Index: trunk/src/org/openstreetmap/josm/data/validation/tests/TagChecker.java
===================================================================
--- trunk/src/org/openstreetmap/josm/data/validation/tests/TagChecker.java	(revision 19194)
+++ trunk/src/org/openstreetmap/josm/data/validation/tests/TagChecker.java	(revision 19195)
@@ -719,6 +719,6 @@
             Map<String, String> matchingTags = tp.data.stream()
                     .filter(i -> Boolean.TRUE.equals(i.matches(tags)))
-                    .filter(i -> i instanceof KeyedItem).map(i -> ((KeyedItem) i).key)
-                    .collect(Collectors.toMap(k -> k, tags::get));
+                    .filter(KeyedItem.class::isInstance).map(i -> ((KeyedItem) i).key)
+                    .collect(Collectors.toMap(k -> k, tags::get, (o, n) -> n));
             if (matchingPresetsOK.stream().noneMatch(
                     tp2 -> matchingTags.entrySet().stream().allMatch(