pub fn super_combine_tys<Infcx, I, R>( infcx: &Infcx, relation: &mut R, a: I::Ty, b: I::Ty, ) -> RelateResult<I, I::Ty>where Infcx: InferCtxtLike<Interner = I>, I: Interner, R: PredicateEmittingRelation<Infcx>,