Tweak Library Integer Division Docs
Improved the documentation and diagnostics related to panicking in the division-like methods in std:
* For signed methods that can overflow, clarified "results in overflow" to "self is -1 and rhs is Self::MIN." This is more concise than saying "results in overflow" and then explaining how it could overflow.
* For floor/ceil_div, corrected the documentation and made it more like the documentation in other methods.
* For signed methods that can overflow, explicitly mention that they are not affected by compiler flags.
* Removed all unused rustc_inherit_overflow_checks attributes. The non-division-like operations will never overflow.
* Added track_caller attributes to all methods that can panic. The panic messages will always be correct. For example, division methods all have / before %.
* Edited the saturating_div documentation to be consistent with similar methods.
Explanation that fields are being used when deriving `(Partial)Ord` on enums
When deriving `std::cmp::Ord` or `std::cmp::PartialOrd` on enums, their fields are compared if the variants are equal.
This means that the last assertion in the following snipped panics.
```rust
use std::cmp::{PartialEq, Eq, PartialOrd, Ord};
#[derive(PartialEq, Eq, PartialOrd, Ord)]
enum Sizes {
Small(usize),
Big(usize),
}
fn main() {
let a = Sizes::Big(3);
let b = Sizes::Big(5);
let c = Sizes::Small(10);
assert!( c < a);
assert_eq!(a, c);
}
```
This is more often expected behavior than not, and can be easily circumvented, as discussed in [this thread](https://users.rust-lang.org/t/how-to-sort-enum-variants/52291/4).
But it is addressed nowhere in the documentation, yet.
So I stumbled across this, as I personally did not expect fields being used in `PartialOrd`.
I added the explanation to the documentation.
Add `#[track_caller]` to the "From implies Into" impl
This pr implements what was mentioned in https://github.com/rust-lang/rust/issues/77474#issuecomment-1074480790
This follows from my URLO https://users.rust-lang.org/t/104497
```rust
#![allow(warnings)]
fn main() {
// Gives a good location
let _: Result<(), Loc> = dbg!(Err::<(), _>(()).map_err(|e| e.into()));
// still doesn't work, gives location of `FnOnce::call_once()`
let _: Result<(), Loc> = dbg!(Err::<(), _>(()).map_err(Into::into));
}
#[derive(Debug)]
pub struct Loc {
pub l: &'static std::panic::Location<'static>,
}
impl From<()> for Loc {
#[track_caller]
fn from(_: ()) -> Self {
Loc {
l: std::panic::Location::caller(),
}
}
}
```
Implement iterator specialization traits on more adapters
This adds
* `TrustedLen` to `Skip` and `StepBy`
* `TrustedRandomAccess` to `Skip`
* `InPlaceIterable` and `SourceIter` to `Copied` and `Cloned`
The first two might improve performance in the compiler itself since `skip` is used in several places. Constellations that would exercise the last point are probably rare since it would require an owning iterator that has references as Items somewhere in its iterator pipeline.
Improvements for `Skip`:
```
# old
test iter::bench_skip_trusted_random_access ... bench: 8,335 ns/iter (+/- 90)
# new
test iter::bench_skip_trusted_random_access ... bench: 2,753 ns/iter (+/- 27)
```
Rollup of 8 pull requests
Successful merges:
- #116090 (Implement strict integer operations that panic on overflow)
- #118811 (Use `bool` instead of `PartiolOrd` as return value of the comparison closure in `{slice,Iteraotr}::is_sorted_by`)
- #119081 (Add Ipv6Addr::is_ipv4_mapped)
- #119461 (Use an interpreter in MIR jump threading)
- #119996 (Move OS String implementation into `sys`)
- #120015 (coverage: Format all coverage tests with `rustfmt`)
- #120027 (pattern_analysis: Remove `Ty: Copy` bound)
- #120084 (fix(rust-analyzer): use new pkgid spec to compare)
r? `@ghost`
`@rustbot` modify labels: rollup
coverage: Format all coverage tests with `rustfmt`
As suggested by <https://github.com/rust-lang/rust/pull/119984#discussion_r1452856806>.
Test files in `tests/` are normally ignored by `x fmt`, but sometimes those files end up being run through `rustfmt` anyway, either by `rust-analyzer` or by hand.
When that happens, it's annoying to have to manually revert formatting changes that are unrelated to the actual changes being made. So it's helpful for the tests in the repository to already have standard formatting beforehand.
However, there are several coverage tests that deliberately use non-standard formatting, so that line counts reveal more information about where code regions begin and end. In those cases, we can use `#[rustfmt::skip]` to prevent that code from being disturbed.
