"area" is not supported in validator asserts

[Dakon]

I can use "area" in a selector in a validator, but if I write something liks

assertMatch: "area railway=station";

This will fail. Worse, I get a backtrace, but no notice which line caused the error:

WARNING: java.lang.IllegalArgumentException: Expecting n/node/w/way/r/relation, but got area
java.lang.IllegalArgumentException: Expecting n/node/w/way/r/relation, but got area
        at org.openstreetmap.josm.data.osm.OsmUtils.createPrimitive(OsmUtils.java:75)
        at org.openstreetmap.josm.data.validation.tests.MapCSSTagChecker.checkAsserts(MapCSSTagChecker.java:705)
        at org.openstreetmap.josm.data.validation.tests.MapCSSTagChecker.addMapCSS(MapCSSTagChecker.java:649)
        at org.openstreetmap.josm.data.validation.tests.MapCSSTagChecker.initialize(MapCSSTagChecker.java:670)
        at org.openstreetmap.josm.data.validation.OsmValidator.initializeTests(OsmValidator.java:323)
        at org.openstreetmap.josm.data.validation.OsmValidator.initializeTests(OsmValidator.java:306)
        at org.openstreetmap.josm.actions.ValidateAction.doValidate(ValidateAction.java:67)
        at org.openstreetmap.josm.actions.ValidateAction.actionPerformed(ValidateAction.java:50)
        at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:2018)
        at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2341)
        at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:402)
        at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:259)
        at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonListener.java:252)
        at java.awt.AWTEventMulticaster.mouseReleased(AWTEventMulticaster.java:289)
        at java.awt.Component.processMouseEvent(Component.java:6505)
        at javax.swing.JComponent.processMouseEvent(JComponent.java:3311)
        at java.awt.Component.processEvent(Component.java:6270)
        at java.awt.Container.processEvent(Container.java:2229)
        at java.awt.Component.dispatchEventImpl(Component.java:4861)
        at java.awt.Container.dispatchEventImpl(Container.java:2287)
        at java.awt.Component.dispatchEvent(Component.java:4687)
        at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4832)
        at java.awt.LightweightDispatcher.processMouseEvent(Container.java:4492)
        at java.awt.LightweightDispatcher.dispatchEvent(Container.java:4422)
        at java.awt.Container.dispatchEventImpl(Container.java:2273)
        at java.awt.Window.dispatchEventImpl(Window.java:2719)
        at java.awt.Component.dispatchEvent(Component.java:4687)
        at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:735)
        at java.awt.EventQueue.access$200(EventQueue.java:103)
        at java.awt.EventQueue$3.run(EventQueue.java:694)
        at java.awt.EventQueue$3.run(EventQueue.java:692)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:76)
        at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:87)
        at java.awt.EventQueue$4.run(EventQueue.java:708)
        at java.awt.EventQueue$4.run(EventQueue.java:706)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:76)
        at java.awt.EventQueue.dispatchEvent(EventQueue.java:705)
        at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:242)
        at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:161)
        at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:150)
        at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:146)
        at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:138)
        at java.awt.EventDispatchThread.run(EventDispatchThread.java:91)

[naoliv]

How to reproduce: ​https://github.com/rurseekatze/OpenRailwayMap/blob/master/validator/openrailwaymap.validator.mapcss + validator.check_assert_local_rules=true