Currently, the language provides no way to throw a checked excption without
either catching it or declaring it to be thrown in the current method.
(Notwithstanding a deprecated methon in Thread)  The generics prototype
introduces a way to throw a checked exception with only a warning, which
is suppressed by default.

I believe this is a serious regression in the language.  We should not
introduce such loopholes in type checking.

class Main {
    static void hiddenThrow(Throwable t) {
        class ExceptionHider<E extends Throwable> {
            void hiddenThrow(Throwable e) throws E {
                throw (E) e;
            }
        }
        new ExceptionHider<RuntimeException>().hiddenThrow(t);
    }
    public static void main(String[] args) // no exception in method declaration
    {
        hiddenThrow(new java.io.IOException()); // throws IOException, hidden
    }
}