14:9
|
7 | fn bar<T: Tm>(_: T) {}
| -- required by this bound in `bar`
...
14 | bar(b);
| ^
| |
| expected an implementor of trait `Tm`
| help: consider borrowing mutably here: `&mut b`
error: aborting due to 2 previous errors
```
In my implementation, I have added a "blacklist" to make these suggestions flexible. In particular, suggesting to borrow can interfere with other suggestions, such as to add another trait bound to a generic argument. I have tried to configure this blacklist to cause the least amount of test case failures, i.e. to model the current behavior as closely as possible (I only had to change one existing test case, and this change was quite clearly an improvement).
Report an error if a lang item has the wrong number of generic arguments
This pull request fixes#83893. The issue is that the lang item code currently checks whether the lang item has the correct item kind (e.g. a `#[lang="add"]` has to be a trait), but not whether the item has the correct number of generic arguments.
This can lead to an "index out of bounds" ICE when the compiler tries to create more substitutions than there are suitable types available (if the lang item was declared with too many generic arguments).
For instance, here is a reduced ("reduced" in the sense that it does not trigger additional errors) version of the example given in #83893:
```rust
#![feature(lang_items,no_core)]
#![no_core]
#![crate_type="lib"]
#[lang = "sized"]
trait MySized {}
#[lang = "add"]
trait MyAdd<'a, T> {}
fn ice() {
let r = 5;
let a = 6;
r + a
}
```
On current nightly, this immediately causes an ICE without any warnings or errors emitted. With the changes in this PR, however, I get no ICE and two errors:
```
error[E0718]: `add` language item must be applied to a trait with 1 generic argument
--> pr-ex.rs:8:1
|
8 | #[lang = "add"]
| ^^^^^^^^^^^^^^^
9 | trait MyAdd<'a, T> {}
| ------- this trait has 2 generic arguments, not 1
error[E0369]: cannot add `{integer}` to `{integer}`
--> pr-ex.rs:14:7
|
14 | r + a
| - ^ - {integer}
| |
| {integer}
error: aborting due to 2 previous errors
Some errors have detailed explanations: E0369, E0718.
For more information about an error, try `rustc --explain E0369`.
```
Unify Regions with RegionVids in UnificationTable
A few test output changes; might be able to revert those but figured I would open this for perf and comments.
r? `@nikomatsakis`
# Stabilization report
## Summary
This stabilizes using macro expansion in key-value attributes, like so:
```rust
#[doc = include_str!("my_doc.md")]
struct S;
#[path = concat!(env!("OUT_DIR"), "/generated.rs")]
mod m;
```
See the changes to the reference for details on what macros are allowed;
see Petrochenkov's excellent blog post [on internals](https://internals.rust-lang.org/t/macro-expansion-points-in-attributes/11455)
for alternatives that were considered and rejected ("why accept no more
and no less?")
This has been available on nightly since 1.50 with no major issues.
## Notes
### Accepted syntax
The parser accepts arbitrary Rust expressions in this position, but any expression other than a macro invocation will ultimately lead to an error because it is not expected by the built-in expression forms (e.g., `#[doc]`). Note that decorators and the like may be able to observe other expression forms.
### Expansion ordering
Expansion of macro expressions in "inert" attributes occurs after decorators have executed, analogously to macro expressions appearing in the function body or other parts of decorator input.
There is currently no way for decorators to accept macros in key-value position if macro expansion must be performed before the decorator executes (if the macro can simply be copied into the output for later expansion, that can work).
## Test cases
- https://github.com/rust-lang/rust/blob/master/src/test/ui/attributes/key-value-expansion-on-mac.rs
- https://github.com/rust-lang/rust/blob/master/src/test/rustdoc/external-doc.rs
The feature has also been dogfooded extensively in the compiler and
standard library:
- https://github.com/rust-lang/rust/pull/83329
- https://github.com/rust-lang/rust/pull/83230
- https://github.com/rust-lang/rust/pull/82641
- https://github.com/rust-lang/rust/pull/80534
## Implementation history
- Initial proposal: https://github.com/rust-lang/rust/issues/55414#issuecomment-554005412
- Experiment to see how much code it would break: https://github.com/rust-lang/rust/pull/67121
- Preliminary work to restrict expansion that would conflict with this
feature: https://github.com/rust-lang/rust/pull/77271
- Initial implementation: https://github.com/rust-lang/rust/pull/78837
- Fix for an ICE: https://github.com/rust-lang/rust/pull/80563
## Unresolved Questions
~~https://github.com/rust-lang/rust/pull/83366#issuecomment-805180738 listed some concerns, but they have been resolved as of this final report.~~
## Additional Information
There are two workarounds that have a similar effect for `#[doc]`
attributes on nightly. One is to emulate this behavior by using a limited version of this feature that was stabilized for historical reasons:
```rust
macro_rules! forward_inner_docs {
($e:expr => $i:item) => {
#[doc = $e]
$i
};
}
forward_inner_docs!(include_str!("lib.rs") => struct S {});
```
This also works for other attributes (like `#[path = concat!(...)]`).
