Reasons for raising ValueExtractorDefinitionException include:
A non-wildcard type parameter has been marked with `@ExtractedValue`
I wonder if mandating the exception in that case will make the experimentation by specific providers impossible. I'd rather have the window open with a "can" in the spec on that subject.
Couldn't an implementation enable such usage via an opt-in switch? That'd make apparent that relying on this functionality may result in portability issues.
if you really want people not to use that feature because of too many hop to go through, then I guess yes that's possible. See where I'm going?
The wording on this has been made more liberal towards extended support by specific providers, hence I'm going to close this one as "Out of Date".