a fn pointer doesn't implement `Fn`/`FnMut`/`FnOnce` if its return type isn't sized
I stumbled upon #83915 which hasn't received much attention recently, and I wanted to revive it since this is one existing soundness hole that seems pretty easy to fix.
I'm not actually sure that the [alternative approach described here](https://github.com/rust-lang/rust/pull/83915#issuecomment-823643322) is sufficient, given the `src/test/ui/function-pointer/unsized-ret.rs` example I provided below. Rebasing the branch mentioned in that comment and testing that UI test, it seems that we actually end up only observing that `str: !Sized` during monomorphization, whereupon we ICE. Even if we were to fix that ICE, ideally we'd be raising an error that a fn pointer is being used badly during _typecheck_ instead of monomorphization, hence adapting the original approach in #83915.
I am happy to close this if people would prefer we rebase the original PR and land that -- I am partly opening to be annoying and get people thinking about this unsoundness again ❤️😸
cc: `@estebank` and `@nikomatsakis`
r? types
Here's a link to the thread: https://rust-lang.zulipchat.com/#narrow/stream/144729-t-types/topic/PR.20.2383915/near/235421351 for more context.
Optimize `array::IntoIter`
`.into_iter()` on arrays was slower than it needed to be (especially compared to slice iterator) since it uses `Range<usize>`, which needs to handle degenerate ranges like `10..4`.
This PR adds an internal `IndexRange` type that's like `Range<usize>` but with a safety invariant that means it doesn't need to worry about those cases -- it only handles `start <= end` -- and thus can give LLVM more information to optimize better.
I added one simple demonstration of the improvement as a codegen test.
(`vec::IntoIter` uses pointers instead of indexes, so doesn't have this problem, but that only works because its elements are boxed. `array::IntoIter` can't use pointers because that would keep it from being movable.)
std: use `sync::RwLock` for internal statics
Since `sync::RwLock` is now `const`-constructible, it can be used for internal statics, removing the need for `sys_common::StaticRwLock`. This adds some extra allocations on platforms which need to box their locks (currently SGX and some UNIX), but these will become unnecessary with the lock improvements tracked in #93740.
Make the `normalize-overflow` rustdoc test actually do something
Since https://github.com/rust-lang/rust/pull/88679, rustdoc doesn't load crates eagerly. Add an explicit `extern crate` item to make sure the crate is loaded and the bug reproduces.
You can verify this fix by adding `// compile-flags: -Znormalize-docs` and running the test to make sure it gives an error.
Improve error for when query is unsupported by crate
This is an improvement to the error message mentioned on #101666. It seems like a good idea to also add [this link to the rustc-dev-guide](https://rustc-dev-guide.rust-lang.org/query.html), if explaining the query system in detail is a concern here, but I'm unsure if there is any restrictions on adding links to error messages.
`.into_iter()` on arrays was slower than it needed to be (especially compared to slice iterator) since it uses `Range<usize>`, which needs to handle degenerate ranges like `10..4`.
This PR adds an internal `IndexRange` type that's like `Range<usize>` but with a safety invariant that means it doesn't need to worry about those cases -- it only handles `start <= end` -- and thus can give LLVM more information to optimize better.
I added one simple demonstration of the improvement as a codegen test.
Since https://github.com/rust-lang/rust/pull/88679, rustdoc doesn't load crates eagerly.
Add an explicit `extern crate` item to make sure the crate is loaded and the bug reproduces.
You can verify this fix by adding `// compile-flags: -Znormalizing-docs` and running the test.
For this rule to have an actual effect, the border-bottom width needs
specified, elsewhere, without also specifying the color. This doesn't
happen. Ever since 88b137d5fe, every spot
where headers get a border assigned to them also assigns the color.
