Rollup of 8 pull requests
Successful merges:
- #127179 (Print `TypeId` as hex for debugging)
- #127189 (LinkedList's Cursor: method to get a ref to the cursor's list)
- #127236 (doc: update config file path in platform-support/wasm32-wasip1-threads.md)
- #127297 (Improve std::Path's Hash quality by avoiding prefix collisions)
- #127308 (Attribute cleanups)
- #127354 (Describe Sized requirements for mem::offset_of)
- #127409 (Emit a wrap expr span_bug only if context is not tainted)
- #127447 (once_lock: make test not take as long in Miri)
r? `@ghost`
`@rustbot` modify labels: rollup
Make tidy problematic const checking fast again
fixes pathological tidy performance described in #127453 by reverting #127428
i think anyone can approve this ASAP, it makes working on this repo significantly worse.
once_lock: make test not take as long in Miri
Allocating 1000 list elements takes a while (`@zachs18` reported >5min), so let's reduce the iteration count when running in Miri. Unfortunately due to this clever `while let i @ 0..LEN =` thing, the count needs to be a constants, and constants cannot be shadowed, so we need to use another trick to hide the `cfg!(miri)` from the docs. (I think this loop condition may be a bit too clever, it took me a bit to decipher. Ideally this would be `while let i = ... && i < LEN`, but that is not stable yet.)
Emit a wrap expr span_bug only if context is not tainted
Fixes#127332
The ICE occurs because of this `span_bug`: 51917e2e69/compiler/rustc_hir_typeck/src/expr_use_visitor.rs (L732-L738)
which is triggered by the fact that we're trying to use an `enum` in a `with` expression instead of a `struct`.
The issue originates in commit 814bfe9335 from PR #127202. As per the title of that commit the ICEing code should not be reachable any more, but looks like it still is.
This PR changes the code so that the `span_bug` will be emitted only if the context is not tainted by a previous error.
Describe Sized requirements for mem::offset_of
The container doesn't have to be sized, but the field must be sized (at least until https://github.com/rust-lang/rust/issues/126151 is stable).
Improve std::Path's Hash quality by avoiding prefix collisions
This adds a bit rotation to the already existing state so that the same sequence of characters chunked at different offsets into separate path components results in different hashes.
The tests are from #127255Closes#127254
LinkedList's Cursor: method to get a ref to the cursor's list
We're already providing `.back()` & `.front()`, for which we hold onto a reference to the parent list, so why not share it? Useful for when you got `LinkedList` -> `CursorMut` -> `Cursor` and cannot take another ref to the list, even though you should be able to. This seems to be completely safe & sound.
The name is, of course, bikesheddable.
Print `TypeId` as hex for debugging
In <https://github.com/rust-lang/rust/pull/127134>, the `Debug` impl for `TypeId` was changed to print a single integer rather than a tuple. Change this again to print as hex for more concise and consistent formatting, as was suggested.
Result:
TypeId(0x1378bb1c0a0202683eb65e7c11f2e4d7)
Specialize `TrustedLen` for `Iterator::unzip()`
Don't check the capacity every time (and also for `Extend` for tuples, as this is how `unzip()` is implemented).
I did this with an unsafe method on `Extend` that doesn't check for growth (`extend_one_unchecked()`). I've marked it as perma-unstable currently, although we may want to expose it in the future so collections outside of std can benefit from it. Then specialize `Extend for (A, B)` for `TrustedLen` to call it.
An alternative way of implementing this is to have a semi-public trait (`#[doc(hidden)]` public, so collections outside of core can implement it) for `extend()` inside tuples, and specialize it from collections. However:
1. This looks more complex to me.
2. This prohibits the option of exposing this somewhen to collections outside of std, as we never expose specializations.
A concern that may arise with the current approach is that implementing `extend_one_unchecked()` correctly must also incur implementing `extend_reserve()`, otherwise you can have UB. This is a somewhat non-local safety invariant. However, I believe this is fine, since to have actual UB you must have unsafe code inside your `extend_one_unchecked()` that makes incorrect assumption, *and* not implement `extend_reserve()`. I've also documented this requirement.
**Benchmark:**
Code:
```rust
#[bench]
fn unzip(b: &mut Bencher) {
b.iter(|| {
for _ in 0..10_000 {
let v: (Vec<_>, VecDeque<_>) =
(black_box(0u32)..black_box(1_000)).map(|i| (i, i * 2)).unzip();
black_box(v);
}
});
}
```
Before:
```
unzip::unzip 14.17ms/iter +/- 374.85µs
```
After:
```
unzip::unzip 5.33ms/iter +/- 164.54µs
```
Currently the second element is a `Vec<(FlatToken, Spacing)>`. But the
vector always has zero or one elements, and the `FlatToken` is always
`FlatToken::AttrTarget` (which contains an `AttributesData`), and the
spacing is always `Alone`. So we can simplify it to
`Option<AttributesData>`.
