Move lifetime resolution module to rustc_hir_analysis.
Now that lifetime resolution has been removed from it, this file has nothing to do in `rustc_resolve`. It's purpose is to compute Debruijn indices for lifetimes, so let's put it in type collection.
scoped threads: pass closure through MaybeUninit to avoid invalid dangling references
The `main` function defined here looks roughly like this, if it were written as a more explicit stand-alone function:
```rust
// Not showing all the `'lifetime` tracking, the point is that
// this closure might live shorter than `thread`.
fn thread(control: ..., closure: impl FnOnce() + 'lifetime) {
closure();
control.signal_done();
// A lot of time can pass here.
}
```
Note that `thread` continues to run even after `signal_done`! Now consider what happens if the `closure` captures a reference of lifetime `'lifetime`:
- The type of `closure` is a struct (the implicit unnameable closure type) with a `&'lifetime mut T` field. References passed to a function are marked with `dereferenceable`, which is LLVM speak for *this reference will remain live for the entire duration of this function*.
- The closure runs, `signal_done` runs. Then -- potentially -- this thread gets scheduled away and the main thread runs, seeing the signal and returning to the user. Now `'lifetime` ends and the memory the reference points to might be deallocated.
- Now we have UB! The reference that as passed to `thread` with the promise of remaining live for the entire duration of the function, actually got deallocated while the function still runs. Oops.
Long-term I think we should be able to use `ManuallyDrop` to fix this without `unsafe`, or maybe a new `MaybeDangling` type. I am working on an RFC for that. But in the mean time it'd be nice to fix this so that Miri with `-Zmiri-retag-fields` (which is needed for "full enforcement" of all the LLVM flags we generate) stops erroring on scoped threads.
Fixes https://github.com/rust-lang/rust/issues/101983
r? `@m-ou-se`
Fix the sanitizer_scs_attr_check.rs test
The test is failing when targeting aarch64 Android. The intent appears to have been to look for a function attributes comment (or the absence of one) on the line preceding the function declaration. But this isn't quite possible with FileCheck and the test as written was looking for a line with `no_scs` after a line with `scs`, which doesn't appear in the output. Instead, match on the function attributes comment on the line following the demangled function name comment.
Improve rustdoc-gui search-color test
Thanks to the add of "functions" in `browser-ui-test`, we can start to reduce the size of the scripts. It'll be very useful for all color checks.
r? `@notriddle`
suggest candidates for unresolved import
Currently we prompt suggestion of candidates(help notes of `use xxx::yyy`) for names which cannot be resolved, but we don't do that for import statements themselves that couldn't be resolved. It seems reasonable to add candidate help information for these statements as well.
Fixes#102711
rustdoc: clean up overly complex `.trait-impl` CSS selectors
When added in 45964368f4, these multi-class selectors were present in the initial commit, but no reason was given why the shorter selector wouldn't work.
update to syn-1.0.102
This update removes the only `.gitignore` found in `rustc-src`:
vendor/syn/tests/.gitignore
vendor/syn-1.0.91/tests/.gitignore
vendor/syn-1.0.95/tests/.gitignore
To check-in `rustc-src` for hermetic builds in environments with
restrictive `.gitignore` policies, one has to remove these
`tests/.gitignore` and patch the respective
`.cargo-checksum.json`.`syn` >1.0.101 includes dtolnay/syn@3c49303bed,
which removes its `tests/.gitignore`. Now the `syn` crates.io package
has no `.gitignore`.
[`rustc-src`'s `vendor`][] is produced from the root `Cargo.toml`,
`src/tools/rust-analyzer/Cargo.toml`,
`compiler/rustc_codegen_cranelift/Cargo.toml`, and
`src/bootstrap/Cargo.toml`. `rustc_codegen_cranelift` does not use
`syn`.
[`rustc-src`'s `vendor`]:
https://github.com/rust-lang/rust/blob/c0784109daa0/src/bootstrap/dist.rs#L934-L940
This was produced with:
cargo update --package syn --precise 1.0.102 \
cargo update --package syn --precise 1.0.102 \
--manifest-path src/tools/rust-analyzer/Cargo.toml
cargo update --package syn --precise 1.0.102 \
--manifest-path src/bootstrap/Cargo.toml
slice: #[inline] a couple iterator methods.
The one I care about and actually saw in the wild not getting inlined is
clone(). We ended up doing a whole function call for something that just
copies two pointers.
I ended up marking as_slice / as_ref as well because make_slice is
inline(always) itself, and is also the kind of think that can kill
performance in hot loops if you expect it to get inlined. But happy to
undo those.
Rollup of 6 pull requests
Successful merges:
- #99696 (Uplift `clippy::for_loops_over_fallibles` lint into rustc)
- #102055 (Move some tests to more reasonable directories)
- #102786 (Remove tuple candidate, nothing special about it)
- #102794 (Make tests capture the error printed by a Result return)
- #102853 (Skip chained OpaqueCast when building captures.)
