proc_macro/bridge: use the cross-thread executor for nested proc-macros
While working on some other changes in the bridge, I noticed that when
running a nested proc-macro (which is currently only possible using
the unstable `TokenStream::expand_expr`), any symbols held by the
proc-macro client would be invalidated, as the same thread would be used
for the nested macro by default, and the interner doesn't handle nested
use.
After discussing with `@eddyb,` we decided the best approach might be to
force the use of the cross-thread executor for nested invocations, as it
will never re-use thread-local storage, avoiding the issue. This
shouldn't impact performance, as expand_expr is still unstable, and
infrequently used.
This was chosen rather than making the client symbol interner handle
nested invocations, as that would require replacing the internal
interner `Vec` with a `BTreeMap` (as valid symbol id ranges could now be
disjoint), and the symbol interner is known to be fairly perf-sensitive.
This patch adds checks to the execution strategy to use the cross-thread
executor when doing nested invocations. An alternative implementation
strategy could be to track this information in the `ExtCtxt`, however a
thread-local in the `proc_macro` crate was chosen to add an assertion so
that `rust-analyzer` is aware of the issue if it implements
`expand_expr` in the future.
r? `@eddyb`
Make `const_eval_select` a real intrinsic
This fixes issues where `track_caller` functions do not have nice panic
messages anymore when there is a call to the function, and uses the
MIR system to replace the call instead of dispatching via lang items.
Fixes#100696.
Make `ReentrantMutex` movable and `const`
As `MovableMutex` is now `const`, it can be used to simplify the implementation and interface of the internal reentrant mutex type. Consequently, the standard error stream does not need to be wrapped in `OnceLock` and `OnceLock::get_or_init_pin()` can be removed.
Implement internal `IsZero` for Wrapping and Saturating for `Vec` optimizations
This implements the `IsZero` trait for the `Wrapping` and `Saturating` types so that users of these types can get the improved performance from the specialization of creating a `Vec` from a single element repeated when it has a zero bit pattern (example `vec![0_i32; 500]`, or after this PR `vec![Wrapping(0_i32); 500]`)
CC #60978
While working on some other changes in the bridge, I noticed that when
running a nested proc-macro (which is currently only possible using
the unstable `TokenStream::expand_expr`), any symbols held by the
proc-macro client would be invalidated, as the same thread would be used
for the nested macro by default, and the interner doesn't handle nested
use.
After discussing with @eddyb, we decided the best approach might be to
force the use of the cross-thread executor for nested invocations, as it
will never re-use thread-local storage, avoiding the issue. This
shouldn't impact performance, as expand_expr is still unstable, and
infrequently used.
This was chosen rather than making the client symbol interner handle
nested invocations, as that would require replacing the internal
interner `Vec` with a `BTreeMap` (as valid symbol id ranges could now be
disjoint), and the symbol interner is known to be fairly perf-sensitive.
This patch adds checks to the execution strategy to use the cross-thread
executor when doing nested invocations. An alternative implementation
strategy could be to track this information in the `ExtCtxt`, however a
thread-local in the `proc_macro` crate was chosen to add an assertion so
that `rust-analyzer` is aware of the issue if it implements
`expand_expr` in the future.
r? @eddyb
Forbid mixing `System` with direct sytem allocator calls
e.g. [on windows](dec689432f/library/std/src/sys/windows/alloc.rs (L129-L178)), trying to mix `System::alloc` and `HeapFree` will not work because of the extra work done to serve higher alignments.
updated description of File struct in std::fs
I've seen several folks confused by the description of `std::fs::File` as "A reference to an open file on the filesystem." Apparently the word `reference` is sometimes taken to mean a Rust `&` reference, leading to confusion. Here's a recent representative [Reddit thread](https://www.reddit.com/r/rust/comments/x4k0lv/comment/imxu7v2/?utm_source=share&utm_medium=web2x&context=3), but I've seen this before as well.
