DepGraphQuery: correctly skip adding edges with not-yet-added nodes
Fixes https://github.com/rust-lang/rust/issues/142152.
The current logic already skips some edges, so I'm not sure how critical it is to have *all* the edges recorded, the logic seems to only be used for debug dumping.
Recording all edges requires supporting holes in the `LinkedGraph` data structure, to add nodes and edges out of order, https://github.com/rust-lang/rust/pull/151821 implements that at cost of complicating the data structure.
Port #[rustc_test_marker] to the attribute parser
Tracking issue: https://github.com/rust-lang/rust/issues/131229
Targets:
Const is for normal tests (const test::TestDescAndFn is inserted before the test fn)
Const/Static/Fn is for custom_test_framework's #[test_case] e.g. tests/ui/custom_test_frameworks/full.rs
r? @JonathanBrouwer
Again I left the use-sites as is since they are early uses.
Don't ICE on layout error in vtable computation
Fixesrust-lang/rust#152030.
Note: I'm including a more general testcase that doesn't use the feature in the original report, but only reproduces with debuginfo disabled. Does it make sense to also include the original testcase?
Make operational semantics of pattern matching independent of crate and module
The question of "when does matching an enum against a pattern of one of its variants read its discriminant" is currently an underspecified part of the language, causing weird behavior around borrowck, drop order, and UB.
Of course, in the common cases, the discriminant must be read to distinguish the variant of the enum, but currently the following exceptions are implemented:
1. If the enum has only one variant, we currently skip the discriminant read.
- This has the advantage that single-variant enums behave the same way as structs in this regard.
- However, it means that if the discriminant exists in the layout, we can't say that this discriminant being invalid is UB. This makes me particularly uneasy in its interactions with niches – consider the following example ([playground](https://play.rust-lang.org/?version=stable&mode=debug&edition=2024&gist=5904a6155cbdd39af4a2e7b1d32a9b1a)), where miri currently doesn't detect any UB (because the semantics don't specify any):
<details><summary>Example 1</summary>
```rust
#![allow(dead_code)]
use core::mem::{size_of, transmute};
#[repr(u8)]
enum Inner {
X(u8),
}
enum Outer {
A(Inner),
B(u8),
}
fn f(x: &Inner) {
match x {
Inner::X(v) => {
println!("{v}");
}
}
}
fn main() {
assert_eq!(size_of::<Inner>(), 2);
assert_eq!(size_of::<Outer>(), 2);
let x = Outer::B(42);
let y = &x;
f(unsafe { transmute(y) });
}
```
</details>
2. For the purpose of the above, enums with marked with `#[non_exhaustive]` are always considered to have multiple variants when observed from foreign crates, but the actual number of variants is considered in the current crate.
- This means that whether code has UB can depend on which crate it is in: https://github.com/rust-lang/rust/issues/147722
- In another case of `#[non_exhaustive]` affecting the runtime semantics, its presence or absence can change what gets captured by a closure, and by extension, the drop order: https://github.com/rust-lang/rust/issues/147722#issuecomment-3674554872
- Also at the above link, there is an example where removing `#[non_exhaustive]` can cause borrowck to suddenly start failing in another crate.
3. Moreover, we currently make a more specific check: we only read the discriminant if there is more than one *inhabited* variant in the enum.
- This means that the semantics can differ between `foo<!>`, and a copy of `foo` where `T` was manually replaced with `!`: rust-lang/rust#146803
- Moreover, due to the privacy rules for inhabitedness, it means that the semantics of code can depend on the *module* in which it is located.
- Additionally, this inhabitedness rule is even uglier due to the fact that closure capture analysis needs to happen before we can determine whether types are uninhabited, which means that whether the discriminant read happens has a different answer specifically for capture analysis.
- For the two above points, see the following example ([playground](https://play.rust-lang.org/?version=nightly&mode=debug&edition=2024&gist=a07d8a3ec0b31953942e96e2130476d9)):
<details><summary>Example 2</summary>
```rust
#![allow(unused)]
mod foo {
enum Never {}
struct PrivatelyUninhabited(Never);
pub enum A {
V(String, String),
Y(PrivatelyUninhabited),
}
fn works(mut x: A) {
let a = match x {
A::V(ref mut a, _) => a,
_ => unreachable!(),
};
let b = match x {
A::V(_, ref mut b) => b,
_ => unreachable!(),
};
a.len(); b.len();
}
fn fails(mut x: A) {
let mut f = || match x {
A::V(ref mut a, _) => (),
_ => unreachable!(),
};
let mut g = || match x {
A::V(_, ref mut b) => (),
_ => unreachable!(),
};
f(); g();
}
}
use foo::A;
fn fails(mut x: A) {
let a = match x {
A::V(ref mut a, _) => a,
_ => unreachable!(),
};
let b = match x {
A::V(_, ref mut b) => b,
_ => unreachable!(),
};
a.len(); b.len();
}
fn fails2(mut x: A) {
let mut f = || match x {
A::V(ref mut a, _) => (),
_ => unreachable!(),
};
let mut g = || match x {
A::V(_, ref mut b) => (),
_ => unreachable!(),
};
f(); g();
}
```
</details>
In light of the above, and following the discussion at rust-lang/rust#138961 and rust-lang/rust#147722, this PR ~~makes it so that, operationally, matching on an enum *always* reads its discriminant.~~ introduces the following changes to this behavior:
- matching on a `#[non_exhaustive]` enum will always introduce a discriminant read, regardless of whether the enum is from an external crate
- uninhabited variants now count just like normal ones, and don't get skipped in the checks
As per the discussion below, the resolution for point (1) above is that it should land as part of a separate PR, so that the subtler decision can be more carefully considered.
