Index: trunk/resources/data/validator/highway.mapcss
===================================================================
--- trunk/resources/data/validator/highway.mapcss	(revision 18103)
+++ trunk/resources/data/validator/highway.mapcss	(revision 18104)
@@ -196,2 +196,14 @@
   suggestAlternative: "junction=circular";
 }
+
+/* #18217 */
+way[highway =~ /^((motorway|trunk|primary|secondary|tertiary)(_link)?|residential|unclassified)$/][area=yes],
+relation[highway =~ /^((motorway|trunk|primary|secondary|tertiary)(_link)?|residential|unclassified)$/][type=multipolygon] {
+  throwError: tr("Area with {0} above {1} is invalid", "highway=*", "highway=service");
+  group: tr("suspicious tag combination");
+  suggestAlternative: "area:highway=*";
+  assertMatch:   "way highway=trunk area=yes";
+  assertMatch:   "relation highway=trunk type=multipolygon";
+  assertNoMatch: "way highway=service area=yes";
+  assertNoMatch: "way highway=trunk";
+}