pg_dump does not honor namespaces when functions are used in index

Dear hackers,

I have a pretty nasty problem to submit to your careful scrutiny.

Please consider the following piece of SQL code:

CREATE SCHEMA bar;
SET search_path = bar;

CREATE FUNCTION bar() RETURNS text AS $$
BEGIN
RETURN 'foobar';
END
$$ LANGUAGE plpgsql IMMUTABLE;

CREATE SCHEMA foo;
SET search_path = foo;

CREATE FUNCTION foo() RETURNS text AS $$
BEGIN
RETURN bar();
END
$$ LANGUAGE plpgsql IMMUTABLE;

SET search_path = public;

CREATE TABLE foobar (d text);
insert into foobar (d) values ('foobar');

set search_path = public, foo, bar;
CREATE INDEX foobar_d on foobar using btree(foo());

Run this on a newly created database, and dump it with pg_dump. You'll
notice that the dump is unusable. Creating a new database from this
dump will trigger the following error:

ERROR: function bar() does not exist
LINE 1: SELECT bar()
^
HINT: No function matches the given name and argument types. You
might need to add explicit type casts.
QUERY: SELECT bar()
CONTEXT: PL/pgSQL function "foo" line 2 at RETURN

How can we fix this?
--
Jean-Baptiste Quenot