Rollup of 11 pull requests
Successful merges:
- #62984 (Add lint for excess trailing semicolons)
- #63075 (Miri: Check that a ptr is aligned and inbounds already when evaluating `*`)
- #63490 (libsyntax: cleanup and refactor `pat.rs`)
- #63507 (When needing type annotations in local bindings, account for impl Trait and closures)
- #63509 (Point at the right enclosing scope when using `await` in non-async fn)
- #63528 (syntax: Remove `DummyResult::expr_only`)
- #63537 (expand: Unimplement `MutVisitor` on `MacroExpander`)
- #63542 (Add NodeId for Arm, Field and FieldPat)
- #63543 (Merge Variant and Variant_)
- #63560 (move test that shouldn't be in test/run-pass/)
- #63570 (Adjust tracking issues for `MaybeUninit<T>` gates)
Failed merges:
r? @ghost
Fix generator size regressions due to optimization
I tested the generator optimizations in #60187 and #61922 on the Fuchsia
build, and noticed that some small generators (about 8% of the async fns
in our build) increased in size slightly.
This is because in #60187 we split the fields into two groups, a
"prefix" non-overlap region and an overlap region, and lay them out
separately. This can introduce unnecessary padding bytes between the two
groups.
In every single case in the Fuchsia build, it was due to there being
only a single variant being used in the overlap region. This means that
we aren't doing any overlapping, period. So it's better to combine the
two regions into one and lay out all the fields at once, which is what
this change does.
r? @cramertj
cc @eddyb @Zoxc
This prevents uninhabited fields from "infecting" the abi and
largest_niche of the generator layout.
This fixes a latent bug, where an uninhabited field could be promoted to
the generator prefix and cause the entire generator to become
uninhabited.
Document that ManuallyDrop::drop should not called more than once
Double dropping is unsound (e.g. https://github.com/rust-lang/rust/issues/60977). This commit documents the fact that `ManuallyDrop::drop` should not be called multiple times on the same instance, as it might not be immediately obvious that this counts as a use of uninitialized data.
Less unsafe in the array example of MaybeUninit docs
I believe this is an acceptable way to initialize elements of `[MaybeUninit<T>; _]` arrays. Miri agrees. Conceptually, we are working at the array level, above the `MaybeUninit`, and as we are replacing it wholesale, this should pose no problem to soundness. And the code is easier to read.
r? @RalfJung
Double dropping is unsound (e.g. https://github.com/rust-lang/rust/issues/60977). This commit documents the fact that `ManuallyDrop::drop` should not be called multiple times on the same instance, as it might not be immediately obvious that this counts as a use of uninitialized data.
Revert "Set test flag when rustdoc is running with --test option"
Reverts https://github.com/rust-lang/rust/pull/59940.
It caused doctests in this repository to no longer be tested including all of the core crate.
Add std::mem::take as suggested in #61129
This PR implements #61129 by adding `std::mem::take`.
The added function is equivalent to:
```rust
std::mem::replace(dest, Default::default())
```
This particular pattern is fairly common, especially when implementing `Future::poll`, where you often need to yield an owned value in `Async::Ready`. This change allows you to write
```rust
return Async::Ready(std::mem::take(self.result));
```
instead of
```rust
return Async::Ready(std::mem::replace(self.result, Vec::new()));
```
EDIT: Changed name from `take` to `swap_default`.
EDIT: Changed name back to `take`.
The name `swap_default` was suggested but rejected. @SimonSapin observed
that this operation isn't really a `swap` in the same sense as
`mem::swap`; it is a `replace`. Since `replace_default` is a bit
misleading, the "correct" name would be `replace_with_default`, which is
quite verbose.
@czipperz observed that we have precedence for using `take` to refer to
methods that replace with `Default` in `Cell::take` and `Option::take`,
so this reverts commit 99c00591c29b472c8a87c4a9342d0e0c508647a3 to
return to the original `take` method name.
The name `replace_with_default` was suggested, but was deemed too
verbose, especially given that we use `take` for methods that replace
with `Default` elsewhere.
