diff --git a/csharp/ql/consistency-queries/PrimaryQlClass.ql b/csharp/ql/consistency-queries/PrimaryQlClass.ql
new file mode 100644
index 00000000000..311c1f97a4c
--- /dev/null
+++ b/csharp/ql/consistency-queries/PrimaryQlClass.ql
@@ -0,0 +1,6 @@
+import csharp
+
+query predicate missingPrimaryQlClass(Element e) {
+  e.getAPrimaryQlClass() = "???" and
+  e.fromSource()
+}