Support using `Self` or projections inside an RPIT/async fn
I reuse the same idea as https://github.com/rust-lang/rust/pull/103449 to use variances to encode whether a lifetime parameter is captured by impl-trait.
The current implementation of async and RPIT replace all lifetimes from the parent generics by `'static`. This PR changes the scheme
```rust
impl<'a> Foo<'a> {
fn foo<'b, T>() -> impl Into<Self> + 'b { ... }
}
opaque Foo::<'_a>::foo::<'_b, T>::opaque<'b>: Into<Foo<'_a>> + 'b;
impl<'a> Foo<'a> {
// OLD
fn foo<'b, T>() -> Foo::<'static>::foo::<'static, T>::opaque::<'b> { ... }
^^^^^^^ the `Self` becomes `Foo<'static>`
// NEW
fn foo<'b, T>() -> Foo::<'a>::foo::<'b, T>::opaque::<'b> { ... }
^^ the `Self` stays `Foo<'a>`
}
```
There is the same issue with projections. In the example, substitute `Self` by `<T as Trait<'b>>::Assoc` in the sugared version, and `Foo<'_a>` by `<T as Trait<'_b>>::Assoc` in the desugared one.
This allows to support `Self` in impl-trait, since we do not replace lifetimes by `'static` any more. The same trick allows to use projections like `T::Assoc` where `Self` is allowed. The feature is gated behind a `impl_trait_projections` feature gate.
The implementation relies on 2 tweaking rules for opaques in 2 places:
- we only relate substs that correspond to captured lifetimes during TypeRelation;
- we only list captured lifetimes in choice region computation.
For simplicity, I encoded the "capturedness" of lifetimes as a variance, `Bivariant` vs `Invariant` for unused vs captured lifetimes. The `variances_of` query used to ICE for opaques.
Impl-trait that do not reference `Self` or projections will have their variances as:
- `o` (invariant) for each parent type or const;
- `*` (bivariant) for each parent lifetime --> will not participate in borrowck;
- `o` (invariant) for each own lifetime.
Impl-trait that does reference `Self` and/or projections will have some parent lifetimes marked as `o` (as the example above), and participate in type relation and borrowck. In the example above, `variances_of(opaque) = ['_a: o, '_b: *, T: o, 'b: o]`.
r? types
cc `@compiler-errors` , as you asked about the issue with `Self` and projections.
Convert predicates into Predicate in the Obligation constructor
instead of having almost all callers do that.
This reduces a bit of boilerplate, and also paves the way for my work towards https://github.com/rust-lang/compiler-team/issues/531 (as it makes it easier to accept both goals and clauses where right now it only accepts predicates).
Some diagnostic-related nits
1. Use `&mut Diagnostic` instead of `&mut DiagnosticBuilder<'_, T>`
2. Make `diag.span_suggestions` take an `IntoIterator` instead of `Iterator`, just to remove some `.into_iter` calls on the caller.
idk if I should add a lint to make sure people use `&mut Diagnostic` instead of `&mut DiagnosticBuilder<'_, T>` in cases where we're just, e.g., adding subdiagnostics to the diagnostic... maybe a followup.
Add support for custom mir
This implements rust-lang/compiler-team#564 . Details about the design, motivation, etc. can be found in there.
r? ```@oli-obk```
Add context to compiler error message
Changed `creates a temporary which is freed while still in use` to `creates a temporary value which is freed while still in use`.
Rollup of 7 pull requests
Successful merges:
- #100508 (avoid making substs of type aliases late bound when used as fn args)
- #101381 (Test that target feature mix up with homogeneous floats is sound)
- #103353 (Fix Access Violation when using lld & ThinLTO on windows-msvc)
- #103521 (Avoid possible infinite loop when next_point reaching the end of file)
- #103559 (first move on a nested span_label)
- #103778 (Update several crates for improved support of the new targets)
- #103827 (Properly remap and check for substs compatibility in `confirm_impl_trait_in_trait_candidate`)
Failed merges:
r? `@ghost`
`@rustbot` modify labels: rollup
Better error for HRTB error from generator interior
cc #100013
This is just a first pass at an error. It could be better, and shouldn't really be emitted in the first place. But this is better than what was being emitted before.
Remove #![allow(rustc::potential_query_instability)] from rustc_infer
Related to #84447
This PR probably needs to be benchmarked to check for regressions.
rework applying closure requirements in borrowck
Previously the promoted closure constraints were registered under the category `ConstraintCategory::ClosureBounds` in `type_check::prove_closure_bounds()` and then mapped back their original category in `regions_infer::best_blame_constraint` using the complicated map `closure_bounds_mapping`.
Now we're registering promoted constraints under their original category and span earlier in `type_check::prove_closure_bounds`.
