This applies for CDI 1.1 and 1.2 which allows Disposer method to accept Producer field.

public class B1 {
	
	@Produces EntityManager em;
	
	public void test(@Disposes EntityManager em){
		//do smt
	}

This code results in error "There is no producer method declared by the (same) bean class that is assignable to the disposed parameter of a disposer method [JSR-346 §3.5.3]"

CDI 1.1 and 1.2 allows also producer filed (see section 3.5)