``@rustbot`` label +A-code-coverage
Move OS String implementation into `sys`
Part of #117276. The new structure is really useful here, since we can easily eliminate a number of ugly `#[path]`-based imports.
In the future, it might be good to move the WTF-8 implementation directly to the OS string implementation, I cannot see it being used anywhere else. That is a story for another PR, however.
Use an interpreter in MIR jump threading
This allows to understand assignments of aggregate constants. This case appears more frequently with GVN promoting aggregates to constants.
Add Ipv6Addr::is_ipv4_mapped
This change consists of cherry-picking the content from the original PR[1], which got closed due to inactivity, and applying the following changes:
* Resolving merge conflicts (obviously)
* Linked to to_ipv4_mapped instead of to_ipv4 in the documentation (seems more appropriate)
* Added the must_use and rustc_const_unstable attributes the original didn't have
I think it's a reasonably useful method to have.
[1] https://github.com/rust-lang/rust/pull/86490
Use `bool` instead of `PartiolOrd` as return value of the comparison closure in `{slice,Iteraotr}::is_sorted_by`
Changes the function signature of the closure given to `{slice,Iteraotr}::is_sorted_by` to return a `bool` instead of a `PartiolOrd` as suggested by the libs-api team here: https://github.com/rust-lang/rust/issues/53485#issuecomment-1766411980.
This means these functions now return true if the closure returns true for all the pairs of values.
Implement strict integer operations that panic on overflow
This PR implements the first part of the ACP for adding panic on overflow style arithmetic operations (https://github.com/rust-lang/libs-team/issues/270), mentioned in #116064.
It adds the following operations on both signed and unsigned integers:
- `strict_add`
- `strict_sub`
- `strict_mul`
- `strict_div`
- `strict_div_euclid`
- `strict_rem`
- `strict_rem_euclid`
- `strict_neg`
- `strict_shl`
- `strict_shr`
- `strict_pow`
Additionally, signed integers have:
- `strict_add_unsigned`
- `strict_sub_unsigned`
- `strict_abs`
And unsigned integers have:
- `strict_add_signed`
The `div` and `rem` operations are the same as normal division and remainder but are added for completeness similar to the corresponding `wrapping_*` operations.
I'm not sure if I missed any operations, I basically found them from the `wrapping_*` and `checked_*` operations on both integer types.
Don't forget that the lifetime on hir types is `'tcx`
This PR just tracks the `'tcx` lifetime to wherever the original objects actually have that lifetime. This code is needed for https://github.com/rust-lang/rust/pull/107606 (now #120131) so that `ast_ty_to_ty` can invoke `lit_to_const` on an argument passed to it. Currently the argument is `&hir::Ty<'_>`, but after this PR it is `&'tcx hir::Ty<'tcx>`.
Tweak the threshold for chunked swapping
Thanks to `@AngelicosPhosphoros` for the tests here, which I copied from #98892.
This is an experiment as a simple alternative to that PR that just tweaks the existing threshold, since that PR showed that 3×Align (like `String`) currently doesn't work as well as it could.
Rollup of 6 pull requests
Successful merges:
- #119997 (Fix impl stripped in rustdoc HTML whereas it should not be in case the impl is implemented on a type alias)
- #120000 (Ensure `callee_id`s are body owners)
- #120063 (Remove special handling of `box` expressions from parser)
- #120116 (Remove alignment-changing in-place collect)
- #120138 (Increase vscode settings.json `git.detectSubmodulesLimit`)
- #120169 (Spelling fix)
r? `@ghost`
`@rustbot` modify labels: rollup
Remove alignment-changing in-place collect
This removes the alignment-changing in-place collect optimization introduced in #110353
Currently stable users can't benefit from the optimization because GlobaAlloc doesn't support alignment-changing realloc and neither do most posix allocators. So in practice it has a negative impact on performance.
Explanation from https://github.com/rust-lang/rust/issues/120091#issuecomment-1899071681:
> > You mention that in case of alignment mismatch -- when the new alignment is less than the old -- the implementation calls `mremap`.
