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Do not assemble candidates for auto traits of opaque types in their defining scope

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This commit is contained in:
Oli Scherer 2024-06-04 16:20:01 +00:00
parent 548c44760f
commit 8ea461da55
16 changed files with 93 additions and 54 deletions
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7
compiler/rustc_trait_selection/src/traits/select/candidate_assembly.rs
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@ -772,7 +772,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
);
}
ty::Alias(ty::Opaque, _) => {
ty::Alias(ty::Opaque, alias) => {
if candidates.vec.iter().any(|c| matches!(c, ProjectionCandidate(_))) {
// We do not generate an auto impl candidate for `impl Trait`s which already
// reference our auto trait.
@ -787,6 +787,11 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
// We do not emit auto trait candidates for opaque types in coherence.
// Doing so can result in weird dependency cycles.
candidates.ambiguous = true;
} else if self.infcx.can_define_opaque_ty(alias.def_id) {
// We do not emit auto trait candidates for opaque types in their defining scope, as
// we need to know the hidden type first, which we can't reliably know within the defining
// scope.
candidates.ambiguous = true;
} else {
candidates.vec.push(AutoImplCandidate)
}