add fixme

This commit is contained in:
Lukas Markeffsky 2024-02-06 20:03:49 +01:00
parent 42cc1d2f97
commit 15ffe839ba
2 changed files with 8 additions and 4 deletions

View file

@ -410,7 +410,10 @@ impl<'tcx> assembly::GoalKind<'tcx> for NormalizesTo<'tcx> {
}
ty::Alias(_, _) | ty::Param(_) | ty::Placeholder(..) => {
// FIXME(ptr_metadata): It would also be possible to return a `Ok(Ambig)` with no constraints.
// This is the "fallback impl" for type parameters, unnormalizable projections
// and opaque types: If the `self_ty` is `Sized`, then the metadata is `()`.
// FIXME(ptr_metadata): This impl overlaps with the other impls and shouldn't
// exist. Instead, `Pointee<Metadata = ()>` should be a supertrait of `Sized`.
let sized_predicate = ty::TraitRef::from_lang_item(
tcx,
LangItem::Sized,

View file

@ -2302,9 +2302,10 @@ fn confirm_builtin_candidate<'cx, 'tcx>(
};
let metadata_ty = self_ty.ptr_metadata_ty_or_tail(tcx, normalize).unwrap_or_else(|tail| {
if tail == self_ty {
// This is the fallback case for type parameters, unnormalizable projections
// and opaque types.
// If the `self_ty` is `Sized`, then the metadata is `()`.
// This is the "fallback impl" for type parameters, unnormalizable projections
// and opaque types: If the `self_ty` is `Sized`, then the metadata is `()`.
// FIXME(ptr_metadata): This impl overlaps with the other impls and shouldn't
// exist. Instead, `Pointee<Metadata = ()>` should be a supertrait of `Sized`.
let sized_predicate = ty::TraitRef::from_lang_item(
tcx,
LangItem::Sized,