 	# Why are there two "genScheduler"s?
 	# Well, to support the babel's es7 async-await polyfill, I have to hack it.
 	scheduleUnhandledRejection = genScheduler 9, (genScheduler 9, (p) ->
-		# Check if current node is the souce node of the rejection.
-		if (not p._pre or hashOnRejected(p._pre)) and not hashOnRejected p
+		if not hashOnRejected p
 			Yaku.onUnhandledRejection p._value, p
-
-		if not isLongStackTrace
-			p._pre = $nil
 
 		return
 	)


	# iter tree
	hashOnRejected = (node) ->
		i = 0
		len = node._pCount


		if isFunction onRejected
			p2._onRejected = onRejected

		p2._pre = p1 if isLongStackTrace
		p1[p1._pCount++] = p2

		# 2.2.6
