BUG #13391: when use in/= & subquery, non exists column can elected.

The following bug has been logged on the website:

Bug reference:      13391
Logged by:          digoal
Email address:      digoal@126.com
PostgreSQL version: 9.4.2
Operating system:   CentOS 6.x x64
Description:

when use in/= & subquery, non exists column can elected.
for exp:
postgres=# create table table1 (c1 int, c2 int, c3 int, c4 text);
CREATE TABLE
postgres=# create table table2 (id int);
CREATE TABLE
postgres=# insert into table1 values (1,2,3,'test');
INSERT 0 1
postgres=# insert into table1 values (2,3,4,'test');
INSERT 0 1
postgres=# insert into table2 values (100);
INSERT 0 1

c1 column not exists in table2, but when table2 in subquery, it can
elected?
postgres=# explain (analyze,verbose) select * from table1 where c1 = (select
c1 from table2 limit 1);
                                                        QUERY PLAN


---------------------------------------------------------------------------------------------------------------------------
 Seq Scan on public.table1  (cost=0.00..116.59 rows=23 width=44) (actual
time=0.020..0.023 rows=2 loops=1)
   Output: table1.c1, table1.c2, table1.c3, table1.c4
   Filter: (table1.c1 = (SubPlan 1))
   SubPlan 1
     ->  Limit  (cost=0.00..0.01 rows=1 width=0) (actual time=0.003..0.003
rows=1 loops=2)
           Output: (table1.c1)
           ->  Seq Scan on public.table2  (cost=0.00..112.30 rows=10230
width=0) (actual time=0.002..0.002 rows=1 loops=2)
                 Output: table1.c1
 Planning time: 0.169 ms
 Execution time: 0.070 ms
(10 rows)

postgres=# explain (analyze,verbose) select * from table1 where c1 in
(select c1 from table2 limit 1);
                                                        QUERY PLAN


---------------------------------------------------------------------------------------------------------------------------
 Seq Scan on public.table1  (cost=0.00..97.34 rows=2270 width=44) (actual
time=0.018..0.022 rows=2 loops=1)
   Output: table1.c1, table1.c2, table1.c3, table1.c4
   Filter: (SubPlan 1)
   SubPlan 1
     ->  Limit  (cost=0.00..0.01 rows=1 width=0) (actual time=0.003..0.003
rows=1 loops=2)
           Output: (table1.c1)
           ->  Seq Scan on public.table2  (cost=0.00..112.30 rows=10230
width=0) (actual time=0.002..0.002 rows=1 loops=2)
                 Output: table1.c1
 Planning time: 0.102 ms
 Execution time: 0.069 ms
(10 rows)

postgres=# select * from table1 where c1 in (select c1 from table2 limit
1);
 c1 | c2 | c3 |  c4
----+----+----+------
  1 |  2 |  3 | test
  2 |  3 |  4 | test
(2 rows)

postgres=# select * from table1 where c1 = (select c1 from table2 limit 1);
 c1 | c2 | c3 |  c4
----+----+----+------
  1 |  2 |  3 | test
  2 |  3 |  4 | test
(2 rows)
postgres=# explain select c1 from table2 limit 1;
ERROR:  column "c1" does not exist
LINE 1: explain select c1 from table2 limit 1;

and there is also can execute with catalog.
postgres=# explain select * from pg_tables where tablename in (select
tablename from tt);
                                    QUERY PLAN

----------------------------------------------------------------------------------
 Nested Loop Left Join  (cost=0.00..32052.66 rows=51 width=199)
   Join Filter: (t.oid = c.reltablespace)
   ->  Nested Loop Left Join  (cost=0.00..32049.20 rows=51 width=139)
         Join Filter: (n.oid = c.relnamespace)
         ->  Seq Scan on pg_class c  (cost=0.00..32040.43 rows=51 width=79)
               Filter: ((relkind = 'r'::"char") AND (SubPlan 1))
               SubPlan 1
                 ->  Seq Scan on tt  (cost=0.00..106.30 rows=9630 width=0)
         ->  Materialize  (cost=0.00..1.15 rows=10 width=68)
               ->  Seq Scan on pg_namespace n  (cost=0.00..1.10 rows=10
width=68)
   ->  Materialize  (cost=0.00..1.04 rows=3 width=68)
         ->  Seq Scan on pg_tablespace t  (cost=0.00..1.03 rows=3 width=68)
(12 rows)

postgres=# explain select tablename from tt;
ERROR:  column "tablename" does not exist
LINE 1: explain select tablename from tt;
                       ^
postgres=# \d tt
      Table "public.tt"
 Column |  Type   | Modifiers
--------+---------+-----------
 id     | integer |

                       ^