- #102868 (Rename `AssocItemKind::TyAlias` to `AssocItemKind::Type`)
Failed merges:
r? `@ghost`
`@rustbot` modify labels: rollup
Make tests capture the error printed by a Result return
An error returned by tests previously would get written directly to stderr, instead of to the capture buffer set up by the test harness. This PR makes it write to the capture buffer so that it can be integrated as part of the test output by build tools such as `buck test`, since being able to read the error message returned by a test is pretty critical to debugging why the test failed.
<br>
**Before:**
```rust
// tests/test.rs
#[test]
fn test() -> Result<(), &'static str> {
println!("STDOUT");
eprintln!("STDERR");
Err("RESULT")
}
```
```console
$ cargo build --test test
$ target/debug/deps/test-???????????????? -Z unstable-options --format=json
{ "type": "suite", "event": "started", "test_count": 1 }
{ "type": "test", "event": "started", "name": "test" }
Error: "RESULT"
{ "type": "test", "name": "test", "event": "failed", "stdout": "STDOUT\nSTDERR\n" }
{ "type": "suite", "event": "failed", "passed": 0, "failed": 1, "ignored": 0, "measured": 0, "filtered_out": 0, "exec_time": 0.00040313 }
```
**After:**
```console
$ target/debug/deps/test-???????????????? -Z unstable-options --format=json
{ "type": "suite", "event": "started", "test_count": 1 }
{ "type": "test", "event": "started", "name": "test" }
{ "type": "test", "name": "test", "event": "failed", "stdout": "STDOUT\nSTDERR\nError: \"RESULT\"" }
{ "type": "suite", "event": "failed", "passed": 0, "failed": 1, "ignored": 0, "measured": 0, "filtered_out": 0, "exec_time": 0.000261894 }
```
Uplift `clippy::for_loops_over_fallibles` lint into rustc
This PR, as the title suggests, uplifts [`clippy::for_loops_over_fallibles`] lint into rustc. This lint warns for code like this:
```rust
for _ in Some(1) {}
for _ in Ok::<_, ()>(1) {}
```
i.e. directly iterating over `Option` and `Result` using `for` loop.
There are a number of suggestions that this PR adds (on top of what clippy suggested):
1. If the argument (? is there a better name for that expression) of a `for` loop is a `.next()` call, then we can suggest removing it (or rather replacing with `.by_ref()` to allow iterator being used later)
```rust
for _ in iter.next() {}
// turns into
for _ in iter.by_ref() {}
```
2. (otherwise) We can suggest using `while let`, this is useful for non-iterator, iterator-like things like [async] channels
```rust
for _ in rx.recv() {}
// turns into
while let Some(_) = rx.recv() {}
```
3. If the argument type is `Result<impl IntoIterator, _>` and the body has a `Result<_, _>` type, we can suggest using `?`
```rust
for _ in f() {}
// turns into
for _ in f()? {}
```
4. To preserve the original behavior and clear intent, we can suggest using `if let`
```rust
for _ in f() {}
// turns into
if let Some(_) = f() {}
```
(P.S. `Some` and `Ok` are interchangeable depending on the type)
I still feel that the lint wording/look is somewhat off, so I'll be happy to hear suggestions (on how to improve suggestions :D)!
Resolves#99272
[`clippy::for_loops_over_fallibles`]: https://rust-lang.github.io/rust-clippy/master/index.html#for_loops_over_fallibles
When added in 45964368f4, these multi-class
selectors were present in the initial commit, but no reason was given why
the shorter selector wouldn't work.
Use BOLT in CI to optimize LLVM
This PR adds an optimization step in the Linux `dist` CI pipeline that uses [BOLT](https://github.com/llvm/llvm-project/tree/main/bolt) to optimize the `libLLVM.so` library built by boostrap.
Steps:
- [x] Use LLVM 15 as a bootstrap compiler and use it to build BOLT
- [x] Compile LLVM with support for relocations (`-DCMAKE_SHARED_LINKER_FLAGS="-Wl,-q"`)
- [x] Gather profile data using instrumented LLVM
- [x] Apply profile to LLVM that has already been PGOfied
- [x] Run with BOLT profiling on more benchmarks
- [x] Decide on the order of optimization (PGO -> BOLT?)
- [x] Decide how we should get `bolt` (currently we use the host `bolt`)
- [x] Clean up
The latest perf results can be found [here](https://github.com/rust-lang/rust/pull/94381#issuecomment-1258269440). The current CI build time with BOLT applied is around 1h 55 minutes.
Add missing documentation for FileNameDisplayPreference variants
Took me a while to find the information when I needed it so hopefully it should save some time for the next ones.
r? ``@thomcc``
Elaborate trait ref to compute object safety.
instead of building them manually from supertraits and associated items.
This allows to have the correct substs for GATs.
Fixes https://github.com/rust-lang/rust/issues/102751
add Vec::push_within_capacity - fallible, does not allocate
This method can serve several purposes. It
* is fallible
* guarantees that items in Vec aren't moved
* allows loops that do `reserve` and `push` separately to avoid pulling in the allocation machinery a second time in the `push` part which should make things easier on the optimizer
* eases the path towards `ArrayVec` a bit since - compared to `push()` - there are fewer questions around how it should be implemented
I haven't named it `try_push` because that should probably occupy a middle ground that will still try to reserve and only return an error in the unlikely OOM case.
resolves#84649