This patch changes the description to "An object providing access to an open file on the filesystem." Hopefully this is clearer.
Fix internal doc link
The doc link from `DedupSortedIter` to `BTreeMap::bulk_build_from_sorted_iter` was broken when building internal documentation,
This prevented me from building internal documentation locally:
```
R:\Rust\rust> $env:RUSTDOCFLAGS="--document-private-items"
R:\Rust\rust> x doc library/std --open --stage 0
Building rustbuild
Compiling bootstrap v0.0.0 (R:\Rust\rust\src\bootstrap)
Finished dev [unoptimized] target(s) in 3.15s
Documenting stage0 std (x86_64-pc-windows-msvc)
Documenting core v0.0.0 (R:\Rust\rust\library\core)
Finished release [optimized] target(s) in 36.42s
Checking core v0.0.0 (R:\Rust\rust\library\core)
Checking rustc-std-workspace-core v1.99.0 (R:\Rust\rust\library\rustc-std-workspace-core)
Checking compiler_builtins v0.1.79
Documenting alloc v0.0.0 (R:\Rust\rust\library\alloc)
error: unresolved link to `BTreeMap::bulk_build_from_sorted_iter`
--> library\alloc\src\collections\btree\dedup_sorted_iter.rs:6:15
|
6 | /// Used by [`BTreeMap::bulk_build_from_sorted_iter`].
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ no item named `BTreeMap` in scope
|
= note: `-D rustdoc::broken-intra-doc-links` implied by `-D warnings`
error: could not document `alloc`
```
safe transmute: use `Assume` struct to provide analysis options
This task was left as a TODO in #92268; resolving it brings [`BikeshedIntrinsicFrom`](https://doc.rust-lang.org/nightly/core/mem/trait.BikeshedIntrinsicFrom.html) more in line with the API defined in [MCP411](https://github.com/rust-lang/compiler-team/issues/411).
**Before:**
```rust
pub unsafe trait BikeshedIntrinsicFrom<
Src,
Context,
const ASSUME_ALIGNMENT: bool,
const ASSUME_LIFETIMES: bool,
const ASSUME_VALIDITY: bool,
const ASSUME_VISIBILITY: bool,
> where
Src: ?Sized,
{}
```
**After:**
```rust
pub unsafe trait BikeshedIntrinsicFrom<Src, Context, const ASSUME: Assume = { Assume::NOTHING }>
where
Src: ?Sized,
{}
```
`Assume::visibility` has also been renamed to `Assume::safety`, as library safety invariants are what's actually being assumed; visibility is just the mechanism by which it is currently checked (and that may change).
r? `@oli-obk`
---
Related:
- https://github.com/rust-lang/compiler-team/issues/411
- https://github.com/rust-lang/rust/issues/99571
Fix `std::collections::HashSet::drain` documentation
Hi!
`std::collections::HashSet::drain` contains small typo in the docstring.
I didn't read too much about the model of contributing to Rust, so merge this PR or close and fix the typo the right way :)
Thanks for Rust!
Windows RNG: Use `BCRYPT_RNG_ALG_HANDLE` by default
This only changes a small amount of actual code, the rest is documentation outlining the history of this module as I feel it will be relevant to any future issues that might crop up.
The code change is to use the `BCRYPT_RNG_ALG_HANDLE` [pseudo-handle](https://docs.microsoft.com/en-us/windows/win32/seccng/cng-algorithm-pseudo-handles) by default, which simply uses the default RNG. Previously we used `BCRYPT_USE_SYSTEM_PREFERRED_RNG` which has to load the system configuration and then find and load that RNG. I suspect this was the cause of failures on some systems (e.g. due to corrupted config). However, this is admittedly speculation as I can't reproduce the issue myself (and it does seem quite rare even in the wild). Still, removing a possible point of failure is likely worthwhile in any case.
r? libs
Support `#[unix_sigpipe = "inherit|sig_dfl"]` on `fn main()` to prevent ignoring `SIGPIPE`
When enabled, programs don't have to explicitly handle `ErrorKind::BrokenPipe` any longer. Currently, the program
```rust
fn main() { loop { println!("hello world"); } }
```
will print an error if used with a short-lived pipe, e.g.
