diff --git a/libcc1/callbacks.hh b/libcc1/callbacks.hh
index b1f3e98d917b98c51d41d75afb5347d608713c1a..dc470c62c48d3ab42188e432ca8701f25fef3b2f 100644
--- a/libcc1/callbacks.hh
+++ b/libcc1/callbacks.hh
@@ -42,6 +42,9 @@ namespace cc1_plugin
     callbacks ();
     ~callbacks ();
 
+    callbacks (const callbacks &) = delete;
+    callbacks &operator= (const callbacks &) = delete;
+
     // Add a callback named NAME.  FUNC is the function to call when
     // this method is invoked.
     void add_callback (const char *name, callback_ftype *func);
@@ -52,10 +55,6 @@ namespace cc1_plugin
 
   private:
 
-    // Declared but not defined to avoid use.
-    callbacks (const callbacks &);
-    callbacks &operator= (const callbacks &);
-
     // The mapping.
     htab_t m_registry;
   };
diff --git a/libcc1/connection.hh b/libcc1/connection.hh
index a0e99bdbd98fd7c9f067d5f54dd40b2f8cfbc0a0..15ad1716a29ed8f3c0dc1449844b30046bac0516 100644
--- a/libcc1/connection.hh
+++ b/libcc1/connection.hh
@@ -48,6 +48,9 @@ namespace cc1_plugin
 
     virtual ~connection () = default;
 
+    connection (const connection &) = delete;
+    connection &operator= (const connection &) = delete;
+
     // Send a single character.  This is used to introduce various
     // higher-level protocol elements.
     status send (char c);
@@ -95,10 +98,6 @@ namespace cc1_plugin
 
   private:
 
-    // Declared but not defined, to prevent use.
-    connection (const connection &);
-    connection &operator= (const connection &);
-
     // Helper function for the wait_* methods.
     status do_wait (bool);
 
diff --git a/libcc1/rpc.hh b/libcc1/rpc.hh
index a8e33577ea180a1f595a4c1845d04537f27c8a0d..429aeb3c127849f04a1a5bbeee70a38b75c660e2 100644
--- a/libcc1/rpc.hh
+++ b/libcc1/rpc.hh
@@ -39,6 +39,9 @@ namespace cc1_plugin
     argument_wrapper () { }
     ~argument_wrapper () { }
 
+    argument_wrapper (const argument_wrapper &) = delete;
+    argument_wrapper &operator= (const argument_wrapper &) = delete;
+
     operator T () const { return m_object; }
 
     status unmarshall (connection *conn)
@@ -49,10 +52,6 @@ namespace cc1_plugin
   private:
 
     T m_object;
-
-    // No copying or assignment allowed.
-    argument_wrapper (const argument_wrapper &);
-    argument_wrapper &operator= (const argument_wrapper &);
   };
 
   // Specialization for any kind of pointer.  This is declared but not
@@ -72,6 +71,9 @@ namespace cc1_plugin
       delete[] m_object;
     }
 
+    argument_wrapper (const argument_wrapper &) = delete;
+    argument_wrapper &operator= (const argument_wrapper &) = delete;
+
     operator const char * () const
     {
       return m_object;
@@ -85,10 +87,6 @@ namespace cc1_plugin
   private:
 
     char *m_object;
-
-    // No copying or assignment allowed.
-    argument_wrapper (const argument_wrapper &);
-    argument_wrapper &operator= (const argument_wrapper &);
   };
 
   // Specialization for gcc_type_array.
@@ -106,6 +104,9 @@ namespace cc1_plugin
       delete m_object;
     }
 
+    argument_wrapper (const argument_wrapper &) = delete;
+    argument_wrapper &operator= (const argument_wrapper &) = delete;
+
     operator const gcc_type_array * () const
     {
       return m_object;
@@ -119,10 +120,6 @@ namespace cc1_plugin
   private:
 
     gcc_type_array *m_object;
-
-    // No copying or assignment allowed.
-    argument_wrapper (const argument_wrapper &);
-    argument_wrapper &operator= (const argument_wrapper &);
   };
 
 #ifdef GCC_CP_INTERFACE_H
@@ -144,6 +141,9 @@ namespace cc1_plugin
       delete m_object;
     }
 
+    argument_wrapper (const argument_wrapper &) = delete;
+    argument_wrapper &operator= (const argument_wrapper &) = delete;
+
     operator const gcc_vbase_array * () const
     {
       return m_object;
@@ -157,10 +157,6 @@ namespace cc1_plugin
   private:
 
     gcc_vbase_array *m_object;
-
-    // No copying or assignment allowed.
-    argument_wrapper (const argument_wrapper &);
-    argument_wrapper &operator= (const argument_wrapper &);
   };
 
   // Specialization for gcc_cp_template_args.
@@ -181,6 +177,9 @@ namespace cc1_plugin
       delete m_object;
     }
 
+    argument_wrapper (const argument_wrapper &) = delete;
+    argument_wrapper &operator= (const argument_wrapper &) = delete;
+
     operator const gcc_cp_template_args * () const
     {
       return m_object;
@@ -194,10 +193,6 @@ namespace cc1_plugin
   private:
 
     gcc_cp_template_args *m_object;
-
-    // No copying or assignment allowed.
-    argument_wrapper (const argument_wrapper &);
-    argument_wrapper &operator= (const argument_wrapper &);
   };
 
   // Specialization for gcc_cp_function_args.
@@ -217,6 +212,9 @@ namespace cc1_plugin
       delete m_object;
     }
 
+    argument_wrapper (const argument_wrapper &) = delete;
+    argument_wrapper &operator= (const argument_wrapper &) = delete;
+
     operator const gcc_cp_function_args * () const
     {
       return m_object;
@@ -230,10 +228,6 @@ namespace cc1_plugin
   private:
 
     gcc_cp_function_args *m_object;
-
-    // No copying or assignment allowed.
-    argument_wrapper (const argument_wrapper &);
-    argument_wrapper &operator= (const argument_wrapper &);
   };
 #endif /* GCC_CP_INTERFACE_H */