Note that this is a breaking change, due to the aforementioned changes in borrow checking behavior, new UB (or at least UB newly detected by miri), as well as drop order around closure captures. However, it seems to me that the combination of this PR with rust-lang/rust#138961 should have smaller real-world impact than rust-lang/rust#138961 by itself.
Fixesrust-lang/rust#142394Fixesrust-lang/rust#146590Fixesrust-lang/rust#146803 (though already marked as duplicate)
Fixes parts of rust-lang/rust#147722Fixesrust-lang/miri#4778
r? @Nadrieril @RalfJung
@rustbot label +A-closures +A-patterns +T-opsem +T-lang
Most of the files within the `dep_graph` module can be moved wholesale
into `rustc_middle`. But two of them (`mod.rs` and `dep_node.rs`) have
the same name as existing files in `rustc_middle`, so for those I just
copied the contents into the existing files.
The commit also moves `QueryContext` and `incremental_verify_ich*`
because they are tightly intertwined with the dep graph code. And a
couple of error structs moved as well.
This includes the types `QueryInfo`, `QueryJob`, `QueryJobId`,
`QueryWaiter`, `QueryLatch`, and `QueryLatchInfo`.
`CycleError` and `QueryStack*` had to come along too, due to type
interdependencies. The `QueryStack*` types are put into a new submodule
`rustc_middle::query::stack`.
A couple of tiny polonius things
Here's a couple of tiny things I had ready to go @jackh726
- a tiny cleanup to avoid round-tripping through `Location`s to check for liveness, since we're already working with points
- while I was there, I fixed the doc which wasn't showing up properly (maybe a rustdoc or bootstrap bug when we build locally or during dist, either way, both don't show up correctly linked most of the time) for `PointIndex`es.
- and in the second commit slightly expand test coverage with [an example](https://internals.rust-lang.org/t/get-mut-map-back-from-entry-api/24003) that would have needed stdlib changes (cc author @Darksonn for visibility here)
More soon.
r? @jackh726
rustdoc: more js cleanup
Continuing the effort of removing `@ts-expect-error` from the codebase wherever possible, this time focusing on `main.js`. Found some oddities with `register_type_impls`, fixed most of them, but the one that I couldn't figure out is what's going on with `sidebarTraitList`. It's queried, then if there are any trait imps, unconditionally overwritten, then latter code assumes that one of these two things has initialized it, but it's not obvious why this would be the case, or if there's a reason this wasn't done in a more straightforwards way.
r? @GuillaumeGomez
improve associated-type suggestions from bounds
Should address invalid suggestions I could come up with, but the suggestion is too hand-crafted and invalid patterns may exist.
r? @estebank
Fix https://github.com/rust-lang/rust/issues/73321
Feed `ErrorGuaranteed` from late lifetime resolution errors through to bound variable resolution
If late lifetime resolution fails for whatever reason, forward to RBV the guarantee that an error was emitted - thereby eliminating the need for a "hack" to suppress subsequent/superfluous error diagnostics.
Fixesrust-lang/rust#152014
r? fmease
rustdoc: sort stable items first
Finally tackling this again now that the search system refactor is done. The tests and the general approach were taken from the original PR.
Set hidden visibility on naked functions in compiler-builtins
88b46460fa made builtin functions hidden, but it doesn't apply to naked functions, which are generated through a different code path.
This was discovered in rust-lang/rust#151486 where aarch64 outline atomics showed up in shared objects, overriding the symbols from compiler-rt.
Rollup of 14 pull requests
Successful merges:
- rust-lang/rust#152323 (Fix ICE in borrowck when recovering `fn_sig` for `-> _`)
- rust-lang/rust#152469 (Remove unused features)
- rust-lang/rust#152515 (Extract `DepKindVTable` constructors to their own module)
- rust-lang/rust#152555 (Port `#[rustc_diagnostic_item]` to the new attribute parsers)
- rust-lang/rust#152218 (Report unconstrained region in hidden types lazily)
- rust-lang/rust#152356 (Improve the `inline_fluent!` macro)
- rust-lang/rust#152392 (Fix ICE in supertrait_vtable_slot when supertrait has missing generics)
- rust-lang/rust#152407 (Add regression test for type_const with unit struct ctor under mGCA)
- rust-lang/rust#152440 (Fix typos and grammar in compiler and build documentation)
- rust-lang/rust#152536 (bootstrap: add explicit UTF-8 encoding to text-mode open() calls)
- rust-lang/rust#152554 (Remove `deprecated_safe` and its corresponding feature gate)
- rust-lang/rust#152556 (doc: move riscv64a23-unknown-linux-gnu to tier 2)
- rust-lang/rust#152563 (Replace "bug" with "issue" in triagebot ping messages)
- rust-lang/rust#152565 (fix missleading error for tuple ctor)
Failed merges:
- rust-lang/rust#152512 (core: Implement feature `float_exact_integer_constants`)
- rust-lang/rust#152296 (Port `rust_nonnull_optimization_guaranteed` and `rustc_do_not_const_check` to the new attribute parser)
If late lifetime resolution fails for whatever reason, forward to RBV
the guarantee that an error was emitted - thereby eliminating the need
for a "hack" to suppress subsequent/superfluous error diagnostics.
