title: Does function written in sql inherit IMMUTABLE or PARALLEL SAFE automatically in PostgreSQL?
body: <p>For example, if I write</p>
  <pre><code>create function foo(int x)
  RETURNS int 
  AS xxxxx
  language 'c' IMMUTABLE PARALLEL SAFE;
  </code></pre>
  <p>and</p>
  <pre><code>create function bar(int x)
  RETURNS int
  AS 'select foo(x)'
  language 'sql';
  </code></pre>
  <p>Would <code>bar()</code> be treated as immutable and parallel safe when performing queries?</p>