Rollup of 5 pull requests
Successful merges:
- #103087 (Documentation BTreeMap::append's behavior for already existing keys)
- #103089 (Mark derived StructuralEq as automatically derived.)
- #103102 (Clarify the possible return values of `len_utf16`)
- #103109 (PhantomData: inline a macro that is used only once)
- #103120 (rustdoc: Do not expect `doc(primitive)` modules to always exist)
Failed merges:
r? `@ghost`
`@rustbot` modify labels: rollup
Clarify the possible return values of `len_utf16`
`char::len_utf16` always return 1 or 2. Clarify this in the docs, in the same way as `char::len_utf8`.
Documentation BTreeMap::append's behavior for already existing keys
`BTreeMap::append` overwrites existing values with new ones. This commit adds explicit documentation for that.
Rollup of 4 pull requests
Successful merges:
- #102857 (Add a regression test for #39137)
- #102953 (Improve docs for `struct_lint_level` function.)
- #103060 (rustdoc: make the help button a link to a page)
- #103115 (Clean up anchors.goml rustdoc GUI test)
Failed merges:
r? `@ghost`
`@rustbot` modify labels: rollup
Fix subst issues with return-position `impl Trait` in trait
1. Fix an issue where we were rebase impl substs onto trait method substs, instead of trait substs
2. Fix an issue where early-bound regions aren't being mapped correctly for RPITIT hidden types
Fixes#102301Fixes#102310Fixes#102334Fixes#102918
Fix missing explanation of where the borrowed reference is used when the same borrow occurs multiple times due to loop iterations
Fix#99824.
Problem of the issue:
If a borrow occurs in a loop, the borrowed reference could be invalidated at the same place at next iteration of the loop. When this happens, the point where the borrow occurs is the same as the intervening point that might invalidate the reference in the loop. This causes a problem for the current code finding the point where the resulting reference is used, so that the explanation of the cause will be missing. As the second point of "explain all errors in terms of three points" (see [leveraging intuition framing errors in terms of points"](https://rust-lang.github.io/rfcs/2094-nll.html#leveraging-intuition-framing-errors-in-terms-of-points), this explanation is very helpful for user to understand the error.
In the current implementation, the searching region for finding the location where the borrowed reference is used is limited to between the place where the borrow occurs and the place where the reference is invalidated. If those two places happen to be the same, which indicates that the borrow and invalidation occur at the same place in a loop, the search will fail.
One solution to the problem is when these two places are the same, find the terminator of the loop, and then use the location of the loop terminator instead of the location of the borrow for the region to find the place where the borrowed reference is used.
pretty: fix to print some lifetimes on HIR pretty-print
HIR pretty-printer doesn't seem to print some lifetimes in types. This PR fixes that.
Closes https://github.com/rust-lang/rust/issues/85089
Update pkg-config
I'd like to be able to cross-compile rustc in a scenario where it'd be really helpful to have cd3ccca7c3. I've done some test builds of the compiler on x86_64 linux, targeting x86_64 linux and aarch64 linux.
Add documentation about the memory layout of `UnsafeCell<T>`
The documentation for `UnsafeCell<T>` currently does not make any promises about its memory layout. This PR adds this documentation, namely that the memory layout of `UnsafeCell<T>` is the same as the memory layout of its inner `T`.
# Use case
Without this layout promise, the following cast would not be legally possible:
```rust
fn example<T>(ptr: *mut T) -> *const UnsafeCell<T> {
ptr as *const UnsafeCell<T>
}
```
A use case where this can come up involves FFI. If Rust receives a pointer over a FFI boundary which provides shared read-write access (with some form of custom synchronization), and this pointer is managed by some Rust struct with lifetime `'a`, then it would greatly simplify its (internal) API and safety contract if a `&'a UnsafeCell<T>` can be created from a raw FFI pointer `*mut T`. A lot of safety checks can be done when receiving the pointer for the first time through FFI (non-nullness, alignment, initialize uninit bytes, etc.) and these properties can then be encoded into the `&UnsafeCell<T>` type. Without this documentation guarantee, this is not legal today outside of the standard library.
