The issue cannot be reproduced with the former testcase of creating external crates because
rust refuses to use "external crate 28_找出字符串中第一个匹配项的下标"
because it is not a valid indentifier (starts with number, and contain non ascii chars)
But still using 28_找出字符串中第一个匹配项的下标.rs as a filename is accepted by previous rustc releases
So we consider it valid, and add an integration test for it to catch any regression on other code related to non ascii filenames.
(cherry picked from commit c6acffeb78)
[beta-1.91] Warn on future errors from temporary lifetimes shortening in Rust 1.92
Pursuant to [discussion on Zulip](https://rust-lang.zulipchat.com/#narrow/channel/474880-t-compiler.2Fbackports/topic/.23145838.3A.20beta-nominated/near/540530631), this implements a future-compatibility warning lint `macro_extended_temporary_scopes` for errors in Rust 1.92 caused by rust-lang/rust#145838:
```
warning: temporary lifetime shortening in Rust 1.92
--> $DIR/macro-extended-temporary-scopes.rs:54:14
|
LL | &struct_temp().field
| ^^^^^^^^^^^^^ this expression creates a temporary value...
...
LL | } else {
| - ...which will be dropped at the end of this block in Rust 1.92
|
= warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
= note: for more information, see <https://doc.rust-lang.org/rustc/lints/listing/warn-by-default.html#macro-extended-temporary-scopes>
= note: consider using a `let` binding to create a longer lived value
```
Implementation-wise, this reuses the existing temporary scoping FCW machinery introduced for the `tail_expr_drop_order` edition lint: this adds `BackwardIncompatibleDropHint` statements to the MIR at the end of the shortened scopes for affected temporaries; these are then checked in borrowck to warn if the temporary is used after the future drop hint. There are trade-offs here: on one hand, I believe this gives some assurance over ad-hoc pattern-recognition that there are no false positives[^1]. On the other hand, this fails to lint on future dangling raw pointers and it complicates the potential addition of explanatory diagnostics or suggestions[^2]. I'm hopeful that the limitation around dangling pointers won't be relevant in real code, though; the only real instance we've seen of breakage so far is future errors in formatting macro invocations, which this should be able to catch.
Release logistics notes:
- This PR targets the beta branch directly, since the breakage it's a FCW for is landing in the next Rust version.
- rust-lang/rust#146098 undoes the breakage this is a FCW for. If that behavior is merged and stabilizes in Rust 1.92, this PR should be reverted (or shouldn't be merged) in order to avoid spurious warnings.
cc `@traviscross`
`@rustbot` label +T-lang
[^1]: In particular, more syntactic approaches are complicated by having to avoid warning on promoted constants; they'd either be full of holes, they'd need a lot of extra logic, or they'd need to hack more MIR-to-HIR mapping into `PromoteTemps`.
[^2]: It's definitely possible to add more context and a suggestion, but the ways I've thought of to do so are either too hacky or too complex to feel appropriate for a last-minute direct-to-beta lint.
Some hygiene doc improvements
Improve some doc comments around SyntaxContext, outer_expn and friends.
Based on discussion at https://github.com/rust-lang/rust/pull/146100.
r? petrochenkov
update fixme in compare_method_predicate_entailment resulting from review of EII
r? `@lcnr`
Just the comment update separately from https://github.com/rust-lang/rust/pull/146348/files since it doesn't really belong in that PR. Should be trivial
Make `AssocItem` aware of its impl kind
The general goal is to have fewer query dependencies by making `AssocItem` aware of its parent impl kind (inherent vs. trait) without having to query the parent def_kind.
See individual commits.
Add --print target-spec-json-schema
This schema is helpful for people writing custom target spec JSON. It can provide autocomplete in the editor, and also serves as documentation when there are documentation comments on the structs, as `schemars` will put them in the schema.
I was motivated to do this because I saw someone write their own version of this schema by hand, so demand for this clearly exists. It's not a lot of effort to implement, so I thought it would make sense.
MCP: https://github.com/rust-lang/compiler-team/issues/905
I think it would also be useful to put this in the sysroot in `etc` so people can link it directly in their editors.
I would have loved to add a test that validates the JSON schema against the spec JSON of every builtin target, but I don't want to do it as the JSON schema validation crates have incredible amounts of dependencies because JSON schema supports a ton of random features. I don't want to add that, even as a dev dependency.
Convert `no_std` and `no_core` to the new attribute infrastructure
r? ```@oli-obk```
Also added a test for these, since we didn't have any and I was kind of surprised new diagnostics didn't break anything hehe
This schema is helpful for people writing custom target spec JSON. It
can provide autocomplete in the editor, and also serves as documentation
when there are documentation comments on the structs, as `schemars` will
put them in the schema.
With this macro we only need to enumerate every variant once. This saves
a lot of duplication already between the definition, the `FromStr` impl
and the `ToJson` impl.
It also enables us to do further things with it like JSON schema
generation.
support integer literals in `${concat()}`
Tracking issue: rust-lang/rust#124225
Adds support for using integer literals as arguments to `${concat()}` macro expressions.
