ty::Predicate::Projection(ref data) => Some(data.to_poly_trait_ref()),
ty::Predicate::Trait(ref data) => Some(data.to_poly_trait_ref()),
ty::Predicate::Equate(..) => None,
+ ty::Predicate::Subtype(..) => None,
ty::Predicate::RegionOutlives(..) => None,
ty::Predicate::TypeOutlives(..) => None,
ty::Predicate::WellFormed(..) => None,