I'd love to, if I could figure a way that doesn't suck.

For example: if my theory method looks like:

    @Theory public <T> void shouldHold(List<T> items) {
        // ...
    }

a data point that is of type List or any subtype of List is eligible, no matter the type of T. But getting the machinery correct to substitute T properly in javaRuntype is tricky at best. Worse, if T comes from the enclosing class, who's to say what T should be?