report call site of inlined scopes for large assignment lints
Addressed issue: #121672
Tracking issue: #83518
r? `@oli-obk`
I tried to follow your comment about what to do [here](https://github.com/rust-lang/rust/issues/121672#issuecomment-1972783675). However, I'm totally unfamiliar with the code so far (this is my first contribution touching compiler code), so I apologize in advance if I did something stupid 😅
In particular, I'm not sure I use the _correct_ source scope to look for inline data, as there is a whole `IndexVec` of them. My changes definitely did something, as can be seen by the added ui test. However, the result is not as anticipated in the issue:
```
LL | let cell = std::cell::UnsafeCell::new(data);
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ value moved from here
```
instead of
```
LL | let cell = std::cell::UnsafeCell::new(data);
| ^^^^ value moved from here
```
raising my suspicion that maybe I got the wrong source scope.
Report higher-ranked trait error when higher-ranked projection goal fails in new solver
~~See HACK comment inline. Not actually sure if it should be marked as a *HACK*, b/c~~ it's kinda a legitimate case we want to care about unless we're going to make the proof tree visitor *smarter* about the leak check than the actual trait solver itself.
Encountered this while battling with `NiceRegionError`s in the old solver b/c I wondered what this code ended up giving us in the *new* solver as a comparison:
```rust
trait Foo {}
impl<T: FnOnce(&())> Foo for T {}
fn baz<T: Foo>() {}
fn main() {
baz::<fn(&'static ())>();
}
```
On master it's pretty bad:
```
error[E0271]: type mismatch resolving `<fn(&()) as FnOnce<(&(),)>>::Output == ()`
--> <source>:8:11
|
8 | baz::<fn(&'static ())>();
| ^^^^^^^^^^^^^^^ types differ
|
note: required for `fn(&'static ())` to implement `Foo`
--> <source>:3:22
|
3 | impl<T: FnOnce(&())> Foo for T {}
| ----------- ^^^ ^
| |
| unsatisfied trait bound introduced here
```
After this PR it's much better:
```
error[E0277]: the trait bound `fn(&'static ()): Foo` is not satisfied
--> /home/mgx/test.rs:8:11
|
8 | baz::<fn(&'static ())>();
| ^^^^^^^^^^^^^^^ the trait `for<'a> FnOnce(&'a ())` is not implemented for `fn(&'static ())`
|
= note: expected a closure with arguments `(&'static (),)`
found a closure with arguments `(&(),)`
note: required for `fn(&'static ())` to implement `Foo`
--> /home/mgx/test.rs:3:22
|
3 | impl<T: FnOnce(&())> Foo for T {}
| ----------- ^^^ ^
| |
| unsatisfied trait bound introduced here
note: required by a bound in `baz`
--> /home/mgx/test.rs:5:11
|
5 | fn baz<T: Foo>() {}
| ^^^ required by this bound in `baz`
```
r? lcnr
Don't call `Span::with_parent` on the good path in `has_stashed_diagnostic`
More unnecessary incurred span tracking avoided by not calling `span.with_parent(None)`. This is useless on its own but makes it much easier to fix other "span tracking on the good path" issues in the future.
r? oli-obk
Make the compiler suggest actual paths instead of visible paths if the visible paths are through any doc hidden path.
close#127011
Currently, when emitting a diagnostic about a valid trait, the compiler suggestes using visible paths of the trait even if they are through a doc hidden path. This PR updates the compiler to suggest actual paths in these cases.
Allow GVN to produce places and not just locals.
That may be too big of a hammer, as we may introduce new deref projections (possible UB footgun + probably not good for perf).
The second commit opts out of introducing projections that don't have a stable offset, which is probably what we want. Hence no new Deref and no new Index projections.
Fixes https://github.com/rust-lang/rust/issues/138936
cc `@scottmcm` `@dianqk`
Currently in case of a Trait object in closure parameter, the compiler
suggests either to use a reference, which is correct or to use an
`impl Trait` which is not. Do not emit this suggestion when the parameter
is part of a closure.
`resolve_ident_in_lexical_scope` checks for an empty name. Why is this
necessary? Because `parse_item_impl` can produce an `impl` block with an
empty trait name in some cases. This is pretty gross and very
non-obvious.
This commit avoids the use of the empty trait name. In one case the
trait name is instead pulled from `TyKind::ImplTrait`, which prevents
the output for `tests/ui/impl-trait/extra-impl-in-trait-impl.rs` from
changing. In the other case we just fail the parse and don't try to
recover. I think losing error recovery in this obscure case is worth
the code cleanup.
This change affects `tests/ui/parser/impl-parsing.rs`, which is split in
two, and the obsolete `..` syntax cases are removed (they are tested
elsewhere).
