bjoernager/rust
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Rollup merge of #122598 - Nadrieril:full-derefpats, r=matthewjasper

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deref patterns: lower deref patterns to MIR

This lowers deref patterns to MIR. This is a bit tricky because this is the first kind of pattern that requires storing a value in a temporary. Thanks to https://github.com/rust-lang/rust/pull/123324 false edges are no longer a problem.

The thing I'm not confident about is the handling of fake borrows. This PR ignores any fake borrows inside a deref pattern. We are guaranteed to at least fake borrow the place of the first pointer value, which could be enough, but I'm not certain.
This commit is contained in:
León Orell Valerian Liehr 2024-04-23 17:25:15 +02:00 • committed by GitHub
commit 332cac2c6d
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51 changed files with 764 additions and 301 deletions
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4
compiler/rustc_const_eval/src/transform/check_consts/check.rs
View file

@ -414,7 +414,7 @@ impl<'tcx> Visitor<'tcx> for Checker<'_, 'tcx> {
BorrowKind::Shared => {
PlaceContext::NonMutatingUse(NonMutatingUseContext::SharedBorrow)
}
BorrowKind::Fake => {
BorrowKind::Fake(_) => {
PlaceContext::NonMutatingUse(NonMutatingUseContext::FakeBorrow)
}
BorrowKind::Mut { .. } => {
@ -487,7 +487,7 @@ impl<'tcx> Visitor<'tcx> for Checker<'_, 'tcx> {
}
}
Rvalue::Ref(_, BorrowKind::Shared | BorrowKind::Fake, place)
Rvalue::Ref(_, BorrowKind::Shared | BorrowKind::Fake(_), place)
| Rvalue::AddressOf(Mutability::Not, place) => {
let borrowed_place_has_mut_interior = qualifs::in_place::<HasMutInterior, _>(
self.ccx,

2
compiler/rustc_const_eval/src/transform/check_consts/resolver.rs
View file

@ -105,7 +105,7 @@ where
fn ref_allows_mutation(&self, kind: mir::BorrowKind, place: mir::Place<'tcx>) -> bool {
match kind {
mir::BorrowKind::Mut { .. } => true,
mir::BorrowKind::Shared | mir::BorrowKind::Fake => {
mir::BorrowKind::Shared | mir::BorrowKind::Fake(_) => {
self.shared_borrow_allows_mutation(place)
}
}

2
compiler/rustc_const_eval/src/transform/validate.rs
View file

@ -965,7 +965,7 @@ impl<'a, 'tcx> Visitor<'tcx> for TypeChecker<'a, 'tcx> {
}
}
},
Rvalue::Ref(_, BorrowKind::Fake, _) => {
Rvalue::Ref(_, BorrowKind::Fake(_), _) => {
if self.mir_phase >= MirPhase::Runtime(RuntimePhase::Initial) {
self.fail(
location,