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prevent opaque types from appearing in impl headers

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This commit is contained in:
Rémy Rakic 2021-07-22 20:21:48 +02:00 • committed by Oli Scherer
parent d00e77078c
commit 7d5bbf55f2
11 changed files with 73 additions and 44 deletions
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23
compiler/rustc_typeck/src/coherence/orphan.rs
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@ -141,13 +141,22 @@ fn orphan_check_impl(tcx: TyCtxt<'_>, def_id: LocalDefId) -> Result<(), ErrorGua
}
}
if let ty::Opaque(def_id, _) = *trait_ref.self_ty().kind() {
let reported = tcx
.sess
.struct_span_err(sp, "cannot implement trait on type alias impl trait")
.span_note(tcx.def_span(def_id), "type alias impl trait defined here")
.emit();
return Err(reported);
// Ensure no opaque types are present in this impl header. See issues #76202 and #86411 for examples,
// and #84660 where it would otherwise allow unsoundness.
if trait_ref.has_opaque_types() {
for ty in trait_ref.substs {
for ty in ty.walk() {
let ty::subst::GenericArgKind::Type(ty) = ty.unpack() else { continue };
let ty::Opaque(def_id, _) = ty.kind() else { continue };
let reported = tcx
.sess
.struct_span_err(sp, "cannot implement trait on type alias impl trait")
.span_note(tcx.def_span(def_id), "type alias impl trait defined here")
.emit();
return Err(reported);
}
}
span_bug!(sp, "opque type not found, but `has_opaque_types` is set")
}
Ok(())