The other is to use `doc(include)`:
```rust
#![feature(external_doc)]
#[doc(include = "lib.rs")]
struct S {}
```
The first works, but is non-trivial for people to discover, and
difficult to read and maintain. The second is a strange special-case for
a particular use of the macro. This generalizes it to work for any use
case, not just including files.
I plan to remove `doc(include)` when this is stabilized. The
`forward_inner_docs` workaround will still compile without warnings, but
I expect it to be used less once it's no longer necessary.
This adds a new lint to `rustc` that is used in rustdoc when a code
block is empty or cannot be parsed as valid Rust code.
Previously this was unconditionally a warning. As such some
documentation comments were (unknowingly) abusing this to pass despite
the `-Dwarnings` used when compiling `rustc`, this should not be the
case anymore.
In https://reviews.llvm.org/D102093 lots of things stopped taking the
DebugLogging boolean parameter. Mercifully we appear to always set
DebugPassManager to false, so I don't think we're losing anything by not
passing this parameter.
Parse unnamed fields of struct and union type
Added the `unnamed_fields` feature gate.
This is a prototype of [RFC 2102](https://github.com/rust-lang/rust/issues/49804), so any suggestions are greatly appreciated.
r? `@petrochenkov`
Remove CrateNum parameter for queries that only work on local crate
The pervasive `CrateNum` parameter is a remnant of the multi-crate rustc idea.
Using `()` as query key in those cases avoids having to worry about the validity of the query key.
rustc_codegen_ssa: only create backend `BasicBlock`s as-needed.
Instead of creating one backend (e.g. LLVM) block per MIR block ahead of time, and then deleting the ones that weren't visited, this PR moves to creating the blocks as they're needed (either reached via the RPO visit, or used as the target of a branch from a different block).
As deleting a block was the only `unsafe` builder method (generally we only *create* backend objects, not *remove* them), that's gone now and codegen is overall a bit safer.
The only change in output is the order of LLVM blocks (which AFAIK has no semantic meaning, other than the first block being the entry block). This happens because the blocks are now created due to control-flow edges, rather than MIR block order.
I'm making this a standalone PR because I keep getting wild perf results when I change *anything* in codegen, but if you want to read more about my plans in this area, see https://github.com/rust-lang/rust/pull/84771#issuecomment-830636256 (and https://github.com/rust-lang/rust/pull/84771#issue-628295651 - but that may be a bit outdated).
(You may notice some of the APIs in this PR, like `append_block`, don't help with the future plans - but I didn't want to include the necessary refactors that pass a build around everywhere, in this PR, so it's a small compromise)
r? `@nagisa` `@bjorn3`
Fix unused attributes on macro_rules.
The `unused_attributes` lint wasn't firing on attributes of `macro_rules` definitions. The consequence is that many attributes are silently ignored on `macro_rules`. The reason is that `unused_attributes` is a late-lint pass, and only has access to the HIR, which does not have macro_rules definitions.
My solution here is to change `non_exported_macro_attrs` to be `macro_attrs` (a list of all attributes used for `macro_rules`, instead of just those for `macro_export`), and then to check this list in the `unused_attributes` lint. There are a number of alternate approaches, but this seemed the most reliable and least invasive. I am open to completely different approaches, though.
One concern is that I don't fully understand the implications of extending `non_exported_macro_attrs` to include non-exported macros. That list was originally added in #62042 to handle stability attributes, so I suspect it was just an optimization since that was all that was needed. It was later extended to be included in SVH in #83901. #80641 also added a use to check for `invalid` attributes, which seems a little odd to me (it didn't validate non-exported macros, and seems highly specific).
