Weld should check if the bean types of beans added through AfterBeanDiscovery.addBean() are valid and throw a DefinitionException if not.

Currently, portable extensions can add beans that have a parameterized type with a wildcard parameter among its bean types. This should not be allowed per http://docs.jboss.org/cdi/spec/1.1/cdi-spec.html#legal_bean_types

Also, if the bean type is a parameterized type containing a type variable, the bean's scope must be @Dependent. This is the same as with producer methods & fields.