Rollup of 7 pull requests
Successful merges:
- #98839 (Add assertion that `transmute_copy`'s U is not larger than T)
- #98998 (Remove branch target prologues from `#[naked] fn`)
- #99198 (add missing null ptr check in alloc example)
- #99344 (rustdoc: avoid inlining items with duplicate `(type, name)`)
- #99351 (Use `typeck_results` to get accurate qpath res for arg mismatch error)
- #99378 (interpret/visitor: add missing early return)
- #99394 (Add regression test for #95230)
Failed merges:
r? `@ghost`
`@rustbot` modify labels: rollup
Use `typeck_results` to get accurate qpath res for arg mismatch error
Improves error message from "function" to actually what we're calling (e.g. enum variant constrcutor) in a few cases 😸
add missing null ptr check in alloc example
`alloc` can return null on OOM, if I understood correctly. So we should never just deref a pointer we get from `alloc`.
Remove branch target prologues from `#[naked] fn`
This patch hacks around rust-lang/rust#98768 for now via injecting appropriate attributes into the LLVMIR we emit for naked functions. I intend to pursue this upstream so that these attributes can be removed in general, but it's slow going wading through C++ for me.
Add assertion that `transmute_copy`'s U is not larger than T
This is called out as a safety requirement in the docs, but because knowing this can be done at compile time and constant folded (just like the `align_of` branch is removed), we can just panic here.
I've looked at the asm (using `cargo-asm`) of a function that both is correct and incorrect, and the panic is completely removed, or is unconditional, without needing build-std.
I don't expect this to cause much breakage in the wild. I scanned through https://miri.saethlin.dev/ub for issues that would look like this (error: Undefined Behavior: memory access failed: alloc1768 has size 1, so pointer to 8 bytes starting at offset 0 is out-of-bounds), but couldn't find any.
That doesn't rule out it happening in crates tested that fail earlier for some other reason, though, but it indicates that doing this is rare, if it happens at all. A crater run for this would need to be build and test, since this is a runtime thing.
Also added a few more transmute_copy tests.
`replace_bound_vars` fast path: check predicates, don't check consts
split out from #98900
`ty::Const` doesn't have precomputed type flags, so
computing `has_vars_bound_at_or_above` for constants
requires us to visit the const and its contained types
and constants. A noop fold should be pretty much equally as
fast so removing it prevents us from walking the constant twice
in case it contains bound vars.
r? `@jackh726`
Rearrange slice::split_mut to remove bounds check
Closes https://github.com/rust-lang/rust/issues/86313
Turns out that all we need to do here is reorder the bounds checks to convince LLVM that all the bounds checks can be removed. It seems like LLVM just fails to propagate the original length information past the first bounds check and into the second one. With this implementation it doesn't need to, each check can be proven inbounds based on the one immediately previous.
I've gradually convinced myself that this implementation is unambiguously better based on the above logic, but maybe this is still deserving of a codegen test?
Also the mentioned borrowck limitation no longer seems to exist.
`arena > Rc` for query results
The `Rc`s have to live for the whole duration as their count cannot go below 1 while stored as part of the query results.
By storing them in an arena we should save a bit of memory because we don't have as many independent allocations and also don't have to clone the `Rc` anymore.
Don't pass InferCtxt to WfPredicates
Simple cleanup. Infer vars will get passed up as obligations and shallowed resolved later. This actually improves one test output.
Rollup of 6 pull requests
Successful merges:
- #98383 (Remove restrictions on compare-exchange memory ordering.)
- #99350 (Be more precise when suggesting removal of parens on unit ctor)
- #99356 (Do not constraint TAITs when checking impl/trait item compatibility)
- #99360 (Do not ICE when we have `-Zunpretty=expanded` with invalid ABI)
- #99373 (Fix source code sidebar tree auto-expand)
- #99374 (Fix doc for `rchunks_exact`)
Failed merges:
r? `@ghost`
`@rustbot` modify labels: rollup
Fix source code sidebar tree auto-expand
Here is the bug:
It was happening because as soon as we found the file (from the URL), every item following it was then opened, even if it wasn't supposed to.
The GUI test ensures that it doesn't happen by adding two nested levels and ensuring only this path is "open".
r? ``@notriddle``
Do not constraint TAITs when checking impl/trait item compatibility
Check out the UI test for the example.
Open to other approaches to fix this issue -- ideally we _would_ be able to collect this opaque type constraint in a way to use it in `find_opaque_ty_constraints`, so we can report a better mismatch error in the incompatible case, and just allow it in the compatible case. But that seems like a bigger refactor, so I wouldn't want to start it unless someone else thought it was a good idea.
cc #99348
r? ``@oli-obk``
Be more precise when suggesting removal of parens on unit ctor
* Fixes#99240 by only suggesting to remove parens on path exprs, not arbitrary expressions with enum type
* Generalizes by suggesting removal of parens on unit struct, too, because why not?
Use ICF (identical code folding) for building rustc
It seems that ICF (identical code folding) is able to remove duplicated functions created by monomorphization from binaries, resulting in smaller binary size and better i-cache utilization. Let's see if it helps for `rustc`.
I'm not sure if `lld` is even used for linking `rustc` on the Linux `dist` builder, let's see.
Use constant eval to do strict mem::uninit/zeroed validity checks
I'm not sure about the code organisation here, I just dumped the check in rustc_const_eval at the root. Not hard to move it elsewhere, in any case.
Also, this means cranelift codegen intrinsics lose the strict checks, since they don't seem to depend on rustc_const_eval, and I didn't see a point in keeping around two copies.
I also left comments in the is_zero_valid methods about "uhhh help how do i do this", those apply to both methods equally.
Also rustc_codegen_ssa now depends on rustc_const_eval... is this okay?
Pinging `@RalfJung` since you were the one who mentioned this to me, so I'm assuming you're interested.
Haven't had a chance to run full tests on this since it's really warm, and it's 1AM, I'll check out any failures/comments in the morning :)
Implement `fmt::Write` for `OsString`
This allows to format into an `OsString` without unnecessary
allocations. E.g.
```
let mut temp_filename = path.into_os_string();
write!(&mut temp_filename, ".tmp.{}", process::id());
```
