Binder API should make ? extends Object binds easier

[jbee]

When binding a supplier for ? extends Object (basically it says it can supply any type) the Binder API makes it hard to bind this to a Supplier as no such Supplier can be provided in a type-safe way since it would need to implement:

class GenericSupplier implements Supplier<? extends Object> { ... }

Such type argument is illegal. A way around is to make the implementing class itself have a type parameter:

class GenericSupplier<T> implements Supplier<T> { ... }

Now binding this is still problematic as it requires a extra method to introduce a type variable so that both the required and the provided type can be based on that variable. There should be a more elegant way to do this sort of thing.

Problem can be found in TestExampleConfigPropertyAnnotationBinds or TestExampleAutoStubbingInterfacesBinds.