Alias for value in RETURN

No need to declare special variable for RETURN command. This variable already exists – $0
You can use it by setting an alias for it.

CREATE FUNCTION add_three_values(v1 anyelement, v2 anyelement, v3 anyelement)
RETURNS anyelement AS $$
DECLARE
result ALIAS FOR $0;
BEGIN
result := v1 + v2 + v3;
RETURN result;
END;
$$ LANGUAGE plpgsql;