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.
document `core::ffi::VaArgSafe`
tracking issue: https://github.com/rust-lang/rust/issues/44930
A modification of https://github.com/rust-lang/rust/pull/146454, keeping just the documentation changes, but not unsealing the trait.
Although conceptually we'd want to unseal the trait, there are many edge cases to supporting arbitrary types. We'd need to exhaustively test that all targets/calling conventions support all types that rust might generate (or generate proper error messages for unsupported cases). At present, many of the `va_arg` implementations assume that the argument is a scalar, and has an alignment of at most 8. That is totally sufficient for an MVP (accepting all of the "standard" C types), but clearly does not cover all rust types.
This PR also adds some various other tests for edge cases of c-variadic:
- the `#[inline]` attribute in its various forms. At present, LLVM is unable to inline c-variadic functions, but the attribute should still be accepted. `#[rustc_force_inline]` already rejects c-variadic functions.
- naked functions should accept and work with a C variable argument list. In the future we'd like to allow more ABIs with naked functions (basically, any ABI for which we accept defining foreign c-variadic functions), but for now only `"C"` and `"C-unwind` are supported
- guaranteed tail calls: c-variadic functions cannot be tail-called. That was already rejected, but there was not test for it.
r? `@workingjubilee`
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.
Rehome 30 `tests/ui/issues/` tests to other subdirectories under `tests/ui/` [#3 of Batch #2]
Part of rust-lang/rust#133895
Methodology:
1. Refer to the previously written `tests/ui/SUMMARY.md`
2. Find an appropriate category for the test, using the original issue thread and the test contents.
3. Add the issue URL at the bottom (not at the top, as that would mess up stderr line numbers)
4. Rename the tests to make their purpose clearer
Inspired by the methodology that `@Kivooeo` was using.
r? `@jieyouxu`
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.
test: remove an outdated normalization for rustc versions
These "you are using $RUSTC_VERSION" help messages were removed in
rust-lang/rust#142943, but rust-lang/rust#142681 started before that and
merged later, so its normalization is vestigial.
Improve suggestion in case a bare URL is surrounded by brackets
Fixes https://github.com/rust-lang/rust/issues/146162.
With this change, output looks like this:
```
|
1 | //! [https://github.com]
| ^^^^^^^^^^^^^^^^^^^^ help: use an automatic link instead: `<https://github.com>`
|
= note: bare URLs are not automatically turned into clickable links
= note: `#[warn(rustdoc::bare_urls)]` on by default
```
cc ```@fmease```
r? ```@lolbinarycat```
support integer literals in `${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
