Function structurally_relate_tys

pub fn structurally_relate_tys<I: Interner, R: TypeRelation<I>>(
    relation: &mut R,
    a: I::Ty,
    b: I::Ty,
) -> RelateResult<I, I::Ty>

Relates a and b structurally, calling the relation for all nested values. Any semantic equality, e.g. of projections, and inference variables have to be handled by the caller.