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.
make `CastError::NeedsDeref` create a `MachineApplicable` suggestion
Fixes#106903
Simple impl for the linked issue. I also made some other small changes:
- `CastError::ErrorGuaranteed` now owns an actual `ErrorGuaranteed`. This better enforces the static guarantees of `ErrorGuaranteed`.
- `CastError::NeedDeref` code simplified a bit, we now just suggest the `*`, instead of the whole expression as well.
Transform async `ResumeTy` in generator transform
- Eliminates all the `get_context` calls that async lowering created.
- Replace all `Local` `ResumeTy` types with `&mut Context<'_>`.
The `Local`s that have their types replaced are:
- The `resume` argument itself.
- The argument to `get_context`.
- The yielded value of a `yield`.
The `ResumeTy` hides a `&mut Context<'_>` behind an unsafe raw pointer, and the `get_context` function is being used to convert that back to a `&mut Context<'_>`.
Ideally the async lowering would not use the `ResumeTy`/`get_context` indirection, but rather directly use `&mut Context<'_>`, however that would currently lead to higher-kinded lifetime errors.
See <https://github.com/rust-lang/rust/issues/105501>.
The async lowering step and the type / lifetime inference / checking are still using the `ResumeTy` indirection for the time being, and that indirection is removed here. After this transform, the generator body only knows about `&mut Context<'_>`.
---
Fixes https://github.com/bjorn3/rustc_codegen_cranelift/issues/1330 CC `@bjorn3`
r? `@compiler-errors`
- Eliminates all the `get_context` calls that async lowering created.
- Replace all `Local` `ResumeTy` types with `&mut Context<'_>`.
The `Local`s that have their types replaced are:
- The `resume` argument itself.
- The argument to `get_context`.
- The yielded value of a `yield`.
The `ResumeTy` hides a `&mut Context<'_>` behind an unsafe raw pointer, and the
`get_context` function is being used to convert that back to a `&mut Context<'_>`.
Ideally the async lowering would not use the `ResumeTy`/`get_context` indirection,
but rather directly use `&mut Context<'_>`, however that would currently
lead to higher-kinded lifetime errors.
See <https://github.com/rust-lang/rust/issues/105501>.
The async lowering step and the type / lifetime inference / checking are
still using the `ResumeTy` indirection for the time being, and that indirection
is removed here. After this transform, the generator body only knows about `&mut Context<'_>`.
Various cleanups around pre-TyCtxt queries and functions
part of #105462
based on https://github.com/rust-lang/rust/pull/106776 (everything starting at [0e2b39f](0e2b39fd1f) is new in this PR)
r? `@petrochenkov`
I think this should be most of the uncontroversial part of #105462.
Rollup of 8 pull requests
Successful merges:
- #105796 (rustdoc: simplify JS search routine by not messing with lev distance)
- #106753 (Make sure that RPITITs are not considered suggestable)
- #106917 (Encode const mir for closures if they're const)
- #107004 (Implement some candidates for the new solver (redux))
- #107023 (Stop using `BREAK` & `CONTINUE` in compiler)
- #107030 (Correct typo)
- #107042 (rustdoc: fix corner cases with "?" JS keyboard command)
- #107045 (rustdoc: remove redundant CSS rule `#settings .setting-line`)
Failed merges:
r? `@ghost`
`@rustbot` modify labels: rollup
Stop using `BREAK` & `CONTINUE` in compiler
Switching them to `Break(())` and `Continue(())` instead.
Entirely search-and-replace, though there's one spot where rustfmt insisted on a reformatting too.
libs-api would like to remove these constants (https://github.com/rust-lang/rust/pull/102697#issuecomment-1385705202), so stop using them in compiler to make the removal PR later smaller.
Implement some candidates for the new solver (redux)
Based on #106718, so the diff is hard to read without it. See [here](98700cf481...compiler-errors:rust:new-solver-new-candidates-2) for an easier view until that one lands.
Of note:
* 44af916020fb43c12070125c45b6dee4ec303bbc fixes a bug where we need to make the query response *inside* of a probe, or else we make no inference progress (I think)
* 50daad5acd2f163d03e7ffab942534f09bc36e2e implements `consider_assumption` for traits and predicates. I'm not sure if using `sup` here is necessary or if `eq` is fine.
