Index: trunk/test/unit/org/openstreetmap/josm/data/validation/OsmValidatorTest.java
===================================================================
--- trunk/test/unit/org/openstreetmap/josm/data/validation/OsmValidatorTest.java	(revision 16442)
+++ trunk/test/unit/org/openstreetmap/josm/data/validation/OsmValidatorTest.java	(revision 16443)
@@ -2,7 +2,10 @@
 package org.openstreetmap.josm.data.validation;
 
+import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.assertNotEquals;
 import static org.junit.Assert.assertTrue;
+
+import java.util.Collections;
 
 import org.junit.Before;
@@ -87,4 +90,15 @@
 
     /**
+     * Non-regression test for <a href="https://josm.openstreetmap.de/ticket/19053">Bug #19053</a>.
+     * {@link OsmValidator#cleanupIgnoredErrors()} must not combine primitives.
+     */
+    @Test
+    public void testCleanupIgnoredErrorsTicket19053() {
+        OsmValidator.addIgnoredError("3000_missing tag", "missing tag");
+        OsmValidator.cleanupIgnoredErrors();
+        assertEquals(Collections.emptyMap(), OsmValidator.getIgnoredErrors());
+    }
+
+    /**
      * Test that tests are really removed, and that core tests cannot be removed
      */