This commit refactors `PlaceContext` to split it into four different
smaller enums based on if the context represents a mutating use,
non-mutating use, maybe-mutating use or a non-use (this is based on the
recommendation from @oli-obk on Zulip[1]).
This commit then introduces a `PlaceContext::AscribeUserTy` variant.
`StatementKind::AscribeUserTy` is now correctly mapped to
`PlaceContext::AscribeUserTy` instead of `PlaceContext::Validate`.
`PlaceContext::AscribeUserTy` can also now be correctly categorized as a
non-use which fixes an issue with constant promotion in statics after a
cast introduces a `AscribeUserTy` statement.
[1]: https://rust-lang.zulipchat.com/#narrow/stream/122657-wg-nll/subject/.2355288.20cast.20fails.20to.20promote.20to.20'static/near/136536949
Update the existing NLL `patterns.rs` test accordingly.
includes changes addressing review feedback:
* Added example to docs for `UserTypeProjections` illustrating how we
build up multiple projections when descending into a pattern with
type ascriptions.
* Adapted niko's suggested docs for `UserTypeProjection`.
* Factored out `projection_ty` from more general `projection_ty_core`
(as a drive-by, made its callback an `FnMut`, as I discovered later
that I need that).
* Add note to docs that `PlaceTy.field_ty(..)` does not normalize its result.
* Normalize as we project out `field_ty`.
I did not think I would need this in the MIR, but in general local
decls are going to need to support this. (That, or we need to be able
define a least-upper-bound for a collection of types encountered via
the pattern compilation.)
(That is, it will pull out some component type held or referenced by
the type annotation.)
Note: this still needs to actually do projection itself. That comes in
a later commit
Shrink `Statement`.
This commit reduces the size of `Statement` from 80 bytes to 56 bytes on
64-bit platforms, by boxing the `AscribeUserType` variant of
`StatementKind`.
This change reduces instruction counts on most benchmarks by 1--3%.
This commit reduces the size of `Statement` from 80 bytes to 56 bytes on
64-bit platforms, by boxing the `AscribeUserType` variant of
`StatementKind`.
This change reduces instruction counts on most benchmarks by 1--3%.
Add regression tests for #55219 and #55241
Also another test where a duplicate-like error appears to have been
suppressed; I'm not 100% sure why this output changes, though I could
imagine that some duplicate suppression is enabled by this PR.
This fixes `issue-28848.rs` -- it also handles another case that the
AST region checker gets wrong (`wf-self-type.rs`). I don't actually
think that this is the *right way* to be enforcing this constraint --
I think we should probably do it more generally, perhaps by editing
`predicates_of` for the impl itself. The chalk-style implied bounds
setup ought to fix this.
This gives at least some explanation for why a borrow is expected to
last for a certain free region. Also:
* Reports E0373: "closure may outlive the current function" with NLL.
* Special cases the case of returning a reference to (or value
referencing) a local variable or temporary (E0515).
* Special case assigning a reference to a local variable in a closure
to a captured variable.
Adds UseAsConst and UseAsStatic to replace Return in consts/statics.
Don't report the arguments to an overloaded operator as CallArguments.
Also don't report "escaping data" in these items.
Prefer unwrap_or_else to unwrap_or in case of function calls/allocations
The contents of `unwrap_or` are evaluated eagerly, so it's not a good pick in case of function calls and allocations. This PR also changes a few `unwrap_or`s with `unwrap_or_default`.
An added bonus is that in some cases this change also reveals if the object it's called on is an `Option` or a `Result` (based on whether the closure takes an argument).
handle underscore bounds in unexpected places
Per the discussion on #54902, I made it a hard error to use lifetime bounds in various places where they used to be permitted:
- `where Foo: Bar<'_>` for example
I also moved error reporting to HIR lowering and added `Error` variants to let us suppress downstream errors that result.
I (imo) improved the error message wording to be clearer, as well.
In the process, I fixed the ICE in #52098.
Fixes#54902Fixes#52098
E0669 refers to a constraint that cannot be coerced into a single LLVM
value, unfortunately right now this uses the Span for the entire inline
assembly statement, which is less than ideal.
This commit preserves the Span from HIR, which lets us emit the error
using the Span for the operand itself in MIR.
Signed-off-by: Levente Kurusa <lkurusa@acm.org>