% ./main | head -n 1
hello world
thread 'main' panicked at 'failed printing to stdout: Broken pipe (os error 32)', library/std/src/io/stdio.rs:1016:9
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
by enabling `#[unix_sigpipe = "sig_dfl"]` like this
```rust
#![feature(unix_sigpipe)]
#[unix_sigpipe = "sig_dfl"]
fn main() { loop { println!("hello world"); } }
```
there is no error, because `SIGPIPE` will not be ignored and thus the program will be killed appropriately:
% ./main | head -n 1
hello world
The current libstd behaviour of ignoring `SIGPIPE` before `fn main()` can be explicitly requested by using `#[unix_sigpipe = "sig_ign"]`.
With `#[unix_sigpipe = "inherit"]`, no change at all is made to `SIGPIPE`, which typically means the behaviour will be the same as `#[unix_sigpipe = "sig_dfl"]`.
See https://github.com/rust-lang/rust/issues/62569 and referenced issues for discussions regarding the `SIGPIPE` problem itself
See the [this](https://rust-lang.zulipchat.com/#narrow/stream/219381-t-libs/topic/Proposal.3A.20First.20step.20towards.20solving.20the.20SIGPIPE.20problem) Zulip topic for more discussions, including about this PR.
Tracking issue: https://github.com/rust-lang/rust/issues/97889
Uplift the `let_underscore` lints from clippy into rustc.
This PR resolves#97241.
This PR adds three lints from clippy--`let_underscore_drop`, `let_underscore_lock`, and `let_underscore_must_use`, which are meant to capture likely-incorrect uses of `let _ = ...` bindings (in particular, doing this on a type with a non-trivial `Drop` causes the `Drop` to occur immediately, instead of at the end of the scope. For a type like `MutexGuard`, this effectively releases the lock immediately, which is almost certainly the wrong behavior)
In porting the lints from clippy I had to copy over a bunch of utility functions from `clippy_util` that these lints also relied upon. Is that the right approach?
Note that I've set the `must_use` and `drop` lints to Allow by default and set `lock` to Deny by default (this matches the same settings that clippy has). In talking with `@estebank` he informed me to do a Crater run (I am not sure what type of Crater run to request here--I think it's just "check only"?)
On the linked issue, there's some discussion about using `must_use` and `Drop` together as a heuristic for when to warn--I did not implement this yet.
r? `@estebank`
Fix a bunch of typo
This PR will fix some typos detected by [typos].
I only picked the ones I was sure were spelling errors to fix, mostly in
the comments.
[typos]: https://github.com/crate-ci/typos
proc_macro/bridge: send diagnostics over the bridge as a struct
This removes some RPC when creating and emitting diagnostics, and
simplifies the bridge slightly.
After this change, there are no remaining methods which take advantage
of the support for `&mut` references to objects in the store as
arguments, meaning that support for them could technically be removed if
we wanted. The only remaining uses of immutable references into the
store are `TokenStream` and `SourceFile`.
r? `@eddyb`
Link “? operator” to relevant chapter in The Book
Before, the text simply asked people to use a symbol which is hard to
search for. Now the text links back to the chapter on error
propagation in The Book. That should help people find the relevant
keywords for further searches.
This PR will fix some typos detected by [typos].
I only picked the ones I was sure were spelling errors to fix, mostly in
the comments.
[typos]: https://github.com/crate-ci/typos
Before, the text simply asked people to use a symbol which is hard to
search for. Now the text links back to the chapter on error
propagation in The Book. That should help people find the relevant
keywords for further searches.