Instantiate higher-ranked transmute goal w/ placeholders before emitting sub-obligations
This avoids an ICE where we weren't keeping track of bound variables correctly in the `Freeze` obligations we emit for transmute goals. We could use `rebind` instead on that goal, but I think it's better just to instantiate the binder.
Fixes#139538
r? `@lcnr` or reassign
Improve presentation of closure signature mismatch from `Fn` trait goal
Flip the order of "expected" and "found" since that wasn't correct.
Don't present the arguments as a tuple, since it leaves a trailing comma. Instead, just use `fn(arg, arg)`.
Finally, be better with binders since we were just skipping binders.
r? oli-obk or reassign
Fix stack overflow in exhaustiveness due to recursive HIR opaque hidden types
This fixes several spicy non-trivial recursive opaque definitions inferred from HIR typeck, ensuring that they don't cause stack overflows in exhaustiveness code, which currently reveals opaques manually in a way that is not overflow aware (as opposed to something like the normalizer folders).
These should eventually be outright rejected, but today (some) non-trivial recursive opaque definitions are accepted, and changing that requires an FCP, so for now just make sure we don't stack overflow :^)
Fixes https://github.com/rust-lang/rust/issues/139402
r? lcnr
borrowck typeck children together with their root
This introduces new cycle errors, even with `feature(inline_const_pat)` removed, see the `non-structural-match-types-cycle-err.rs` test.
The new cycle error happens as the layout of `async`-blocks relies on their `optimized_mir`. As that now depends on `mir_borrowck` of its typeck parent, computing the layout of an `async`-block during MIR building, e.g. when evaluating a named `const` pattern. I think there's currently no way to have a named const pattern whose type references an async block while being allowed? cc `@oli-obk` `@RalfJung`
I cannot think of other cases where we currently rely on the MIR of a typeck children while borrowchecking their parent. The crater run came back without any breakage. My work here will prevent any future features which rely on this as we'll get locked into borrowchecking them together as I continue to work on https://github.com/rust-lang/types-team/issues/129, cc `@rust-lang/types.`
r? compiler-errors
Fix trait upcasting to dyn type with no principal when there are projections
#126660 (which I had originally authored, lol) had a subtle bug that is the moral equivalent of #114036, which is that when upcasting from `dyn Principal<Projection = Ty> + AutoTrait` to `dyn AutoTrait`, we were dropping the trait ref for `Principal` but not its projections (if there were any).
With debug assertions enabled, this triggers the assertion I luckily added in a2a0cfe825, but even without debug assertions this is a logical bug since we had a dyn type with just a projection bound but no principal, so it caused a type mismatch.
This does not need an FCP because this should've been covered by the FCP in #126660, but we just weren't testing a case when casting from a `dyn` type with projections 😸Fixes#139418
r? ````@oli-obk```` (or anyone)
compiler: report error when trait object type param reference self
Fixes#139082.
Emits an error when `Self` is found in the projection bounds of a trait
object. In type aliases, `Self` has no meaning, so `type A = &'static
dyn B` where `trait B = Fn() -> Self` will expands to `type A = &'static
Fn() -> Self` which is illegal, causing the region solver to bail out
when hitting the uninferred Self.
r? ````@compiler-errors```` ````@fee1-dead````
Tell LLVM about impossible niche tags
I was trying to find a better way of emitting discriminant calculations, but sadly had no luck.
So here's a fairly small PR with the bits that did seem worth bothering:
1. As the [`TagEncoding::Niche` docs](https://doc.rust-lang.org/nightly/nightly-rustc/rustc_abi/enum.TagEncoding.html#variant.Niche) describe, it's possible to end up with a dead value in the input that's not already communicated via the range parameter attribute nor the range load metadata attribute. So this adds an `llvm.assume` in non-debug mode to tell LLVM about that. (That way it can tell that the sides of the `select` have disjoint possible values.)
2. I'd written a bunch more tests, or at least made them parameterized, in the process of trying things out, so this checks in those tests to hopefully help future people not trip on the same weird edge cases, like when the tag type is `i8` but yet there's still a variant index and discriminant of `258` which doesn't fit in that tag type because the enum is really weird.
Make error message for missing fields with `..` and without `..` more consistent
When `..` is not present, we say "missing field `bar` in initializer", but when it is present we say "missing mandatory field `bar`". I don't see why the primary error message should change, b/c the root cause is the same.
Let's harmonize these error messages and instead use a label to explain that `..` is required b/c it's not defaulted.
r? estebank
Fixes#139445.
The additional errors aren't great but the first one is still good and
it's the most important, and imperfect errors are better than ICEing.
