Error message with select ... indexed by

[pgulutzan]

I have Ubuntu 14.04 and Tarantool 1.8, pulled from source today.
I use an example which was shown when Issue#2134 was closed.
box.sql.execute("CREATE TABLE a (id PRIMARY KEY, a INTEGER);");
box.sql.execute("CREATE INDEX i on a(a);");
box.sql.execute("INSERT INTO a VALUES (1,2), (3,4), (5,6);");
box.sql.execute("EXPLAIN SELECT id FROM a INDEXED BY i");
Result: - error: keyword "BY" is reserved
There is no error with delete ... indexed by.