This commit splits the `#[rustc_deny_explicit_impl(implement_via_object = ...)]` attribute
into two attributes `#[rustc_deny_explicit_impl]` and `#[rustc_do_not_implement_via_object]`.
This allows us to have special traits that can have user-defined impls but do not have the
automatic trait impl for trait objects (`impl Trait for dyn Trait`).
Rollup of 5 pull requests
Successful merges:
- #134366 (Fix logical error with what text is considered whitespace.)
- #134514 (Improve dependency_format a bit)
- #134519 (ci: use ubuntu `24` instead of `latest`)
- #134551 (coverage: Rename `basic_coverage_blocks` to just `graph`)
- #134553 (add member constraints comment)
r? `@ghost`
`@rustbot` modify labels: rollup
Instead use dcx.abort_if_error() or guar.raise_fatal() instead. These
guarantee that an error actually happened previously and thus we don't
silently abort.
coverage: Rename `basic_coverage_blocks` to just `graph`
During coverage instrumentation, this variable always holds the current function's coverage graph, which is a simplified view of its MIR control-flow graph. The new name is clearer in context, and also shorter.
---
This is purely a rename, so there is no functional change.
Improve dependency_format a bit
* Make `DependencyList` an `IndexVec` rather than emulating one using a `Vec` (which was off-by-one as LOCAL_CRATE was intentionally skipped)
* Update some comments for the fact that we now use `#[global_allocator]` rather than `extern crate alloc_system;`/`extern crate alloc_jemalloc;` for specifying which allocator to use. We still use a similar mechanism for the panic runtime, so refer to the panic runtime in those comments instead.
* An unrelated refactor to `create_and_enter_global_ctxt` I forgot to include in https://github.com/rust-lang/rust/pull/134302. This refactor is too small to be worth it's own PR.
Fix logical error with what text is considered whitespace.
There appears to be a logical issue around what counts as leading white-space. There is code which does a subtraction assuming that no errors will be reported inside the leading whitespace. However we compute the length of that whitespace with std::char::is_whitespace and not rustc_lexer::is_whitespace. The former will include a no-break space while later will excluded it. We can only safely make the assumption that no errors will be reported in whitespace if it is all "Rust Standard" whitespace. Indeed an error does occur in unicode whitespace if it contains a no-break space. In that case the subtraction will cause a ICE (for a compiler in debug mode) as described in https://github.com/rust-lang/rust/issues/132918.
The arbitrary self types v2 work introduces a check for shadowed
methods, whereby a method in some "outer" smart pointer type may called
in preference to a method in the inner referent. This is bad if the
outer pointer adds a method later, as it may change behavior, so we
ensure we error in this circumstance.
It was intended that this new shadowing detection system only comes into
play for users who enable the `arbitrary_self_types` feature (or of
course everyone later if it's stabilized). It was believed that the
new deshadowing code couldn't be reached without building the custom
smart pointers that `arbitrary_self_types` enables, and therefore there
was no risk of this code impacting existing users.
However, it turns out that cunning use of `Pin::get_ref` can cause
this type of shadowing error to be emitted now. This commit adds a test
for this case.
During coverage instrumentation, this variable always holds the coverage graph,
which is a simplified view of the MIR control-flow graph. The new name is
clearer in context, and also shorter.
Rename `elem_offset` to `element_offset`
Tracking issue: #126769
Renames `slice::elem_offset` to `slice::element_offset` and improves the documentation of it and its related methods.
The current documentation can be misinterpreted (as explained [here](https://github.com/rust-lang/rust/issues/126769#issuecomment-2453363897)).
docs: Mention `spare_capacity_mut()` in `Vec::set_len`
I recently went down a small rabbit hole when trying to identify safe use of `Vec::set_len`. The solution was `Vec::spare_capacity_mut`. I think the docs on `Vec::set_len` benefit from mentioning this method.
A possible counter-argument could be that the [clippy lint `uninit_vec`](https://rust-lang.github.io/rust-clippy/master/index.html#/uninit_vec) already nudges people in the right direction. However, I think a working example on `Vec::set_len` is still beneficial.
Happy to hear your thoughts on the matter. 😊
Use `MixedBitSet`s in const qualif
These analyses' domains should be very homogeneous, having compressed bitmaps on huge cfgs should make a difference (and doesn’t have an impact on the smaller / regular cfgs in our benchmarks).
This is a >40% walltime reduction on [this stress test](https://github.com/Manishearth/icu4x_compile_sample) extracted from a real world ICU case, and a 10x or so max-rss reduction.
cc `@oli-obk` `@RalfJung`
Should help with (or fix) issue #134404.
Speed up `Parser::expected_tokens`
The constant pushing/clearing of `Parser::expected_tokens` during parsing is slow. This PR speeds it up greatly.
r? `@estebank`
Make sure we handle `backwards_incompatible_lint` drops appropriately in drop elaboration
In #131326, a new kind of scheduled drop (`drop_kind: DropKind::Value` + `backwards_incompatible_lint: true`) was added so that we could insert a new kind of no-op MIR statement (`backward incompatible drop`) for linting purposes.
These drops were intended to have *no side-effects*, but drop elaboration code forgot to handle these drops specially and they were handled otherwise as normal drops in most of the code. This ends up being **unsound** since we insert more than one drop call for some values, which means that `Drop::drop` could be called more than once.
This PR fixes this by splitting out the `DropKind::ForLint` and adjusting the code. I'm not totally certain if all of the places I've adjusted are either reachable or correct, but I'm pretty certain that it's *more* correct than it was previously.
cc `@dingxiangfei2009`
r? nikomatsakis
Fixes#134482
