Vala's attribute CCode doesn't include a "since" property, useful to set GObject Introspection "version" property for methods.

Example:

class Gda.Numeric {
   [CCode since=5.0.2]
   public void set_double (double val);
}

Can be parsed to GIR as:

<record name="Numeric"
            c:type="GdaNumeric"
[...]
 <method name="set_double"
              c:identifier="gda_numeric_set_double"
              version="5.0.2">
[...]