@a = (1)[1,0];          # @a has two elements
                            # OK, this one is fine

    # but what about these:

    @b = (1,undef)[1,0,2];  # @b has three elements
                            # where does that third element come from?

    # or we could rewrite the above B case like this
    # and still get three elements:
    @b = (1)[1,0,2];        # why three and not *TWO*?

    @a = (1)[  1,2];        # @a has no elements
                            # !?