So once we end up with java.io.Cloneable$Serializable$$Proxy$, that gets passed to getProxyClass() and this comes into play: https://github.com/weld/core/blob/10a1d11af8c815a2a4a8fc5a4061698215e602b0/impl/src/main/java/org/jboss/weld/bean/proxy/ProxyFactory.java#L353-L360

So the final proxy class name in this case would be org.jboss.weld.io.Serializable$$Cloneable$Proxy$_$$_Weld$Proxy$.