t1 := NewChanArgs(t)
		CheckSize(t1)

	case TCHANARGS:
		t1 := t.ChanArgs()
		CalcSize(t1) // just in case
		// Make sure size of t1.Elem() is calculated at this point. We can
		// use CalcSize() here rather than CheckSize(), because the top-level
		// (possibly recursive) type will have been calculated before the fake
		// chanargs is handled.
		CalcSize(t1.Elem())
		if t1.Elem().width >= 1<<16 {