Index: data/validator/geometry.mapcss
===================================================================
--- data/validator/geometry.mapcss	(revision 14973)
+++ data/validator/geometry.mapcss	(working copy)
@@ -139,7 +139,12 @@
 way[highway][area!=yes][!tunnel][!covered] > node {
   set node_in_highway;
 }
-way[building][building!=no] > node.node_in_highway!.first_last_node {
+way[highway][area!=yes][!tunnel][!covered] >[index=1] node,
+way[highway][area!=yes][!tunnel][!covered] >[index=-1] node {
+  set first_last_highway_node;
+}
+
+way[building][building!=no] > node.node_in_highway!.first_last_highway_node {
   throwWarning: tr("node connects highway and building");
 }