Join order optimizer hints inconsistently resolve table names

--source include/have_sequence.inc

create table t1 (a int, b int, key idx_a(a));

insert into t1 select seq, seq from seq_1_to_10;

create table t2 as select * from t1;

set optimizer_switch='derived_merge=on';

--echo # Default join order is t2, t1

explain select * from

  (select /*+ qb_name(qb1)*/ t1.* from t1, t2 where t1.a = t2.a and t1.a < 100) as DT1;

--echo # Hint applied

explain select /*+ join_order(t1@qb1,t2@qb1)*/ * from

  (select /*+ qb_name(qb1)*/ t1.* from t1, t2 where t1.a = t2.a and t1.a < 100) as DT1;

--echo # Variation of the same hint but now it is ignored without a warning

explain select /*+ join_order(@qb1 t1, t2)*/ * from

  (select /*+ qb_name(qb1)*/ t1.* from t1, t2 where t1.a = t2.a and t1.a < 100) as DT1;

--echo # Hint is applied although tables are inside another query block

explain select /*+ join_order(t1, t2)*/ * from

  (select t1.* from t1, t2 where t1.a = t2.a and t1.a < 100) as DT1;

--echo # Run the same statements with derived merging turned off

set optimizer_switch='derived_merge=off';

--echo # Warning is generated and the hint is ignored despite correct syntax

explain select /*+ join_order(t1@qb1,t2@qb1)*/ * from

  (select /*+ qb_name(qb1)*/ t1.* from t1, t2 where t1.a = t2.a and t1.a < 100) as DT1;

--echo # Hint is applied, everything is correct

explain select /*+ join_order(@qb1 t1, t2)*/ * from

  (select /*+ qb_name(qb1)*/ t1.* from t1, t2 where t1.a = t2.a and t1.a < 100) as DT1;

--echo # Warning is generated, it is correct

explain select /*+ join_order(t1, t2)*/ * from

  (select t1.* from t1, t2 where t1.a = t2.a and t1.a < 100) as DT1;