Handle inference variables in `CollectAllMismatches` correctly
1. Fix#106240
2. Treat int/float type variables correctly (see `src/test/ui/iterators/invalid-iterator-chain-with-int-infer.rs`), so we can point out things like "`Iterator::Item` changed to `{integer}` here"
Move autoderef to `rustc_hir_analysis`
Not sure if this is a change we actually want, but autoderef really is only (functionally) used by `rustc_hir_analysis` and `rustc_hir_typeck`, so it probably should live there.
Instead, implement a separate autoderef helper in `TypeErrCtxt` for the one use-case that goes against the ordering of the crate graph..
Clean up `OnUnimplementedFormatString::verify`
Lift the always-allowed symbols to a static array and replace a `match iter().find(...)` with `iter().any(...)`
Prefer non-`[type error]` candidates during selection
Fixes#102130Fixes#106351
r? types
note: Alternatively we could filter out error where-clauses during param-env construction? But we still need to filter out impls with errors during `match_impl`, I think.
Note predicate span on `ImplDerivedObligation`
Seems obvious to point out the where-clause that introduces the `ImplDerivedObligation` :)
r? `@estebank`
Check `impl`'s `where` clauses in `consider_impl_candidate` in experimental solver
Check impl's nested predicates as part of the recursive evaluate in `consider_impl_candidate`.
<sub>Unless, for some reason, these are intentionally **not** checked here -- in which case, I really don't understand where they're being checked...<sub>
r? ```@lcnr```
remove E0280
After looking at #61137 I tried my hand at E0280. I'm unable to find a reasonable example that emits the error. There are a couple of old examples that compile with the current compiler ([#26217](https://github.com/rust-lang/rust/issues/26217), [#42114](https://github.com/rust-lang/rust/issues/42114), [#27113](https://github.com/rust-lang/rust/issues/27113)) and there is a [bug with chalk](b7cdb635c4/src/test/ui/chalkify/bugs/async.rs) that makes it emit the error, with a couple more chalk bugs on zulip.
It seems like the error is supposed to be emitted from unfulfilled where bounds, of which two are related to borrow checking (error in where T: 'a or where 'a: 'b) and thus tend to emit errors like "lifetime may not live long enough" from borrow checking instead. The final case is with type equality constraints (where <T as Iterator>::Item == u32), which is unimplemented ([#20041](https://github.com/rust-lang/rust/issues/20041)). That such different problems are supposed to have the same error code also seems strange to me.
Since the error seems to only be emitted when using chalk I propose to remove it and replace it with an ICE instead. A crater run might be warranted.
Pinging `@jackh726` due to removal of chalk test that now ICEs.
Simplify some canonical type alias names
* delete the `Canonicalized<'tcx>` type alias in favor for `Canonical<'tcx>`
* `CanonicalizedQueryResponse` -> `CanonicalQueryResponse`
I don't particularly care about the latter, but it should be consistent. We could alternatively delete the first alias and rename the struct to `Canonicalized`, and then keep the name of `CanonicalizedQueryResponse` untouched.
Remove invalid case for mutable borrow suggestion
If we have a call such as `foo(&mut buf)` and after reference
collapsing the type is inferred as `&T` where-as the required type is
`&mut T`, don't suggest `foo(&mut mut buf)`. This is wrong syntactically
and the issue lies elsewhere, not in the borrow.
Fixes#105645
Simplify match statement
Add multiple tests
- 1 test for checking `N + 1 + 1` does not unify with `N+1`
- 2 tests for checking that a function that uses two parameters only returns the parameter that
is actually used.
- Check exact repeat predicates
Instead of just switching to a probe, check for different matches, and see how many there are.
If one, unify it, otherwise return true and let it be unified later.
fix [type error] for error E0029 and E0277
check explicitly for the type references error
if ty.references_error() is true change the error to be err.delay_as_bug() and prevent the error E0029 and E0277 from emitting out this fix#105946
check explicitly for the type references error
if ty.references_error() is true change the error to be err.delay_as_bug()
and prevent the error E0029 and E0277 from emitting out
this fix#105946
Rollup of 6 pull requests
Successful merges:
- #105846 (Account for return-position `impl Trait` in trait in `opt_suggest_box_span`)
- #106385 (Split `-Zchalk` flag into `-Ztrait-solver=(classic|chalk|next)` flag)
- #106403 (Rename `hir::Map::{get_,find_}parent_node` to `hir::Map::{,opt_}parent_id`, and add `hir::Map::{get,find}_parent`)
- #106462 (rustdoc: remove unnecessary wrapper around sidebar and mobile logos)
- #106464 (Update Fuchsia walkthrough with new configs)
- #106478 (Tweak wording of fn call with wrong number of args)
Failed merges:
r? `@ghost`
`@rustbot` modify labels: rollup
Rename `hir::Map::{get_,find_}parent_node` to `hir::Map::{,opt_}parent_id`, and add `hir::Map::{get,find}_parent`
The `hir::Map::get_parent_node` function doesn't return a `Node`, and I think that's quite confusing. Let's rename it to something that sounds more like something that gets the parent hir id => `hir::Map::parent_id`. Same with `find_parent_node` => `opt_parent_id`.
Also, combine `hir.get(hir.parent_id(hir_id))` and similar `hir.find(hir.parent_id(hir_id))` function into new functions that actually retrieve the parent node in one call. This last commit is the only one that might need to be looked at closely.
Don't deduce a signature that makes a closure cyclic
Sometimes when elaborating supertrait bounds for closure signature inference, we end up deducing a closure signature that is cyclical because either a parameter or the return type references a projection mentioning `Self` that also has escaping bound vars, which means that it's not eagerly replaced with an inference variable.
Interestingly, this is not *just* related to my PR that elaborates supertrait bounds for closure signature deduction. The committed test `supertrait-hint-cycle-3.rs` shows **stable** code that is fixed by this PR:
```rust
trait Foo<'a> {
type Input;
}
impl<F: Fn(u32)> Foo<'_> for F {
type Input = u32;
}
fn needs_super<F: for<'a> Fn(<F as Foo<'a>>::Input) + for<'a> Foo<'a>>(_: F) {}
fn main() {
needs_super(|_: u32| {});
}
```
Fixes#105401Fixes#105396
r? types
