Consider following annotation of g_variant_equal:

/**
 * g_variant_equal:
 * @one: (type GVariant): a #GVariant instance
 * @two: (type GVariant): a #GVariant instance
 * @returns: %TRUE if @one and @two are equal

produces following .gir snippet parameters:

        <parameters>
          <parameter name="two" transfer-ownership="none">
            <doc xml:whitespace="preserve">a #GVariant instance</doc>
            <type name="Variant" c:type="gconstpointer"/>
          </parameter>
        </parameters>

girparser.c then fails to deduce that input argument is actually pointer, because there is no '*' mark in the c:type.