diff --git a/include/powsybl/iidm/ExtensionAdder.hpp b/include/powsybl/iidm/ExtensionAdder.hpp
index 7f9e88bb6..f8eb80914 100644
--- a/include/powsybl/iidm/ExtensionAdder.hpp
+++ b/include/powsybl/iidm/ExtensionAdder.hpp
@@ -42,10 +42,6 @@ class ExtensionAdder {
      */
     explicit ExtensionAdder(Extendable& extendable);
 
-    /**
-     * Destructor
-     */
-    virtual ~ExtensionAdder() noexcept = default;
 
     /**
      * Copy constructor
@@ -57,6 +53,11 @@ class ExtensionAdder {
      */
     ExtensionAdder(ExtensionAdder&&) noexcept = default;
 
+    /**
+     * Destructor
+     */
+    virtual ~ExtensionAdder() noexcept = default;
+
 private:
     /**
      * Creates the extension.
diff --git a/include/powsybl/iidm/extensions/SlackTerminalAdder.hpp b/include/powsybl/iidm/extensions/SlackTerminalAdder.hpp
index 798dc7bbc..cd2438fca 100644
--- a/include/powsybl/iidm/extensions/SlackTerminalAdder.hpp
+++ b/include/powsybl/iidm/extensions/SlackTerminalAdder.hpp
@@ -26,11 +26,6 @@ class SlackTerminalAdder : public ExtensionAdder {
      */
     explicit SlackTerminalAdder(Extendable& extendable);
 
-    /**
-     * Destructor
-     */
-    ~SlackTerminalAdder() noexcept override = default;
-
     /**
      * Copy constructor
      */
@@ -41,6 +36,11 @@ class SlackTerminalAdder : public ExtensionAdder {
      */
     SlackTerminalAdder(SlackTerminalAdder&&) = default;
 
+    /**
+     * Destructor
+     */
+    ~SlackTerminalAdder() noexcept override = default;
+
     /**
      * Copy assignment operator
      */