BUG #6411: Backend process' crash when a foreign table is used in a dependent subquery on select clause

The following bug has been logged on the website:

Bug reference:      6411
Logged by:          Using a Foreign Table in a Dependent Subquery
Email address:      emre.hasegeli@tart.com.tr
PostgreSQL version: 9.1.2
Operating system:   Linux 3.0.0-14-generic #23-Ubuntu SMP Mon Nov 21 2
Description:=20=20=20=20=20=20=20=20

I installed Dave Page's MySQL Foreign Data Wrapper on GitHub [1]. It works
fine until foreign table is used in a dependent subquery on select clause.

How to reproduce:

Create extension mysql_fdw;

Create server AMySQLServer
    foreign data wrapper mysql_fdw=20
    options (address '***', port '3306');

Create user mapping for public=20
    server AMySQLServer
    options (username '***', password '***');

Create foreign table AForeignTable (id integer) server AMySQLServer options
(query 'Select id from ASchema.ATable');

Select id, (select true from AForeignTable where AForeignTable.id =3D
ATable.id) from ATable;

WARNING:  57P02: terminating connection because of crash of another server
process
DETAIL:  The postmaster has commanded this server process to roll back the
current transaction and exit, because another server process exited
abnormally and possibly corrupted shared memory.
HINT:  In a moment you should be able to reconnect to the database and
repeat your command.

[1] https://github.com/dpage/mysql_fdw