diff --git a/src/static_schema.cpp b/src/static_schema.cpp
index 6815015..50a6370 100644
--- a/src/static_schema.cpp
+++ b/src/static_schema.cpp
@@ -216,3 +216,8 @@
 {
     throw std::runtime_error{"Internal error: StaticSchema::leafTypeName(std::string) not implemented. The tests should not have called this overload."};
 }
+
+bool StaticSchema::isConfig([[maybe_unused]] const std::string& leafPath) const
+{
+    throw std::runtime_error{"Internal error: StaticSchema::isConfigLeaf(std::string) not implemented. The tests should not have called this overload."};
+}