variable.c:1206
void
rb_autoload_load(klass, id)
    VALUE klass;
    ID id;
{
    VALUE file;
    NODE *load = autoload_delete(klass, id);

    if (!load || !(file = load->nd_lit) || rb_provided(RSTRING(file)->ptr)) {
	const_missing(klass, id);
    }
    rb_require_safe(file, load->nd_nth);
}
