diff --git a/gtsam/hybrid/HybridNonlinearFactorGraph.h b/gtsam/hybrid/HybridNonlinearFactorGraph.h
index 5f04851d4..b48e8bb5c 100644
--- a/gtsam/hybrid/HybridNonlinearFactorGraph.h
+++ b/gtsam/hybrid/HybridNonlinearFactorGraph.h
@@ -42,6 +42,16 @@ class GTSAM_EXPORT HybridNonlinearFactorGraph : public HybridFactorGraph {
   using IsNonlinear = typename std::enable_if<
       std::is_base_of<NonlinearFactor, FACTOR>::value>::type;
 
+  /// Check if T has a value_type derived from FactorType.
+  template <typename T>
+  using HasDerivedValueType = typename std::enable_if<
+      std::is_base_of<HybridFactor, typename T::value_type>::value>::type;
+
+  /// Check if T has a pointer type derived from FactorType.
+  template <typename T>
+  using HasDerivedElementType = typename std::enable_if<std::is_base_of<
+      HybridFactor, typename T::value_type::element_type>::value>::type;
+
  public:
   using Base = HybridFactorGraph;
   using This = HybridNonlinearFactorGraph;     ///< this class
@@ -114,15 +124,13 @@ class GTSAM_EXPORT HybridNonlinearFactorGraph : public HybridFactorGraph {
    * copied)
    */
   template <typename CONTAINER>
-  Base::Base::HasDerivedElementType<CONTAINER> push_back(
-      const CONTAINER& container) {
+  HasDerivedElementType<CONTAINER> push_back(const CONTAINER& container) {
     Base::push_back(container.begin(), container.end());
   }
 
   /// Push back non-pointer objects in a container (factors are copied).
   template <typename CONTAINER>
-  Base::Base::HasDerivedValueType<CONTAINER> push_back(
-      const CONTAINER& container) {
+  HasDerivedValueType<CONTAINER> push_back(const CONTAINER& container) {
     Base::push_back(container.begin(), container.end());
   }