Syntactically accept `become` expressions (explicit tail calls experiment)
This adds `ast::ExprKind::Become`, implements parsing and properly gates the feature.
cc `@scottmcm`
There's no need to store it in `Queries`. We can just use a local
variable, because it's always used shortly after it's produced.
The commit also removes the `tcx.analysis()` call in `ongoing_codegen`,
because it's easy to ensure that's done beforehand.
All this makes the dataflow within `run_compiler` easier to follow, at
the cost of making one test slightly more verbose, which I think is a
good tradeoff.
Revert #112758 and add test case
Fixes#112831.
Cannot unwrap `update_resolution` for `resolution.single_imports.remove(&Interned::new_unchecked(import));` because there is a relationship between the `Import` and `&NameBinding` in `NameResolution`. This issue caused by my unfamiliarity with the data structure and I apologize for it.
This PR had been reverted, and test case have been added.
r? `@Nilstrieb`
cc `@petrochenkov`
Sort the errors from arguments checking so that suggestions are handled properly
Fixes#112507
The algorithm of `find_issue` does not make sure the index comes out in order, which will make suggesting `remove` or `add` arguments broken in some cases.
Modifying the algorithm to obey order involves much more trivial change, so it's better to order the `errors` after iterations.
Rustdoc: search: color item type and reduce size to avoid clashing
- rustdoc: search: color item type same as item
- rustdoc: search: reduce item type size to 0.875rem to avoid clashing with path and item
Add `implement_via_object` to `rustc_deny_explicit_impl` to control object candidate assembly
Some built-in traits are special, since they are used to prove facts about the program that are important for later phases of compilation such as codegen and CTFE. For example, the `Unsize` trait is used to assert to the compiler that we are able to unsize a type into another type. It doesn't have any methods because it doesn't actually *instruct* the compiler how to do this unsizing, but this is later used (alongside an exhaustive match of combinations of unsizeable types) during codegen to generate unsize coercion code.
Due to this, these built-in traits are incompatible with the type erasure provided by object types. For example, the existence of `dyn Unsize<T>` does not mean that the compiler is able to unsize `Box<dyn Unsize<T>>` into `Box<T>`, since `Unsize` is a *witness* to the fact that a type can be unsized, and it doesn't actually encode that unsizing operation in its vtable as mentioned above.
The old trait solver gets around this fact by having complex control flow that never considers object bounds for certain built-in traits:
2f896da247/compiler/rustc_trait_selection/src/traits/select/candidate_assembly.rs (L61-L132)
However, candidate assembly in the new solver is much more lovely, and I'd hate to add this list of opt-out cases into the new solver. Instead of maintaining this complex and hard-coded control flow, instead we can make this a property of the trait via a built-in attribute. We already have such a build attribute that's applied to every single trait that we care about: `rustc_deny_explicit_impl`. This PR adds `implement_via_object` as a meta-item to that attribute that allows us to opt a trait out of object-bound candidate assembly as well.
r? `@lcnr`
Don't consider TAIT normalizable to hidden ty if it would result in impossible item bounds
See test for example where we shouldn't consider it possible to alias-relate a TAIT and hidden type.
r? `@lcnr`
Don't ICE on bound var in `reject_fn_ptr_impls`
We may try to use an impl like `impl<T: FnPtr> PartialEq {}` to satisfy a predicate like `for<T> T: PartialEq` -- don't ICE in that case.
Fixes#112735
Treat TAIT equation as always ambiguous in coherence
Not sure why we weren't treating all TAIT equality as ambiguous -- this behavior combined with `DefineOpaqueTypes::No` leads to coherence overlap failures, since we incorrectly consider impls as not overlapping because the obligation `T: From<Foo>` doesn't hold.
Fixes#112765
Continue folding in query normalizer on weak aliases
Fixes#112752Fixes#112731 (same root cause, so didn't make a test for it)
fixes#112776
r? ```@oli-obk```
Rewrite various resolve/diagnostics errors as translatable diagnostics
additional question:
For trivial strings is it ever accepted to use `fluent_generated::foo` in a `label` for example? Or is an empty struct `Diagnostic` preferred?
`#[test]` function signature verification improvements
This PR contains two improvements to the expansion of the `#[test]` macro.
The first one fixes https://github.com/rust-lang/rust/issues/112360 by correctly recovering item statements if the signature verification fails.
