--- bin/emerge.orig	2007-06-08 14:17:56.000000000 -0700
+++ bin/emerge	2007-07-07 20:02:50.000000000 -0700
@@ -4649,6 +4649,7 @@
 
 	xterm_titles = "notitles" not in settings.features
 	myroot = settings["ROOT"]
+	portdb = trees[myroot]["porttree"].dbapi
 	dep_check_trees = {}
 	dep_check_trees[myroot] = {}
 	dep_check_trees[myroot]["vartree"] = \
@@ -4701,6 +4702,12 @@
 			# deep world update would pull in.  Don't prune if the cpv is in
 			# system or world though, since those sets trigger greedy update
 			# of all slots.
+			visible_in_portdb = [cpv for cpv in pkgs if portdb.match("="+cpv)]
+			if visible_in_portdb:
+				# For consistency with the update algorithm, keep the highest
+				# visible version and prune any versions that are either masked
+				# or no longer exist in the portage tree.
+				pkgs = visible_in_portdb
 			pkgs = [portage.best(pkgs)]
 		for pkg in pkgs:
 			if fakedb.cpv_exists(pkg):