Hello Heikki,
probably I found a bug in patch:
CREATE FUNCTION fx(i integer) RETURNS integer LANGUAGE plpgsql AS $$begin raise notice '>>%<<', i; return i;
end;$$;
CREATE FUNCTION fx1(integer) RETURNS text LANGUAGE sql AS $_$ select case $1 when 1 then 'A' else 'B' end$_$;
CREATE FUNCTION fx2(text) RETURNS text LANGUAGE sql AS $_$ select case $1 when 'A' then 'a' else 'b' end$_$;
CREATE TABLE foo ( a integer
);
COPY foo (a) FROM stdin;
1
0
\.
postgres=# select fx2(fx1(fx(a))) from foo;
NOTICE: >>1<<
ERROR: invalid expression parameter reference (1 levels up, while
stack is only 1 elements deep)
Regards
Pavel