The second one forbids non-lifetime generics on `#[test]` functions. These were previously allowed if the function returned `()`, but always caused an inference error:
before:
```text
error[E0282]: type annotations needed
--> src/lib.rs:2:1
|
1 | #[test]
| ------- in this procedural macro expansion
2 | fn foo<T>() {}
| ^^^^^^^^^^^^^^ cannot infer type
```
after:
```text
error: functions used as tests can not have any non-lifetime generic parameters
--> src/lib.rs:2:1
|
2 | fn foo<T>() {}
| ^^^^^^^^^^^^^^
```
Also includes some basic tests for test function signature verification, because I couldn't find any (???) in the test suite.
[libs] Simplify `unchecked_{shl,shr}`
There's no need for the `const_eval_select` dance here. And while I originally wrote the `.try_into().unwrap_unchecked()` implementation here, it's kinda a mess in MIR -- this new one is substantially simpler, as shown by the old one being above the inlining threshold but the new one being below it in the `mir-opt/inline/unchecked_shifts` tests.
We don't need `u32::checked_shl` doing a dance through both `Result` *and* `Option` 🙃
Don't record adjustments twice in `note_source_of_type_mismatch_constraint`
We call `lookup_method` a few times in `note_source_of_type_mismatch_constraint`, but that function has side-effects to the typeck results. Replace it with a less side-effect-y variant of the function for use in diagnostics.
Specifically the ICE in #112532 happens because we're recording deref adjustments twice for a call receiver, which causes `ExprUseVisitor` to be angry.
Fixes#112532
Don't capture `&[T; N]` when contents isn't read
Fixes the check in #111831Fixes#112607, although I decided to test the root cause rather than including the example in the issue as a test.
cc `@BoxyUwU`
Remove `box_free` lang item
This PR removes the `box_free` lang item, replacing it with `Box`'s `Drop` impl. Box dropping is still slightly magic because the contained value is still dropped by the compiler.
Add `<meta charset="utf-8">` to `-Zdump-mir-spanview` output
Without an explicit `<meta charset>` declaration, some browsers (e.g. Safari) won't detect the page encoding as UTF-8, causing unicode characters in the dump output to display incorrectly.
[rustdoc] Fix invalid handling of "going back in history" when "go to only search result" setting is enabled
You can test the fix [here](https://rustdoc.crud.net/imperio/back-in-history-fix/lib2/index.html). Enable "Directly go to item in search if there is only one result", then search for `HasALongTraitWithParams` and finally go back to previous page. It should be back on the `index.html` page.
The reason for this bug is that the JS state is cached as is, so when we go back to the page, it resumes where it was left, somewhat (very weird), meaning the search is run again etc. The best way to handle this is to force the JS re-execution in this case so that it doesn't try to resume from where it left and then lead us back to the current page.
r? ``@notriddle``
Add `AliasKind::Weak` for type aliases.
`type Foo<T: Debug> = Bar<T>;` does not check `T: Debug` at use sites of `Foo<NotDebug>`, because in contrast to a
```rust
trait Identity {
type Identity;
}
impl<T: Debug> Identity for T {
type Identity = T;
}
<NotDebug as Identity>::Identity
```
type aliases do not exist in the type system, but are expanded to their aliased type immediately when going from HIR to the type layer.
Similarly:
* a private type alias for a public type is a completely fine thing, even though it makes it a bit hard to write out complex times sometimes
* rustdoc expands the type alias, even though often times users use them for documentation purposes
* diagnostics show the expanded type, which is confusing if the user wrote a type alias and the diagnostic talks about another type that they don't know about.
For type alias impl trait, these issues do not actually apply in most cases, but sometimes you have a type alias impl trait like `type Foo<T: Debug> = (impl Debug, Bar<T>);`, which only really checks it for `impl Debug`, but by accident prevents `Bar<T>` from only being instantiated after proving `T: Debug`. This PR makes sure that we always check these bounds explicitly and don't rely on an implementation accident.
To not break all the type aliases out there, we only use it when the type alias contains an opaque type. We can decide to do this for all type aliases over an edition.
Or we can later extend this to more types if we figure out the back-compat concerns with suddenly checking such bounds.
As a side effect, easily allows fixing https://github.com/rust-lang/rust/issues/108617, which I did.
fixes https://github.com/rust-lang/rust/issues/108617