Overall, there doesn't seem to be a clear story of when `unused_attributes` should be used versus an error like E0518. I considered alternatively using an "allow list" of built-in attributes that can be used on macro_rules (allow, warn, deny, forbid, cfg, cfg_attr, macro_export, deprecated, doc), but I feel like that could be a pain to maintain.
Some built-in attributes already present hard-errors when used with macro_rules. These are each hard-coded in various places:
- `derive`
- `test` and `bench`
- `proc_macro` and `proc_macro_derive`
- `inline`
- `global_allocator`
The primary motivation is that I sometimes see people use `#[macro_use]` in front of `macro_rules`, which indicates there is some confusion out there (evident that there was even a case of it in rustc).
Remove support for floating-point constants in asm!
Floating-point constants aren't very useful anyways and this simplifies
the code since the type check can now be done in typeck.
cc `@rust-lang/wg-inline-asm`
r? `@nagisa`
Reachable statics have reachable initializers
Static initializer can read other statics. Initializers are evaluated at
compile time, and so their content could become inlined into another
crate. Ensure that initializers of reachable statics are also reachable.
Previously, when an item incorrectly considered to be unreachable was
reached from another crate an attempt would be made to codegen it. The
attempt could fail with an ICE (in the case MIR wasn't available to do
so) in some circumstances the attempt could also succeed resulting in
a local codegen of non-local items, including static ones.
Fixes#84455.
rustc_codegen_ssa: generate MSVC cleanup pads on demand, like GNU landing pads.
This unblocks #84993 in terms of codegen tests, as it brings the MSVC-style (`cleanup_pad`) EH (LLVM) block order in line with the GNU-style (`landing_pad`) EH (LLVM) block order, by having both of them be on-demand (instead of MSVC-style being eager and GNU-style lazy/on-demand).
It also unifies the two implementations a bit, similar to #84699, but in the opposite direction (as that attempt made both kinds of EH pads eagerly built).
~~Opening as draft because I haven't done enough Windows testing just yet, of both this PR, and of #84993 rebased on it.~~ (**EDIT**: seems to be working as expected)
r? `@nagisa`
CTFE validation: handle pointers in str
I also finally learned how I can match *some* NOTEs in a ui test without matching all of them, and applied that to some const tests in the 2nd commit where I added NOTE because I did not know what I was doing. I can separate this into its own PR if you prefer.
Fixes https://github.com/rust-lang/rust/issues/83182
r? `@oli-obk`
Check for inline assembly in THIR unsafeck
#83129 was merged recently and added a THIR unsafe checker. This adds a check for inline assembly. (and this is 2x simpler than the MIR version, which has to check for `asm` and `llvm_asm` in two separate spots!)
see also rust-lang/project-thir-unsafeck#7
Remove some unncessary spaces from pretty-printed tokenstream output
In addition to making the output look nicer for all crates, this also
aligns the pretty-printing output with what the `rental` crate expects.
This will allow us to eventually disable a backwards-compat hack in a
follow-up PR.
See https://github.com/rust-lang/rust/issues/84428 for some background information about why we want to make this change. Note that this change would be desirable (but not particularly necessary) even if `rental` didn't exist, so we're not adding any crate-specific hacks into the compiler.
In addition to making the output look nicer for all crates, this also
aligns the pretty-printing output with what the `rental` crate expects.
This will allow us to eventually disable a backwards-compat hack in a
follow-up PR.
Warn about unused `pub` fields in non-`pub` structs
This pull request fixes#85255. The current implementation of dead code analysis is too prudent because it marks all `pub` fields of structs as live, even though they cannot be accessed from outside of the current crate if the struct itself only has restricted or private visibility.
I have changed this behavior to take the containing struct's visibility into account when looking at field visibility and liveness. This also makes dead code warnings more consistent; consider the example given in #85255:
```rust
struct Foo {
a: i32,
pub b: i32,
}
struct Bar;
impl Bar {
fn a(&self) -> i32 { 5 }
pub fn b(&self) -> i32 { 6 }
}
fn main() {
let _ = Foo { a: 1, b: 2 };
let _ = Bar;
}
```
Current nightly already warns about `Bar::b()`, even though it is `pub` (but `Bar` is not). It should therefore also warn about `Foo::b`, which it does with the changes in this PR.
swap function order for better read flow
I was reading this error message for the first time.
