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.
Various changes to name resolution of anon consts
Sorry this PR is kind of all over the place ^^'
Fixes#111012
- Rewrites anon const nameres to all go through `fn resolve_anon_const` explicitly instead of `visit_anon_const` to ensure that we do not accidentally resolve anon consts as if they are allowed to use generics when they aren't. Also means that we dont have bits of code for resolving anon consts that will get out of sync (i.e. legacy const generics and resolving path consts that were parsed as type arguments)
- Renames two of the `LifetimeRibKind`, `AnonConst -> ConcreteAnonConst` and `ConstGeneric -> ConstParamTy`
- Noticed while doing this that under `generic_const_exprs` all lifetimes currently get resolved to errors without any error being emitted which was causing a bunch of tests to pass without their bugs having been fixed, incidentally fixed that in this PR and marked those tests as `// known-bug:`. I'm fine to break those since `generic_const_exprs` is a very unstable incomplete feature and this PR _does_ make generic_const_exprs "less broken" as a whole, also I can't be assed to figure out what the underlying causes of all of them are. This PR reopens#77357#83993
- Changed `generics_of` to stop providing generics and predicates to enum variant discriminant anon consts since those are not allowed to use generic parameters
- Updated the error for non 'static lifetime in const arguments and the error for non 'static lifetime in const param tys to use `derive(Diagnostic)`
I have a vague idea why const-arg-in-const-arg.rs, in-closure.rs and simple.rs have started failing which is unfortunate since these were deliberately made to work, I think lifetime resolution being broken just means this regressed at some point and nobody noticed because the tests were not testing anything :( I'm fine breaking these too for the same reason as the tests for #77357#83993. I couldn't get `// known-bug` to work for these ICEs and just kept getting different stderr between CI and local `--bless` so I just removed them and will create an issue to track re-adding (and fixing) the bugs if this PR lands.
r? `@cjgillot` cc `@compiler-errors`
Adds the extended error documentation for E0523 to indicate that the
error is no longer produced by the compiler.
Update the E0464 documentation to include example code that produces the
error.
Remove the error message E0523 from the compiler and replace it with an
internal compiler error.
document + UI test `E0208` and make its output more user-friendly
Cleans up `E0208`'s output a lot. It could actually be useful for someone learning about variance now. I also added a UI test for it in `tests/ui/error-codes/` and wrote some docs for it.
r? `@GuillaumeGomez` another error code, can't be bothered to find the issue :P. Obviously there's some compiler stuff, so you'll have to hand it off.
Part of https://github.com/rust-lang/rust/issues/61137.
remove unreachable error code `E0490`
AFAIK, the untested and undocumented error code `E0490` is now unreachable, it was from the days of the original borrow checker.
cc ``@GuillaumeGomez`` #61137
remove unreachable error code `E0313`
Fixes#103742
Makes #103433 redundant
Implements removal of `E0313`. I agree with the linked issue that this error code is unreachable but if someone could confirm that would be great, are crater runs done for this sort of thing?
Also removed a redundant `// ignore-tidy-filelength` that I found while reading code.
cc ``@GuillaumeGomez`` #61137
Add some UI tests and reword error-code docs
Added UI tests for `E0013` and `E0015`. Error code docs for `E0015` were a bit unclear (they referred to all non-const errors in const context, when only non-const functions applied), so I touched them up a bit.
I also fixed up some issues in the new `error_codes.rs` tidy check (linked #106341), that I overlooked previously.
r? ``@GuillaumeGomez``
