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.
