Marko Lukša created CDI-394: ------------------------------- Summary: Section 5.2.4 does not consider multiple bounds Key: CDI-394 URL: https://issues.jboss.org/browse/CDI-394 Project: CDI Specification Issues Issue Type: Bug Components: Resolution Affects Versions: 1.1.PFD Reporter: Marko Lukša The bullets of section 5.2.4 only talk about a single upper/lower bound, but type variables and wildcards can have many upper bounds. Incorporating multiple bounds into the rules is not as simple as adding "is assignable from/to *any* upper bound". In some cases, *every* upper bound needs to be assignable from/to a type. Also, since you can theoretically have {{Foo<T extends Animal & Dog>}} ({{Dog}} of course extends {{Animal}}), simply adding the words *any* or *every* is not enough. Consider the following example: {code} Terrier extends Dog extends Animal required: Foo<M extends Angry & Dog> bean: Foo<T extends Angry & Dog> assignable bean: Foo<T extends Angry & Animal> assignable bean: Foo<T extends Angry & Terrier> not assignable {code} In order to take multiple bounds into account, bullet 5 would need to be changed from: {quote} • the required type parameter and the bean type parameter are both type variables and *the* upper bound of the required type parameter is assignable to *the* upper bound, if any, of the bean type parameter. {quote} to: {quote} • the required type parameter and the bean type parameter are both type variables and *each* upper bound of the required type parameter is assignable to *at least one* upper bound of the bean type parameter {quote} But, this would incorrectly make the bean type assignable to the required type in the following theoretical cases: {code} required: Foo<M extends Angry & Dog> bean: Foo<T extends Angry & Dog & Terrier> not assignable bean: Foo<T extends Angry & Animal & Terrier> not assignable {code} -- This message is automatically generated by JIRA. If you think it was sent incorrectly, please contact your JIRA administrators For more information on JIRA, see: http://www.atlassian.com/software/jira