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Enforce non-lifetime-binders in supertrait preds are not object safe

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This commit is contained in:
Michael Goulet 2023-03-07 05:51:43 +00:00
parent febd59e122
commit 720cc40fa7
4 changed files with 111 additions and 3 deletions
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21
compiler/rustc_trait_selection/src/traits/object_safety.rs
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@ -17,10 +17,10 @@ use rustc_errors::{DelayDm, FatalError, MultiSpan};
use rustc_hir as hir;
use rustc_hir::def_id::DefId;
use rustc_middle::ty::subst::{GenericArg, InternalSubsts};
use rustc_middle::ty::ToPredicate;
use rustc_middle::ty::{
self, EarlyBinder, Ty, TyCtxt, TypeSuperVisitable, TypeVisitable, TypeVisitor,
};
use rustc_middle::ty::{ToPredicate, TypeVisitableExt};
use rustc_session::lint::builtin::WHERE_CLAUSES_OBJECT_SAFETY;
use rustc_span::symbol::Symbol;
use rustc_span::Span;
@ -139,6 +139,10 @@ fn object_safety_violations_for_trait(
if !spans.is_empty() {
violations.push(ObjectSafetyViolation::SupertraitSelf(spans));
}
let spans = super_predicates_have_non_lifetime_binders(tcx, trait_def_id);
if !spans.is_empty() {
violations.push(ObjectSafetyViolation::SupertraitNonLifetimeBinder(spans));
}
violations.extend(
tcx.associated_items(trait_def_id)
@ -348,6 +352,21 @@ fn predicate_references_self<'tcx>(
}
}
fn super_predicates_have_non_lifetime_binders(
tcx: TyCtxt<'_>,
trait_def_id: DefId,
) -> SmallVec<[Span; 1]> {
// If non_lifetime_binders is disabled, then exit early
if !tcx.features().non_lifetime_binders {
return SmallVec::new();
}
tcx.super_predicates_of(trait_def_id)
.predicates
.iter()
.filter_map(|(pred, span)| pred.has_non_region_late_bound().then_some(*span))
.collect()
}
fn trait_has_sized_self(tcx: TyCtxt<'_>, trait_def_id: DefId) -> bool {
generics_require_sized_self(tcx, trait_def_id)
}