An assertion in `to_attr_token_stream` can can also be removed, because
`new_tokens.len()` was always 0 or 1, which means than `range.len()`
is always greater than or equal to it, because `range.is_empty()` is
always false (as per the earlier assertion).
The only place it is meaningfully used is in a panic message in
`TokenStream::from_ast`. But `node.span()` doesn't need to be printed
because `node` is also printed and it must contain the span.
Bootstrap command refactoring: quality-of-life improvements (step 4)
Continuation of https://github.com/rust-lang/rust/pull/127120.
This PR simply introduce two new functions (`BootstrapCommand:run` and `command`) that make it a bit easier to use commands in bootstrap. It also adds several `#[must_use]` annotations. This shouldn't (hopefully) have any effect on behavior.
Especially the first commit IMO makes any code that runs commands more readable, and allows using the API in a fluent way, without needing to jump back and forth between the command and the `Build(er)`.
Tracking issue: https://github.com/rust-lang/rust/issues/126819
r? `@onur-ozkan`
Don't check the capacity every time (and also for `Extend` for tuples, as this is how `unzip()` is implemented).
I did this with an unsafe method on `Extend` that doesn't check for growth (`extend_one_unchecked()`). I've marked it as perma-unstable currently, although we may want to expose it in the future so collections outside of std can benefit from it. Then specialize `Extend for (A, B)` for `TrustedLen` to call it.
It may seem that an alternative way of implementing this is to have a semi-public trait (`#[doc(hidden)]` public, so collections outside of core can implement it) for `extend()` inside tuples, and specialize it from collections. However, it is impossible due to limitations of `min_specialization`.
A concern that may arise with the current approach is that implementing `extend_one_unchecked()` correctly must also incur implementing `extend_reserve()`, otherwise you can have UB. This is a somewhat non-local safety invariant. However, I believe this is fine, since to have actual UB you must have unsafe code inside your `extend_one_unchecked()` that makes incorrect assumption, *and* not implement `extend_reserve()`. I've also documented this requirement.
Don't try to label `ObligationCauseCode::CompareImplItem` for an RPITIT, since it has no name
The old (current) trait solver has a limitation that when a where clause in param-env must be normalized using the same where clause, then we get spurious errors in `normalize_param_env_or_error`. I don't think there's an issue tracking it, but it's the root cause for many of the "fixed-by-next-solver" labeled issues.
Specifically, these errors may occur when checking predicate entailment of the GAT that comes out of desugaring RPITITs. Since we use `ObligationCauseCode::CompareImplItem` for these predicates, we try calling `item_name` on an RPITIT which fails, since the RPITIT has no name.
We simply suppress this logic when we're reporting a predicate entailment error for an RPITIT. RPITITs should never have predicate entailment errors, *by construction*, but they may due to this bug in the old solver.
Addresses the ICE in #127331, though doesn't fix the underlying issue (which is fundamental to the old solver).
r? types
Uplift outlives components to `rustc_type_ir`
We need this to uplift `push_outlives_components`, since the elaborator uses `push_outlives_components` to elaborate type outlives obligations and I want to uplift elaboration.
This ends up reworking and inlining a fair portion of the `GenericArg::walk_shallow` function, whose only callsite was this one. I believe I got the logic correct, but may be worthwhile to look at it closely just in case. Unfortunately github was too dumb to understand that this is a rename + change -- I could also rework the git history to split the "copy the file over" part from the actual logical changes if that makes this easier to review.
r? lcnr
Elaboration tweaks
Removes `Filter::OnlySelfThatDefines` and reimplements `transitive_bounds_that_define_assoc_item` as a separate function, since I don't want to have to uplift that mode since it's both an implementation detail (only exists to avoid cycles in astconv) and requires exposing `Ident` as an associated type on `Interner`.
r? lcnr
offset_from, offset: clearly separate safety requirements the user needs to prove from corollaries that automatically follow
By landing https://github.com/rust-lang/rust/pull/116675 we decided that objects larger than `isize::MAX` cannot exist in the address space of a Rust program, which lets us simplify these rules.
For `offset_from`, we can even state that the *absolute* distance fits into an `isize`, and therefore exclude `isize::MIN`. This PR also changes Miri to treat an `isize::MIN` difference like the other isize-overflowing cases.