Rollup of 11 pull requests
Successful merges:
- #101389 (Tone down explanation on RefCell::get_mut)
- #101798 (Make `from_waker`, `waker` and `from_raw` unstably `const`)
- #101881 (Remove an unused struct field `late_bound`)
- #101904 (Add help for invalid inline argument)
- #101966 (Add unit test for identifier Unicode emoji diagnostics)
- #101979 (Update release notes for 1.64)
- #101985 (interpret: expose generate_stacktrace without full InterpCx)
- #102004 (Try to clarify what's new in 1.64.0 ffi types)
- #102005 (rustdoc: remove unused CSS `td.summary-column`)
- #102017 (Add all submodules to the list of directories tidy skips)
- #102019 (Remove backed off PRs from relnotes)
Failed merges:
r? `@ghost`
`@rustbot` modify labels: rollup
This class was originally added in 73b97c7e7c
to support hiding and showing the item, because `main.js` went through all
`docblock` elements in the DOM and added toggles to them.
73b97c7e7c/src/librustdoc/html/static/main.js (L1856-L1867)
The `item-decl` is no longer auto-hidden since
c96f86de30 removed it.
`item-decl` used to be called `type-decl`: that name was changed in
8b7a2dd462.
The `docblock` class is no longer used for implementing toggles, since
rustdoc switched to using `<details>` elements.
Avoid duplicating StorageLive in let-else
cc `@est31`
Fix#101867Fix#101932#101410 introduced directives to activate storages of bindings in let-else earlier. However, since it is using the machinery of `match` and friends for pattern matching and binding, those storages are activated for the second time. This PR adjusts this behavior and avoid the duplicated activation for let-else statements.
Add all submodules to the list of directories tidy skips
Tidy contains a blacklist of directories that it is not visiting. This list is also used by the `replace-version-placeholder` tool added by #100591 , to determine the directories to do its replacement from. Generally, tidy does not check submodules, but this is not done consistently for all submodules. This PR adds the submodules that were previously missing, so that the `replace-version-placeholder` tool does not attempt to change content of the books. This was needed because `rustc-dev-guide` contains the placeholder, leading to #102014.
Fixes#102014
interpret: expose generate_stacktrace without full InterpCx
In Miri we sometimes want to emit diagnostics without having a full `&InterpCx` available. To avoid duplicating code, this adds a way to get a stacktrace from an arbitrary slice of interpreter frames, that Miri can use with access to just a thread manager.
Update release notes for 1.64
This PR makes a few updates to the release notes to bring them on-par with the release notes of other releases:
* The wording on some items has been changed to be more consistent and better describe what each change means, rather than using the PR title.
* Items that were also in the compatibility notes have been removed from the other sections, only keeping them in the compat notes.
* Diagnostics and ICE fixes have been removed from the notes.
* The cargo section has been made more consistent.
r? ``@Mark-Simulacrum``
cc ``@rust-lang/release`` ``@joshtriplett``
Add unit test for identifier Unicode emoji diagnostics
Seems current diagnostics has some support for emoji usages, however it seems outdated and incomplete. This adds a simple unit test to showcase the status quo.
Add help for invalid inline argument
Fixes#101712
Removed 1 part of the test as its identical with another one. Do let me know if this is undesirable, so I can revert those changes.
Make `from_waker`, `waker` and `from_raw` unstably `const`
Make
- `Context::from_waker`
- `Context::waker`
- `Waker::from_raw`
`const`.
Also added a small test.
Tone down explanation on RefCell::get_mut
The language around `RefCell::get_mut` is remarkably sketchy and especially to the novice seems to quite strongly discourage using the method ("be cautious", "Also, please be aware", "special circumstances", "usually not what you want"). It was added six years ago in #40634 due to confusion about when to use `get_mut` and `borrow_mut`.
While its signature limits the use-cases for `get_mut`, there is no chance for a safety footgun, and readers can be made aware of `borrow_mut` more softly. I've also just sent a [PR](https://github.com/rust-lang/rust-clippy/issues/9044) to lint situations where `get_mut` could be used to improve ergonomics and performance.
So this PR tones down the language around `get_mut` and also brings it more in line with [`std::sync::Mutex::get_mut()`](https://doc.rust-lang.org/stable/std/sync/struct.Mutex.html#method.get_mut).
