macro_rules: Add an expansion-local cache to span marker
Most tokens in a macro body typically have the same syntax context.
So the cache should usually be hit.
This change can either be combined with https://github.com/rust-lang/rust/pull/119689, or serve as its alternative, depending on perf results.
Unions are not `PointerLike`
I introduced the `PointerLike` trait to enforce `dyn*` coercions only from types that share the same ABI as a pointer. On top of needing to be scalar, they also should not be unions, since CTFE chokes on scalar reads for union types.
Fixes#119695
Impl trait diagnostic tweaks
1. Tweak some names for `impl Trait` being used in the wrong position
2. Remove two helper functions that are no longer needed since RPITIT is stable, and which causes matches to be a bit obtuse.
3. Split and fix the part where the error notes that it's "only allowed in XX"
Fixes#119629
Exhaustiveness: remove `Matrix.wildcard_row`
To compute exhaustiveness, we check whether an extra row with a wildcard added at the end of the match expression would be reachable. We used to store an actual such row of patterns in the `Matrix`, but it's a bit redundant since we know it only contains wildcards. It was kept because we used it to get the type of each column (and relevancy). With this PR, we keep track of the types (and relevancy) directly.
This is part of me splitting up https://github.com/rust-lang/rust/pull/119581 for ease of review.
r? `@compiler-errors`
Populate `yield` and `resume` types in MIR body while body is being initialized
I found it weird that we went back and populated these types *after* the body was constructed. Let's just do it all at once.
Stop allowing `rustc::potential_query_instability` on all of
rustc_mir_transform and instead allow it on a case-by-case basis if it
is safe to do so. In this particular crate, all instances were safe to
allow.
rustc_span: More consistent span combination operations
Also add more tests for using `tt` in addition to `ident`, and some other minor tweaks, see individual commits.
This is a part of https://github.com/rust-lang/rust/pull/119412 that doesn't yet add side tables for metavariable spans.
rustc_mir_transform: Make DestinationPropagation stable for queries
By using `FxIndexMap` instead of `FxHashMap`, so that the order of visiting of locals is deterministic.
We also need to bless
`copy_propagation_arg.foo.DestinationPropagation.panic*.diff`. Do not review the diff of the diff. Instead look at the diff files before and after this commit. Both before and after this commit, 3 statements are replaced with nop. It's just that due to change in ordering, different statements are replaced. But the net result is the same. In other words, compare this diff (before fix):
* 090d5eac72/tests/mir-opt/dest-prop/copy_propagation_arg.foo.DestinationPropagation.panic-unwind.diff
With this diff (after fix):
* f603babd63/tests/mir-opt/dest-prop/copy_propagation_arg.foo.DestinationPropagation.panic-unwind.diff
and you can see that both before and after the fix, we replace 3 statements with `nop`s.
I find it _slightly_ surprising that the test this PR affects did not previously fail spuriously due to the indeterminism of `FxHashMap`, but I guess in can be explained with the predictability of small `FxHashMap`s with `usize` (`Local`) keys, or something along those lines.
This should fix [this](https://github.com/rust-lang/rust/pull/119252#discussion_r1436101791) comment, but I wanted to make a separate PR for this fix for a simpler development and review process.
Part of https://github.com/rust-lang/rust/issues/84447 which is E-help-wanted.
r? `@cjgillot` who is reviewer for the highly related PR https://github.com/rust-lang/rust/pull/119252.
rustc_span: Optimize syntax context comparisons
Including comparisons with root context.
- `eq_ctxt` doesn't require retrieving full `SpanData`, or taking the span interner lock twice.
- Checking `SyntaxContext` for "rootness" is cheaper than extracting a full outer `ExpnData` for it and checking *it* for rootness.
The internal lint for `eq_ctxt` is also tweaked to detect `a.ctxt() != b.ctxt()` in addition to `a.ctxt() == b.ctxt()`.
Avoid specialization in the metadata serialization code
With the exception of a perf-only specialization for byte slices and byte vectors.
This uses the same trick of introducing a new trait and having the Encodable and Decodable derives add a bound to it as used for TyEncoder/TyDecoder. The new code is clearer about which encoder/decoder uses which impl and it reduces the dependency of rustc on specialization, making it easier to remove support for specialization entirely or turn it into a construct that is only allowed for perf optimizations if we decide to do this.
Rollup of 9 pull requests
Successful merges:
- #119208 (coverage: Hoist some complex code out of the main span refinement loop)
- #119216 (Use diagnostic namespace in stdlib)
- #119414 (bootstrap: Move -Clto= setting from Rustc::run to rustc_cargo)
- #119420 (Handle ForeignItem as TAIT scope.)