* We decided that all of the `instantiate_constituent_tys_for_*` functions are verbose but ok, since they need to be exhaustive and the logic between each of them is not similar enough, right?
r? ``@lcnr``
Revert "Improve heuristics whether `format_args` string is a source literal"
This reverts commit e6c02aad93 (from #106195).
Keeps the code improvements from the PR and the test (as a known-bug).
Works around #106408 while a proper fix is discussed more thoroughly in #106505, as proposed by `@tmandry.`
Reopens#106191
r? compiler-errors
Do not filter substs in `remap_generic_params_to_declaration_params`.
The relevant filtering should have been performed by borrowck.
Fixes https://github.com/rust-lang/rust/issues/105826
r? types
finish trait solver skeleton work
### 648d661b4e0fcf55f7082894f577377eb451db4b
The previous implementation didn't remove provisional entries which depended on the current goal if we're forced to rerun in case the provisional result of that entry is different from the new result. For reference, see https://rust-lang.github.io/chalk/book/recursive/search_graph.html.
We should also treat inductive cycles as overflow, not ordinary ambiguity.
### 219a5de2517cebfe20a2c3417bd302f7c12db70c 6a1912be539dd5a3b3c10be669787c4bf0c1868a
These two commits move canonicalization to the start of the queries which simplifies a bunch of stuff. I originally intended to keep stuff canonicalized for a while because I expected us to add a additional caches the trait solver, either for candidate assembly or for projections. We ended up not adding (and expect to not need) any of them so this just ends up being easier to understand.
### d78d5ad0979e965afde6500bccfa119b47063506
adds a special `eq` for the solver which doesn't care about obligations or spans
### 18704e6a78b7703e1bbb3856f015cb76c0a07a06
implements https://rust-lang.zulipchat.com/#narrow/stream/364551-t-types.2Ftrait-system-refactor/topic/projection.20cache
r? `@compiler-errors`
Switching them to `Break(())` and `Continue(())` instead.
libs-api would like to remove these constants, so stop using them in compiler to make the removal PR later smaller.
dont randomly use `_` to print out const generic arguments
const generics seem to get printed out as `_` for no reason a lot of the time, as someone who spends a lot of time with const generics this has gotten ✨ very annoying ✨. Latest example would be #106423 where the ICE messaged formatted a `ty::Const` containing no infer vars, as `_`.
For some reason printing of the const argument on arrays was custom instead of using the existing logic for printing `ty::Const`. Additionally the existing logic for printing `ty::Const` would print out `_` for anon consts that are in a separate crate leading to weird diagnostics (see second commit). There ought to be less cases of consts randomly getting printed as `_` hiding valuable info now.
Add 'static lifetime suggestion when GAT implied 'static requirement from HRTB
Fix for issue #105507
The problem:
When generic associated types (GATs) are from higher-ranked trait bounds (HRTB), they are implied 'static requirement (see
[Implied 'static requirement from higher-ranked trait bounds](https://blog.rust-lang.org/2022/10/28/gats-stabilization.html#implied-static-requirement-from-higher-ranked-trait-bounds) for more details). If the user did not explicitly specify the `'static` lifetime when using the GAT, the current error message will only point out the type `does not live long enough` where the type is used, but not where the GAT is specified and how to fix the problem.
The solution:
Add notes at the span where the problematic GATs are specified and suggestions of how to fix the problem by adding `'static` lifetime at the right spans.
Rollup of 7 pull requests
Successful merges:
- #104505 (Remove double spaces after dots in comments)
- #106784 (prevent E0512 from emitting [type error] by checking the references_error)
- #106834 (new trait solver: only consider goal changed if response is not identity)
- #106889 (Mention the lack of `windows_mut` in `windows`)
- #106963 (Use `scope_expr_id` from `ProbeCtxt`)
- #106970 (Switch to `EarlyBinder` for `item_bounds` query)
- #106980 (Hide `_use_mk_alias_ty_instead` in `<AliasTy as Debug>::fmt`)
Failed merges:
r? `@ghost`
`@rustbot` modify labels: rollup
Switch to `EarlyBinder` for `item_bounds` query
Part of the work to finish #105779 (also see https://github.com/rust-lang/types-team/issues/78).
Several queries `X` have a `bound_X` variant that wraps the output in `EarlyBinder`. This adds `EarlyBinder` to the return type of the `item_bounds` query and removes `bound_item_bounds`.
r? `@lcnr`
