title: PL/SQL negation of "member of" collection does not negate
body: <p>I've got a PL/SQL collection that contains an empty element (in the minimal working example it's only that, but the behavior is the same with additional elements). When I now query whether this collection has a specific number as element, it returns <code>false</code> as expected. But the strange thing is that negating the query also yields an answer of <code>false</code>.</p>
  <p>Can anyone confirm this behavior or direct me towards my failed assumptions here?</p>
  <pre><code>DECLARE
    TYPE number_t IS TABLE OF NUMBER;
    nt1 number_t := number_t();
  BEGIN
    nt1.extend();
    dbms_output.put_line('Start');        -- prints 'Start'
    IF 1 member of nt1 THEN
      dbms_output.put_line('Member');     -- does not execute
    END IF;
    IF not 1 member of nt1 THEN
      dbms_output.put_line('Not member'); -- does not execute
    END IF;
    IF not (1 member of nt1) THEN
      dbms_output.put_line('Not member'); -- does not execute
    END IF;
  END;
  </code></pre>
  <p>Observed on: Oracle Database 11g Enterprise Edition Release 11.2.0.4.0 - 64bit</p>
  <p>Not yet tested on other installations.</p>