See commit messages.
Fixes#99245
Spans are independent of the body being borrow-checked, so they don't
need remapping when promoting type-tests and they yield more specific
error spans inside bodies of closures/inline consts.
Don't use `ConstraintCategory::ClosureBounds`!
Set the category and the span for the promoted constraints to that of
the original constraint earlier than before.
This eliminates the need for `closure_bounds_mapping`.
Fix late-bound lifetime closure ICEs in HIR typeck and MIR borrowck
During HIR typeck, we need to teach astconv to treat late-bound regions within a closure body as free, fixing escaping bound vars ICEs in both of the issues below.
However, this then gets us to MIR borrowck, which itself needs to be taught how to instantiate free region vids for late-bound regions that come from items that _aren't_ the typeck root (for now, just closures).
Fixes#103771Fixes#103736
Change #[suggestion_*] attributes to use style="..."
As discussed [on Zulip](https://rust-lang.zulipchat.com/#narrow/stream/336883-i18n/topic/.23100717.20tool_only_span_suggestion), this changes `#[(multipart_)suggestion_{short,verbose,hidden}(...)]` attributes to plain `#[(multipart_)suggestion(...)]` attributes with a `style = "{short,verbose,hidden}"` parameter.
It also adds a new style, `tool-only`, that corresponds to `tool_only_span_suggestion`/`tool_only_multipart_suggestion` and causes the suggestion to not be shown in human-readable output at all.
Best reviewed commit-by-commit, there's a bit of noise in there.
cc #100717 `@compiler-errors`
r? `@davidtwco`
(almost) Always use `ObligationCtxt` when dealing with canonical queries
Hope this is a step in the right direction. cc rust-lang/types-team#50.
r? `@lcnr`
Accept `TyCtxt` instead of `TyCtxtAt` in `Ty::is_*` functions
Functions in answer:
- `Ty::is_freeze`
- `Ty::is_sized`
- `Ty::is_unpin`
- `Ty::is_copy_modulo_regions`
This allows to remove a lot of useless `.at(DUMMY_SP)`, making the code a bit nicer :3
r? `@compiler-errors`
Change reported_violations to use IndexSet
It is being used to iterate and to insert, without a lot of lookups
so hopefully it won't be a perf hit
Change MiniGraph.nodes to use IndexSet
It is being used to iterate and to insert, without performing lookups
so hopefully it won't be a perf hit
Change RegionConstraintData.givens to a FxIndexSet
This might result in a perf hit. Remove was being used in `givens`,
and `FxIndexSet` doesn't allow calling remove without losing the
fixed iteration order. So it was necessary to change remove to
`shift_remove`, but this method is slower.
Change OpaqueTypesVisitor to use stable sets and maps
This could also be a perf hit.
Make TraitObject visitor use a stable set
Don't carry MIR location in `ConstraintCategory::CallArgument`
It turns out that `ConstraintCategory::CallArgument` cannot just carry a MIR location in it, since we may bubble them up to totally different MIR bodies.
So instead, revert the commit a6b5f95fb0, and instead just erase regions from the original `Option<Ty<'tcx>>` that it carried, so that it doesn't ICE with the changes in #103220.
Best reviewed in parts -- the first is just a revert, and the second is where the meaningful changes happen.
Fixes#103624
Clean up hidden type registration
work on https://github.com/rust-lang/rust/issues/101186
Actually passing down the relation and using it instead of `eq` for the hidden type comparison has *no* effect whatsoever and allows for no further improvements at the call sites. I decided the increased complexity was not worth it and thus did not include that change in this PR.
r? `@compiler-errors`
Don't ICE when reporting borrowck errors involving regions from `anonymous_lifetime_in_impl_trait`
The issue here is that when we have:
```
trait Trait<'a> { .. }
fn foo(arg: impl Trait) { .. }
```
The anonymous lifetime `'_` that we generate for `arg: impl Trait` doesn't end up in the argument type (which is a param) but in a where-clause of the function, in a predicate whose self type is that param ty.
Fixes#101660
r? ``@cjgillot``
Deny hashing ty/re/ct inference variables
cc `@cjgillot` and https://github.com/rust-lang/rust/pull/102695#issuecomment-1275706528
r? `@lcnr`
best reviewed one commit at a time, mostly because the second commit that fixes `ClosureOutlivesRequirement` is mostly noise because of losing its `<'tcx>` lifetime parameter.
Fix missing explanation of where the borrowed reference is used when the same borrow occurs multiple times due to loop iterations
Fix#99824.
