variable.c:1025
static int
ivar_i(key, entry, ary)
    ID key;
    struct global_entry *entry;
    VALUE ary;
{
    if (rb_is_instance_id(key)) {
	rb_ary_push(ary, rb_str_new2(rb_id2name(key)));
    }
    return ST_CONTINUE;
}
