pl/pgsql incorrect syntax checking on select .... into ... ?

Missed comma in select ... into construction don't raise ERROR both on
compiling and run time.

create table temp_table(i1 int, i2 int, i3 int, i4 int);
insert into temp_table(i1,i2,i3,i4) values (1,2,3,4);

CREATE OR REPLACE FUNCTION test_select_inti()
RETURNS bool AS
$$
declare
var_i1 int;
var_i2 int;
var_i3 int;
var_i4 int;
begin

-- ---- missed comma \/ ----
select i1,i2, i3, i4 into var_i1,var_i2 var_i3, var_i4
from temp_table;

raise notice '%, %, %, %',var_i1,var_i2,var_i3,var_i4;

return true;
end
$$ LANGUAGE plpgsql VOLATILE SECURITY DEFINER;

select test_select_inti();

#NOTICE: 1, 2, <NULL>, <NULL>