In practice, it was only ever used with `ArenaCacheSelector`. Change it to a single boolean
`arena_cache` rather than allowing queries to specify an arbitrary type.
Tweak future opaque ty pretty printing
1. The `Return` type of a generator doesn't need to be a lang item just for diagnostic printing of types
2. We shouldn't suppress the `Output = Ty` of a opaque future if the type is a int or float var.
Adjust and slightly generalize operator error suggestion
(in no particular order)
* Stop passing around a whole extra `ProjectionPredicate`
* Add spaces around `=` in `Trait<..., Output = Ty>` suggestion
* Some code clean-ups, including
* add `lang_item_for_op` to turn a `Op` into a `DefId`
* avoid `SourceMap` because we don't really need to render an expr
* Remove `TypeParamVisitor` in favor of just checking `ty.has_param_types_or_consts` -- this acts a bit differently, but shouldn't cause erroneous suggestions (actually might generalize them a bit)
* We now suggest `Output = Ty` in the `where` clause suggestion when we fail to add `Struct<T>` and `T`.
I can split this out into more PRs if needed, but they're all just miscellaneous generalizations, changes, and nitpicks I saw when messing with this operator code.
translations(rustc_session): migrates rustc_session to use SessionDiagnostic - Pt. 2
# Description
This is the second part of the `rustc_session` [migration](https://github.com/rust-lang/rust/issues/100717#issuecomment-1220279883).
**Please only review this [commit](5018581957) that belongs to the part 2. The other ones are from the PR [#100753](https://github.com/rust-lang/rust/pull/100753) that is not yet merged.**
In this PR, we migrate the files `session.rs` and `config.rs`.
Please not that we have to `allow` the lints rules in some functions from `session.rs` because they are (at least I believe) part of the diagnostic machinery.
const_generics: correctly deal with bound variables
removes the hack in `resolve` which was needed because we evaluated constants without caring about their bound variables.
Each commit should be fairly self-contained, even if they build on each other
r? `@jackh726`
This commit removes the allows rules for the SessionDiagnostic lint
that were being used in the session.rs file.
Thanks to the PR #101230 we do not need to annotate the methods with
the allow rule as they are part of the diagnostic machinery.
rustc: Parameterize `ty::Visibility` over used ID
It allows using `LocalDefId` instead of `DefId` when possible, and also encode cheaper `Visibility<DefIndex>` into metadata.
- Add a `HandleCycleError` enum to rustc_query_system, along with a `handle_cycle_error` function
- Move `Value` to rustc_query_system, so `handle_cycle_error` can use it
- Move the `Value` impls from rustc_query_impl to rustc_middle. This is necessary due to orphan rules.
`BindingAnnotation` refactor
* `ast::BindingMode` is deleted and replaced with `hir::BindingAnnotation` (which is moved to `ast`)
* `BindingAnnotation` is changed from an enum to a tuple struct e.g. `BindingAnnotation(ByRef::No, Mutability::Mut)`
* Associated constants added for convenience `BindingAnnotation::{NONE, REF, MUT, REF_MUT}`
One goal is to make it more clear that `BindingAnnotation` merely represents syntax `ref mut` and not the actual binding mode. This was especially confusing since we had `ast::BindingMode`->`hir::BindingAnnotation`->`thir::BindingMode`.
I wish there were more symmetry between `ByRef` and `Mutability` (variant) naming (maybe `Mutable::Yes`?), and I also don't love how long the name `BindingAnnotation` is, but this seems like the best compromise. Ideas welcome.
