Pattern Migration 2024: try to suggest eliding redundant binding modifiers
This is based on #136475. Only the last commit is new.
This is a simpler, more restrictive alternative to #136496, meant to partially address #136047. If a pattern can be migrated to Rust 2024 solely by removing redundant binding modifiers, this will make that suggestion; otherwise, it uses the old suggestion of making the pattern fully explicit.
Relevant tracking issue: #131414
``@rustbot`` label A-diagnostics A-patterns A-edition-2024
r? ``@Nadrieril``
fix tail call checks wrt `#[track_caller]`
Only check the caller + disallow caller having the attribute.
fixes#134336
r? `@compiler-errors`
<sub>apparently there were no tests for `#[track_caller]` before... ooops</sub>
Simplify some code for lowering THIR patterns
I've been playing around with some radically different ways of storing THIR patterns, and while those experiments haven't yet produced a clear win, I have noticed various smaller things in the existing code that can be made a bit nicer.
Some of the more significant changes:
- With a little bit of extra effort (and thoughtful use of Arc), we can completely remove an entire layer of `'pat` lifetimes from the intermediate data structures used for match lowering.
- In several places, lists of THIR patterns were being double-boxed for no apparent reason.
mir_build: Rename `thir::cx::Cx` to `ThirBuildCx` and remove `UserAnnotatedTyHelpers`
A combination of two loosely-related tweaks that would otherwise conflict with each other:
- `Cx` is a pretty unhelpful type name, especially when jumping between THIR-building and MIR-building while trying to make changes to THIR data structures.
- The `UserAnnotatedTyHelpers` trait doesn't appear to provide any benefit over a simple helper function, and its `tcx()` method is currently completely unnecessary.
No functional change.
mir_build: Simplify `lower_pattern_range_endpoint`
By accumulating ascriptions and inline-consts in separate vectors, we can streamline some previously-tricky code for dealing with range patterns.
Add a couple of missing `ensure_sufficient_stacks`
r? `@saethlin` I hope you didn't spend time on this already.
(I couldn't sleep, opened `check_tail_calls`, there was a single call where it could happen, might as well fix it)
This PR adds a couple of missing `ensure_sufficient_stack`s:
- one in `check_tail_calls` that prevented the #135709 backport on some targets.
- after that was fixed, the test still didn't pass starting at 4MB, so I also added one in `check_unsafety` and that made it pass.
I didn't add an `rmake` test purposefully limiting the min stack size on `issue-74564-if-expr-stack-overflow.rs`, but we could if we wanted to.
On `apple-aarch64-darwin`, this is enough to make `RUST_MIN_STACK=$((1024*1024*3)) ./x test tests/ui --test-args tests/ui/issues/issue-74564-if-expr-stack-overflow.rs` pass for me locally, and it does stack overflow otherwise.
This aligns the main error message a bit more with the phrasing in the
Edition Guide and provides a bit more information on the labels to
(hopefully!) aid in understanding.
This does mean that we have to resolve the list of arm IDs twice, but it's
unclear whether that even matters, whereas the cleaner signature is a nice
improvement.
Rework "long type names" printing logic
Make it so more type-system types can be printed in a shortened version (like `Predicate`s).
Centralize printing the information about the "full type name path".
Make the "long type path" for the file where long types are written part of `Diag`, so that it becomes easier to keep track of it, and ensure it will always will be printed out last in the diagnostic by making its addition to the output implicit.
Tweak the shortening of types in "expected/found" labels.
Remove dead file `note.rs`.
Rename `tcx.ensure()` to `tcx.ensure_ok()`, and improve the associated docs
This is all based on my archaeology for https://rust-lang.zulipchat.com/#narrow/channel/182449-t-compiler.2Fhelp/topic/.60TyCtxtEnsure.60.
The main renamings are:
- `tcx.ensure()` → `tcx.ensure_ok()`
- `tcx.ensure_with_value()` → `tcx.ensure_done()`
- Query modifier `ensure_forwards_result_if_red` → `return_result_from_ensure_ok`
Hopefully these new names are a better fit for the *actual* function and purpose of these query call modes.
Implement MIR lowering for unsafe binders
This is the final bit of the unsafe binders puzzle. It implements MIR, CTFE, and codegen for unsafe binders, and enforces that (for now) they are `Copy`. Later on, I'll introduce a new trait that relaxes this requirement to being "is `Copy` or `ManuallyDrop<T>`" which more closely models how we treat union fields.
Namely, wrapping unsafe binders is now `Rvalue::WrapUnsafeBinder`, which acts much like an `Rvalue::Aggregate`. Unwrapping unsafe binders are implemented as a MIR projection `ProjectionElem::UnwrapUnsafeBinder`, which acts much like `ProjectionElem::Field`.
Tracking:
- https://github.com/rust-lang/rust/issues/130516
Make it so more type-system types can be printed in a shortened version (like `Predicate`s).
Centralize printing the information about the "full type name path".
Make the "long type path" for the file where long types are written part of `Diag`, so that it becomes easier to keep track of it, and ensure it will always will be printed out last in the diagnostic by making its addition to the output implicit.
Tweak the shortening of types in "expected/found" labels.
Remove dead file `note.rs`.
Merge `PatKind::Path` into `PatKind::Expr`
Follow-up to #134228
We always had a duplication where `Path`s could be represented as `PatKind::Path` or `PatKind::Lit(ExprKind::Path)`. We had to handle both everywhere, and still do after #134228, so I'm removing it now.
Deduplicate operand creation between scalars, non-scalars and string patterns
just something that felt duplicated and would make pattern type handling a bit more roundabout.
Lower index bounds checking to `PtrMetadata`, this time with the right fake borrow semantics 😸
Change `Rvalue::RawRef` to take a `RawRefKind` instead of just a `Mutability`. Then introduce `RawRefKind::FakeForPtrMetadata` and use that for lowering index bounds checking to a `PtrMetadata`. This new `RawRefKind::FakeForPtrMetadata` acts like a shallow fake borrow in borrowck, which mimics the semantics of the old `Rvalue::Len` operation we're replacing.
We can then use this `RawRefKind` instead of using a span desugaring hack in CTFE.
cc ``@scottmcm`` ``@RalfJung``
