diff --git a/include/sdbus-c++/AdaptorInterfaces.h b/include/sdbus-c++/AdaptorInterfaces.h
index c64ae00..b760913 100644
--- a/include/sdbus-c++/AdaptorInterfaces.h
+++ b/include/sdbus-c++/AdaptorInterfaces.h
@@ -141,6 +141,7 @@ namespace sdbus {
 
     protected:
         using base_type = AdaptorInterfaces;
+        ~AdaptorInterfaces() = default;
     };
 
 }
diff --git a/include/sdbus-c++/Message.h b/include/sdbus-c++/Message.h
index e70c9f5..f252401 100644
--- a/include/sdbus-c++/Message.h
+++ b/include/sdbus-c++/Message.h
@@ -44,7 +44,7 @@ namespace sdbus {
     class ObjectPath;
     class Signature;
     template <typename... _ValueTypes> class Struct;
-    struct UnixFd;
+    class UnixFd;
     class MethodReply;
     namespace internal {
         class ISdBus;
diff --git a/include/sdbus-c++/ProxyInterfaces.h b/include/sdbus-c++/ProxyInterfaces.h
index 406bb16..3e63e92 100644
--- a/include/sdbus-c++/ProxyInterfaces.h
+++ b/include/sdbus-c++/ProxyInterfaces.h
@@ -175,6 +175,7 @@ namespace sdbus {
 
     protected:
         using base_type = ProxyInterfaces;
+        ~ProxyInterfaces() = default;
     };
 
 }
diff --git a/include/sdbus-c++/TypeTraits.h b/include/sdbus-c++/TypeTraits.h
index 881e88a..4680829 100644
--- a/include/sdbus-c++/TypeTraits.h
+++ b/include/sdbus-c++/TypeTraits.h
@@ -41,7 +41,7 @@ namespace sdbus {
     template <typename... _ValueTypes> class Struct;
     class ObjectPath;
     class Signature;
-    struct UnixFd;
+    class UnixFd;
     class MethodCall;
     class MethodReply;
     class Signal;