pg_get_viewdef() drops casts, causing broken definitions

PostgreSQL 9.5.2.

I ran into this while doing a pgupgrade; it refused to re-import a view =
that was operating correctly on 9.2.

Summary: The view text returned by pg_get_viewdef() strips some casts, =
which can result in an error in trying to recreate the view.  This means =
you can't successfully recreate those views from a pg_dump.

Recreated:

xof=3D# drop table b;
DROP TABLE
xof=3D# CREATE TABLE a (i integer);
CREATE TABLE
xof=3D# INSERT INTO a SELECT generate_series(1,100);
INSERT 0 100
xof=3D# CREATE TABLE b (i integer);
CREATE TABLE
xof=3D# INSERT INTO b values(100);
INSERT 0 1
xof=3D# CREATE VIEW vb AS SELECT i FROM b WHERE i =3D ANY((SELECT =
array_agg(i) FROM a)::integer[]);
CREATE VIEW
xof=3D# SELECT * FROM vb;
 i =20
-----
100
(1 row)

xof=3D# select pg_get_viewdef('vb');
                     pg_get_viewdef                     =20
----------------------------------------------------------
 SELECT b.i                                             +
   FROM b                                               +
  WHERE (b.i =3D ANY (( SELECT array_agg(a.i) AS array_agg+
           FROM a)));
(1 row)

Note the missing cast.

It's missing from pg_dump as well, of course, since it uses that same =
function:

--
-- Name: vb; Type: VIEW; Schema: public; Owner: xof
--

CREATE VIEW vb AS
SELECT b.i
  FROM b
 WHERE (b.i =3D ANY (( SELECT array_agg(a.i) AS array_agg
          FROM a)));


ALTER TABLE vb OWNER TO xof;

But recreating it from that definition results in an error:

xof=3D# drop view vb;
DROP VIEW
xof=3D# CREATE VIEW vb AS
xof-#  SELECT b.i
xof-#    FROM b
xof-#   WHERE (b.i =3D ANY (( SELECT array_agg(a.i) AS array_agg
xof(#            FROM a)));
ERROR:  operator does not exist: integer =3D integer[]
LINE 4:   WHERE (b.i =3D ANY (( SELECT array_agg(a.i) AS array_agg
                    ^
HINT:  No operator matches the given name and argument type(s). You =
might need to add explicit type casts.

--
-- Christophe Pettus
  xof@thebuild.com