diff --git a/kernel/scopeinfo.cc b/kernel/scopeinfo.cc
index 0b32ac3d130..7ed9ebf33f7 100644
--- a/kernel/scopeinfo.cc
+++ b/kernel/scopeinfo.cc
@@ -29,7 +29,8 @@ template <typename I, typename Filter> void ModuleHdlnameIndex::index_items(I be
 		if (!filter(item))
 			continue;
 		std::vector<IdString> path = parse_hdlname(item);
-		lookup.emplace(item, tree.insert(path, item));
+		if (!path.empty())
+			lookup.emplace(item, tree.insert(path, item));
 	}
 }