diff --git a/src/db/db/dbNetlistCompare.cc b/src/db/db/dbNetlistCompare.cc
index 7069b63e4..22f5ae964 100644
--- a/src/db/db/dbNetlistCompare.cc
+++ b/src/db/db/dbNetlistCompare.cc
@@ -2018,6 +2018,11 @@ NetlistComparer::NetlistComparer (NetlistCompareLogger *logger)
   m_max_n_branch = 100;
 }
 
+NetlistComparer::~NetlistComparer ()
+{
+  //  .. nothing yet ..
+}
+
 void
 NetlistComparer::exclude_caps (double threshold)
 {
diff --git a/src/db/db/dbNetlistCompare.h b/src/db/db/dbNetlistCompare.h
index a7d447892..f7b9cc5c0 100644
--- a/src/db/db/dbNetlistCompare.h
+++ b/src/db/db/dbNetlistCompare.h
@@ -147,6 +147,11 @@ public:
    *  "a" is null if there is no match for b and vice versa.
    */
   virtual void subcircuit_mismatch (const db::SubCircuit * /*a*/, const db::SubCircuit * /*b*/) { }
+
+private:
+  //  No copying
+  NetlistCompareLogger (const NetlistCompareLogger &);
+  NetlistCompareLogger &operator= (const NetlistCompareLogger &);
 };
 
 /**
@@ -160,6 +165,11 @@ public:
    */
   NetlistComparer (NetlistCompareLogger *logger = 0);
 
+  /**
+   *  @brief Destructor
+   */
+  ~NetlistComparer ();
+
   /**
    *  @brief Mark two nets as identical
    *
@@ -266,6 +276,11 @@ public:
    */
   bool compare (const db::Netlist *a, const db::Netlist *b, db::NetlistCompareLogger *logger) const;
 
+private:
+  //  No copying
+  NetlistComparer (const NetlistComparer &);
+  NetlistComparer &operator= (const NetlistComparer &);
+
 protected:
   bool compare_circuits (const db::Circuit *c1, const db::Circuit *c2, db::DeviceCategorizer &device_categorizer, db::CircuitCategorizer &circuit_categorizer, db::CircuitPinMapper &circuit_pin_mapper, const std::vector<std::pair<const Net *, const Net *> > &net_identity, bool &pin_mismatch, std::map<const db::Circuit *, CircuitMapper> &c12_circuit_and_pin_mapping, std::map<const db::Circuit *, CircuitMapper> &c22_circuit_and_pin_mapping) const;
   bool all_subcircuits_verified (const db::Circuit *c, const std::set<const db::Circuit *> &verified_circuits) const;
@@ -294,6 +309,13 @@ template<> struct type_traits<db::NetlistComparer> : public tl::type_traits<void
   typedef tl::false_tag has_default_constructor;
 };
 
+template<> struct type_traits<db::NetlistCompareLogger> : public tl::type_traits<void>
+{
+  //  mark "NetlistDeviceExtractor" as having a default ctor and no copy ctor
+  typedef tl::false_tag has_copy_constructor;
+  typedef tl::false_tag has_default_constructor;
+};
+
 }
 
 #endif
diff --git a/src/db/db/dbNetlistCrossReference.h b/src/db/db/dbNetlistCrossReference.h
index 5438187a4..03754def8 100644
--- a/src/db/db/dbNetlistCrossReference.h
+++ b/src/db/db/dbNetlistCrossReference.h
@@ -269,6 +269,10 @@ public:
   }
 
 private:
+  //  No copying
+  NetlistCrossReference (const db::NetlistCrossReference &);
+  NetlistCrossReference &operator= (const db::NetlistCrossReference &);
+
   tl::weak_ptr<db::Netlist> mp_netlist_a, mp_netlist_b;
   std::vector<std::pair<const db::Circuit *, const db::Circuit *> > m_circuits;
   std::list<PerCircuitData> m_per_circuit_data;
@@ -296,4 +300,16 @@ private:
 
 }
 
+namespace tl
+{
+
+template<> struct type_traits<db::NetlistCrossReference> : public tl::type_traits<void>
+{
+  //  mark "NetlistDeviceExtractor" as having a default ctor and no copy ctor
+  typedef tl::false_tag has_copy_constructor;
+  typedef tl::false_tag has_default_constructor;
+};
+
+}
+
 #endif