removeWaiter(node);
                throw new InterruptedException();
              }

              // Otherwise re-read and check doneness. If we loop then it must have been a spurious
              // wakeup
              localValue = value;
              if (localValue != null & !(localValue instanceof SetFuture)) {
                return getDoneValue(localValue);
              }

              // timed out?

                removeWaiter(node);
                throw new InterruptedException();
              }

              // Otherwise re-read and check doneness. If we loop then it must have been a spurious
              // wakeup
              localValue = value;
              if (localValue != null & !(localValue instanceof SetFuture)) {
                return getDoneValue(localValue);
              }

              // timed out?

//
//go:nosplit
func futexwakeup(addr *uint32, cnt uint32) {
	ret := futex(unsafe.Pointer(addr), _FUTEX_WAKE_PRIVATE, cnt, nil, nil, 0)
	if ret >= 0 {
		return
	}

	// I don't know that futex wakeup can return
	// EAGAIN or EINTR, but if it does, it would be
	// safe to loop and call futex again.
	systemstack(func() {
		print("futexwakeup addr=", addr, " returned ", ret, "\n")
	})

	orig, extra []int
}{
	{nil, nil},
	{[]int{}, nil},
	{nil, []int{}},
	{[]int{}, []int{}},
	{nil, []int{22}},
	{[]int{}, []int{22}},
	{make([]int, 2, 4), nil},
	{make([]int, 2, 4), []int{}},
	{make([]int, 2, 4), []int{22}},
	{make([]int, 2, 4), []int{22, 33, 44}},
}

func TestAppend(t *testing.T) {
	for i, test := range appendTests {
		origLen, extraLen := len(test.orig), len(test.extra)

	gp.param = nil
	if mysg.releasetime > 0 {
		blockevent(mysg.releasetime-t0, 2)
	}
	mysg.c = nil
	releaseSudog(mysg)
	if closed {
		if c.closed == 0 {
			throw("chansend: spurious wakeup")
		}
		panic(plainError("send on closed channel"))
	}
	return true
}

// send processes a send operation on an empty channel c.
// The value ep sent by the sender is copied to the receiver sg.

	// and each iteration makes its own copy of the value c.
	var runcases []runtimeSelect
	if len(cases) > 4 {
		// Slice is heap allocated due to runtime dependent capacity.
		runcases = make([]runtimeSelect, len(cases))
	} else {
		// Slice can be stack allocated due to constant capacity.
		runcases = make([]runtimeSelect, len(cases), 4)
	}

	haveDefault := false

    waiter1.interrupt();

    waiter1.join();
    waiter2.awaitWaiting(); // should still be blocked

    LockSupport.unpark(waiter2); // spurious wakeup
    waiter2.awaitWaiting(); // should eventually re-park

    future.set(null);
    waiter2.join();
  }

  public void testRemoveWaiter_polling() throws Exception {

// outlined init function "fn" (and vice versa); so that we can use
// the mappings later on to update relocations.
func recordFuncForVar(v *ir.Name, fn *ir.Func) {
	if varToMapInit == nil {
		varToMapInit = make(map[*ir.Name]*ir.Func)
		MapInitToVar = make(map[*ir.Func]*ir.Name)
	}
	varToMapInit[v] = fn
	MapInitToVar[fn] = v
}

// allBlank reports whether every node in exprs is blank.
func allBlank(exprs []ir.Node) bool {

		}
		r += size
	}
	if r == len(s) {
		return s, true
	}

	b := make([]byte, len(s)+2*utf8.UTFMax)
	w := copy(b, s[0:r])
	for r < len(s) {
		// Out of room? Can only happen if s is full of
		// malformed UTF-8 and we're replacing each
		// byte with RuneError.
		if w >= len(b)-2*utf8.UTFMax {
			nb := make([]byte, (len(b)+utf8.UTFMax)*2)
			copy(nb, b[0:w])
			b = nb
		}

    private final AtomicInteger counter = new AtomicInteger(0);
    private final ConcurrentMap<Object, Integer> uids =
        Platform.tryWeakKeys(new MapMaker()).makeMap();

    private Integer getUid(Object obj) {
      Integer uid = uids.get(obj);
      if (uid == null) {
        // One or more integer values could be skipped in the event of a race