- #119468 (rustdoc-search: tighter encoding for f index)
- #119628 (remove duplicate test)
- #119638 (fix cyle error when suggesting to use associated function instead of constructor)
- #119640 (library: Fix warnings in rtstartup)
- #119642 (library: Fix a symlink test failing on Windows)
r? `@ghost`
`@rustbot` modify labels: rollup
fix cyle error when suggesting to use associated function instead of constructor
Fixes https://github.com/rust-lang/rust/issues/119625.
The first commit fixes the infinite recursion and makes the cycle error actually show up. We do this by making the `Display` for `ty::Instance` impl respect `with_no_queries` so that it can be used in query descriptions.
The second commit fixes the cycle error `resolver_for_lowering` -> `normalize` -> `resolve_instance` (for evaluating const) -> `lang_items` (for `drop_in_place`) -> `resolver_for_lowering` (for collecting lang items). We do this by simply skipping the suggestion when encountering an unnormalized type.
Use diagnostic namespace in stdlib
This required a minor fix to have the diagnostics shown in third party crates when the `diagnostic_namespace` feature is not enabled. See 5d63f5d8d1 for details. I've opted for having a single PR for both changes as it's really not that much code. If it is required it should be easy to split up the change into several PR's.
r? `@compiler-errors`
coverage: Hoist some complex code out of the main span refinement loop
The span refinement loop in `spans.rs` takes the spans that have been extracted from MIR, and modifies them to produce more helpful output in coverage reports.
It is also one of the most complicated pieces of code in the coverage instrumentor. It has an abundance of moving pieces that make it difficult to understand, and most attempts to modify it end up accidentally changing its behaviour in unacceptable ways.
This PR nevertheless tries to make a dent in it by hoisting two pieces of special-case logic out of the main loop, and into separate preprocessing passes. Coverage tests show that the resulting mappings are *almost* identical, with all known differences being unimportant.
This should hopefully unlock further simplifications to the refinement loop, since it now has fewer edge cases to worry about.
Exhaustiveness: Statically enforce revealing of opaques
In https://github.com/rust-lang/rust/pull/116821 it was decided that exhaustiveness should operate on the hidden type of an opaque type when relevant. This PR makes sure we consistently reveal opaques within exhaustiveness. This makes it possible to remove `reveal_opaque_ty` from the `TypeCx` trait which was an unfortunate implementation detail.
r? `@compiler-errors`
Rollup of 8 pull requests
Successful merges:
- #119151 (Hide foreign `#[doc(hidden)]` paths in import suggestions)
- #119350 (Imply outlives-bounds on lazy type aliases)
- #119354 (Make `negative_bounds` internal & fix some of its issues)
- #119506 (Use `resolutions(()).effective_visiblities` to avoid cycle errors in `report_object_error`)
- #119554 (Fix scoping for let chains in match guards)
- #119563 (Check yield terminator's resume type in borrowck)
- #119589 (cstore: Remove unnecessary locking from `CrateMetadata`)
- #119622 (never patterns: Document behavior of never patterns with macros-by-example)
r? `@ghost`
`@rustbot` modify labels: rollup
By using FxIndexMap instead of FxHashMap, so that the order of visiting
of locals is deterministic.
We also need to bless
copy_propagation_arg.foo.DestinationPropagation.panic*.diff. Do not
review the diff of the diff. Instead look at the diff file before and
after this commit. Both before and after this commit, 3 statements are
replaced with nop. It's just that due to change in ordering, different
statements are replaced. But the net result is the same.
cstore: Remove unnecessary locking from `CrateMetadata`
Locks and atomics in `CrateMetadata` fields were necessary before https://github.com/rust-lang/rust/pull/107765 when `CStore` was cloneable, but now they are not necessary and can be removed after restructuring the code a bit to please borrow checker.
All remaining locked fields in `CrateMetadata` are lazily populated caches.
Check yield terminator's resume type in borrowck
In borrowck, we didn't check that the lifetimes of the `TerminatorKind::Yield`'s `resume_place` were actually compatible with the coroutine's signature. That means that the lifetimes were totally going unchecked. Whoops!
This PR implements this checking.
Fixes#119564
r? types
Fix scoping for let chains in match guards
If let guards were previously represented as a different type of guard in HIR and THIR. This meant that let chains in match guards were not handled correctly because they were treated exactly like normal guards.
- Remove `hir::Guard` and `thir::Guard`.
- Make the scoping different between normal guards and if let guards also check for let chains.
closes#118593
Use `resolutions(()).effective_visiblities` to avoid cycle errors in `report_object_error`
Inside of `report_object_error`, using the `effective_visibilities` query causes cycles since it calls `type_of`, which itself may call `typeck`, which may end up reporting its own object-safety errors.
Fixes#119346Fixes#119502
Hide foreign `#[doc(hidden)]` paths in import suggestions
Stops the compiler from suggesting to import foreign `#[doc(hidden)]` paths.
```@rustbot``` label A-suggestion-diagnostics