>
> I was trying to note that this isn't really the case in practice, due to the semantics of Rust's allocator APIs. The only use of the allocator within the `in_place_collect` implementation itself is [a call to `Allocator::shrink()`](db7125f008/library/alloc/src/vec/in_place_collect.rs (L299-L303)), which per its documentation [allows decreasing the required alignment](https://doc.rust-lang.org/1.75.0/core/alloc/trait.Allocator.html). However, in stable Rust, the only available `Allocator` is [`Global`](https://doc.rust-lang.org/1.75.0/alloc/alloc/struct.Global.html), which delegates to the registered `GlobalAlloc`. Since `GlobalAlloc::realloc()` [cannot change the required alignment](https://doc.rust-lang.org/1.75.0/core/alloc/trait.GlobalAlloc.html#method.realloc), the implementation of [`<Global as Allocator>::shrink()`](db7125f008/library/alloc/src/alloc.rs (L280-L321)) must fall back to creating a brand-new allocation, `memcpy`ing the data into it, and freeing the old allocation, whenever the alignment doesn't remain exactly the same.
>
> Therefore, the underlying allocator, provided by libc or some other source, has no opportunity to internally `mremap()` the data when the alignment is changed, since it has no way of knowing that the allocation is the same.
Remove special handling of `box` expressions from parser
#108471 added a temporary hack to parse `box expr`. It's been almost a year since then, so I think it's safe to remove the special handling.
As a drive-by cleanup, move `parser/removed-syntax*` tests to their own directory.
Fix impl stripped in rustdoc HTML whereas it should not be in case the impl is implemented on a type alias
Fixes#119015.
I talked about it a bit with ```@petrochenkov.``` They might change what `EffectiveVisibilities` return for impl items like this one and make them not only reachable but also re-exported, which would fix this case. It could also potentially break other things, so it'll be done whenever they can and then we can check together.
Surprisingly, this fix is making rustdoc even closer to rustc in term of errors (the CI currently fails because currently accepted broken codes aren't working anymore with this change). Not sure exactly why though. This is linked to https://github.com/rust-lang/rust/pull/110631 from what I could find.
So either I'm missing something here, or we consider it's ok and we consider the failing tests as "should fail" and I'll update `rustdoc-ui` ones.
r? ```@notriddle```
internal: add `max_line_length` to `.editorconfig`
This helps with setting proper visual guides/rulers for the right margin in some editors/IDEs (e.g. CLion)
Avoid code generation for ThinVec<Diagnostic>'s destructor in the query system
This avoids 2 instances of the destructor of `ThinVec<Diagnostic>` from being included in `execute_job`. It also outlines the cold branch in `store_side_effects` / `store_side_effects_for_anon_node`.
perf: Don't track specific live points for promoteds
We don't query this information out of the promoted (it's basically a single "unit" regardless of the complexity within it) and this saves on re-initializing the SparseIntervalMatrix's backing IndexVec with mostly empty rows for all of the leading regions in the function. Typical promoteds will only contain a few regions that need up be uplifted, while the parent function can have thousands.
For a simple function repeating println!("Hello world"); 50,000 times this reduces compile times from 90 to 15 seconds in debug mode. The previous implementations re-initialization led to an overall roughly n^2 runtime as each promoted initialized slots for ~n regions, now we scale closer to linearly (5000 hello worlds takes 1.1 seconds).
cc https://github.com/rust-lang/rust/issues/50994, https://github.com/rust-lang/rust/issues/86244
Don't use `ReErased` to detect type test promotion failed
Using `ReErased` here is convenient because it implicitly stores the state that we are explicitly recording with the `failed` variable now, but I also think it adds a tiny bit of complexity that is not worth it.
r? `@aliemjay`
`single_use_lifetimes`: Don't suggest deleting lifetimes with bounds
Closes#117965
```
9 | pub fn get<'b: 'a>(&'b self) -> &'a str {
| ^^ -- ...is used only here
| |
| this lifetime...
```
In this example, I think the `&'b self` can be replaced with the bound itself, yielding `&'a self`, but this would require a deeper refactor. Happy to do as a follow-on PR if desired.
Teach tidy about line/col information for malformed features
This makes it significantly easier to find the specific feature, since you can now just click it in the command line of your IDE
Avoid ICEs in trait names without `dyn`
Check diagnostic is error before downgrading. Fix#119633.
Account for traits using self-trait by name without `dyn`. Fix#119652.
Expose Obligations created during type inference.
This PR is a first pass at exposing the trait obligations generated and solved for during the type-check progress. Exposing these obligations allows for rustc plugins to use the public interface for proof trees (provided by the next gen trait solver).
The changes proposed track *all* obligations during the type-check process, this is desirable to not only look at the trees of failed obligations, but also those of successfully proved obligations. This feature is placed behind an unstable compiler option `track-trait-obligations` which should be used together with the `next-solver` option. I should note that the main interface is the function `inspect_typeck` made public in `rustc_hir_typeck/src/lib.rs` which allows the caller to provide a callback granting access to the `FnCtxt`.
r? `@lcnr`
