Improve E0308 error message for `impl Trait` return mismatches
When a function returns `impl Trait`, all branches must return the same concrete type. Previously, the compiler showed:
expected `First` because of return type
This was misleading, as it suggested the return type was `First`, rather than any single type implementing the trait.
Update the diagnostic to:
expected a single type implementing `Value` because of return type
Also highlight the first return expression to make it clearer why subsequent returns do not match.
When a function returns `impl Trait`, all branches must return the same
concrete type. Previously, the compiler showed:
expected `First` because of return type
This was misleading, as it suggested the return type was `First`, rather
than any single type implementing the trait.
Update the diagnostic to:
expected a single type implementing `Value` because of return type
Also highlight the first return expression to make it clearer why
subsequent returns do not match.
Signed-off-by: Usman Akinyemi <usmanakinyemi202@gmail.com>
core::sync: rename `Exclusive` to `SyncView` and make improvements
This PR implements the renaming of `core::sync::Exclusive` to `SyncView` as decided in rust-lang/rust#98407. To preserve the ability to search for the old name, it adds `Exclusive` as a `doc_alias`.
It also makes the following additional changes:
- Converting the `get_mut` method to being an instance of `AsMut::as_mut`. In the process, it makes both the new `impl AsMut` and the existing `impl AsRef` `const`, and it also renames `get_pin_mut` to `as_pin_mut` for consistency. This direction follows a suggestion from rust-lang/rust#98407.
- Adding an `as_pin` method that can only be used when the wrapped type implements `Sync`, to complete the square of access methods.
- Making as many of the existing `impl`s `const` as possible; this involved making the existing `impl Default` no longer derived.
- Adding `impl`s for `AsyncFnOnce`, `AsyncFnMut`, and `AsyncFn`, akin to the existing `impls` for `FnOnce`, `FnMut`, and `Fn`.
It does not yet do the following, which may be desirable:
- Fixing/improving the documentation to address the concern pointed out in rust-lang/rust#146245.
It previously did the following, but this was removed after discussion:
- Adding an `impl` for (`const`) `Iterator`, which felt in line with the existing `impl`s for `Future` and `Coroutine`.
also removes E0452 and splits
`tests/rustdoc-ui/lints/renamed-lint-still-applies` into 2 tests
this is because of delayed warn lint being lost on compiler aborting on
error
Tweak wording of failed predicate in inference error
Special case message talking about `Predicate` that couldn't be satisfied when in inference errors so that we don't say "cannot satisfy `_: Trait`" and instead say "type must implement `Trait`".
Special case message talking about `Predicate` that couldn't be satisfied when in inference errors so that we don't say "cannot satisfy `_: Trait`" and instead say "type must implement `Trait`".
There is a bunch of complexity supporting the "cannot check whether the
hidden type of opaque type satisfies auto traits" error that shows up in
`tests/ui/impl-trait/auto-trait-leak.rs`. This is an obscure error that
shows up in a single test. If we are willing to downgrade that error
message to a cycle error, we can do the following.
- Simplify the `type_of_opaque` return value.
- Remove the `cycle_stash` query modifier.
- Remove the `CyclePlaceholder` type.
- Remove the `SelectionError::OpaqueTypeAutoTraitLeakageUnknown`
variant.
- Remove a `FromCycleError` impl.
- Remove `report_opaque_type_auto_trait_leakage`.
- Remove the `StashKey::Cycle` variant.
- Remove the `CycleErrorHandling::Stash` variant.
That's a lot! I think this is a worthwhile trade-off.
Tweak some of our internal `#[rustc_*]` TEST attributes
I think I might be the one who's used the internal TEST attrs `#[rustc_{dump_predicates,object_lifetime_default,outlives,variance}]` the most in recent times, I might even be the only one. As such I've noticed some recent-ish issues that haven't been fixed so far and which keep bothering me. Moreover I have a longstanding urge to rename several of these attributes which I couldn't contain anymore.
[`#[rustc_*]` TEST attributes](https://rustc-dev-guide.rust-lang.org/compiler-debugging.html#rustc_-test-attributes) are internal attributes that basically allow you to dump the output of specific queries for use in UI tests or for debugging purposes.
1. When some of these attributes were ported over to the new parsing API, their targets were unnecessarily restricted. I've kept encountering these incorrect "attribute cannot be used" errors all the while HIR analysis happily & correctly dumped the requested data below it. I've now relaxed their targets.
2. Since we now have target checking for the internal attributes I figured that it's unhelpful if we still intentionally crashed on invalid targets, so I've got rid of that.
3. I've always been annoyed that most of these (very old) attributes don't contain the word `dump` in their name (rendering their purpose non-obvious) and that some of their names diverge quite a bit from the corresponding query name. I've now rectified that. The new names take longer to type but it's still absolutely acceptable imo.
---
I haven't renamed all of the TEST attributes to follow the `rustc_dump_` scheme since that's quite tedious. If it's okay with you I'd like to postpone that (e.g., `rustc_{def_path,hidden_type…,layout,regions,symbol_name}`).
I've noticed that the parsers for TEST attrs are spread across `rustc_dump.rs`, `rustc_internal.rs` & `test_attrs.rs` which is a bit confusing. Since the new names are prefixed with `rustc_dump_` I've moved their parsers into `rustc_dump.rs` but of course they are still TEST attrs. IIRC, `test_attrs.rs` also contains non-`rustc_`-TEST attrs, so we can't just merge these two files. I guess that'll sort itself out in the future when I tackle the other internal TEST attrs.
r\? Jana || Jonathan
Remove unhelpful hint from trivial bound errors
The `= help: see issue #48214` hint on trivial bound errors isn't useful, most users hitting these errors aren't trying to use the `trivial_bounds` feature. The `disabled_nightly_features` call already handles suggesting the feature gate on nightly.
Closesrust-lang/rust#152872
mark two polonius tests as known-bug
As described in https://github.com/rust-lang/rust/issues/153215, we want to track these two tests in case anything changes and when/if other fixes land.
As discussed in this week's meeting, r? @jackh726 (or anyone)
fix refining_impl_trait suggestion with return_type_notation
using `#![feature(return_type_notation)] `on top of `refining_impl_trait` made the lint suggest a pretty wild “wrap the body in `<Self as Trait>::f(..)”` fix instead of the simple “just copy the return type from the trait”. this patch makes the lint always suggest the plain return-type replacement based on the trait signature (by grabbing the original snippet when possible), so you don’t get RTN-style desugarings in the help
new test here
fixesrust-lang/rust#151663
Remove "failed to resolve" and use the same format we use in other resolution errors "cannot find `name`".
```
error[E0433]: cannot find `nonexistent` in `existent`
--> $DIR/custom_attr_multisegment_error.rs:5:13
|
LL | #[existent::nonexistent]
| ^^^^^^^^^^^ could not find `nonexistent` in `existent`
```
Usman Akinyemi