Spell out other trait diagnostic
I recently saw somebody confused about the diagnostic thinking it was suggesting to add an `as` cast. This change is longer but I think it's clearer
Only compute vtable information during codegen
This PR removes vtable information from the `Object` and `TraitUpcasting` candidate sources in the trait solvers, and defers the computation of relevant information to `Instance::resolve`. This is because vtables really aren't a thing in the trait world -- they're an implementation detail in codegen.
Previously it was just easiest to tangle this information together since we were already doing the work of looking at all the supertraits in the trait solver, and specifically because we use traits to represent when it's possible to call a method via a vtable (`Object` candidate) and do upcasting (`Unsize` candidate). but I am somewhat suspicious we're doing a *lot* of extra work, especially in polymorphic contexts, so let's see what perf says.
Make proof tree probing and `Candidate`/`CandidateSource` generic over interner
`<TyCtxt<'tcx>>` is ugly, but will become `<I>` when things actually become generic.
r? lcnr
Check that alias-relate terms are WF if reporting an error in alias-relate
Check that each of the left/right term is WF when deriving a best error obligation for an alias-relate goal. This will make sure that given `<i32 as NotImplemented>::Assoc = ()` will drill down into `i32: NotImplemented` since we currently treat the projection as rigid.
r? lcnr
Use a consistent way to filter out bounds instead of splitting it into three places
just a small cleanup, no logic change.
Initially the code had me looking for why anything was special here, only to realize there's nothing interesting going on
Use `Variance` glob imported variants everywhere
Fully commit to using the globbed variance. Could be convinced the other way, and change this PR to not use the globbed variants anywhere, but I'd rather we do one or the other.
r? lcnr
Harmonize using root or leaf obligation in trait error reporting
When #121826 changed the error reporting to use root obligation and not the leafmost obligation, it didn't actually make sure that all the other diagnostics helper functions used the right obligation.
Specifically, when reporting similar impl candidates we are looking for impls of the root obligation, but trying to match them against the trait ref of the leaf obligation.
This does a few other miscellaneous changes. There's a lot more clean-up that could be done here, but working with this code is really grief-inducing due to how messy it has become over the years. Someone really needs to show it love. 😓
r? ``@estebank``
Fixes#126129
Use `tidy` to sort crate attributes for all compiler crates.
We already do this for a number of crates, e.g. `rustc_middle`, `rustc_span`, `rustc_metadata`, `rustc_span`, `rustc_errors`.
For the ones we don't, in many cases the attributes are a mess.
- There is no consistency about order of attribute kinds (e.g. `allow`/`deny`/`feature`).
- Within attribute kind groups (e.g. the `feature` attributes), sometimes the order is alphabetical, and sometimes there is no particular order.
- Sometimes the attributes of a particular kind aren't even grouped all together, e.g. there might be a `feature`, then an `allow`, then another `feature`.
This commit extends the existing sorting to all compiler crates, increasing consistency. If any new attribute line is added there is now only one place it can go -- no need for arbitrary decisions.
Exceptions:
- `rustc_log`, `rustc_next_trait_solver` and `rustc_type_ir_macros`, because they have no crate attributes.
- `rustc_codegen_gcc`, because it's quasi-external to rustc (e.g. it's ignored in `rustfmt.toml`).
r? `@davidtwco`
For E0277 suggest adding `Result` return type for function when using QuestionMark `?` in the body.
Adding suggestions for following function in E0277.
```rust
fn main() {
let mut _file = File::create("foo.txt")?;
}
```
to
```rust
fn main() -> Result<(), Box<dyn std::error::Error>> {
let mut _file = File::create("foo.txt")?;
return Ok(());
}
```
According to the issue #125997, only the code examples in the issue are targeted, but the issue covers a wider range of situations.
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We already do this for a number of crates, e.g. `rustc_middle`,
`rustc_span`, `rustc_metadata`, `rustc_span`, `rustc_errors`.
For the ones we don't, in many cases the attributes are a mess.
- There is no consistency about order of attribute kinds (e.g.
`allow`/`deny`/`feature`).
- Within attribute kind groups (e.g. the `feature` attributes),
sometimes the order is alphabetical, and sometimes there is no
particular order.
- Sometimes the attributes of a particular kind aren't even grouped
all together, e.g. there might be a `feature`, then an `allow`, then
another `feature`.
This commit extends the existing sorting to all compiler crates,
increasing consistency. If any new attribute line is added there is now
only one place it can go -- no need for arbitrary decisions.
Exceptions:
- `rustc_log`, `rustc_next_trait_solver` and `rustc_type_ir_macros`,
because they have no crate attributes.
- `rustc_codegen_gcc`, because it's quasi-external to rustc (e.g. it's
ignored in `rustfmt.toml`).
Make `ObligationEmittingRelation`s emit `Goal` rather than `Obligation`
Helps avoid needing to uplift `Obligation` into the solver. We still can't get rid of `ObligationCause`, but we can keep it as an associated type for `InferCtxtLike` and just give it a `dummy` function.
There's some shuttling between `Goal` and `Obligation` that may be perf-sensitive... Let's see what rust-timer says.
r? lcnr
