TypeDecorator types columns crashing on select([Model.table.c.custom_type_column])

select() doesn't work with custom columns when they are used as Foo.table.c.custom_column not Foo.custom_column, here is the code to demonstrate this

import json
from sqlalchemy.types import TypeDecorator, UnicodeText, VARCHAR
from sqlalchemy import ForeignKey, select
from sqlalchemy import create_engine
from sqlalchemy.orm import sessionmaker, relationship
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy import Column, Integer


Base = declarative_base()
engine = create_engine('sqlite://', echo=True)
Session = sessionmaker(autoflush=False, bind=engine)

class JSONSerialized(TypeDecorator):
    """
    Represents an immutable structure as a json-serialized string.
    """

    impl = UnicodeText
#    impl = VARCHAR

    def process_bind_param(self, value, dialect):
        if value is not None:
            value = unicode(json.dumps(value))

        return value

    def process_result_value(self, value, dialect):
        if value is not None:
            value = json.loads(value)
        return value

    def copy(self):
        return JSONSerialized()

class Foo(Base):
    __tablename__ = 'users'
    id = Column(Integer(), primary_key=True)
    values = Column(JSONSerialized(), nullable=False)


session = Session()
Base.metadata.create_all(engine)

session.add_all([i}) for i in xrange(3)](Foo(values={'i':))
session.commit()

# this works:
session.execute(select([Foo.values](Foo.id,)))
# this doesnt:
session.execute(select([Foo.__table__.c.values](Foo.__table__.c.id,)))

gives:

2012-12-07 14:48:31,570 INFO sqlalchemy.engine.base.Engine PRAGMA table_info("users")
2012-12-07 14:48:31,570 INFO sqlalchemy.engine.base.Engine ()
2012-12-07 14:48:31,571 INFO sqlalchemy.engine.base.Engine 
CREATE TABLE users (
    id INTEGER NOT NULL, 
    "values" TEXT NOT NULL, 
    PRIMARY KEY (id)
)


2012-12-07 14:48:31,571 INFO sqlalchemy.engine.base.Engine ()
2012-12-07 14:48:31,572 INFO sqlalchemy.engine.base.Engine COMMIT
2012-12-07 14:48:31,573 INFO sqlalchemy.engine.base.Engine BEGIN (implicit)
2012-12-07 14:48:31,574 INFO sqlalchemy.engine.base.Engine INSERT INTO users ("values") VALUES (?)
2012-12-07 14:48:31,574 INFO sqlalchemy.engine.base.Engine (u'{"i": 0}',)
2012-12-07 14:48:31,574 INFO sqlalchemy.engine.base.Engine INSERT INTO users ("values") VALUES (?)
2012-12-07 14:48:31,574 INFO sqlalchemy.engine.base.Engine (u'{"i": 1}',)
2012-12-07 14:48:31,575 INFO sqlalchemy.engine.base.Engine INSERT INTO users ("values") VALUES (?)
2012-12-07 14:48:31,575 INFO sqlalchemy.engine.base.Engine (u'{"i": 2}',)
2012-12-07 14:48:31,575 INFO sqlalchemy.engine.base.Engine COMMIT
2012-12-07 14:48:31,576 INFO sqlalchemy.engine.base.Engine BEGIN (implicit)
2012-12-07 14:48:31,576 INFO sqlalchemy.engine.base.Engine SELECT users.id, users."values" 
FROM users
2012-12-07 14:48:31,576 INFO sqlalchemy.engine.base.Engine ()
2012-12-07 14:48:31,577 INFO sqlalchemy.engine.base.Engine SELECT users.id, <bound method ImmutableColumnCollection.values of <sqlalchemy.sql.expression.ImmutableColumnCollection object at 0x2efa290>> 
FROM users
2012-12-07 14:48:31,577 INFO sqlalchemy.engine.base.Engine ()
Traceback (most recent call last):
  File "custom_type.py", line 51, in <module>
    session.execute(select([Foo.__table__.c.values](Foo.__table__.c.id,)))
  File "/home/virhilo/Projekty/sqlalchemy_experiments/local/lib/python2.7/site-packages/sqlalchemy/orm/session.py", line 884, in execute
    clause, params or {})
  File "/home/virhilo/Projekty/sqlalchemy_experiments/local/lib/python2.7/site-packages/sqlalchemy/engine/base.py", line 649, in execute
    params)
  File "/home/virhilo/Projekty/sqlalchemy_experiments/local/lib/python2.7/site-packages/sqlalchemy/engine/base.py", line 751, in _execute_clauseelement
    compiled_sql, distilled_params
  File "/home/virhilo/Projekty/sqlalchemy_experiments/local/lib/python2.7/site-packages/sqlalchemy/engine/base.py", line 865, in _execute_context
    context)
  File "/home/virhilo/Projekty/sqlalchemy_experiments/local/lib/python2.7/site-packages/sqlalchemy/engine/base.py", line 858, in _execute_context
    context)
  File "/home/virhilo/Projekty/sqlalchemy_experiments/local/lib/python2.7/site-packages/sqlalchemy/engine/default.py", line 330, in do_execute
    cursor.execute(statement, parameters)
sqlalchemy.exc.OperationalError: (OperationalError) near "<": syntax error u'SELECT users.id, <bound method ImmutableColumnCollection.values of <sqlalchemy.sql.expression.ImmutableColumnCollection object at 0x2efa290>> \nFROM users' ()

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