Hi, tossing my 0.02$ in. I believe that anything you cannot boil down to a specific class during type var. resolution should result in exception. E.g. regarding your questions: Type variable, as in any other case where you have a MyClass<T>. As long as you do not define T, you have a type variable in place. Same scenario I think. I probably fail to see any real difference here? (correct me please ;) My understanding is the same. Actually this brings it down to the very same problem as in Event.select(), on requirement on type variable are pretty much the same for select() and fire(). IMHO the snippet SHOULD FAIL as soon as it hits select() method. Relaxing the conditions on select() doesn't make much sense to me for it should fail with the very same problem on fire(), right? BTW I am curious, what would the above snippet do in OWB? One more note: Be it one way or the other, the terms "to contain a type variable" and "unresolvable type variable" could use a clarification in the spec. Matej ----- Original Message ----- From: "Martin Kouba" <mkouba(a)redhat.com&gt; To: "cdi-dev" <cdi-dev(a)lists.jboss.org&gt; Sent: Tuesday, February 23, 2016 9:14:46 AM Subject: [cdi-dev] Type variable check for Event.select() and Event.fire() Hi all, I'd like to discuss the following two sentences taken from "10.2.1. The Event interface"). 1. Event.select() "If the specified type contains a type variable, an IllegalArgumentException is thrown." So what should happen if you pass a raw type like List.class? The Class.getTypeParameters() method returns [E]. Does it mean the type contains a type variable? And what about "event.select(new TypeLiteral<List<?>>() {})"? 2. Event.fire() "If the runtime type of the event object contains an unresolvable type variable, an IllegalArgumentException is thrown." To my understanding: 1. the runtime type = eventPayload.getClass() 2. get type variables = getTypeParameters() 3. unresolvable = it's not possible to resolve the variable, nor from the Event injetion point nor from the selected type (Event.select()), anything else? 3. Example snippet Should the following snippet fail or not? It currently fails in Weld during event.select(). But even if we relax the check it will not be always possible to resolve all the type variables, i.e. the subsequent {{fire()}} invocation might fail. Or am I missing anything? @Inject Event<Object> event; public void testSelectSubtypeWithWildcard() { List<String> updatedList = new ArrayList<>(); updatedList.add("foo"); Event<List<?>> child = event.select(new TypeLiteral<List<?>>() {}); child.fire(updatedList); } Thanks, Martin _______________________________________________ cdi-dev mailing list cdi-dev(a)lists.jboss.org https://lists.jboss.org/mailman/listinfo/cdi-dev Note that for all code provided on this list, the provider licenses the code under the Apache License, Version 2 (http://www.apache.org/licenses/LICENSE-2.0.html). For all other ideas provided on this list, the provider waives all patent and other intellectual property rights inherent in such information.