Integer formatting such as `1_000` is preserved by this.
match clang's `va_arg` assembly on arm targets
tracking issue: https://github.com/rust-lang/rust/issues/44930
For this example
```rust
#![feature(c_variadic)]
#[unsafe(no_mangle)]
unsafe extern "C" fn variadic(a: f64, mut args: ...) -> f64 {
let b = args.arg::<f64>();
let c = args.arg::<f64>();
a + b + c
}
```
We currently generate (via llvm):
```asm
variadic:
sub sp, sp, #12
stmib sp, {r2, r3}
vmov d0, r0, r1
add r0, sp, #4
vldr d1, [sp, #4]
add r0, r0, #15
bic r0, r0, #7
vadd.f64 d0, d0, d1
add r1, r0, #8
str r1, [sp]
vldr d1, [r0]
vadd.f64 d0, d0, d1
vmov r0, r1, d0
add sp, sp, #12
bx lr
```
LLVM is not doing a good job. In fact, it's well-known that LLVM's implementation of `va_arg` is kind of bad, and we implement it ourselves (based on clang) for many targets already. For arm, our own `emit_ptr_va_arg` saves 3 instructions.
Next, it turns out it's important for LLVM to explicitly start and end the lifetime of the `va_list`. In https://github.com/rust-lang/rust/pull/146059 I already end the lifetime, but when looking at this again, I noticed that it is important to also start it, see https://godbolt.org/z/EGqvKTTsK: failing to explicitly start the lifetime uses an extra register.
So, the combination of `emit_ptr_va_arg` with starting/ending the lifetime makes rustc emit exactly the instructions that clang generates::
```asm
variadic:
sub sp, sp, #12
stmib sp, {r2, r3}
vmov d16, r0, r1
vldr d17, [sp, #4]
vadd.f64 d16, d16, d17
vldr d17, [sp, #12]
vadd.f64 d16, d16, d17
vmov r0, r1, d16
add sp, sp, #12
bx lr
```
The arguments to `emit_ptr_va_arg` are based on [the clang implementation](03dc2a41f3/clang/lib/CodeGen/Targets/ARM.cpp (L798-L844)).
r? ``@workingjubilee`` (I can re-roll if your queue is too full, but you do seem like the right person here)
try-job: armhf-gnu
Skip typeck for items w/o their own typeck context
Skip items which forward typeck to their ancestor.
Should remove some potential but unnecessary typeck query waits, hence might improve performance for the parallel frontend.
Thanks to `@ywxt` for a fix suggestion
Fixesrust-lang/rust#141951
Revert `assert!` desugaring changes (#122661)
Reverts rust-lang/rust#122661 to prevent rust-lang/rust#145770 slipping into beta.
cc `@estebank` (FYI)
### Review remarks
- Commit 1 is the MCVE reported in rust-lang/rust#145770 added as a regression test `tests/ui/macros/assert-desugaring-145770.rs`. Against `master`, this test fails.
- Commit 2 reverts rust-lang/rust#122661 (with a merge conflict fixed). `tests/ui/macros/assert-desugaring-145770.rs` now passes.
Less greedily parse `[const]` bounds
> [!IMPORTANT]
> If you're coming here from any beta backport nomination thread on Zulip, only the last commit is truly relevant (the first commit doesn't need to be backported, it only contains test modifications)!
Don't consider `[` to start a bound, only consider `[const]` in its entirety to do so. This drastically reduces (but doesn't eliminate!) the chance of *real* breakages. Like `const`, `~const` and `async` before, `[const]` unavoidably brings along theoretical breakages, see preexisting tests: `macro-const-trait-bound-theoretical-regression.rs` and `macro-async-trait-bound-theoretical-regression.rs`.
Side note: It's unfortunate that we have to do this but apart from the known fact that MBE hurts forward compatibility, the `[const]` syntax is simply a bit scuffed (also CC'ing https://github.com/rust-lang/rust/issues/146122, section (3)).
Fixes [after beta backport] rust-lang/rust#146417.
* 1st commit: Restore the original test intentions of several preexisting related tests that were unfortunately lost over time
* I've added a bunch of SCREAMING comments to make it less likely to be lost again
* CC PR rust-lang/rust#119099 which added most of these tests
* CC [#144409 (comment)](https://github.com/rust-lang/rust/pull/144409#discussion_r2337587513) for further context (NB: It's not the only PR that negatively affected the test intention)
* 2nd commit: Actually address the regression
r? `@oli-obk` or anyone
This reverts commit 1eeb8e8b15, reversing
changes made to 324bf2b9fd.
Unfortunately the assert desugaring change is not backwards compatible,
see RUST-145770.
Code such as
```rust
#[derive(Debug)]
struct F {
data: bool
}
impl std::ops::Not for F {
type Output = bool;
fn not(self) -> Self::Output { !self.data }
}
fn main() {
let f = F { data: true };
assert!(f);
}
```
would be broken by the assert desugaring change. We may need to land
the change over an edition boundary, or limit the editions that the
desugaring change impacts.
