Bug with function returning composite types.

Functions that return composite types are called more times than expected.

Example script:
---------------
begin;

create table composite_types_test (
a integer,
b integer,
c integer,
d integer,
e integer,
f integer,
g integer,
h integer,
i integer,
j integer
);

insert into composite_types_test values (0,1,2,3,4,5,6,7,8,9);

create function bug_function () returns composite_types_test
volatile
language plpgsql
as $$
declare r composite_types_test;
begin
select * into r from composite_types_test;
raise notice 'in bug_function';
return r;
end;
$$;

select bug_function();

select (bug_function()).*;
rollback;
---------------

Example Output:
---------------
BEGIN
CREATE TABLE
INSERT 0 1
CREATE FUNCTION
psql:sql/bug_example.sql:30: NOTICE: in bug_function
bug_function
-----------------------
(0,1,2,3,4,5,6,7,8,9)
(1 row)

psql:sql/bug_example.sql:32: NOTICE: in bug_function
psql:sql/bug_example.sql:32: NOTICE: in bug_function
psql:sql/bug_example.sql:32: NOTICE: in bug_function
psql:sql/bug_example.sql:32: NOTICE: in bug_function
psql:sql/bug_example.sql:32: NOTICE: in bug_function
psql:sql/bug_example.sql:32: NOTICE: in bug_function
psql:sql/bug_example.sql:32: NOTICE: in bug_function
psql:sql/bug_example.sql:32: NOTICE: in bug_function
psql:sql/bug_example.sql:32: NOTICE: in bug_function
psql:sql/bug_example.sql:32: NOTICE: in bug_function
a | b | c | d | e | f | g | h | i | j
---+---+---+---+---+---+---+---+---+---
0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9
(1 row)

ROLLBACK
---------------

Kyle Butt