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Rollup merge of #132209 - compiler-errors:modifiers, r=fmease

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Fix validation when lowering `?` trait bounds

Pass the unlowered (`rustc_hir`) polarity to `lower_poly_trait_ref`.

This allows us to actually *validate* that generic args are actually valid on `?Trait` paths. This actually regressed in #113671 because that PR changed the behavior where we were inadvertently re-lowering paths as `BoundPolarity::Positive`, which was also coincidentally the only place we were enforcing the generics on `?Trait` paths were correct.
This commit is contained in:
Jubilee 2024-10-31 17:50:40 -07:00 • committed by GitHub
commit e31988cfc9
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13 changed files with 119 additions and 58 deletions
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6
compiler/rustc_hir_analysis/src/hir_ty_lowering/bounds.rs
View file

@ -168,12 +168,6 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
match hir_bound {
hir::GenericBound::Trait(poly_trait_ref) => {
let hir::TraitBoundModifiers { constness, polarity } = poly_trait_ref.modifiers;
let polarity = match polarity {
rustc_ast::BoundPolarity::Positive => ty::PredicatePolarity::Positive,
rustc_ast::BoundPolarity::Negative(_) => ty::PredicatePolarity::Negative,
rustc_ast::BoundPolarity::Maybe(_) => continue,
};
let _ = self.lower_poly_trait_ref(
&poly_trait_ref.trait_ref,
poly_trait_ref.span,

2
compiler/rustc_hir_analysis/src/hir_ty_lowering/dyn_compatibility.rs
View file

@ -51,7 +51,7 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
&trait_bound.trait_ref,
trait_bound.span,
hir::BoundConstness::Never,
ty::PredicatePolarity::Positive,
hir::BoundPolarity::Positive,
dummy_self,
&mut bounds,
PredicateFilter::SelfOnly,

47
compiler/rustc_hir_analysis/src/hir_ty_lowering/mod.rs
View file

@ -668,7 +668,7 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
trait_ref: &hir::TraitRef<'tcx>,
span: Span,
constness: hir::BoundConstness,
polarity: ty::PredicatePolarity,
polarity: hir::BoundPolarity,
self_ty: Ty<'tcx>,
bounds: &mut Bounds<'tcx>,
predicate_filter: PredicateFilter,
@ -690,15 +690,6 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
Some(self_ty),
);
if let hir::BoundConstness::Always(span) | hir::BoundConstness::Maybe(span) = constness
&& !self.tcx().is_const_trait(trait_def_id)
{
self.dcx().emit_err(crate::errors::ConstBoundForNonConstTrait {
span,
modifier: constness.as_str(),
});
}
let tcx = self.tcx();
let bound_vars = tcx.late_bound_vars(trait_ref.hir_ref_id);
debug!(?bound_vars);
@ -708,6 +699,36 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
bound_vars,
);
let polarity = match polarity {
rustc_ast::BoundPolarity::Positive => ty::PredicatePolarity::Positive,
rustc_ast::BoundPolarity::Negative(_) => ty::PredicatePolarity::Negative,
rustc_ast::BoundPolarity::Maybe(_) => {
// Validate associated type at least. We may want to reject these
// outright in the future...
for constraint in trait_segment.args().constraints {
let _ = self.lower_assoc_item_constraint(
trait_ref.hir_ref_id,
poly_trait_ref,
constraint,
&mut Default::default(),
&mut Default::default(),
constraint.span,
predicate_filter,
);
}
return arg_count;
}
};
if let hir::BoundConstness::Always(span) | hir::BoundConstness::Maybe(span) = constness
&& !self.tcx().is_const_trait(trait_def_id)
{
self.dcx().emit_err(crate::errors::ConstBoundForNonConstTrait {
span,
modifier: constness.as_str(),
});
}
match predicate_filter {
PredicateFilter::All
| PredicateFilter::SelfOnly
@ -763,11 +784,11 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
// since we should have emitted an error for them earlier, and they
// would not be well-formed!
if polarity != ty::PredicatePolarity::Positive {
assert!(
self.dcx().has_errors().is_some(),
self.dcx().span_delayed_bug(
constraint.span,
"negative trait bounds should not have assoc item constraints",
);
continue;
break;
}
// Specify type to assert that error was already reported in `Err` case.