@VisibleForTesting
    static class HashCode128 extends HashCode {
        private final long bits1;
        private final long bits2;

        public HashCode128(long bits1, long bits2) {
            this.bits1 = bits1;
            this.bits2 = bits2;
        }

        @Override
        public int length() {
            return 16;
        }

        @Override

    Random rand = new Random(0);
    int keyBits = 32;
    int hashBits = function.bits();
    for (int bit1 = 0; bit1 < keyBits; bit1++) {
      for (int bit2 = 0; bit2 < keyBits; bit2++) {
        if (bit2 <= bit1) continue;
        int delta = (1 << bit1) | (1 << bit2);
        int[] same = new int[hashBits];
        int[] diff = new int[hashBits];
        // go through trials to compute probability

		}

		var pid32 int32
		if pid == math.MaxUint64 {
			pid32 = -1
		} else {
			pid32 = int32(pid)
		}

		v, err := p.readVal()
		if err != nil {
			return err
		}

		*ev = rawEvent{
			typ:         EvBatch,
			args:        p.args[:0],
			batchPid:    pid32,
			batchOffset: off,
		}
		ev.args = append(ev.args, pid, v)

		ch <- true
	}()
	a = [5]int{1, 2, 3, 4, 5}
	<-ch
}

// Blows up a naive compiler.
func TestRaceNestedArrayCopy(t *testing.T) {
	ch := make(chan bool, 1)
	type (
		Point32   [2][2][2][2][2]Point
		Point1024 [2][2][2][2][2]Point32
		Point32k  [2][2][2][2][2]Point1024
		Point1M   [2][2][2][2][2]Point32k
	)
	var a, b Point1M
	go func() {
		a[0][1][0][1][0][1][0][1][0][1][0][1][0][1][0][1][0][1][0][1].y = 1