Double check that hidden types match the expected hidden type
Fixes https://github.com/rust-lang/rust/issues/113278 specifically, but I left a TODO for where we should also add some hardening.
It feels a bit like papering over the issue, but at least this way we don't get unsoundness, but just surprising errors. Errors will be improved and given spans before this PR lands.
r? `@compiler-errors` `@lcnr`
Remove Scope::Elision from bound-vars resolution.
This scope is a remnant of HIR-based lifetime resolution.
It's only role was to ensure that object lifetime resolution falled back to `'static`. This can be done using `ObjectLifetimeDefault` scope.
Include the computed alignment of the violating field when rejecting
transparent types with non-trivially aligned ZSTs.
ZST member fields in transparent types must have an alignment of 1 (to
ensure it does not raise the layout requirements of the transparent
field). The current error message looks like this:
LL | struct Foobar(u32, [u32; 0]);
| ^^^^^^^^ has alignment larger than 1
This patch changes the report to include the alignment of the violating
field:
LL | struct Foobar(u32, [u32; 0]);
| ^^^^^^^^ has alignment of 4, which is larger than 1
In case of unknown alignments, it will yield:
LL | struct Foobar<T>(u32, [T; 0]);
| ^^^^^^ may have alignment larger than 1
This allows developers to get a better grasp why a specific field is
rejected. Knowing the alignment of the violating field makes it easier
to judge where that alignment-requirement originates, and thus hopefully
provide better hints on how to mitigate the problem.
This idea was proposed in 2022 in #98071 as part of a bigger change.
This commit simply extracts this error-message change, to decouple it
from the other diagnostic improvements.
Querify unused trait check.
This code transitively loads information for all bodies, and from resolutions. As it does not return a value, it should be beneficial to have it as a query.
Properly document `lifetime_mapping` in `OpaqueTy`
Also use an `Option` to signify that the value is actually present, instead of just no captured lifetimes.
Make it clearer that we're just checking for an RPITIT
Tiny nit to use `is_impl_trait_in_trait` more, to make it clearer that we're just checking whether a def-id is an RPITIT, rather than doing something meaningful with the `opt_rpitit_info`.
r? `@spastorino`
Rollup of 8 pull requests
Successful merges:
- #113413 (Add needs-triage to all new issues)
- #113426 (Don't ICE in `resolve_bound_vars` when associated return-type bounds are in bad positions)
- #113427 (Remove `variances_of` on RPITIT GATs, remove its one use-case)
- #113441 (miri: check that assignments do not self-overlap)
- #113453 (Remove unused from_method from rustc_on_unimplemented)
- #113456 (Avoid calling report_forbidden_specialization for RPITITs)
- #113466 (Update cargo)
- #113467 (Fix comment of `fn_can_unwind`)
r? `@ghost`
`@rustbot` modify labels: rollup
Remove `variances_of` on RPITIT GATs, remove its one use-case
It doesn't make sense to implement variances on a GAT anyways, since we don't relate GATs with variance:
85bf07972a/compiler/rustc_middle/src/ty/relate.rs (L569-L579)
r? ``@spastorino``
Effects/keyword generics MVP
This adds `feature(effects)`, which adds `const host: bool` to the generics of const functions, const traits and const impls. This will be used to replace the current logic around const traits.
r? `@oli-obk`