I was a little bit confused when reading that part:
```
foo.bar(); // we can now use this method since i32 implements the Foo trait
```
At the time I was reading `// we can now use this method` I wasn't sure why. It only made sense when reading on. So swapping these parts results in a better read flow.
coverage bug fixes and some refactoring
This replaces the relevant commits (2 and 3) from PR #85082, and also corrects an error querying for coverageinfo.
1. `coverageinfo` query needs to use the same MIR as codegen
I ran into an error trying to fix dead block coverage and realized the
`coverageinfo` query is getting a different MIR compared to the
codegenned MIR, which can sometimes be a problem during mapgen.
I changed that query to use the `InstandeDef` (which includes the
generic parameter substitutions, prosibly specific to const params)
instead of the `DefId` (without unknown/default const substitutions).
2. Simplified body_span and filtered span code
Some code cleanup extracted from future (but unfinished) commit to fix
coverage in attr macro functions.
3. Spanview needs the relevant body_span used for coverage
The coverage body_span doesn't always match the function body_span.
r? ```@tmandry```
Preserve `SyntaxContext` for invalid/dummy spans in crate metadata
Fixes#85197
We already preserved the `SyntaxContext` for invalid/dummy spans in the
incremental cache, but we weren't doing the same for crate metadata.
If an invalid (lo/hi from different files) span is written to the
incremental cache, we will decode it with a 'dummy' location, but keep
the original `SyntaxContext`. Since the crate metadata encoder was only
checking for `DUMMY_SP` (dummy location + root `SyntaxContext`),
the metadata encoder would treat it as a normal span, encoding the
`SyntaxContext`. As a result, the final span encoded to the metadata
would change across sessions, even if the crate itself was unchanged.
This could lead to an 'unstable fingerprint' ICE under the following conditions:
1. We compile a crate with an invalid span using incremental compilation. The metadata encoder discards the `SyntaxContext` since the span is invalid, while the incremental cache encoder preserves the `SyntaxContext`
2. From another crate, we execute a foreign query, decoding the invalid span from the metadata as `DUMMY_SP` (e.g. with `SyntaxContext::root()`). This span gets hashed into the query fingerprint. So far, this has always happened through the `optimized_mir` query.
3. We recompile the first crate using our populated incremental cache, without changing anything. We load the (previously) invalid span from our incremental cache - it gets converted to a span with a dummy (but valid) location, along with the original `SyntaxContext`. This span gets written out to the crate metadata - since it now has a valid location, we preserve its `SyntaxContext`.
4. We recompile the second crate, again using a populated incremental cache. We now re-run the foreign query `optimized_mir` - the foreign crate hash is unchanged, but we end up decoding a different span (it now ha a non-root `SyntaxContext`). This results in the fingerprint changing, resulting in an ICE.
This PR updates our encoding of spans in the crate metadata to mirror
the encoding of spans into the incremental cache. We now always encode a
`SyntaxContext`, and encode location information for spans with a
non-dummy location.
Use the object crate for metadata reading
This allows sharing the metadata reader between cg_llvm, cg_clif and other codegen backends.
This is not currently useful for rlib reading with cg_spirv ([rust-gpu](https://github.com/EmbarkStudios/rust-gpu/)) as it uses tar rather than ar as .rlib format, but it is useful for dylib reading required for loading proc macros. (cc `@eddyb)`
The object crate is already trusted as dependency of libstd through backtrace. As far as I know it supports reading all object file formats used by targets for which we support rust dylibs with crate metadata, but I am not certain. If this happens to not be the case, I could keep using LLVM for reading dylib metadata.
Marked as WIP for a perf run and as it is based on #83637.
Improve error message for non-exhaustive matches on non-exhaustive enums
This pull request fixes#85227. For an enum marked with `#[non_exhaustive]` and not defined in the current crate, the error message for non-exhaustive matches now mentions the fact that the enum is marked as non-exhaustive:
```
error[E0004]: non-exhaustive patterns: `_` not covered
--> main.rs:12:11
|
12 | match e {
| ^ pattern `_` not covered
|
= help: ensure that all possible cases are being handled, possibly by adding wildcards or more match arms
= note: the matched value is of type `E`, which is marked as non-exhaustive
```
Store VariantIdx to distinguish enum variants
This saves ~24% of the instructions on the match-stress-enum benchmark, but I'm not 100% sure that this is OK - if we ever compare two constructors across enums (e.g., a Result and an Option), then this is obviously insufficient; I can experiment with continuing to store the DefId for comparison purposes in that case.
