BUG #18449: Altering column type fails when an SQL routine depends on the column

The following bug has been logged on the website:

Bug reference:      18449
Logged by:          Alexander Lakhin
Email address:      exclusion@gmail.com
PostgreSQL version: 16.2
Operating system:   Ubuntu 22.04
Description:

The following script:
CREATE TABLE t(a int, b varchar);
CREATE FUNCTION f(i int) RETURNS text LANGUAGE SQL
RETURN (SELECT b FROM t WHERE a = $1);

ALTER TABLE t ALTER COLUMN b TYPE text;
fails with:
ERROR:  unexpected object depending on column: function f(integer)

on REL_14_STABLE .. master since e717a9a18.