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