LinkerFlavor::Gcc does not always mean GNU ld specifically. And in the
case of at least the solaris ld in illumos, that flag is unrecognized
and will cause the linking step to fail.
Add support for const operands and options to global_asm!
On x86, the default syntax is also switched to Intel to match asm!.
Currently `global_asm!` only supports `const` operands and the `att_syntax` option. In the future, `sym` operands will also be supported. However there is no plan to support any of the other operand types or options since they don't make sense in the context of `global_asm!`.
r? `@nagisa`
have on_completion record subcycles
have on_completion record subcycles
Rework `on_completion` method so that it removes all
provisional cache entries that are "below" a completed
node (while leaving those entries that are not below
the node).
This corrects an imprecise result that could in turn lead
to an incremental compilation failure. Under the old
scheme, if you had:
* A depends on...
* B depends on A
* C depends on...
* D depends on C
* T: 'static
then the provisional results for A, B, C, and D would all
be entangled. Thus, if A was `EvaluatedToOkModuloRegions`
(because of that final condition), then the result for C and
D would also be demoted to "ok modulo regions".
In reality, though, the result for C depends only on C and itself,
and is not dependent on regions. If we happen to evaluate the
cycle starting from C, we would never reach A, and hence the
result would be "ok".
Under the new scheme, the provisional results for C and D
are moved to the permanent cache immediately and are not affected
by the result of A.
Fixes#83538
r? `@Aaron1011`
Fix diagnostic for cross crate private tuple struct constructors
Fixes#78708.
There was already some limited support for certain cross-crate scenarios but that didn't handle a tuple struct rexported from an inner module for example (e.g. the NonZero* types as seen in #85049).
```Rust
➜ cat bug.rs
fn main() {
let _x = std::num::NonZeroU32(12);
let n = std::num::NonZeroU32::new(1).unwrap();
match n {
std::num::NonZeroU32(i) => {},
}
}
```
**Before:**
<details>
```Rust
➜ rustc +nightly bug.rs
error[E0423]: expected function, tuple struct or tuple variant, found struct `std::num::NonZeroU32`
--> bug.rs:2:14
|
2 | let _x = std::num::NonZeroU32(12);
| ^^^^^^^^^^^^^^^^^^^^^^^^ help: use struct literal syntax instead: `std::num::NonZeroU32 { 0: val }`
|
::: /home/luqman/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/core/src/num/nonzero.rs:148:1
[snip]
error[E0532]: expected tuple struct or tuple variant, found struct `std::num::NonZeroU32`
--> bug.rs:5:9
|
5 | std::num::NonZeroU32(i) => {},
| ^^^^^^^^^^^^^^^^^^^^^^^ help: use struct pattern syntax instead: `std::num::NonZeroU32 { 0 }`
|
::: /home/luqman/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/core/src/num/nonzero.rs:148:1
[snip]
error: aborting due to 2 previous errors
Some errors have detailed explanations: E0423, E0532.
For more information about an error, try `rustc --explain E0423`.
```
</details>
**After:**
<details>
```Rust
➜ /rust/build/x86_64-unknown-linux-gnu/stage1/bin/rustc bug.rs
error[E0423]: cannot initialize a tuple struct which contains private fields
--> bug.rs:2:14
|
2 | let _x = std::num::NonZeroU32(12);
| ^^^^^^^^^^^^^^^^^^^^
|
note: constructor is not visible here due to private fields
--> /rust/library/core/src/num/nonzero.rs:148:1
[snip]
error[E0532]: cannot match against a tuple struct which contains private fields
--> bug.rs:5:9
|
5 | std::num::NonZeroU32(i) => {},
| ^^^^^^^^^^^^^^^^^^^^
|
note: constructor is not visible here due to private fields
--> bug.rs:5:30
|
5 | std::num::NonZeroU32(i) => {},
| ^ private field
error: aborting due to 2 previous errors
Some errors have detailed explanations: E0423, E0532.
For more information about an error, try `rustc --explain E0423`.
```
</details>
One question is if we should only collect the needed info for the cross-crate case after encountering an error instead of always doing it. Perf run perhaps to gauge the impact.
