--- /dev/null
+--TEST--
+"filter" tag applies the filter on "if" tags
+--TEMPLATE--
+{% filter upper %}
+{% if items %}
+{{ items|join(', ') }}
+{% endif %}
+
+{% if items.3 is defined %}
+FOO
+{% else %}
+{{ items.1 }}
+{% endif %}
+
+{% if items.3 is defined %}
+FOO
+{% elseif items.1 %}
+{{ items.0 }}
+{% endif %}
+
+{% endfilter %}
+--DATA--
+return array('items' => array('a', 'b'))
+--EXPECT--
+A, B
+
+B
+
+A