 	$resolved = 1
 	$pending = 2
 
-	$promiseTrace = '_pStack'
-	$settlerTrace = '_sStack'
-
-	# These are some symbols. They won't be used to store data.
-	$circularChain = 'promise_circular_chain'
-
-	$invalid_argument = 'invalid_argument'
+	$promiseTrace = '_pt'
+	$settlerTrace = '_st'
 
 	$fromPrevious = 'From previous event:'
 

	settleWithX = (p, x) ->
		# 2.3.1
		if x == p and x
			settlePromise p, $rejected, genTypeError($circularChain)
			return

		# 2.3.2

	###
	assertIterable = (obj) ->
		return if obj instanceof Array
		throw genTypeError 'invalid_argument'

	###*
	 * Generate type error object.