Problem of the issue:
If a borrow occurs in a loop, the borrowed reference could be invalidated at the same place at next iteration of the loop. When this happens, the point where the borrow occurs is the same as the intervening point that might invalidate the reference in the loop. This causes a problem for the current code finding the point where the resulting reference is used, so that the explanation of the cause will be missing. As the second point of "explain all errors in terms of three points" (see [leveraging intuition framing errors in terms of points"](https://rust-lang.github.io/rfcs/2094-nll.html#leveraging-intuition-framing-errors-in-terms-of-points), this explanation is very helpful for user to understand the error.
In the current implementation, the searching region for finding the location where the borrowed reference is used is limited to between the place where the borrow occurs and the place where the reference is invalidated. If those two places happen to be the same, which indicates that the borrow and invalidation occur at the same place in a loop, the search will fail.
One solution to the problem is when these two places are the same, find the terminator of the loop, and then use the location of the loop terminator instead of the location of the borrow for the region to find the place where the borrowed reference is used.
More dupe word typos
I only picked those changes (from the regex search) that I am pretty certain doesn't change meaning and is just a typo fix. Do correct me if any fix is undesirable and I can revert those. Thanks.
Use correct location for type tests in promoted constants
Previously we forgot to remap the location in a type test collected when visiting the body of a promoted constant back to the usage location, causing an ICE when trying to get span information for that type test.
Fixes https://github.com/rust-lang/rust/issues/102117
don't ICE when normalizing closure input tys
We were ICEing while rendering diagnostics because `universe_causes` is expected to track every universe created in the typeck's infcx.
`normalize_and_add_constraints` doesn't update `universe_causes`
when creating new universes, causing an ICE. Remove it!
Add spans to better track normalization constraints.
Fix couple places where `universe_causes` is not updated correctly to
track newly added universes.
Fixes#102800
~Fixess #99665~ (UPDATE: no longer true; the issue has a different failure path than when this PR was created and should be fixed by #101708, but the changes in this PR are still correct and should prevent potential future ICEs)
Remove `mir::CastKind::Misc`
As discussed in #97649 `mir::CastKind::Misc` is not clear, this PR addresses that by creating a new enum variant for every valid cast.
r? ````@oli-obk````
`normalize_and_add_constraints` doesn't add entries in `universe_causes`
when creating new universes, causing an ICE. Remove it!
Add spans to track normalization constraints.
Fix couple places where `universe_causes` is not updated correctly to
track newly added universes.
Update bootstrap compiler to 1.65.0
This PR updates the bootstrap compiler to Rust 1.65.0, removing the various `cfg(bootstrap)`s.
r? `@Mark-Simulacrum`
Neither require nor imply lifetime bounds on opaque type for well formedness
The actual hidden type can live arbitrarily longer than any individual lifetime and arbitrarily shorter than all but one of the lifetimes.
fixes#86218fixes#84305
This is a **breaking change** but it is a necessary soundness fix
Look at move place's type when suggesting mutable reborrow
Not sure why we are looking at the use site's ty instead of the move site's ty in order to suggest reborrowing the move site, but it was suppressing a perfectly valid reborrow suggestion.
r? `@estebank` who i think touched this last in 520461f1fb, though that was quite a while ago so feel free to reassign.
fix a ui test
use `into`
fix clippy ui test
fix a run-make-fulldeps test
implement `IntoQueryParam<DefId>` for `OwnerId`
use `OwnerId` for more queries
change the type of `ParentOwnerIterator::Item` to `(OwnerId, OwnerNode)`
On later stages, the feature is already stable.
Result of running:
rg -l "feature.let_else" compiler/ src/librustdoc/ library/ | xargs sed -s -i "s#\\[feature.let_else#\\[cfg_attr\\(bootstrap, feature\\(let_else\\)#"
Initial implementation of dyn*
This PR adds extremely basic and incomplete support for [dyn*](https://smallcultfollowing.com/babysteps//blog/2022/03/29/dyn-can-we-make-dyn-sized/). The goal is to get something in tree behind a flag to make collaboration easier, and also to make sure the implementation so far is not unreasonable. This PR does quite a few things:
* Introduce `dyn_star` feature flag
* Adds parsing for `dyn* Trait` types
* Defines `dyn* Trait` as a sized type
* Adds support for explicit casts, like `42usize as dyn* Debug`
* Including const evaluation of such casts
* Adds codegen for drop glue so things are cleaned up properly when a `dyn* Trait` object goes out of scope
* Adds codegen for method calls, at least for methods that take `&self`
Quite a bit is still missing, but this gives us a starting point. Note that this is never intended to become stable surface syntax for Rust, but rather `dyn*` is planned to be used as an implementation detail for async functions in dyn traits.
Joint work with `@nikomatsakis` and `@compiler-errors.`
r? `@bjorn3`
