SQLite

Here is another test case that does not require manually disabling the
query flattener:

<blockquote><verbatim>
CREATE TABLE t5(a, b, c, d);
CREATE INDEX t5a ON t5(a);
CREATE INDEX t5b ON t5(b);
CREATE TABLE t6(e);
INSERT INTO t6 VALUES(1);
INSERT INTO t5 VALUES(1,1,1,1), (2,2,2,2);
SELECT * FROM t5 WHERE (a=1 OR b=2) AND c IN (
  SELECT e FROM (SELECT DISTINCT e FROM t6) WHERE e=1
);
</verbatim></blockquote>

The failure in this test case also goes back to check-in [020b8b106fc8f840f6b506e1c9c3bc75676daec3] on 2015-05-29.