# Caveats
Casting in the opposite direction is still not valid, even with this documentation change:
```rust
fn example2<T>(ptr: &UnsafeCell<T>) -> &mut T {
let t = ptr as *const UnsafeCell<T> as *mut T;
unsafe { &mut *t }
}
```
This is because the only legal way to obtain a mutable pointer to the contents of the shared reference is through [`UnsafeCell::get`](https://doc.rust-lang.org/std/cell/struct.UnsafeCell.html#method.get) and [`UnsafeCell::raw_get`](https://doc.rust-lang.org/std/cell/struct.UnsafeCell.html#method.raw_get). Although there might be a desire to also make this legal at some point in the future, that part is outside the scope of this PR. Also see this relevant [Zulip thread](https://rust-lang.zulipchat.com/#narrow/stream/136281-t-lang.2Fwg-unsafe-code-guidelines/topic/transmuting.20.26.20-.3E.20.26mut).
# Alternatives
Instead of adding a new documentation promise, it's also possible to add a new method to `UnsafeCell<T>` with signature `pub fn from_ptr_bikeshed(ptr: *mut T) -> *const UnsafeCell<T>` which indirectly only allows one-way casting to `*const UnsafeCell<T>`.
std: use `sync::Mutex` for internal statics
Since `sync::Mutex` is now `const`-constructible, it can be used for internal statics, removing the need for `sys_common::StaticMutex`. This adds some extra allocations on platforms which need to box their mutexes (currently SGX and some UNIX), but these will become unnecessary with the lock improvements tracked in #93740.
I changed the program argument implementation on Hermit, it does not need `Mutex` but can use atomics like some UNIX systems (ping `@mkroening` `@stlankes).`
Get rid of `rustc_query_description!`
**I am not entirely sure whether this is an improvement and would like to get your feedback on it.**
Helps with #96524.
Queries can provide an arbitrary expression for their description and their caching behavior. Before, these expressions where stored in a `rustc_query_description` macro emitted by the `rustc_queries` macro, and then used in `rustc_query_impl` to fill out the methods for the `QueryDescription` trait.
Instead, we now emit two new modules from `rustc_queries` containing the functions with the expressions. `rustc_query_impl` calls these functions now instead of invoking the macro.
Since we are now defining some of the functions in `rustc_middle::query`, we now need all the imports for the key types mthere as well.
r? `@cjgillot`
Rollup of 6 pull requests
Successful merges:
- #102773 (Use semaphores for thread parking on Apple platforms)
- #102884 (resolve: Some cleanup, asserts and tests for lifetime ribs)
- #102954 (Add missing checks for `doc(cfg_hide(...))`)
- #102998 (Drop temporaries created in a condition, even if it's a let chain)
- #103003 (Fix `suggest_floating_point_literal` ICE)
- #103041 (Update cargo)
Failed merges:
r? `@ghost`
`@rustbot` modify labels: rollup
Update cargo
12 commits in b8f30cb23c4e5f20854a4f683325782b7cff9837..b332991a57c9d055f1864de1eed93e2178d49440 2022-10-10 19:16:06 +0000 to 2022-10-13 22:05:28 +0000
- Differentiate the warning when an alias (built-in or user-defined) shadows an external subcommand (rust-lang/cargo#11170)
- chore: Update tests for latest clap (rust-lang/cargo#11235)
- feat(publish): Support 'publish.timeout' config behind '-Zpublish-timeout' (rust-lang/cargo#11230)
- Add missing edition (rust-lang/cargo#11231)
- doc(profiles): add module level doc (rust-lang/cargo#11219)
- refactor(publish): Clarify which SourceId is being used (rust-lang/cargo#11216)
- Add new SourceKind::SparseRegistry to differentiate sparse registries (rust-lang/cargo#11209)
- Fix deadlock when build scripts are waiting for input on stdin (rust-lang/cargo#11205)
- refactor: New variant `FeaturesFor::ArtifactDep` (rust-lang/cargo#11184)
- Fix rustdoc warning about unclosed HTML tag (rust-lang/cargo#11221)
- refactor(tests): Prepare for wait-for-publish test changes (rust-lang/cargo#11210)
- Add configuration option for controlling crates.io protocol (rust-lang/cargo#11215)
