NPE with MapCSS validator

[naoliv]

While trying to validate a highway with this .mapcss file:

*[name = *ref] {
  throwWarning: tr("{0} e {1} são iguais; adicionar nome completo da rodovia", "{0.key}", "{1.key}");
}

(since I am playing with this new .mapcss file I don't know if it's valid; it didn't give any parsing error on console)

Repository Root: http://josm.openstreetmap.de/svn
Build-Date: 2013-12-31 02:34:29
Last Changed Author: simon04
Revision: 6572
Repository UUID: 0c6e7542-c601-0410-84e7-c038aed88b3b
URL: http://josm.openstreetmap.de/svn/trunk
Last Changed Date: 2013-12-31 01:38:06 +0100 (Tue, 31 Dec 2013)
Last Changed Rev: 6572

Identification: JOSM/1.5 (6572 pt_BR) Linux Debian GNU/Linux unstable (sid)
Memory Usage: 225 MB / 1756 MB (135 MB allocated, but free)
Java version: 1.7.0_45, Oracle Corporation, OpenJDK 64-Bit Server VM
Java package: openjdk-7-jre:amd64-7u45-2.4.3-4
VM arguments: [-Djava.net.useSystemProxies=true, -Dawt.useSystemAAFontSettings=on]
Dataset consistency test: No problems found

Plugin: AddrInterpolation (30034)
Plugin: Create_grid_of_ways (29854)
Plugin: FixAddresses (29971)
Plugin: ImageryCache (30135)
Plugin: OpeningHoursEditor (30117)
Plugin: PicLayer (29854)
Plugin: SimplifyArea (30145)
Plugin: buildings_tools (30057)
Plugin: editgpx (29854)
Plugin: geotools (30147)
Plugin: jts (29854)
Plugin: merge-overlap (30034)
Plugin: notes (v0.8)
Plugin: opendata (30097)
Plugin: pdfimport (29913)
Plugin: poly (29854)
Plugin: reverter (30031)
Plugin: tagging-preset-tester (30017)
Plugin: turnrestrictions (30145)
Plugin: undelete (29854)
Plugin: utilsplugin2 (30017)

java.lang.NullPointerException
	at java.util.regex.Matcher.appendReplacement(Matcher.java:758)
	at org.openstreetmap.josm.data.validation.tests.MapCSSTagChecker$TagCheck.insertArguments(MapCSSTagChecker.java:237)
	at org.openstreetmap.josm.data.validation.tests.MapCSSTagChecker$TagCheck.getDescriptionForMatchingSelector(MapCSSTagChecker.java:301)
	at org.openstreetmap.josm.data.validation.tests.MapCSSTagChecker$TagCheck.getErrorForPrimitive(MapCSSTagChecker.java:323)
	at org.openstreetmap.josm.data.validation.tests.MapCSSTagChecker.visit(MapCSSTagChecker.java:342)
	at org.openstreetmap.josm.data.validation.tests.MapCSSTagChecker.visit(MapCSSTagChecker.java:357)
	at org.openstreetmap.josm.data.osm.Way.accept(Way.java:212)
	at org.openstreetmap.josm.data.validation.Test.visit(Test.java:157)
	at org.openstreetmap.josm.actions.ValidateAction$ValidationTask.realRun(ValidateAction.java:171)
	at org.openstreetmap.josm.gui.PleaseWaitRunnable.doRealRun(PleaseWaitRunnable.java:82)
	at org.openstreetmap.josm.gui.PleaseWaitRunnable.run(PleaseWaitRunnable.java:150)
	at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:471)
	at java.util.concurrent.FutureTask.run(FutureTask.java:262)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
	at java.lang.Thread.run(Thread.java:744)